Null models for explain a community dynamics coastal North Patagonian in ephemeral pools (Puaucho, 38°S, Araucania region, Chile).

Null models for explain a community dynamics coastal North Patagonian in ephemeral pools (Puaucho, 38°S, Araucania region, Chile). | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 23 February 2026 V1 Latest version Share on Null models for explain a community dynamics coastal North Patagonian in ephemeral pools (Puaucho, 38°S, Araucania region, Chile). Authors : Patricio De los Rios 0000-0001-5056-7003 [email protected] , Eriko Carreño , Jorge Farías 0009-0004-8938-5580 , Carlos Esse , Francisco Correa-Araneda , Affef Baaloudj , Sara Chaib , Meriem Gharbi , Hadeer Amer , and Mauricio Urbina Authors Info & Affiliations https://doi.org/10.22541/au.177186692.22559291/v1 96 views 42 downloads Contents Abstract Acknowledgements Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract The ephemeral pools are ecosystems that are present during specific seasons such as rainy or snow melting season, and these communities within these pools are characterized by dormancy eggs production that hatch when the environmental conditions are favourable, Additionally, these communities are characterized by high species diversity. The aim of the present study was to provide a first descriptions of community species structure in a group of ephemeral pools in North Patagonian coast (38°S), based on null models of presence-absence species. The studied site was the zone called “Puaucho dunes,” that is characterized by presence of ephemeral pools that are present during rainy season in southern autumn-winter (May-September). The results of null models’ analysis revealed that species associations were random for all sampled periods, these results would be explained because there are many repeated species for all included sites. It is a first description of community cycle during rainy season, and it revealed interesting patterns for understand the species dynamics of studied sites, which included widespread species such as calanoid copepod Boeckella gracilis, as well as endemic fairy shrimp Branchinecta rocaensis. The present study agrees with fragmentary studies for other ephemeral pools mainly in central and southern Patagonia. Null models for explain a community dynamics coastal North Patagonian in ephemeral pools (Puaucho, 38°S, Araucania region, Chile). [Redacted for peer-review] Abstract The ephemeral pools are ecosystems that are present during specific seasons such as rainy or snow melting season, and these communities within these pools are characterized by dormancy eggs production that hatch when the environmental conditions are favourable, Additionally, these communities are characterized by high species diversity. The aim of the present study was to provide a first descriptions of community species structure in a group of ephemeral pools in North Patagonian coast (38°S), based on null models of presence-absence species. The studied site was the zone called “Puaucho dunes,” that is characterized by presence of ephemeral pools that are present during rainy season in southern autumn-winter (May-September). The results of null models’ analysis revealed that species associations were random for all sampled periods, these results would be explained because there are many repeated species for all included sites. It is a first description of community cycle during rainy season, and it revealed interesting patterns for understand the species dynamics of studied sites, which included widespread species such as calanoid copepod Boeckella gracilis , as well as endemic fairy shrimp Branchinecta rocaensis . The present study agrees with fragmentary studies for other ephemeral pools mainly in central and southern Patagonia. Keywords: ephemeral pools, zooplankton, amphipods, diapause, null models. Introduction The ephemeral pools are present during rainy season or snow melting, and these are characterized by the presence of high number of species (Pinceel et al., 2016, 2017; De los Ríos-Escalante et al., 2021). Also, these types t of sites are characterized by extinction-colonization process because these species have reproduction of diapause eggs, that hatch when the environmental conditions are favourable (Saiz-Escudero et al., 2023; Parry et al., 2023). These process when there are many close pool systems involves the procedures of metapopulations and metacommunities where are include also individuals exchange due to migratory process, which involves a complex scenario of colonization and extinction process of involved species (Diniz et al., 2023). Also, the dispersion process is enhanced by natural events such as wind or aquatic migratory birds (Parry et al., 2023), as well as human intervention (Cukier et al., 2023). The presence of ephemeral pools in Chile has scarce studies that are reported for arid and semi-arid coast plains in the Central and Austral zone of Chile (De los Ríos-Escalante & Woelfl, 2023). Some of these sites have endemic species mainly the called large Branchiopods such as Anostracans ( Branchinecta genus) (Rogers et a., 2021), Diplostraca ( Lynceus huentelauquensis ) and Laevicaudata ( Leptestheria venezuelica ), that are characterized by the presence of endemic species (Sigvardt et al., 2019; Rogers et al., 2021). One of the most studied z zones with ephemeral pools is the called Patagonia which involves the Southern and Austral zones according to the descriptions of De los Rios-Escalante & Woelfl (2023). The main studied zone is located in the Austral zone (De los Ríos et al., 2017), where there are many pools originated by snow smelting during early spring (September-October), in these pools it is possible found large bodies of zooplankton species such as Daphnia dadayana, Boeckella poppei, Parabroteas sarsi , and Branchinecta genus (De los Ríos-Escalante & Woelfl, 2023). Also, these species reported are characterized by high pigmentation as protection against natural ultraviolet radiation exposure (Balseiro et al., 2023; De los Ríos-Escalante & Woelfl, 2023). Another zone with ephemeral pools that has scarce studies is the coast of the Araucania Region (38°S), which is in a dune zone that has a group of shallow temporal pools originated during the rainy season (De los Ríos-Escalante et al., 2021). The aim of the present study is to do a first description of the crustacean zooplanktonic community dynamics during the rainy season of ephemeral pools in Puaucho dunes, on the coast of Northern Chilean Patagonia. Material and Methods Study site : the studied site is the called zone “dunas de Puaucho” (Fig. 1), which is characterized by the presence of dunes on the coast of Araucania region, Northern Chilean Patagonia with vascular macrophytes that involve species such as Rumex cuneifolius Campd., Juncus balticus Willd. ssp. mexicanus , Scirpus olneyi A. Gray, Cotula coronopifolia L., Anthoxanthum utriculatum (Ruiz et Pav.) Schouten et Veldkamp, Distichlisspicata (L.) Greene, Ammophila arenaria (L.) Linky Ambrosia chamissonis (Less,) Greene (De los Ríos-Escalante et al., 2015). The studied site has approximately 10-20 shallow ephemeral pools (< 25 m 2 , < 1 m depth), that are generated during the rainy season (May-September), and the rest of the year the site is dry (De los Ríos-Escalante et al., 2021). The study area belongs to one of eight dunary camps of coastal zone of Araucania region that are in a fluviomarine holoceanic plain close fluvial wetlands and estuaries that generate a complex and dynamics oceanic influence, the climate is characterized by a rainy and template climate with oceanic influence (Peña-Cortes et al., 2008). The climate a dry season between December and February with scarce precipitation (40-60 mm monthy), whereas during rainy season (June-August) the precipitations are between 150-200 mm monthy with temperatures between 0-10°C (Sarricolea et al., 2017). During the sampled periods of 08 th and 28 th June, were considered six pools located in southern zone of studied sites these sites were enumerated from 1 to 6, because only these sites were present, whereas for remaining sampled periods, were included other sites located north of studied zones that were present due the rainy season, these sites were numerated between 7 to 15 (Table 1). Samples analysis: Crustacean samples taken from zooplankton was collected by filtering a volume of 10 L with a screen of 100 μm mesh size, that which were fully screened to avoid underestimating species richness and abundance (De los Ríos-Escalante, et al., 2021). The specimens collected were fixed in absolute ethanol (70 %), identified according to specialized literature (Araya & Zúñiga, 1985; Reid, 1985; Bayly, 1992; González, 2003), and quantified in the laboratory. Additional, temperature, conductivity, physicochemical variables from water were recorded throw multiparametric sampler (YSI EC30A). Data analysis: To characterize the structure of community, in first place, community index of richness, relative abundance, dominance, from biological matrix were calculated. It done ANOVA between stations for analyse the differences between communitary and physico-chemical índices, also for characterize the physico-chemical temporal dynamics of water were done ANOVA between each variable between stations. For null model analysis, a species presence/absence matrix was constructed, with the species in rows and the sites in columns, we calculated a Checkerboard score (“C-score”), which is a quantitative index of occurrence that measures the extent to which species co-occur less frequently than expected by chance (Gotelli, 2000). A community is structured by competition when the C-score is significantly larger than expected by chance (Gotelli, 2000; Tondoh, 2006; Tiho and Josens, 2007). We compared co-occurrence patterns with null expectations via simulation. Gotelli and Ellison (2013) suggested the statistical null models (1) Fixed-Fixed: in this model, the row and column sums of the matrix are preserved. Thus, each random community contains the same number of species as the original community (fixed column), and each species occurs with the same frequency as in the original community (fixed row). (2) Fixed-Equiprobable: in this algorithm only the row sums are fixed, and the columns are treated as equiprobable. This null model considers all the samples (column) as equally available for all species. (3) Fixed-Proportional: in this algorithm the totals of species occurrence are maintained as in the original community, and the probability that a species occurs at a site (column) is proportional to the column total for that sample. For evaluate the temporal distribution patterns of crustacean communities, it was done a non parametric multidimensional scaling analysis (NMDS). For this purpose it utilized a Bray-Curtis distance matrix on the abundance previously transformed. Also, it was done an ANOSIM analysis for analyze the similitudes and differences between crustacean communities using the season (spring-winter) as factor. Finally for identify the taxa contribution for temporal patterns, it was done a percentual similitude analysis (SIMPER). To analyse the relation between physicochemical and biological variables, the redundancy analyses (RDA) were performed. The null model and multivariate analyses were performed using the R software (R Development Core Team, 2023) and the package EcosimR (Gotelli and Ellison, 2013; Carvajal-Quintero et al., 2015). Results Communitary analysis It was recorded marked differences between all diversity indices between Spring and Winter seasons. The crustacean abundance was 10 times more than spring in comparison to winter (p = 0.003), similar to equity indices that was slightly upper than spring (p = 0.029). About richness it observed a significantly upper meaning in spring (4.6 species) in comparison to winter (3.3 species)(p = 0.045)(Figure 2). During spring the cladocerans ( Ceriodaphnia dubia , Chydorus sphaericus , Leydigia ), with calanoid B . gracilis , cyclopoids Mesocyclops sp., ostracoda, and Hyalella costera were the most abundant (Table 2). The dominant taxa in winter were the calanoid Boeckella gracilis which can coexist with unidentified Ostracoda (Table 2). The Shannon index that integrates richness and equality, was higher in spring (0.85) in comparison to winter (0.5)(p = 0.002). Physicochemical variables The physicochemical variables recorded significant differences between spring and winter seasons. The chlorophyll reported upper values in spring in comparison to winter (p = 0.02). The conductivity and TDS have upper values in spring in comparison to winter (p < 0.01). Finally, the temperature showed markedly significant differences between spring and winter (p = 0.0005) with a mean temperature of 14°C during spring and 12°C in winter (Fig. 3). Null models The results of the null model analysis revealed the random presence of species associations for each season sample, and for total samples, for all simulation models, this means the absence of regulator patterns for species associations that which can be probably to the presence of many repeated species for all sites (Table 3). Multivariate analysis The NMDS showed the formation of two groups from a zooplanktonic community in spring and season. In according with ANOSIM both groups are significantly different (R = 0,265; p = 0,008). During spring it observed an upper relation with species sich as C. dubia, B. gracilis, Ostracoda and Cop. Calan, whereas in winter the dominant in abundance and occurrence taxa were Cop. Cyclop, Nauplius, Leydigia and H. costera (Fig. 4). The SIMPER analysis denoted that dissimilitude general value between winter and spring was 0.0887, that indicates that difference relatively lower in comparison between both seasons, although determinate taxa contribute more to this difference. The calanoids copepods (Cop. Calan), and Nauplius were the main taxa that explain differences between seasons (P < 0.001) that suggests that their season differences are not random. These results showed also that Cop. Calan and C. dubia increased in spring, whereas Nauplius and Cop. Cyclop., are frequent in winter (Table 4). The redundance analysis explained the 91 % variance in composition and structure of zooplanktonic community in comparison to the environmental variables. The temperature showed an association with zooplankton during spring season, whereas the water conductivity and total dissolved solids were determinant during winter season. Finally, the chlorophyll showed a lower contribution to the total variability explained (Fig. 5). Discussion The obtained results revealed the presence of an increase of species number in the last three sampled periods, which would be like reports for other similar temporary pools in central and northern Patagonia, where the sampled periods would include periods 30 days after snow smelt (De los Ríos et al., 2017). Although the sites have not fish presence, the zooplankton composition was characterized by low bodies zooplankton species, because it has not large bodies species such as Daphnia dadayana, Parabroteas sarsi or Boeckella poppei that can be reported for fishless shallow ponds in Northern Argentinean Patagonia (Balseiro et al., 2023). The species reported were like first descriptions for this site (De los Ríos-Escalante et al., 2015, 2021), but these reports were based on observations done in early spring (September-October), but don´t include variations during rainy season. The exposed results revealed the marked seasonality, that in the present study happens during and after raniy season, in this scenario the presence of water inputs would enhance the hatching of resting eggs, and when water inputs increases, the conductivity decreases, that can sustain abundant zooplankton species, and when the rainy season decreases, the evaporation increases with consequent conductivity increasing that would not sustain abundant zooplankton species (Badosa et al., 2017). Within the species reported the presence of Branchinecta rocaensis has been reported previously (De los Ríos-Escalante et al., 2021), the present result revealed the presence of this species under low chlorophyll concentration and mineral contents, which coexist with B. gracilis and ostracoda , that would be associated to oligotrophic environments. These results would be like observations for Branchinecta habitats at central and southern Patagonia (De los Ríos et al., 2017; De los Ríos-Escalante & Woelfl, 2023). The presence of Branchinecta rocaensis remarks the presence of this species that is markedly endemic of southern Argentina and Chile (Rogers et al., 2021). The presence of these many repeated species for studied pools in the studied site would explain the results of all simulations of co-occurrence null models, these results would be like the first descriptions for this studied site (De los Ríos-Escalante et al., 2015, 2021), as well as central and southern Patagonia (De los Rios et al 2017). The exposed results revealed the existence of complex system because it would have a combined effects of species in diapause and natural dispersion by water birds and winds, such as those observed for central Chilean coastal ephemeral pools (Olmo et al., 2022). In this scenario, the studied site would be interesting on multiple viewpoints such as population genetics, mathematical models, and potential bioindicator organisms (Badosa et al., 2017; De los Ríos-Escalante & Woelfl, 2023). Acknowledgements [Redacted for peer-review] Author contributions Author contributions [Redacted for peer-review] Declaration of interests X The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Data availability statement : All data are included in tables of the manuscript. References Araya, J.M., Zúñiga, L.R.,1985. Manual taxonómico del zooplancton lacustre de Chile. Bol. Limnol., Universidad Austral de Chile, 8, 1-110. Badosa, A., Frisch, D., Green, A. Rico, C., Gomez, A., 2017. 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Subphyllum: Crustacea Superclass: Allotriocarida Class: Branchiopoda Subclass: Sarsostraca Order: Anostraca Suborder: Anostracina Family: Branchinectidae Genus: Branchinecta Verrill, 1869 (sensu Rogers & Coronel, 2011) Branchinecta rocaensis Cohen, 1982. Subclass: Phyllopoda Superorder: Diplostraca Order: Anomopoda Family: Daphnidae Genus: Ceriodaphnia , Dana, 1853 Ceriodaphnia dubia Richard, 1894 Family: Chydoridae Genus: Chydorus Leach, 1816 Chydorus sphaericus (O.F. Müller, 1776) Genus: Leydigia Kurz, 1875 Leydigia leydigi (Schödler, 1863) Superclass: Multicrustacea Class: Copepoda Infraclass: Neocopepoda Superorder: Gymnoplea Order: Calanoida Family: Centropagidae Genus: Boeckella Guerne & Richard, 1889 Superoder: Podoplea Order: Cyclopoida Suborder: Cyclopida Family: Cyclopidae Genus: Mesocyclops Sars, G.O., 1914. Class: Malacosrtraca Subclass: Eumalacostraca Superoderer: Peracarida Order: Amphipoda Suborder: Senticaudata Infraorder: Talitrida Parvorder: Talitridira Superfamily: Hyaloidea Family: Hyalellidae Genus: Hyalella S.I. Smith, 1874 Hyalella costera Gonzalez & Watling, 2001 Superclass: Oligostraca Class: Ostracoda Table 2. Abundance (ind/L) of species reported for studied sites during the sampling period Site Date Season Site B. rocaensis C. dubia Ch. sphaericus L. leydigi B. gracilis Cal. copepodites Mesocyclops Nauplius H. costera Ostracoda indet. Total ind. Total sp. 1 08/06/2019 Winter Pool 1 0.00 0.00 0.00 0.00 0.30 1.40 0.00 0.10 0.00 0.00 1.90 1 2 08/06/2019 Winter Pool 2 0.00 0.00 0.00 0.00 0.00 0.40 0.00 0.00 0.10 0.00 0.50 1 3 08/06/2019 Winter Pool 3 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.00 0.01 0.00 0.21 1 4 08/06/2019 Winter Pool 4 0.00 0.00 0.00 0.00 0.00 0.10 0.00 0.00 0.00 0.10 0.20 2 5 08/06/2019 Winter Pool 5 0.00 0.00 0.00 0.00 0.00 0.10 0.00 0.00 0.00 0.00 0.10 1 6 08/06/2019 Winter Pool 6 0.00 0.00 0.00 0.00 0.00 0.10 0.00 0.00 0.00 0.10 0.20 1 7 28/06/2019 Winter Pool 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.00 3.00 1 8 28/06/2019 Winter Pool 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 1.00 1 9 28/06/2019 Winter Pool 3 0.00 0.00 0.00 0.00 1.25 0.00 0.00 1.00 0.00 1.25 3.50 2 10 28/06/2019 Winter Pool 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 1.00 1 11 28/06/2019 Winter Pool 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 1.00 1 12 28/06/2019 Winter Pool 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 1.00 2.00 1 13 31/07/2019 Winter Pool 1 0.00 0.00 0.00 0.60 0.01 0.60 0.00 0.40 0.00 6.40 8.01 3 14 31/07/2019 Winter Pool 2 0.00 3.00 0.00 0.20 2.60 6.60 0.00 3.00 0.00 0.01 15.42 5 15 31/07/2019 Winter Pool 3 0.00 0.00 0.00 0.40 0.60 0.80 0.00 2.80 0.00 0.20 4.80 3 16 31/07/2019 Winter Pool 4 0.00 0.00 0.00 0.00 0.80 0.40 0.00 1.00 0.01 8.80 11.41 4 17 31/07/2019 Winter Pool 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 18.40 19.20 2 18 31/07/2019 Winter Pool 6 0.00 0.00 0.00 0.00 0.01 0.01 0.00 0.00 0.01 34.80 34.84 4 19 31/07/2019 Winter Pool 7 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 22.80 23.02 4 20 31/07/2019 Winter Pool 8 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 41.60 41.81 3 21 31/07/2019 Winter Pool 9 0.00 0.00 0.00 0.00 0.60 0.20 0.00 0.00 0.00 50.00 50.81 3 22 31/07/2019 Winter Pool 10 0.00 0.00 0.00 0.00 0.40 0.01 0.00 0.00 0.00 1.60 2.01 2 23 31/07/2019 Winter Pool 11 0.00 0.00 0.00 0.00 0.40 0.00 0.00 0.00 0.01 9.60 10.01 3 24 31/07/2019 Winter Pool 12 0.00 0.00 0.00 0.00 0.40 0.00 0.00 0.20 0.01 2.20 2.81 3 25 31/07/2019 Winter Pool 13 0.00 0.00 0.01 0.00 1.40 7.60 0.00 0.40 3.20 0.40 13.01 4 26 31/07/2019 Winter Pool 14 0.40 0.00 0.00 0.00 0.20 0.00 0.00 0.00 0.00 0.40 1.00 3 27 31/07/2019 Winter Pool 15 0.00 0.00 0.00 0.00 0.01 0.01 0.00 0.00 0.20 0.01 0.23 3 28 06/09/2019 Spring Pool 1 0.00 0.20 0.00 0.00 0.40 0.00 0.00 0.00 0.80 2.80 4.20 4 29 06/09/2019 Spring Pool 2 0.00 1.00 0.00 0.00 4.00 18.40 0.00 0.00 0.00 0.01 23.41 3 30 06/09/2019 Spring Pool 3 0.00 2.40 0.00 0.00 2.20 5.60 0.00 0.00 0.00 0.60 10.80 3 31 06/09/2019 Spring Pool 4 0.00 2.80 0.00 0.00 2.00 18.00 0.00 0.00 0.00 2.20 25.00 3 32 06/09/2019 Spring Pool 5 0.00 0.40 0.00 0.00 1.40 16.00 0.20 0.00 0.00 2.40 20.40 4 33 06/09/2019 Spring Pool 6 0.00 8.40 0.00 0.00 25.20 112.00 0.00 0.00 0.00 14.00 159.60 3 34 06/09/2019 Spring Pool 7 0.00 0.60 0.00 0.00 0.40 7.80 0.00 0.00 0.00 2.00 10.80 3 35 06/09/2019 Spring Pool 8 0.00 0.80 0.00 0.00 1.20 1.60 0.20 0.00 0.01 16.80 20.61 5 36 06/09/2019 Spring Pool 9 0.00 0.40 0.00 0.00 0.00 3.60 0.00 0.00 0.20 8.80 13.00 4 37 06/09/2019 Spring Pool 10 0.00 0.01 0.00 0.00 0.01 0.00 0.01 0.00 0.00 4.80 4.83 4 38 06/09/2019 Spring Pool 11 0.00 0.20 0.00 0.00 0.40 0.00 0.00 0.00 0.20 6.80 7.60 4 39 06/09/2019 Spring Pool 12 0.00 0.80 0.00 0.00 0.80 10.00 0.00 0.00 0.00 3.00 14.60 4 40 06/09/2019 Spring Pool 13 0.00 1.00 0.00 0.00 0.80 6.00 0.00 0.00 0.00 3.60 11.40 3 41 06/09/2019 Spring Pool 14 0.00 0.80 0.00 0.00 0.80 8.00 0.00 0.00 0.00 6.00 15.60 3 42 06/09/2019 Spring Pool 15 0.00 6.40 0.00 0.00 0.20 9.20 0.00 0.00 0.00 0.80 16.60 3 43 27/09/2019 Spring Pool 1 0.00 35.40 0.00 0.00 306.80 141.60 0.00 0.00 0.00 0.01 483.81 3 44 27/09/2019 Spring Pool 2 0.00 14.00 0.00 0.00 0.00 3.80 0.00 0.00 0.01 0.40 18.21 4 45 27/09/2019 Spring Pool 3 0.00 19.60 0.00 0.00 19.60 98.00 0.00 0.00 0.00 0.01 137.21 3 46 27/09/2019 Spring Pool 4 0.00 3.60 0.00 0.00 3.00 7.00 0.00 0.00 0.00 0.01 13.61 3 47 27/09/2019 Spring Pool 5 0.00 1.00 0.00 0.00 0.01 1.60 0.00 0.40 0.01 0.80 3.83 5 48 27/09/2019 Spring Pool 6 0.00 1.20 0.00 0.00 0.40 7.80 0.40 0.00 0.20 0.40 10.40 5 49 27/09/2019 Spring Pool 7 0.00 2.40 0.00 0.00 1.20 0.01 0.00 0.00 1.80 6.20 11.61 4 50 27/09/2019 Spring Pool 8 0.00 7.00 0.00 0.00 14.00 210.00 0.00 0.00 0.00 28.00 259.00 4 51 27/09/2019 Spring Pool 9 0.00 33.60 0.00 0.00 22.40 112.00 0.00 0.00 0.01 56.00 224.01 4 52 27/09/2019 Spring Pool 10 0.00 28.80 0.00 0.00 9.60 230.40 0.00 0.00 0.01 0.01 268.82 4 53 27/09/2019 Spring Pool 11 0.00 322.40 0.00 0.00 12.40 136.40 24.80 0.00 0.01 24.80 520.81 5 54 27/09/2019 Spring Pool 12 0.00 243.20 0.00 0.00 0.01 30.40 0.01 0.00 0.01 30.40 304.03 5 55 27/09/2019 Spring Pool 13 0.00 33.60 0.00 0.00 0.01 16.80 0.00 0.00 0.01 134.40 184.82 4 56 27/09/2019 Spring Pool 14 0.00 40.80 0.00 0.00 13.60 258.40 0.01 0.00 0.01 40.80 353.62 5 Table 3. Results of null model of species co-occurrence for sampled periods for studied sites. Date Observed index Mean index Standard Effect Size Variance P 08/06/2019 Fixed-Fixed 1.333 1.333 NA 0.000 0.999 Fixed-Proportional 1.333 1.437 -0.116 0.800 0.555 Fixed-Equiprobable 0.792 1.333 1.611 0.112 0.122 28/06/2019 Fixed-Fixed 2.000 2.000 NA 0.000 0.999 Fixed-Proportional 0.976 2.000 1.023 1.000 0.488 Fixed-Equiprobable 1.344 2.000 1.344 0.882 0.672 31/07/2019 Fixed-Fixed 3.571 3.434 -0.460 0.028 0.714 Fixed-Proportional 3.571 6.260 -1.612 3.241 0.948 Fixed-Equiprobable 3.371 2.832 0.839 0.390 0.222 06/09/2019 Fixed-Fixed 0.600 0.600 NA 0.000 0.999 Fixed-Proportional 0.600 4.867 -1.956 4.761 0.988 Fixed-Equiprobable 0.600 0.756 -0.421 0.137 0.840 27/09/2019 Fixed-Fixed 0.000 0.000 0.000 0.000 0.999 Fixed-Proportional 0.000 3.015 -2.381 1.603 0.999 Fixed-Equiprobable 0.000 0.852 -1.230 0.480 0.999 Total Fixed-Fixed 29.429 29.287 0.161 0.775 0.440 Fixed-Proportional 29.429 64.326 -2.726 163.860 0.999 Fixed-Equiprobable 20.429 37.726 -1.577 21.408 0.947 Taxa Average Contribution Spring Average abundance Winter Average abundance p -value s.l Cop.Calan (Calanoida Copepods 0.0155 1.093 0.755 0.001 *** Ostracoda 0.0149 0.625 n.s. Nauplius 0.0133 0.807 1.080 0.001 *** C.dubia (Ceriodaphnia dubia) 0.0084 1.044 0.854 0.007 ** Cop.Ciclop (Cyclopoid Copepods) 0.0083 0.866 1.043 0.012 * Table 4. Simper analysis results for the taxa contribution to the differences between seasons. Figure captions: Fig. 1. General location of coastal pools study sites. Fig. 2. Community indices (mean ± standard deviation) and variance analysis of zooplanktonic biologic matrix between spring and wintry seasons. Fig. 3. Physicochemical variables (mean ± standard deviation) and variance analysis between spring and wintry seasons. Fig 4. Non-metric multidimensional scaling analysis (NMDS) and ANOSIM variance analysis obtained from zooplankton biological matrix, using seasons as factors. Fig. 5. Triplot of redundance analysis of biological and physicochemical data matrix. Fig. 1 Fig. 2. Fig. 3 Fig. 4 Fig. 5 Information & Authors Information Version history V1 Version 1 23 February 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords community ecology freshwater invertebrate natural history Authors Affiliations Patricio De los Rios 0000-0001-5056-7003 [email protected] Universidad Católica de Temuco View all articles by this author Eriko Carreño Universidad Catolica de Temuco View all articles by this author Jorge Farías 0009-0004-8938-5580 Universidad de La Frontera View all articles by this author Carlos Esse Universidad Autonoma de Chile View all articles by this author Francisco Correa-Araneda Universidad Autonoma de Chile View all articles by this author Affef Baaloudj Université 8 Mai 1945 Guelma View all articles by this author Sara Chaib Université 8 Mai 1945 Guelma View all articles by this author Meriem Gharbi Université 8 Mai 1945 Guelma View all articles by this author Hadeer Amer Kafrelsheikh University View all articles by this author Mauricio Urbina Universidad de Concepcion View all articles by this author Metrics & Citations Metrics Article Usage 96 views 42 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Patricio De los Rios, Eriko Carreño, Jorge Farías, et al. Null models for explain a community dynamics coastal North Patagonian in ephemeral pools (Puaucho, 38°S, Araucania region, Chile).. Authorea . 23 February 2026. DOI: https://doi.org/10.22541/au.177186692.22559291/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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