Biotic resistance at different spatial scales did not inhibit the colonization success of an exotic submerged aquatic plant.

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Márcio Silveira, Vanessa de Carvalho Harthman This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4248767/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Feb, 2026 Read the published version in Biological Invasions → Version 1 posted 5 You are reading this latest preprint version Abstract The success of exotic species in different environments is affected by biotic and abiotic filters, whose effects depend on the spatial scale employed. This study tested the hypotheses that (i) native species richness and abiotic conditions explain the sucess of exotic species Hydrilla verticillata and (ii) that biological resistance to invasion provided by diversity varies at different scales. The samples were collected at 176 georeferenced points in Rosana Reservoir. In each sampling site, measurements of fetch , distance between shores, organic matter concentration and grain size at sediment, depth, Secchi disk depth, conductivity, pH, and species richness of submerged macrophytes in three different scales (small, medium and large) were taken. Our results demonstrated that the occurrence of H. verticillata was positively correlated with increase in native species richness at three scales, with no difference between scales, as well as between fetch and distance between reservoir shores. However, it responded negatively to the concentration of organic matter in the sediment and depth. The results allowed the following conclusions: (i) biotic resistance did not reduce the success of exotic invasive H. verticillata , (ii) contrary to expectations, the competition mechanism did not influence the occurrence of this species at a small scale, (iii) at the moment, abiotic factors may be more important than biotic resistance in determining the success of this species at reservoir, but this relationship may change in the future and (iv) possibly, the dominant general pattern in invasion ecology at multiple spatial scales may be one of "biotic acceptance" in certain environments. macrophytes introduced species invasibility subtropical reservoir Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Exotic species have attracted the attention of various researchers, both due to their negative impacts on communities and ecosystems (Mack et al. 2000) and their relevance for testing general ecological theories (Tilman 1993 , 1997 ; Levine 2000 , 2001 ; Davis et al. 2001 ; Moore et al. 2001 ). Currently, few ecosystems remain free from the introduction of exotic species (Vitousek et al. 1997 ). Most research on biological invasions is conducted in terrestrial ecosystems (e.g., Hector 2001; Thomaz et al. 2015 ), with a significant bias towards temperate regions that receive more attention than tropical and subtropical ones (Petenon and Pivello 2008 ). However, there is a special interest in understanding and possibly preventing the introduction of exotic species in aquatic environments, as these ecosystems exhibit high biodiversity, explained, among other factors, by the presence of aquatic macrophytes that increase habitat complexity at different spatial scales (Dibble et al. 2006 ). Some studies indicate that at larger spatial scales, the success of exotic species increases with increasing species richness (Levine and D'Antonio 1999 ), suggesting that exotic species and native species respond similarly to environmental conditions. However, at smaller spatial scales (e.g., plots of a few square meters), where environmental conditions are similar, most studies demonstrate that the success of exotic species declines with the richness of the native community. This can be explained by niche overlap and competitive exclusion, which drive the relationship between exotic species and native species at these smaller scales (Shea and Chesson 2002 ; Michelan et al. 2010 ). Although these hypotheses are plausible, they are rarely tested simultaneously, especially in situ in aquatic environments. The susceptibility of the environment to invasion by new organisms (invasibility) is a factor that can determine the establishment of species in different habitats (Lonsdale 1999 ). Reservoirs are considerably different environments from natural ecosystems, and their characteristics (e.g., increased inundation area and disturbance intensity) facilitate introductions and dispersal of species to other aquatic ecosystems (Havel et al. 2005 ). The relationship between ecosystem invasibility by exotic species and the diversity of native species has long concerned naturalists. Darwin (1859) formally proposed that communities with higher species richness were less susceptible to invasions, especially aquatic communities. The relationship between species diversity and invasibility ("biotic resistance") was further addressed by Elton ( 1958 ), whose ideas have since underpinned discussions on invasions over the past 50 years, making it one of the most cited topics in invasion-related scientific literature (Levine and D'Antonio 1999 ). Biotic resistance against invasion is caused by mechanisms associated with allelopathy, predation, herbivory, parasitism (Gurevitch, 2011) and competition regarding use of space and nutrient uptake, which are most inflfluential biotic resistance mechanisms in plants (Levine and Antonio 1999; Levine et al. 2004 ; Gurevitch et al. 2011 ; Byun et al. 2014 ). Within this context, the use of resources by native species might reduce the invasive performance of exotic species as long as these species use similar resources to the native ones (Levine and Antonio 1999; Levine et al. 2004 ). Despite, other studies have demonstrated that even communities with higher species richness can be as vulnerable to introductions as poorer communities (Dunstan and Johnson 2004 ; Capers et al. 2007 ), thus, the introduction of exotic species can also occur in areas with lower species richness. Studies have shown that abiotic factors also have a significant effect on plant growth and reproduction, and thus these factors can determine the success or failure of exotic plant species introductions (Spence, 1982 ; Barrett et al. 1993; Van den Berg et al. 2003 ). Sediment characteristics, along with other physicochemical features such as water transparency and nutrient availability (Sousa et al. 2010 ), act as abiotic filters to plant species introductions in aquatic ecosystems and play an important long-term role in the establishment and survival of rooted submerged macrophytes (Harwell and Havens 2003 ). In this study, was analyzed the relationship between native species richness and the probability of occurrence of the exotic species Hydrilla verticillata at three different spatial scales. Additionally, we evaluated the probability of exotic species occurrence in relation to morphometric characteristics and sediment composition. Were tested the following hypotheses: (i) the invasion success of Hydrilla verticillata is positively related to native species richness at large and medium spatial scales but negatively related to native species richness at small spatial scales, and (ii) abiotic factors such as light penetration in the water, fetch (an indicator of wave disturbance), and sediment organic matter are important predictors of H. verticillata success. Hypothesis (i) was based on biotic resistance (Elton 1958 ), while hypothesis (ii) is based on the fact that abiotic environmental filters can be determinants of exotic species invasion success. Materials and Methods Study Area Rosana Reservoir The Rosana reservoir is located in the lower Paranapanema River section (22°36'S 52°50'W). The reservoir was flooded in November 1986 and covers an area of 350 km², operating as a run-of-the-river type, with a residence time of 18.6 days and shallow depth (CESP, 1998) (Fig. 1 ). Aquatic plants are commonly found in the reservoir, with the submerged species Egeria densa being among the most abundant and with the highest vegetative cover. Other species are also found, such as E. najas , Eichhornia azurea , Eichhornia crassipes, Salvinia herzogii , Echinodorus tenellus , Nymphaea amazonum , Typha domingensis , and several species of grasses (Thomaz et al. 2005 ). >>> Fig. 1 Data Collection Data collection was conducted in the Rosana Reservoir in October 2010. Sampling involved recording the presence (1) or absence (0) of submerged macrophyte species at 176 previously demarcated and georeferenced points. Species sampling was performed using a long-handled rake (approximately 4 m), which was dragged along the sediment to the maximum depth limit colonized by macrophytes. However, 89 points located upstream of the reservoir were excluded from the analyses because the absence of Hydrilla verticillata in these locations may be due to dispersal limitations (see Fig. 1 , points demarcated by the rectangle on the map). Sampling at Different Spatial Scales At each sampling point, an area of approximately 1200m² was selected and subdivided into three scales: (i) small scale (rake area of 0.02m², with 10 sampling units for each collection point, n = 870 sampling units; for analysis, the species found in each rake were considered); (ii) medium scale (transects of ~ 60x4, equivalent to 240 m², with one transect at each sampling point, n = 87 sampling units; for analysis at this scale, only the species found in the transect were considered); and (iii) large scale, an area of ~ 60x20, equivalent to 1200 m², where the species composed of the aggregate of 10 sampling units of 0.02m², along with the species found at the medium scale were considered (n = 87 sampling units). Samples at different scales were used to test hypothesis (i). Sampling of Abiotic Variables At all sampled points, the minimum (Z min ) and maximum (Z max ) depth of occurrence of submerged macrophytes were determined, with Z min and Z max being determined perpendicular to each transect using the metric scale of the rake handle. Additionally, at each sampling point, the straight-line distance (in meters) from the shoreline ahead of the point was determined to assess the influence of reservoir width on submerged macrophyte colonization. Furthermore, the following abiotic variables: electrical conductivity (µS cm^ −1 ), pH, Secchi disk transparency (m), and fetch (distance free for wind action; km), were measured to assess the influence of these abiotic variables on submerged macrophyte colonization in the Rosana Reservoir. Fetch can be considered as a variable indicating wave disturbance caused by wind. The fetch calculation used the following equation proposed by Håkanson and Jansson (1983) and modified by Azza et al. ( 2007 ). where Ef (km) is the effective fetch (i.e., the distance in open water where waves are induced by the wind), xi (km) is the straight-line distance or length from the point towards land or an island, and ai (degrees) is the angle of inclination in the direction of the wind, starting from 0° with increments every 6° up to + 42° and − 42°. However, unlike the referenced authors above, who considered the central line as the one corresponding to the azimuth of the most prevalent winds, we applied as the central line the one that formed an angle of 90° in relation to the shoreline. We opted for this change because the wind originates from various directions in the reservoir, and because wave disturbances are apparently greater when the winds reach the macrophytes coming from the frontal direction (i.e., at 90° in relation to the shoreline). A sediment sample was collected at each sampling point to determine the grain size distribution and organic matter content (% OM sed g DW). The grain size distribution was determined using the Wentworth scale (Wentworth 1922 ; Suguto 1973 ). Additionally, the estimate of organic matter present in the sediment was obtained by the ratio of the initial and final masses after burning 20g of sediment in a muffle furnace at 560°C for about four hours. The collection of data on abiotic variables at all sampling points was used to test hypothesis (ii). Statistical Analyses Logistic regressions were applied to test the probability of occurrence of H. verticillata in response to the richness of native species recorded at the three sampled scales. Logistic regression was also applied to the abiotic variables: electrical conductivity, pH, Secchi depth, fetch , distance between shores, sediment organic matter, and depth of the reservoir where the plants were sampled. The positive effect of any of these variables would be confirmed if the probability of occurrence of H. verticillata increases as the tested variable increases, while the opposite would indicate a negative effect of the variable. To assess the effect of the distance between shores and depth on sediment organic matter values, a simple linear regression was applied. Finally, to determine the type of sediment the H. verticillata colonizes, a principal component analysis (PCA) was conducted using the grain sizes found at each sampling point. A factorial ANOVA was performed with the PCA axes to verify if there was a significant difference between the sediment types of locations colonized and not colonized by H. verticillata . All tests and figures were conducted using StatisticaTM 7.0 software. Results A total of 13 species of submerged macrophytes were recorded for the entire Rosana Reservoir, with an average of (2.8 ± 1.46) for large scale, (2.05 ± 1.19) for medium scale, and (1.18 ± 0.94) for small scale. In all scales, the probability of occurrence of H. verticillata was significantly positive related to the increase in richness of native species (Table 1 : Fig. 2 a,b and c). The occurrence of H. verticillata at each sampling point and across the three scales varied between 1 and 4 species. Table 1 Results of logistic regression using the presence of H. verticillata as the dependent variable, and as continuous variables, the native species richness at three scales (small, medium, and large), and the abiotic variables, electrical conductivity, pH, Secchi disk transparency, fetch, distance between shores, % OMsed g DW, and reservoir depth. Parameters Estimates X 2 McFadden’s rho 2 Odds ratio p Small scale 1.982 310.618 0.269 7.258 < 0.001 Medium scale 1.822 47.814 0.394 6.185 < 0.001 Large scale 1.219 24.958 0.207 3.382 < 0.001 Electrical conductivity 0.052 0.846 0.007 1.053 0.357 pH 0.339 0.860 0.007 1.404 0.353 Secchi disk transparency -0.303 0.174 0.001 0.738 0.676 Fetch 1.064 15.150 0.126 2.900 < 0.001 Distance between shores 1.608 29.409 0.244 4.994 < 0.001 % OMsed g DW -3.049 81.129 0.675 0.047 < 0.001 Reservoir depth -10.655 89.216 0.742 0.000 < 0.001 McFadden's estimates the proportion of variation explained by the logistic model; The odds ratio tests the relative risk according to the richness of ENs at three scales: small, medium, and large, and the abiotic variables: electrical conductivity, pH, Secchi disk, fetch, distance between shores, % OMsed g DW, and reservoir depth. >>> Fig. 2 Considering the abiotic variables, the probability of occurrence of Hydrilla verticillata was not significantly affected by electrical conductivity, pH, and Secchi disk depth (Table 1 ). However, logistic regression showed that the probability of occurrence of H. verticillata significantly increases with the increase in abiotic variables of fetch and distance between shores (Table 1 ; Figs. 3 a-b). Nevertheless, the distance between shores exhibited the best model generated by the analysis (Table 1 ). As for the variables of sediment organic matter and reservoir depth, with the gradual increase in these variables, there was a significant decrease in the probability of occurrence H. verticillata (Table 1 ; Figs. 3 c-d), with the analysis result showing a better logistic model for the depth variable (Table 1 ). >>> Fig. 3 >>> Table 1 The results of the linear regression between sediment organic matter versus depth and distance between shores showed that with increasing depth, there was a significant increase in the percentage of organic matter (β = 0.74, R 2 = 0.54, p < 0.001; Fig. 4 a). However, for the distance between shores, the relationship was inverse, with a significant reduction in sediment organic matter percentage with increasing distance between shores of the reservoir (β= − 0.49, R 2 = 0.26, p >> Fig. 4 The results of the principal component analysis (PCA) using the grain size data demonstrated that the sediment of the Rosana Reservoir is composed of different types of granules (Fig. 5 ). However, the result of the ANOVA with the PCA axes showed that there was no significant difference in sediment type between locations where the H. verticillata was present and those where it was absent (F = 1.02; p > 0.05). >>> Fig. 5 Discussion The results of this study demonstrated that, contrary to what was expected by our hypothesis, the probability of occurence of H. verticillata was high with increases in species richness across all spatial scales. Moreover, the fetch and distance between the shores also significantly increased the probability of occurrence of H. verticillata , but its occurrence was negatively impacted by increases in organic matter sediment and reservoir depth. Recent studies (e.g., Fridley et al. 2004 ; Herben et al. 2004 ; Grey 2009 ) have examined the role of spatial scales in explaining conflicting results between co-occurrence patterns of exotic and native species (Chen et al. 2010 ). However, it is common to find in the literature records of negative relationships between exotic and native species at small scales (e.g., Naeem et al. 2000 ; Brown and Peet 2003 ), and positive relationships at large spatial scales (e.g., Davies et al. 2005 ; Capers et al. 2007 ). The reason for opposite patterns occurring at different scales is the predominant type of interaction. At smaller scales, competition determines community patterns, thus making the relationship between exotic and native species negative (Levine and D’Antonio 1999; Hector et al. 2001 ; Levine et al. 2004 ; Capers et al. 2007 ; Fridley et al. 2007). On the other hand, at larger scales, increased environmental heterogeneity and resource availability may elevate the co-occurrence between exotic and native species (Davis et al. 2000 ; Dunstan and Johnson 2004 ). In our results, the regression analysis showed that the probability of occurrence of H. verticillata was positively related to the increase in native species richness at the three spatial scales analyzed. Several studies have demonstrated that the presence of an exotic species can impact the development of other native species (Michelan et al. 2010 ; Silveira et al. 2018 ; Louback-Franco et al. 2019 ). However, other studies have demonstrated that the presence of an exotic species can facilitate the presence of other native species (Thomaz et al. 2012 ; Silveira and Thomaz 2019 ). Thus, possibly the competition between submerged macrophyte native species and H. verticillata may not have been important enough to affect the presence of H. verticillata at the small scales we addressed. At the same time, these findings allow us to reject the hypothesis that biological resistance to exotic species invasion, represented by species diversity, varies at different spatial scales. With these results, along with many other field studies in natural ecosystems, we can possibly demonstrate that the dominant general pattern in invasion ecology at multiple spatial scales is one of "biotic acceptance" in certain environments, where, natural ecosystems tend to accommodate the establishment and coexistence of introduced species despite the presence, abundance (Stohlgren et al. 2006), and/or native species richness. Some authors have demonstrated using a competition-based model with negative relationships at small scales that these relationships can become positive when the number of resources available to the entire community is altered (Byers and Noonburg 2003 ). Despite the predominance of records of negative relationships at small spatial scales, a positive relationship has been reported between some communities containing exotic and native species at small scales in various systems such as California chaparral, savannas, and coniferous forests (Keeley et al. 2003 ). This suggests that the relationships between exotic and native species are not simply determined by competition but also by other factors such as increased resource availability for a wide range of species. Fluctuation and resource availability have received considerable attention in ecological studies (Davis et al. 2000 ; Blumenthal 2005 ), as these mechanisms propose that invasion can be facilitated in locations with high resource availability (Funk and Vitousek 2007 ). Possibly, this resource fluctuation may occur at various spatial scales in natural or artificial ecosystems such as reservoirs, and consequently determine the locations to be invaded by new species. This would help explain why the hypothesis of biotic resistance is so often rejected under natural (non-experimental) conditions, as also suggested by our results (Sax 2001 ; Cleland et al. 2004 ; Dunstan and Johnson 2004 ; Stohlgren et al. 2008 ). However, while native species richness in the reservoir did not influence the success of the exotic species here studied, it can be observed that the probability of occurrence of H. verticillata was determined by some abiotic factors. Firstly, dispersal can be an important factor in determining the locations where the H. verticillata occurred. Thus, fetch (wave disturbance) played a significant role in the probability of occurrence of H. verticillata throughout the reservoir, especially in areas closer to the dam, where there is a wide distance between shores (see results), which possibly increases fetch values, and consequently dispersal. Therefore, even though our results have shown that native species richness did not influence the probability of occurrence of H. verticillata , we can predict that hydrilla could possibly colonize locations highly disturbed by waves in the reservoir. Another important factor for the probability of occurrence of H. verticillata was the depth of the reservoir. Unlike what was found in the Itaipu reservoir, where the presence of hydrilla was recorded in deeper locations (Thomaz et al. 2009 ; Florêncio et al. 2021), it can be observed that the probability of occurrence H. verticillata occurred in shallower areas in the reservoir (see results), possibly because these areas have low concentrations of organic matter in the sediment and greater availability of sub-aquatic radiation. Consistently, the probability of occurrence of H. verticillata was negatively related to the increase in sediment organic matter concentrations, a fact also demonstrated by some authors in experimental studies (e.g., Barko and Smart 1986 ; Silveira and Thomaz 2015 ; Silveira and Thomaz 2022 ) and field observations (e.g., Sousa et al. 2009 , 2010 ; Silveira 2015 ). In fact, this abiotic variable is directly related to the width of the reservoir and consequently to the probability of occurrence of H. verticillata (see Fig. 4 b), as narrower locations possibly experience an increase in the amount of allochthonous material entering from the shores compared to wider locations. Thus, we found that there was an increase in sediment organic matter concentrations in narrower locations (see Fig. 5 b). Some authors have evidenced the formation of toxic components generated by anaerobic decomposition in sediment (Barko and Smart 1983 , 1986 ), which can cause anoxia and compromise the development of aquatic plants (e.g., Moore et al. 1992 ; Pezeshki 2001 ; Blokhina et al. 2003 ), a fact also demonstrated for H. verticillata (Spencer and Ksander 1995 ). Lastly, regarding the physical composition of the sediment, our results indicated that the reservoir has a heterogeneous sediment type, dominated by various types of granules, and the presence or absence of the H. verticillata was reported in all these different sediments. Thus, we predict that sediment grain size did not influence the colonization of H. verticillata , but rather the sediment quality concerning organic matter concentrations. In summary, our results demonstrate that the probability of occurrence of H. verticillata in the Rosana reservoir was not influenced by native species richness at three spatial scales, and abiotic factors such as morphometry ( fetch ), distance of reservoir shores,sediment organic matter and depth of the reservoir where the plants were sampled, can determine the success or failure of the occurrence of this species. At the same time, the success of probability of occurrence of H. verticillata was positively related to the native species richness at three different spatial scales. These results suggest that biotic resistance is of little importance for H. verticillata success at the reservoir. But, at the moment, some abiotic factors are more important for inhibiting of probability of occurrence of H. verticillata in the reservoir than biotic resistance. Nevertheless, due to the various changes in environmental quality that these aquatic environments may undergo or even due to the presence of the exotic species being better established, this relationship may change in the future. Declarations Acknowledgements The authors thanks Dr. Sidinei Magela Thomaz by suggestions in all manuscript. M.J. Silveira is grateful as National Council for Scientific and Technological Development - CNPq for providing a student schollarship. Funds for this research were provided by the Long-Term Ecological Project Program (LETR), funded by CNPq and by the Itaipu Binacional, PDTA/FPTI-BR. The English was corrected using ChatGPT. References Azza N, Van de Koppel J, Denny P, Kansiime F (2007) Shoreline vegetation distribution in relation to wave exposure and bay characteristics in a tropical great lake, Lake Victoria. J Trop Ecol 23:353–360 Barko JW, Smart RM (1986) Sediment-related mechanisms of growth limitation in submersed macrophytes. Ecology 65:1328–1340 Barko JW, Smart RM (1983) Effects of organic matter additions to sediment on the growth of aquatic plants. J Ecol 71:161–175 Barret SCH, Eckert CG, Husband BC (1993) Evolutionary processes in aquatic plant populations. Aquat Bot 44:105–145 Blokhina O, Virolainen E, Fagerstedt KV (2003) Antioxidants, oxidative damage and oxygen deprivation stress: a review. Ann Botany 91:179–194 Blumenthal D (2005) Interrelated causes of plant invasion. Science 310:243–244 Brown RL, Peet RK (2003) Diversity and invasibility of southern Appalachian plant communities. Ecology 84:32–39 Byers JE, Noonburg EG (2003) Scale-dependent effects of biotic resistance to biological invasion. Ecology 84:1428–1433 Byun C, de Blois S, Brisson J (2014) Interactions between abiotic constraint, propagule pressure, and biotic resistance regulate plant invasion. Oecologia 178:285–296 Capers RS, Selsky R, Bugbee GJ, White JC (2007) Aquatic plant community invisibility and scale-dependent patterns in native and invasive species richness. Ecology 88:3135–3143 Chen H, Qian H, Syreas G, Crossland M (2010) Native-exotic species richness relationships across spatial scales and biotic homogenization in wetland plant communities of Illinois. USA Divers Distrib 16:737–743 Cleland EE, Smith MD, Andelman J, Bowles C, Carney KM, Horner-Devine MC, Drake JM, Emer SM, Gramling JM, VanderMast DB (2004) Invasion in space and time: non-native species richness and relative abundance respond to interannual variation in productivity and diversity. Ecol Lett 7:947–957 Davies KF, Chesson P, Harrison S, Inouye BD, Melbourne BA, Rice KJ (2005) Spatial heterogeneity explains the scale dependence of the native–exotic diversity relationship. Ecology 86:1602–1610 Davis MA, Grime JP, Thompson K (2000) Fluctuating resources in plant communities: a general theory of invasibility. J Ecol 88:528–534 Davis MA, Thompson K, Grime JP (2001) Charles S. Elton and dissociation of invasion ecology from the rest of ecology. Divers Distrib 7:97–102 Dibble ED, Thomaz SM, Padial AA (2006) Spatial complexity measured at a multi-scale in three aquatic plant species. J Freshw Ecol 21:239–247 Dunstan PK, Johnson CR (2004) Invasion rates increase with species richness in marine epibenthic communities by two mechanisms. Oecologia 138:285–295 Elton CS (1958) The Ecology of Invasions by Animals and Plants. Methuen, London. (Reprinted 2000 by The University of Chicago Press) Florencio, Alves DC, Silveira FM, Lansac-Tôha MJ, Thomaz FM, S.M (2021) The success of the invasive macrophyte Hydrilla verticillata and its interactions with the native Egeria najas in response to environmental factors and plant abundance in a subtropical reservoir. Aquat Bot 175:1–9 Fridley JD, Brown RL, Bruno JF (2004) Null models of exotic invasion and scale dependent patterns of native and exotic species richness. Ecology 85:3215–3222 Funk J, Vitousek PM (2007) Resource use efficiency and plant invasion in low resource systems. Nature 446:1079–1081 Grey EK (2009) Scale-dependent relationships between native richness, resource stability and exotic cover in dock fouling communities of Washington, USA. Divers Distrib 15:1073–1080 Gurevitch J, Fox GA, Wardle GM, Inderjit, Taub D (2011) Emergent insights from the synthesis of conceptual frameworks for biological invasions. Ecol Lett 14:407–418 Hakanson L, Jansson M (1983) Principles of lake sedimentology. Springer- Harwell MC, Havens KE (2003) Experimental studies on the recovery potential of submerged aquatic vegetation after flooding and desiccation in a large subtropical lake. Aquat Bot 77:135–151 Havel JE, Lee CE, Zanden MJV (2005) Do reservoirs facilitate invasions into landscapes? BioScience, 55, 518–525 Hector A, Dobson K, Minns A, Bazeley-White E, Lawton JH (2001) Community diversity and invasion resistance: an experimental test in a grassland ecosystem and a review of comparable studies. Ecol Res 16:819–831 Herben T, Mandak B, Bimova K, Munzbergova Z (2004) Invasibility and species richness of a community: A neutral model and a survey of published data. Ecology 85:3223–3233 Keeley JE, Lubin D, Fortheringham CJ (2003) Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada. Ecol Appl 13:1355–1374 Levine JM, D'Antonio CM (1999) Elton revisited: a review of evidence linking diversity and invasibility. Oikos 87:15–26 Levine JM (2001) Local interactions, dispersal, and native and exotic plant diversity along a California stream. Oikos 5:397–408 Levine JM (2000) Species diversity and biological invasions: relating local process to community pattern. Science 288:852–854 Levine JM, Adler PB, Yelenik SG (2004) A meta-analysis of biotic resistance to exotic plant invasions. Ecol Lett 7:975–989 Louback-Franco N, Dainez-Filho MS, Souz DC, Thomaz SM (2019) A native species does not prevent the colonization success of an introduced submerged macrophyte, even at low propagule pressure. Hydrobiologia 7:975–989 Lonsdale WM (1999) Global patterns of plant invasions and the concept of invasibility. Ecology 80:1522–1536 Michelan TS, Thomaz SM, Mormul RP, Carvalho P (2010) Effects of an exotic invasive macrophyte (tropical signalgrass) on native plant community composition, species richness and functional diversity. Freshw Biol 55:1315–1326 Moore JL, Mouquet N, Lawton JH, Loreau M (2001) Coexistence, saturation and invasion resistance in simulated plant assemblages. Oikos 94:303–314 Moore PA, Reddy KR, Graetz DA (1992) Water quality-nutrient transformations in sediments as influenced by oxygen supply. J Environ Qual 21:387–393 Naeem S, Knops JMH, Tilman D, Howe KM, Kennedy T, Gale S (2000) Plant diversity increases resistance to invasions in the absence of covarying extrinsic factors. Oikos 91:97–108 Petenon D, Pivello VR (2008) Plantas invasoras: representatividade da pesquisa dos países tropicais no contexto mundial. Natureza Conservação 6:66–77 Pezeshki SR (2001) Wetland plant responses to soil flooding. Environ Exp Bot 46:299–312 Sax DF (2001) Latitudinal gradients and geographic ranges of exotic species implications for biogeography. J Biogeogr 28:139–150 Silveira MJ, Thomaz SM (2015) Growth of a native versus an invasive submerged aquatic macrophyte difers in relation to mud and organic matter concentrations in sediment. Aquat Bot 124:5–91 Silveira MJ (2015) The efect of habitat and sediment type on the occurrence of non-native and native species of aquatic macrophyte in subtropical regions. Bioscience J 31:268–274 Silveira MJ, Alves DC, Thomaz SM (2018) Efects of the density of the invasive macrophyte Hydrilla verticillata and root competition on growth of one native macrophyte in diferent sediment fertilities. Ecol Res. https://doi.org/10.1007/s11284-018-1602-4 Silveira MJ, Thomaz SM (2019) Interspecifc associations between Hydrilla verticillata and three dominant native genera of submerged macrophytes are taxa dependent. Aquat Sci 81:21 Silveira MJ, Thomaz SM (2022) Efects of interactions between abiotic and biotic factors on growth of a nonnative macrophyte. Biol Invasions. https://doi.org/10.1007/s10530-022-02924-1 Shea K, Chesson P (2002) Community ecology theory as a framework for biological invasions. Trends Ecol Evol 17:170–176 Sousa WTZ, Thomaz SM, Murphy KJ, Silveira MJ, Mormul RP (2009) Environmental predictors of the occurrence of exotic Hydrilla verticillata (Lf) Royle and native Egeria najas Planch. in a sub-tropical river foodplain: the Upper River Parana. Hydrobiologia 632:65–78 Sousa WTZ, Thomaz SM, Murphy KJ (2010) Response of native Egeria najas Planch. and invasive Hydrilla verticillata (L.f.) Royle to altered hydroecological regime in a subtropical river. Aquat Bot 92:40–48 Spence DHN (1982) The zonation of plants in freshwater lakes. Adv Ecol Res 12:37–126 Spencer DF, Ksander GG (1995) Differential effects of the microbial metabolite, acetic acid, on sprouting of aquatic plant propagules. Aquat Bot 52:107–119 Stohlgren TJ, Flather C, Jarmevich CS, Barnett DT, Kartesz J (2008) Rejoinder to Harrison (2008): The myth of plant species saturation. Ecol Lett 11:324–326 Suguto K (1973) Introdução à sedimentologia. São Paulo, Edgard Blucher Thomaz SM, Carvalho P, Mormul RP, Ferreira FA, Silveira MJ, Michelan TS (2009) Temporal trends and effects of diversity on occurrence of exotic macrophytes in a large reservoir. Acta Oecol 35:614–620 Thomaz SM, Pagioro TA, Bini LM, Roberto MC (2005) Ocorrência e distribuição espacial de macrófitas aquáticas em reservatórios. In: Rodrigues, L., Thomaz, S.M., Agostinho, A.A., Gomes, L.C. (Eds.), Biocenoses em reservatórios: padrões espaciais e temporais. São Carlos, RiMaEditora, 39–46 Thomaz SM, Kovalenko KE, Havel JE, Kats LB (2015) Aquatic invasive species: general trends in the literature and introduction to the special issue. Hydrobiologia 746:1–12 Thomaz SM, Agostinho AA, Gomes LC, Silveira MJ, Rejamánek M, Aslan CE, Chow E (2012) Using space-for-time substitution and time sequence approaches in invasion ecology. Freshw Biol 746:1–12 Tilman D (1997) Community invasibility, recruitment limitation, and grassland biodiversity. Ecology 78:81–92 Tilman D (1993) Species richness of experimental productivity gradients-how important is colonization limitation. Ecology 74:2179–2191 Van den Berg MS, Joosse W, Coops H (2003) A statistical model predicting the occurrence and dynamics of submerged macrophytes in shallow lakes in the Netherlands. Hydrobiologia 506:611–623 Vitousek PM, D’Antonio CM, Loope LL, Rejmanek M, Westbrooks R (1997) Introduced species: A significant component of human-caused global change. New Z J Ecol 21:1–16 Wentworth CK (1922) A scale of grade and class terms for clastic sediments. J Geol 30:377–392 Cite Share Download PDF Status: Published Journal Publication published 04 Feb, 2026 Read the published version in Biological Invasions → Version 1 posted Reviewers agreed at journal 23 May, 2024 Reviewers invited by journal 22 Apr, 2024 Editor invited by journal 13 Apr, 2024 Editor assigned by journal 13 Apr, 2024 First submitted to journal 10 Apr, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4248767","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":293991307,"identity":"e3489f3a-1aa4-45f7-a46b-07922af1b94a","order_by":0,"name":"Márcio Silveira","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYBAC+QYeg8M/aurk2PsPH/zMY1CXwMB++JgEPi0GB/gKH/MckzBmnJGWLD2nQiKBgSct3QKvFgb+z8a8TRKJjTN4zJj/nAFqkdAx/4FfC+82ad4GsJZvzLltIC08Zjfw+wWo5SdIS//ZbcRpYTgA1PIQpKUhd5s1kVp4zH8bgrXkPJPm/QfRgjfEgFrMpCWB3p/YkMMmzQu2RQe/FoPDQC2gQJaWSDMGa2HjSUvDq0W+vQeoBRiVfPyHH37mbaur5ycUlQzM6AJseJWPglEwCkbBKCAKAACFa0thZd9NBAAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0002-6490-176X","institution":"UEMG: Universidade do Estado de Minas Gerais","correspondingAuthor":true,"prefix":"","firstName":"Márcio","middleName":"","lastName":"Silveira","suffix":""},{"id":293991308,"identity":"3926fa23-00e3-4661-ae9c-922f5d451157","order_by":1,"name":"Vanessa de Carvalho Harthman","email":"","orcid":"","institution":"Universidade Federal de Mato Grosso do Sul","correspondingAuthor":false,"prefix":"","firstName":"Vanessa","middleName":"de Carvalho","lastName":"Harthman","suffix":""}],"badges":[],"createdAt":"2024-04-10 17:46:44","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4248767/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4248767/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10530-026-03752-3","type":"published","date":"2026-02-04T15:57:53+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":55288121,"identity":"f9ebf8be-59d7-40a7-a0a2-a13e1bc571df","added_by":"auto","created_at":"2024-04-25 08:36:01","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":384655,"visible":true,"origin":"","legend":"\u003cp\u003eRosana Reservoir demonstrating the sampled points colonized and not colonized by \u003cem\u003eHydrilla verticillata\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/5c14fa4f3277503f6b5c20d7.jpg"},{"id":55287396,"identity":"802ab7aa-dc34-4ad4-9f3b-7d048f2118b4","added_by":"auto","created_at":"2024-04-25 08:28:01","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":161130,"visible":true,"origin":"","legend":"\u003cp\u003eProbability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e as a function of native speciesrichness at three different scales: small scale (a), medium scale (b), large scale (c).\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/8f1b58be664f9fea78e8b503.jpg"},{"id":55287392,"identity":"55206efd-591b-45d2-9dcc-f6e20ac71c15","added_by":"auto","created_at":"2024-04-25 08:28:01","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":268288,"visible":true,"origin":"","legend":"\u003cp\u003eProbability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e as a function of fetch (a), distance between shores (b), % OMsed g DW (c), and depth of the reservoir where the plants were sampled - \"Reservoir depth (d).\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/9e674f3db9fd57213745274d.jpg"},{"id":55288957,"identity":"7255c8fb-1b45-4769-a9a6-2da8448df666","added_by":"auto","created_at":"2024-04-25 08:44:01","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":163358,"visible":true,"origin":"","legend":"\u003cp\u003eLinear relationship between sediment organic matter and Reservoir depth (a) and distance between reservoir shores (b).\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/f46043258af19dc9fa885022.jpg"},{"id":55287393,"identity":"1dad6150-f54a-4daf-9b25-f8d114843d3a","added_by":"auto","created_at":"2024-04-25 08:28:01","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":40858,"visible":true,"origin":"","legend":"\u003cp\u003eScatter plot of sediment grain size analysis: Silt + Clay = Mud; Very Fine Sand = VFS; Fine Sand = FS; Medium Sand = MS; Coarse Sand = CS; Very Coarse Sand = VCS. Where \u003cem\u003eH. verticillata\u003c/em\u003e was absent = hollow circles or present = black circles.\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/848856e4b215affe8e2fd765.jpg"},{"id":102235700,"identity":"6d5093b3-c5a8-40ec-b1dd-9eb3a1ad2c64","added_by":"auto","created_at":"2026-02-09 16:17:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1583664,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4248767/v1/c8d00c7a-2e4b-4826-a452-414a031b5525.pdf"}],"financialInterests":"","formattedTitle":"Biotic resistance at different spatial scales did not inhibit the colonization success of an exotic submerged aquatic plant.","fulltext":[{"header":"Introduction","content":"\u003cp\u003eExotic species have attracted the attention of various researchers, both due to their negative impacts on communities and ecosystems (Mack et al. 2000) and their relevance for testing general ecological theories (Tilman \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e1993\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Levine \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2000\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Davis et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Currently, few ecosystems remain free from the introduction of exotic species (Vitousek et al. \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1997\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMost research on biological invasions is conducted in terrestrial ecosystems (e.g., Hector 2001; Thomaz et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), with a significant bias towards temperate regions that receive more attention than tropical and subtropical ones (Petenon and Pivello \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). However, there is a special interest in understanding and possibly preventing the introduction of exotic species in aquatic environments, as these ecosystems exhibit high biodiversity, explained, among other factors, by the presence of aquatic macrophytes that increase habitat complexity at different spatial scales (Dibble et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSome studies indicate that at larger spatial scales, the success of exotic species increases with increasing species richness (Levine and D'Antonio \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), suggesting that exotic species and native species respond similarly to environmental conditions. However, at smaller spatial scales (e.g., plots of a few square meters), where environmental conditions are similar, most studies demonstrate that the success of exotic species declines with the richness of the native community. This can be explained by niche overlap and competitive exclusion, which drive the relationship between exotic species and native species at these smaller scales (Shea and Chesson \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Michelan et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Although these hypotheses are plausible, they are rarely tested simultaneously, especially in situ in aquatic environments.\u003c/p\u003e \u003cp\u003eThe susceptibility of the environment to invasion by new organisms (invasibility) is a factor that can determine the establishment of species in different habitats (Lonsdale \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Reservoirs are considerably different environments from natural ecosystems, and their characteristics (e.g., increased inundation area and disturbance intensity) facilitate introductions and dispersal of species to other aquatic ecosystems (Havel et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe relationship between ecosystem invasibility by exotic species and the diversity of native species has long concerned naturalists. Darwin (1859) formally proposed that communities with higher species richness were less susceptible to invasions, especially aquatic communities. The relationship between species diversity and invasibility (\"biotic resistance\") was further addressed by Elton (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1958\u003c/span\u003e), whose ideas have since underpinned discussions on invasions over the past 50 years, making it one of the most cited topics in invasion-related scientific literature (Levine and D'Antonio \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Biotic resistance against invasion is caused by mechanisms associated with allelopathy, predation, herbivory, parasitism (Gurevitch, 2011) and competition regarding use of space and nutrient uptake, which are most inflfluential biotic resistance mechanisms in plants (Levine and Antonio 1999; Levine et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Gurevitch et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Byun et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Within this context, the use of resources by native species might reduce the invasive performance of exotic species as long as these species use similar resources to the native ones (Levine and Antonio 1999; Levine et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Despite, other studies have demonstrated that even communities with higher species richness can be as vulnerable to introductions as poorer communities (Dunstan and Johnson \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Capers et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), thus, the introduction of exotic species can also occur in areas with lower species richness.\u003c/p\u003e \u003cp\u003eStudies have shown that abiotic factors also have a significant effect on plant growth and reproduction, and thus these factors can determine the success or failure of exotic plant species introductions (Spence, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e1982\u003c/span\u003e; Barrett et al. 1993; Van den Berg et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Sediment characteristics, along with other physicochemical features such as water transparency and nutrient availability (Sousa et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2010\u003c/span\u003e), act as abiotic filters to plant species introductions in aquatic ecosystems and play an important long-term role in the establishment and survival of rooted submerged macrophytes (Harwell and Havens \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2003\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, was analyzed the relationship between native species richness and the probability of occurrence of the exotic species \u003cem\u003eHydrilla verticillata\u003c/em\u003e at three different spatial scales. Additionally, we evaluated the probability of exotic species occurrence in relation to morphometric characteristics and sediment composition. Were tested the following hypotheses: (i) the invasion success of \u003cem\u003eHydrilla verticillata\u003c/em\u003e is positively related to native species richness at large and medium spatial scales but negatively related to native species richness at small spatial scales, and (ii) abiotic factors such as light penetration in the water, fetch (an indicator of wave disturbance), and sediment organic matter are important predictors of \u003cem\u003eH. verticillata\u003c/em\u003e success. Hypothesis (i) was based on biotic resistance (Elton \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1958\u003c/span\u003e), while hypothesis (ii) is based on the fact that abiotic environmental filters can be determinants of exotic species invasion success.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Area\u003c/h2\u003e \u003cdiv id=\"Sec4\" class=\"Section3\"\u003e \u003ch2\u003eRosana Reservoir\u003c/h2\u003e \u003cp\u003eThe Rosana reservoir is located in the lower Paranapanema River section (22\u0026deg;36'S 52\u0026deg;50'W). The reservoir was flooded in November 1986 and covers an area of 350 km\u0026sup2;, operating as a run-of-the-river type, with a residence time of 18.6 days and shallow depth (CESP, 1998) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Aquatic plants are commonly found in the reservoir, with the submerged species \u003cem\u003eEgeria densa\u003c/em\u003e being among the most abundant and with the highest vegetative cover. Other species are also found, such as \u003cem\u003eE. najas\u003c/em\u003e, \u003cem\u003eEichhornia azurea\u003c/em\u003e, \u003cem\u003eEichhornia crassipes, Salvinia herzogii\u003c/em\u003e, \u003cem\u003eEchinodorus tenellus\u003c/em\u003e, \u003cem\u003eNymphaea amazonum\u003c/em\u003e, \u003cem\u003eTypha domingensis\u003c/em\u003e, and several species of grasses (Thomaz et al. \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003eData Collection\u003c/h2\u003e \u003cp\u003eData collection was conducted in the Rosana Reservoir in October 2010. Sampling involved recording the presence (1) or absence (0) of submerged macrophyte species at 176 previously demarcated and georeferenced points. Species sampling was performed using a long-handled rake (approximately 4 m), which was dragged along the sediment to the maximum depth limit colonized by macrophytes. However, 89 points located upstream of the reservoir were excluded from the analyses because the absence of \u003cem\u003eHydrilla verticillata\u003c/em\u003e in these locations may be due to dispersal limitations (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, points demarcated by the rectangle on the map).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eSampling at Different Spatial Scales\u003c/h2\u003e \u003cp\u003eAt each sampling point, an area of approximately 1200m\u0026sup2; was selected and subdivided into three scales: (i) small scale (rake area of 0.02m\u0026sup2;, with 10 sampling units for each collection point, n\u0026thinsp;=\u0026thinsp;870 sampling units; for analysis, the species found in each rake were considered); (ii) medium scale (transects of ~\u0026thinsp;60x4, equivalent to 240 m\u0026sup2;, with one transect at each sampling point, n\u0026thinsp;=\u0026thinsp;87 sampling units; for analysis at this scale, only the species found in the transect were considered); and (iii) large scale, an area of ~\u0026thinsp;60x20, equivalent to 1200 m\u0026sup2;, where the species composed of the aggregate of 10 sampling units of 0.02m\u0026sup2;, along with the species found at the medium scale were considered (n\u0026thinsp;=\u0026thinsp;87 sampling units). Samples at different scales were used to test hypothesis (i).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eSampling of Abiotic Variables\u003c/h2\u003e \u003cp\u003eAt all sampled points, the minimum (Z\u003csub\u003emin\u003c/sub\u003e) and maximum (Z\u003csub\u003emax\u003c/sub\u003e) depth of occurrence of submerged macrophytes were determined, with Z\u003csub\u003emin\u003c/sub\u003e and Z\u003csub\u003emax\u003c/sub\u003e being determined perpendicular to each transect using the metric scale of the rake handle. Additionally, at each sampling point, the straight-line distance (in meters) from the shoreline ahead of the point was determined to assess the influence of reservoir width on submerged macrophyte colonization. Furthermore, the following abiotic variables: electrical conductivity (\u0026micro;S cm^\u003csup\u003e\u0026minus;1\u003c/sup\u003e), pH, Secchi disk transparency (m), and fetch (distance free for wind action; km), were measured to assess the influence of these abiotic variables on submerged macrophyte colonization in the Rosana Reservoir. \u003cem\u003eFetch\u003c/em\u003e can be considered as a variable indicating wave disturbance caused by wind. The fetch calculation used the following equation proposed by H\u0026aring;kanson and Jansson (1983) and modified by Azza et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003c/span\u003e \u003c/p\u003e \u003cp\u003ewhere \u003cem\u003eEf\u003c/em\u003e (km) is the effective \u003cem\u003efetch\u003c/em\u003e (i.e., the distance in open water where waves are induced by the wind), xi (km) is the straight-line distance or length from the point towards land or an island, and ai (degrees) is the angle of inclination in the direction of the wind, starting from 0\u0026deg; with increments every 6\u0026deg; up to +\u0026thinsp;42\u0026deg; and \u0026minus;\u0026thinsp;42\u0026deg;. However, unlike the referenced authors above, who considered the central line as the one corresponding to the azimuth of the most prevalent winds, we applied as the central line the one that formed an angle of 90\u0026deg; in relation to the shoreline. We opted for this change because the wind originates from various directions in the reservoir, and because wave disturbances are apparently greater when the winds reach the macrophytes coming from the frontal direction (i.e., at 90\u0026deg; in relation to the shoreline).\u003c/p\u003e \u003cp\u003eA sediment sample was collected at each sampling point to determine the grain size distribution and organic matter content (% OM\u003csub\u003esed\u003c/sub\u003e g DW). The grain size distribution was determined using the Wentworth scale (Wentworth \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e1922\u003c/span\u003e; Suguto \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e1973\u003c/span\u003e). Additionally, the estimate of organic matter present in the sediment was obtained by the ratio of the initial and final masses after burning 20g of sediment in a muffle furnace at 560\u0026deg;C for about four hours. The collection of data on abiotic variables at all sampling points was used to test hypothesis (ii).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analyses\u003c/h2\u003e \u003cp\u003eLogistic regressions were applied to test the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e in response to the richness of native species recorded at the three sampled scales. Logistic regression was also applied to the abiotic variables: electrical conductivity, pH, Secchi depth, \u003cem\u003efetch\u003c/em\u003e, distance between shores, sediment organic matter, and depth of the reservoir where the plants were sampled. The positive effect of any of these variables would be confirmed if the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e increases as the tested variable increases, while the opposite would indicate a negative effect of the variable.\u003c/p\u003e \u003cp\u003eTo assess the effect of the distance between shores and depth on sediment organic matter values, a simple linear regression was applied. Finally, to determine the type of sediment the \u003cem\u003eH. verticillata\u003c/em\u003e colonizes, a principal component analysis (PCA) was conducted using the grain sizes found at each sampling point. A factorial ANOVA was performed with the PCA axes to verify if there was a significant difference between the sediment types of locations colonized and not colonized by \u003cem\u003eH. verticillata\u003c/em\u003e. All tests and figures were conducted using StatisticaTM 7.0 software.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 13 species of submerged macrophytes were recorded for the entire Rosana Reservoir, with an average of (2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.46) for large scale, (2.05\u0026thinsp;\u0026plusmn;\u0026thinsp;1.19) for medium scale, and (1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94) for small scale. In all scales, the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was significantly positive related to the increase in richness of native species (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e: Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea,b and c). The occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e at each sampling point and across the three scales varied between 1 and 4 species.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResults of logistic regression using the presence of \u003cem\u003eH. verticillata\u003c/em\u003e as the dependent variable, and as continuous variables, the native species richness at three scales (small, medium, and large), and the abiotic variables, electrical conductivity, pH, Secchi disk transparency, fetch, distance between shores, % OMsed g DW, and reservoir depth.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEstimates\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eX\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMcFadden\u0026rsquo;s\u003c/p\u003e \u003cp\u003erho\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOdds ratio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmall scale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e310.618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.269\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7.258\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedium scale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.822\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47.814\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.394\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.185\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLarge scale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.219\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e24.958\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.207\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.382\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectrical conductivity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.052\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.846\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.053\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.357\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.339\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.404\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.353\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSecchi disk transparency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.303\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.174\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.738\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.676\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFetch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.064\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15.150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.126\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistance between shores\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.608\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29.409\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.244\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4.994\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e% OMsed g DW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-3.049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e81.129\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.675\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.047\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReservoir depth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-10.655\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e89.216\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.742\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eMcFadden's estimates the proportion of variation explained by the logistic model;\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eThe odds ratio tests the relative risk according to the richness of ENs at three scales: small, medium, and large, and the abiotic variables: electrical conductivity, pH, Secchi disk, fetch, distance between shores, % OMsed g DW, and reservoir depth.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003c/h2\u003e \u003cp\u003eConsidering the abiotic variables, the probability of occurrence of \u003cem\u003eHydrilla verticillata\u003c/em\u003e was not significantly affected by electrical conductivity, pH, and Secchi disk depth (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). However, logistic regression showed that the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e significantly increases with the increase in abiotic variables of \u003cem\u003efetch\u003c/em\u003e and distance between shores (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e; Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea-b). Nevertheless, the distance between shores exhibited the best model generated by the analysis (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). As for the variables of sediment organic matter and reservoir depth, with the gradual increase in these variables, there was a significant decrease in the probability of occurrence \u003cem\u003eH. verticillata\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e; Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec-d), with the analysis result showing a better logistic model for the depth variable (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003c/h2\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/h2\u003e \u003cp\u003eThe results of the linear regression between sediment organic matter versus depth and distance between shores showed that with increasing depth, there was a significant increase in the percentage of organic matter (β\u0026thinsp;=\u0026thinsp;0.74, R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.54, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). However, for the distance between shores, the relationship was inverse, with a significant reduction in sediment organic matter percentage with increasing distance between shores of the reservoir (β= \u0026minus;\u0026thinsp;0.49, R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.26, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003c/h2\u003e \u003cp\u003eThe results of the principal component analysis (PCA) using the grain size data demonstrated that the sediment of the Rosana Reservoir is composed of different types of granules (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). However, the result of the ANOVA with the PCA axes showed that there was no significant difference in sediment type between locations where the \u003cem\u003eH. verticillata\u003c/em\u003e was present and those where it was absent (F\u0026thinsp;=\u0026thinsp;1.02; p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e\u0026gt;\u0026gt;\u0026gt; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003c/h2\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe results of this study demonstrated that, contrary to what was expected by our hypothesis, the probability of occurence of \u003cem\u003eH. verticillata\u003c/em\u003e was high with increases in species richness across all spatial scales. Moreover, the \u003cem\u003efetch\u003c/em\u003e and distance between the shores also significantly increased the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e, but its occurrence was negatively impacted by increases in organic matter sediment and reservoir depth.\u003c/p\u003e \u003cp\u003eRecent studies (e.g., Fridley et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Herben et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Grey \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) have examined the role of spatial scales in explaining conflicting results between co-occurrence patterns of exotic and native species (Chen et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). However, it is common to find in the literature records of negative relationships between exotic and native species at small scales (e.g., Naeem et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Brown and Peet \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2003\u003c/span\u003e), and positive relationships at large spatial scales (e.g., Davies et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Capers et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). The reason for opposite patterns occurring at different scales is the predominant type of interaction. At smaller scales, competition determines community patterns, thus making the relationship between exotic and native species negative (Levine and D\u0026rsquo;Antonio 1999; Hector et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Levine et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Capers et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Fridley et al. 2007). On the other hand, at larger scales, increased environmental heterogeneity and resource availability may elevate the co-occurrence between exotic and native species (Davis et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Dunstan and Johnson \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). In our results, the regression analysis showed that the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was positively related to the increase in native species richness at the three spatial scales analyzed. Several studies have demonstrated that the presence of an exotic species can impact the development of other native species (Michelan et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Silveira et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Louback-Franco et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). However, other studies have demonstrated that the presence of an exotic species can facilitate the presence of other native species (Thomaz et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Silveira and Thomaz \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Thus, possibly the competition between submerged macrophyte native species and \u003cem\u003eH. verticillata\u003c/em\u003e may not have been important enough to affect the presence of \u003cem\u003eH. verticillata\u003c/em\u003e at the small scales we addressed. At the same time, these findings allow us to reject the hypothesis that biological resistance to exotic species invasion, represented by species diversity, varies at different spatial scales. With these results, along with many other field studies in natural ecosystems, we can possibly demonstrate that the dominant general pattern in invasion ecology at multiple spatial scales is one of \"biotic acceptance\" in certain environments, where, natural ecosystems tend to accommodate the establishment and coexistence of introduced species despite the presence, abundance (Stohlgren et al. 2006), and/or native species richness.\u003c/p\u003e \u003cp\u003eSome authors have demonstrated using a competition-based model with negative relationships at small scales that these relationships can become positive when the number of resources available to the entire community is altered (Byers and Noonburg \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Despite the predominance of records of negative relationships at small spatial scales, a positive relationship has been reported between some communities containing exotic and native species at small scales in various systems such as California chaparral, savannas, and coniferous forests (Keeley et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). This suggests that the relationships between exotic and native species are not simply determined by competition but also by other factors such as increased resource availability for a wide range of species.\u003c/p\u003e \u003cp\u003eFluctuation and resource availability have received considerable attention in ecological studies (Davis et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Blumenthal \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), as these mechanisms propose that invasion can be facilitated in locations with high resource availability (Funk and Vitousek \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Possibly, this resource fluctuation may occur at various spatial scales in natural or artificial ecosystems such as reservoirs, and consequently determine the locations to be invaded by new species. This would help explain why the hypothesis of biotic resistance is so often rejected under natural (non-experimental) conditions, as also suggested by our results (Sax \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Cleland et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Dunstan and Johnson \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Stohlgren et al. \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever, while native species richness in the reservoir did not influence the success of the exotic species here studied, it can be observed that the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was determined by some abiotic factors. Firstly, dispersal can be an important factor in determining the locations where the \u003cem\u003eH. verticillata\u003c/em\u003e occurred. Thus, \u003cem\u003efetch\u003c/em\u003e (wave disturbance) played a significant role in the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e throughout the reservoir, especially in areas closer to the dam, where there is a wide distance between shores (see results), which possibly increases \u003cem\u003efetch\u003c/em\u003e values, and consequently dispersal. Therefore, even though our results have shown that native species richness did not influence the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e, we can predict that hydrilla could possibly colonize locations highly disturbed by waves in the reservoir.\u003c/p\u003e \u003cp\u003eAnother important factor for the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was the depth of the reservoir. Unlike what was found in the Itaipu reservoir, where the presence of hydrilla was recorded in deeper locations (Thomaz et al. \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Flor\u0026ecirc;ncio et al. 2021), it can be observed that the probability of occurrence \u003cem\u003eH. verticillata\u003c/em\u003e occurred in shallower areas in the reservoir (see results), possibly because these areas have low concentrations of organic matter in the sediment and greater availability of sub-aquatic radiation. Consistently, the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was negatively related to the increase in sediment organic matter concentrations, a fact also demonstrated by some authors in experimental studies (e.g., Barko and Smart \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1986\u003c/span\u003e; Silveira and Thomaz \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Silveira and Thomaz \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) and field observations (e.g., Sousa et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2009\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Silveira \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). In fact, this abiotic variable is directly related to the width of the reservoir and consequently to the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e (see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb), as narrower locations possibly experience an increase in the amount of allochthonous material entering from the shores compared to wider locations. Thus, we found that there was an increase in sediment organic matter concentrations in narrower locations (see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb). Some authors have evidenced the formation of toxic components generated by anaerobic decomposition in sediment (Barko and Smart \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1983\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1986\u003c/span\u003e), which can cause anoxia and compromise the development of aquatic plants (e.g., Moore et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Pezeshki \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Blokhina et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2003\u003c/span\u003e), a fact also demonstrated for \u003cem\u003eH. verticillata\u003c/em\u003e (Spencer and Ksander \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). Lastly, regarding the physical composition of the sediment, our results indicated that the reservoir has a heterogeneous sediment type, dominated by various types of granules, and the presence or absence of the \u003cem\u003eH. verticillata\u003c/em\u003e was reported in all these different sediments. Thus, we predict that sediment grain size did not influence the colonization of \u003cem\u003eH. verticillata\u003c/em\u003e, but rather the sediment quality concerning organic matter concentrations.\u003c/p\u003e \u003cp\u003eIn summary, our results demonstrate that the probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e in the Rosana reservoir was not influenced by native species richness at three spatial scales, and abiotic factors such as morphometry (\u003cem\u003efetch\u003c/em\u003e), distance of reservoir shores,sediment organic matter and depth of the reservoir where the plants were sampled, can determine the success or failure of the occurrence of this species. At the same time, the success of probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was positively related to the native species richness at three different spatial scales. These results suggest that biotic resistance is of little importance for \u003cem\u003eH. verticillata\u003c/em\u003e success at the reservoir. But, at the moment, some abiotic factors are more important for inhibiting of probability of occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e in the reservoir than biotic resistance. Nevertheless, due to the various changes in environmental quality that these aquatic environments may undergo or even due to the presence of the exotic species being better established, this relationship may change in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThe authors thanks Dr. Sidinei Magela Thomaz by suggestions in all manuscript. M.J. Silveira is grateful as National Council for Scientific and Technological Development - CNPq for providing a student schollarship. Funds for this research were provided by the Long-Term Ecological Project Program (LETR), funded by CNPq and by the Itaipu Binacional, PDTA/FPTI-BR. The English was corrected using ChatGPT.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAzza N, Van de Koppel J, Denny P, Kansiime F (2007) Shoreline vegetation distribution in relation to wave exposure and bay characteristics in a tropical great lake, Lake Victoria. J Trop Ecol 23:353\u0026ndash;360\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarko JW, Smart RM (1986) Sediment-related mechanisms of growth limitation in submersed macrophytes. Ecology 65:1328\u0026ndash;1340\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarko JW, Smart RM (1983) Effects of organic matter additions to sediment on the growth of aquatic plants. J Ecol 71:161\u0026ndash;175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarret SCH, Eckert CG, Husband BC (1993) Evolutionary processes in aquatic plant populations. Aquat Bot 44:105\u0026ndash;145\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlokhina O, Virolainen E, Fagerstedt KV (2003) Antioxidants, oxidative damage and oxygen deprivation stress: a review. Ann Botany 91:179\u0026ndash;194\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlumenthal D (2005) Interrelated causes of plant invasion. Science 310:243\u0026ndash;244\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrown RL, Peet RK (2003) Diversity and invasibility of southern Appalachian plant communities. Ecology 84:32\u0026ndash;39\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eByers JE, Noonburg EG (2003) Scale-dependent effects of biotic resistance to biological invasion. Ecology 84:1428\u0026ndash;1433\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eByun C, de Blois S, Brisson J (2014) Interactions between abiotic constraint, propagule pressure, and biotic resistance regulate plant invasion. Oecologia 178:285\u0026ndash;296\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCapers RS, Selsky R, Bugbee GJ, White JC (2007) Aquatic plant community invisibility and scale-dependent patterns in native and invasive species richness. Ecology 88:3135\u0026ndash;3143\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen H, Qian H, Syreas G, Crossland M (2010) Native-exotic species richness relationships across spatial scales and biotic homogenization in wetland plant communities of Illinois. USA Divers Distrib 16:737\u0026ndash;743\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCleland EE, Smith MD, Andelman J, Bowles C, Carney KM, Horner-Devine MC, Drake JM, Emer SM, Gramling JM, VanderMast DB (2004) Invasion in space and time: non-native species richness and relative abundance respond to interannual variation in productivity and diversity. Ecol Lett 7:947\u0026ndash;957\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavies KF, Chesson P, Harrison S, Inouye BD, Melbourne BA, Rice KJ (2005) Spatial heterogeneity explains the scale dependence of the native\u0026ndash;exotic diversity relationship. Ecology 86:1602\u0026ndash;1610\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavis MA, Grime JP, Thompson K (2000) Fluctuating resources in plant communities: a general theory of invasibility. J Ecol 88:528\u0026ndash;534\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavis MA, Thompson K, Grime JP (2001) Charles S. Elton and dissociation of invasion ecology from the rest of ecology. Divers Distrib 7:97\u0026ndash;102\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDibble ED, Thomaz SM, Padial AA (2006) Spatial complexity measured at a multi-scale in three aquatic plant species. J Freshw Ecol 21:239\u0026ndash;247\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDunstan PK, Johnson CR (2004) Invasion rates increase with species richness in marine epibenthic communities by two mechanisms. Oecologia 138:285\u0026ndash;295\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElton CS (1958) The Ecology of Invasions by Animals and Plants. Methuen, London. (Reprinted 2000 by The University of Chicago Press)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFlorencio, Alves DC, Silveira FM, Lansac-T\u0026ocirc;ha MJ, Thomaz FM, S.M (2021) The success of the invasive macrophyte \u003cem\u003eHydrilla verticillata\u003c/em\u003e and its interactions with the native \u003cem\u003eEgeria najas\u003c/em\u003e in response to environmental factors and plant abundance in a subtropical reservoir. Aquat Bot 175:1\u0026ndash;9\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFridley JD, Brown RL, Bruno JF (2004) Null models of exotic invasion and scale dependent patterns of native and exotic species richness. Ecology 85:3215\u0026ndash;3222\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFunk J, Vitousek PM (2007) Resource use efficiency and plant invasion in low resource systems. Nature 446:1079\u0026ndash;1081\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrey EK (2009) Scale-dependent relationships between native richness, resource stability and exotic cover in dock fouling communities of Washington, USA. Divers Distrib 15:1073\u0026ndash;1080\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGurevitch J, Fox GA, Wardle GM, Inderjit, Taub D (2011) Emergent insights from the synthesis of conceptual frameworks for biological invasions. Ecol Lett 14:407\u0026ndash;418\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHakanson L, Jansson M (1983) Principles of lake sedimentology. Springer-\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarwell MC, Havens KE (2003) Experimental studies on the recovery potential of submerged aquatic vegetation after flooding and desiccation in a large subtropical lake. Aquat Bot 77:135\u0026ndash;151\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHavel JE, Lee CE, Zanden MJV (2005) Do reservoirs facilitate invasions into landscapes? BioScience, 55, 518\u0026ndash;525\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHector A, Dobson K, Minns A, Bazeley-White E, Lawton JH (2001) Community diversity and invasion resistance: an experimental test in a grassland ecosystem and a review of comparable studies. Ecol Res 16:819\u0026ndash;831\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHerben T, Mandak B, Bimova K, Munzbergova Z (2004) Invasibility and species richness of a community: A neutral model and a survey of published data. Ecology 85:3223\u0026ndash;3233\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKeeley JE, Lubin D, Fortheringham CJ (2003) Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada. Ecol Appl 13:1355\u0026ndash;1374\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevine JM, D'Antonio CM (1999) Elton revisited: a review of evidence linking diversity and invasibility. Oikos 87:15\u0026ndash;26\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevine JM (2001) Local interactions, dispersal, and native and exotic plant diversity along a California stream. Oikos 5:397\u0026ndash;408\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevine JM (2000) Species diversity and biological invasions: relating local process to community pattern. Science 288:852\u0026ndash;854\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevine JM, Adler PB, Yelenik SG (2004) A meta-analysis of biotic resistance to exotic plant invasions. Ecol Lett 7:975\u0026ndash;989\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLouback-Franco N, Dainez-Filho MS, Souz DC, Thomaz SM (2019) A native species does not prevent the colonization success of an introduced submerged macrophyte, even at low propagule pressure. Hydrobiologia 7:975\u0026ndash;989\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLonsdale WM (1999) Global patterns of plant invasions and the concept of invasibility. Ecology 80:1522\u0026ndash;1536\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMichelan TS, Thomaz SM, Mormul RP, Carvalho P (2010) Effects of an exotic invasive macrophyte (tropical signalgrass) on native plant community composition, species richness and functional diversity. Freshw Biol 55:1315\u0026ndash;1326\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoore JL, Mouquet N, Lawton JH, Loreau M (2001) Coexistence, saturation and invasion resistance in simulated plant assemblages. Oikos 94:303\u0026ndash;314\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoore PA, Reddy KR, Graetz DA (1992) Water quality-nutrient transformations in sediments as influenced by oxygen supply. J Environ Qual 21:387\u0026ndash;393\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNaeem S, Knops JMH, Tilman D, Howe KM, Kennedy T, Gale S (2000) Plant diversity increases resistance to invasions in the absence of covarying extrinsic factors. Oikos 91:97\u0026ndash;108\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePetenon D, Pivello VR (2008) Plantas invasoras: representatividade da pesquisa dos pa\u0026iacute;ses tropicais no contexto mundial. Natureza Conserva\u0026ccedil;\u0026atilde;o 6:66\u0026ndash;77\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePezeshki SR (2001) Wetland plant responses to soil flooding. Environ Exp Bot 46:299\u0026ndash;312\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSax DF (2001) Latitudinal gradients and geographic ranges of exotic species implications for biogeography. J Biogeogr 28:139\u0026ndash;150\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilveira MJ, Thomaz SM (2015) Growth of a native versus an invasive submerged aquatic macrophyte difers in relation to mud and organic matter concentrations in sediment. Aquat Bot 124:5\u0026ndash;91\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilveira MJ (2015) The efect of habitat and sediment type on the occurrence of non-native and native species of aquatic macrophyte in subtropical regions. Bioscience J 31:268\u0026ndash;274\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilveira MJ, Alves DC, Thomaz SM (2018) Efects of the density of the invasive macrophyte \u003cem\u003eHydrilla verticillata\u003c/em\u003e and root competition on growth of one native macrophyte in diferent sediment fertilities. Ecol Res. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11284-018-1602-4\u003c/span\u003e\u003cspan address=\"10.1007/s11284-018-1602-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilveira MJ, Thomaz SM (2019) Interspecifc associations between \u003cem\u003eHydrilla verticillata\u003c/em\u003e and three dominant native genera of submerged macrophytes are taxa dependent. Aquat Sci 81:21\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilveira MJ, Thomaz SM (2022) Efects of interactions between abiotic and biotic factors on growth of a nonnative macrophyte. Biol Invasions. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10530-022-02924-1\u003c/span\u003e\u003cspan address=\"10.1007/s10530-022-02924-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShea K, Chesson P (2002) Community ecology theory as a framework for biological invasions. Trends Ecol Evol 17:170\u0026ndash;176\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSousa WTZ, Thomaz SM, Murphy KJ, Silveira MJ, Mormul RP (2009) Environmental predictors of the occurrence of exotic \u003cem\u003eHydrilla verticillata\u003c/em\u003e (Lf) Royle and native \u003cem\u003eEgeria najas\u003c/em\u003e Planch. in a sub-tropical river foodplain: the Upper River Parana. Hydrobiologia 632:65\u0026ndash;78\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSousa WTZ, Thomaz SM, Murphy KJ (2010) Response of native \u003cem\u003eEgeria najas\u003c/em\u003e Planch. and invasive \u003cem\u003eHydrilla verticillata\u003c/em\u003e (L.f.) Royle to altered hydroecological regime in a subtropical river. Aquat Bot 92:40\u0026ndash;48\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpence DHN (1982) The zonation of plants in freshwater lakes. Adv Ecol Res 12:37\u0026ndash;126\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpencer DF, Ksander GG (1995) Differential effects of the microbial metabolite, acetic acid, on sprouting of aquatic plant propagules. Aquat Bot 52:107\u0026ndash;119\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStohlgren TJ, Flather C, Jarmevich CS, Barnett DT, Kartesz J (2008) Rejoinder to Harrison (2008): The myth of plant species saturation. Ecol Lett 11:324\u0026ndash;326\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuguto K (1973) Introdu\u0026ccedil;\u0026atilde;o \u0026agrave; sedimentologia. S\u0026atilde;o Paulo, Edgard Blucher\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThomaz SM, Carvalho P, Mormul RP, Ferreira FA, Silveira MJ, Michelan TS (2009) Temporal trends and effects of diversity on occurrence of exotic macrophytes in a large reservoir. Acta Oecol 35:614\u0026ndash;620\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThomaz SM, Pagioro TA, Bini LM, Roberto MC (2005) Ocorr\u0026ecirc;ncia e distribui\u0026ccedil;\u0026atilde;o espacial de macr\u0026oacute;fitas aqu\u0026aacute;ticas em reservat\u0026oacute;rios. In: Rodrigues, L., Thomaz, S.M., Agostinho, A.A., Gomes, L.C. (Eds.), Biocenoses em reservat\u0026oacute;rios: padr\u0026otilde;es espaciais e temporais. S\u0026atilde;o Carlos, RiMaEditora, 39\u0026ndash;46\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThomaz SM, Kovalenko KE, Havel JE, Kats LB (2015) Aquatic invasive species: general trends in the literature and introduction to the special issue. Hydrobiologia 746:1\u0026ndash;12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThomaz SM, Agostinho AA, Gomes LC, Silveira MJ, Rejam\u0026aacute;nek M, Aslan CE, Chow E (2012) Using space-for-time substitution and time sequence approaches in invasion ecology. Freshw Biol 746:1\u0026ndash;12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTilman D (1997) Community invasibility, recruitment limitation, and grassland biodiversity. Ecology 78:81\u0026ndash;92\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTilman D (1993) Species richness of experimental productivity gradients-how important is colonization limitation. Ecology 74:2179\u0026ndash;2191\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVan den Berg MS, Joosse W, Coops H (2003) A statistical model predicting the occurrence and dynamics of submerged macrophytes in shallow lakes in the Netherlands. Hydrobiologia 506:611\u0026ndash;623\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVitousek PM, D\u0026rsquo;Antonio CM, Loope LL, Rejmanek M, Westbrooks R (1997) Introduced species: A significant component of human-caused global change. New Z J Ecol 21:1\u0026ndash;16\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWentworth CK (1922) A scale of grade and class terms for clastic sediments. J Geol 30:377\u0026ndash;392\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"biological-invasions","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"binv","sideBox":"Learn more about [Biological Invasions](https://www.springer.com/journal/10530)","snPcode":"10530","submissionUrl":"https://submission.nature.com/new-submission/10530/3","title":"Biological Invasions","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"macrophytes, introduced species, invasibility, subtropical reservoir","lastPublishedDoi":"10.21203/rs.3.rs-4248767/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4248767/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe success of exotic species in different environments is affected by biotic and abiotic filters, whose effects depend on the spatial scale employed. This study tested the hypotheses that (i) native species richness and abiotic conditions explain the sucess of exotic species \u003cem\u003eHydrilla verticillata\u003c/em\u003e and (ii) that biological resistance to invasion provided by diversity varies at different scales. The samples were collected at 176 georeferenced points in Rosana Reservoir. In each sampling site, measurements of \u003cem\u003efetch\u003c/em\u003e, distance between shores, organic matter concentration and grain size at sediment, depth, Secchi disk depth, conductivity, pH, and species richness of submerged macrophytes in three different scales (small, medium and large) were taken. Our results demonstrated that the occurrence of \u003cem\u003eH. verticillata\u003c/em\u003e was positively correlated with increase in native species richness at three scales, with no difference between scales, as well as between \u003cem\u003efetch\u003c/em\u003e and distance between reservoir shores. However, it responded negatively to the concentration of organic matter in the sediment and depth. The results allowed the following conclusions: (i) biotic resistance did not reduce the success of exotic invasive\u003cem\u003e H. verticillata\u003c/em\u003e, (ii) contrary to expectations, the competition mechanism did not influence the occurrence of this species at a small scale, (iii) at the moment, abiotic factors may be more important than biotic resistance in determining the success of this species at reservoir, but this relationship may change in the future and (iv) possibly, the dominant general pattern in invasion ecology at multiple spatial scales may be one of \"biotic acceptance\" in certain environments.\u003c/p\u003e","manuscriptTitle":"Biotic resistance at different spatial scales did not inhibit the colonization success of an exotic submerged aquatic plant.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-25 08:27:56","doi":"10.21203/rs.3.rs-4248767/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2024-05-23T15:16:56+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-04-22T09:47:32+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Biological Invasions","date":"2024-04-13T19:20:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-04-13T13:12:06+00:00","index":"","fulltext":""},{"type":"submitted","content":"Biological Invasions","date":"2024-04-10T13:46:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"biological-invasions","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"binv","sideBox":"Learn more about [Biological Invasions](https://www.springer.com/journal/10530)","snPcode":"10530","submissionUrl":"https://submission.nature.com/new-submission/10530/3","title":"Biological Invasions","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"89ab08fe-d41f-435a-803e-e009e09f0915","owner":[],"postedDate":"April 25th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-09T16:15:57+00:00","versionOfRecord":{"articleIdentity":"rs-4248767","link":"https://doi.org/10.1007/s10530-026-03752-3","journal":{"identity":"biological-invasions","isVorOnly":false,"title":"Biological Invasions"},"publishedOn":"2026-02-04 15:57:53","publishedOnDateReadable":"February 4th, 2026"},"versionCreatedAt":"2024-04-25 08:27:56","video":"","vorDoi":"10.1007/s10530-026-03752-3","vorDoiUrl":"https://doi.org/10.1007/s10530-026-03752-3","workflowStages":[]},"version":"v1","identity":"rs-4248767","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4248767","identity":"rs-4248767","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}