Floating Island of Trees and Myths: The Rare 2022 Nzera Bay Event in Lake Victoria

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Mfilinge, Mwita J. Chacha, Baraka Sekadende This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7113959/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Floating islands are not unique to Lake Victoria. Their recurrence reflects underlying hydrological and ecological processes linked to seasonal variability in lake water levels, which can facilitate their detachment and mobility, rather than superstition or unexplained forces. In April 2022, a rare and unusual large floating island appeared in Nzera Bay, Lake Victoria, near Kahunda village, captivating the Tanzanian public and prompting scientific investigation. Unlike typical papyrus mats, this island supported large trees, marshes, emergent macrophytes, and diverse fauna, including birds and reptiles. A multidisciplinary team was formed to investigate the island’s origin, composition, movement, and cultural significance. Field surveys and GIS-based satellite tracking revealed that the island detached from wetland vegetation near Kasheka village between 15–20 April 2022, likely due to a combination of persistent strong winds, waves and elevated water levels following prolonged drought and heavy rains. Morphometric analysis estimated the island’s area at 7.1 hectares, with an average soil thickness of 2 meters. Vegetation surveys identified 27 plant species, including three tree species and a ground orchid of conservation concern ( Eulophiaangolensis ). Soil samples showed high organic content, suggesting buoyancy-enhancing decomposition processes. Ethnographic interviews highlighted traditional beliefs, medicinal uses, and ritual practices linked to floating islands. Although floating islands contribute ecological benefits, their movement poses threats to navigation, fisheries, and cage farming in their path. This study provides scientific insights and offers management recommendations, including harvesting for organic compost and spatial monitoring, to mitigate potential impacts in Lake Victoria. Floating Island Lake Victoria Nzera Bay Wetlands Kahunda Village Figures Figure 1 Figure 2 Introduction Lake Victoria, the largest tropical lake in the world, is fringed by extensive wetlands that play a vital ecological role in biodiversity support and ecosystem functioning. These wetlands, comprised mainly of papyrus swamps, floating mats, and rooted marshes, serve as critical habitats for aquatic plants, fish, birds, reptiles, and invertebrates (Denny 1993 ; Howard-Williams and Gaudet 1985 ; Kansiime et al. 2007 ). The lake’s wetland zones are categorized into two primary types: rooted systems anchored in terrestrial margins and floating systems formed by dense vegetative mats (Kansiime and Nalubega 1999 ; White 1983 ). Floating mats, such as those dominated by Cyperus papyrus and Miscanthidium spp., often extend over the water column and are held afloat by interlaced rhizome networks and trapped organic matter (Redhead-Milne 1952 ; Kassenga 1997 ). Globally, floating islands have been documented across diverse freshwater systems. For instance, Lake Titicaca in Peru is home to over 70 artificial floating islands constructed by the Uros people using buoyant reeds for habitation and tourism (Flores and Rendón 2011 ). Additionally, floating treatment wetlands—engineered systems mimicking natural islands—have been used since the 1980s to enhance freshwater restoration and water quality in lakes and ponds (Headley and Tanner 2012 ). While floating islands are a known phenomenon in Lake Victoria, their occurrence is usually limited to small-scale papyrus rafts, locally known as "Lutende." However, in April 2022, an exceptionally large and forested floating island unexpectedly appeared in Nzera Bay near Kahunda village, Tanzania. This unusual event, involving a 7.1-hectare island with trees, emergent macrophytes, and animal life, sparked public attention and scientific curiosity. Unlike typical papyrus patches, this island supported entire ecological communities, including Syzygiumcordatum , Ficus spp., and reptiles like monitor lizards. The formation and dislodgment of such large floating islands remain poorly understood. Past studies (Azza 2006 ; Gippel 2020 ; Ondari et al. 2023 ) suggest that combinations of drought, fluctuating water levels, sediment decomposition, and extreme wind events may weaken wetland root systems, leading to detachment. However, empirical data on such mechanisms in the Lake Victoria basin are scarce. Floating islands have also been implicated in obstructing ferry routes, damaging cage farming operations, and affecting fishery activities (Kansiime et al. 2007 ; Gippel 2020 ). Culturally, floating islands hold diverse meanings among communities living around Lake Victoria. Local beliefs associate them with supernatural forces, medicinal uses, and sacred rituals (Timberlake et al. 1993 ). Yet, these socio-cultural dimensions remain undocumented in scientific literature. In response to this unprecedented event, a multidisciplinary research team was tasked to investigate the floating island. The key objectives of this study were to: examine the ecological and climatic factors contributing to the detachment of the island, map and track its movement using GIS and remote sensing tools, identify plant species and vegetation types across the island, analyze the soil composition associated with the island's buoyancy, and assess traditional beliefs, cultural values, and community perceptions surrounding the island. This study contributes to the growing body of literature on floating island dynamics, integrating ecological, spatial, and anthropological insights to inform management strategies in large lake ecosystems. Materials and Methods Study Area and Survey Coverage The study was conducted in Nzera Bay, located on the southwestern shore of Lake Victoria, Tanzania. The focal point was a massive floating island that appeared near Kahunda village in Sengerema District, Mwanza Region, 2°24'27.95" S and 32°03'32.12" E. The lake, situated at an elevation of 1,134 m above sea level, spans an area of 68,000 km² and supports rich aquatic biodiversity and livelihoods across its basin (Kassenga 1997 ). Nzera Bay, protected from strong waves by surrounding islands such as Maisome and Rubondo, is particularly known for its calm waters and dense marshlands (White 1983 ) (Plate 1). Fieldwork was undertaken between 15th and 21st May 2022, covering five shoreline villages: Kahunda, Kasheka, Katwe, Nyamimina, and Nzera. Additional static and drifting islands in Mwanza and Geita regions were also surveyed to contextualize the floating island’s scale, vegetation, and structure. Methodological Approach A multidisciplinary approach was adopted, combining field ecology, GIS and satellite tracking, botanical classification, soil sampling, and socio-cultural interviews. i) Desktop Review A preliminary literature review was conducted to gather global and regional insights on floating island dynamics, vegetation composition, detachment mechanisms, and socio-economic impacts. Sources included academic papers, GIS archives, and satellite datasets from Sentinel-2 and Google Earth. ii) Field Survey and Island Morphometry Island morphometry was determined by boating around its perimeter using a handheld GPS receiver (Garmin eTrex32x) to capture spatial coordinates. The area was calculated in ArcGIS Pro using a polygon tool. Island thickness (soil layer depth) was measured at 8 transect points using a 2-meter corer. Water depth beneath the island was also recorded. iii) Vegetation Identification A line-transect method was applied to identify plant species across the island. Vegetation types were classified physiognomically (e.g., marshes, swamps, woody patches). Plant specimens that could not be identified in the field were collected, pressed, and sent to the University of Dar es Salaam Herbarium for formal identification. Endemic and conservation status was verified using the IUCN Red List (2022), CITES Appendices, and the List of East African Plants (LEAP 1996 ). iv) Soil Sampling Soil cores were extracted from both the center and periphery of the island for analysis of composition and buoyancy properties. Samples were analyzed for organic content using loss-on-ignition (LOI) methods. Soil color, texture, and stratification were documented in the field. v) Wildlife Observation Direct observations were made to record vertebrate and invertebrate species present on the island. This included gastropods, birds, reptiles (e.g., monitor lizards), and snakes. Photographic documentation supported species identification. vi) GIS Tracking and Movement Mapping Using sequential satellite images from April to May 2022, the island’s movement was mapped in ArcGIS. Movement was analyzed in three phases: (i) detachment from origin near Kasheka, (ii) stop near Kahunda village, and (iii) final drift to current position. Cloud cover, wind speed, and rainfall patterns were overlaid to correlate meteorological conditions with the island’s mobility. vii) Cultural Assessment Semi-structured interviews and focus group discussions were held with elders, fishers, local leaders, and traditional healers. Respondents were selected purposively to provide historical and cultural context. Topics included traditional beliefs, medicinal uses, ritual practices, and community perceptions of floating islands. Data Analysis Descriptive statistics were used to summarize morphometric, vegetation, and soil characteristics. Plant species diversity was analyzed using species richness and frequency distribution by family. Organic matter content was expressed as percentage ash-free dry weight. Satellite data were georeferenced and processed in ArcGIS Pro and QGIS to map trajectories and generate visual overlays of movement phases. Qualitative data from interviews were thematically analyzed to extract common beliefs, uses, and cultural narratives related to the island. Content was triangulated across respondents to ensure reliability and cultural sensitivity. Results and Discussion Formation, fragmentation and movement of islands Morphometric assessment of the floating island at Kahunda (Plate 2), revealed an area of approximately 71,426 m² (7.1 ha), with a perimeter of 1.2 km and soil thickness ranging from 1.5 m at the edges to 4 m at the center. The average thickness was 2.0 m, composed of soft, black organic-rich soil with a mean organic content of 98.3% ash-free dry weight. Such high organic matter concentration is known to enhance buoyancy, allowing large vegetated islands to float intact even with considerable biomass (Mitsch and Gosselink 2015 ). Satellite image analysis confirmed the island’s detachment between 15–20 April 2022 from a wetland near Kasheka village (Plate 3). It subsequently drifted to a temporary stop near Kahunda village (21–23 April) and reached its maiden location just south of Kahunda by 27 April (Plate 4 and 5a&b), where it remained until June 2024, the northwest original front position of the island points southeast, indicating that the island could have been spinning while moving. Thereafter the island drifted towards south west of Nzera Bay near the shores of Mnyala village where it is currently located (Personal commun. from fisheries officers). These movements correlated with strong winds, reported to have reached ~ 40 km/h, and heavy rainfall events, which likely dislodged the island by increasing water levels beneath the wetland mat (Azza 2006 ; Ondari et al. 2023 ). Similar floating phenomena have been documented globally such as in the White Nile Basin (Ondari et al. 2023 ) and Australia’s Pirron Yallock Lake (Gippel 2020 ) often attributed to climatic variability and hydrological pulses. In northeastern Mexico, the sinkhole known as Zacatón is famous for its 15 floating islands, driven by subterranean activity beneath limestone landscapes (Morse & Keeler, 2000 ). Closer to East Africa, Oliver and McKaye ( 1982 ) documented floating islands on Lake Malawi, which often originate from swamp vegetation dislodged by strong winds and waves during the rainy season. Similar cases have been recorded in Florida and other temperate wetlands (Kadlec and Wallace 2009 ). All these findings point to the fact that floating islands typically form under specific environmental conditions. They are composed primarily of loosely bound organic soils, intertwined root systems, and a mosaic of aquatic and upland plant species. Seasonal water level changes are a key trigger. During dry periods, vegetation at the shoreline grows over desiccated sediments and stabilizes them with roots. When water levels rise again especially during heavy rains these mats become buoyant, lifting entire chunks of soil and vegetation into the water column (Mitchell and Gumbricht 1993 ). In addition, gases produced by microbial decomposition within organic-rich lake sediments may contribute to the buoyancy of detached material. Specifically, methane and other gases (carbon dioxide (CO2), and potentially hydrogen sulfide (H2S) produced during anaerobic decomposition of organic matter) can become trapped within sediment layers and within biofilms, creating bubbles that can contribute to the overall buoyancy of the island and potentially causing them to detach from the sediment. This process can lead to the formation of floating mats or other detached material in the water column. Wind and wave action further break down weakened sections of the shoreline, particularly in lakes with fluctuating water levels and high fetch exposure (Wetzel 2001 ). Over time, plants establish themselves on these floating mats, stabilizing them and sometimes allowing the formation of semi-permanent islands. Lake Victoria provides a suitable environment for such phenomena including the rare 2022 Nzera Bay event in Lake Victoria. Other reports indicate that the lake has experienced marked water level fluctuations, particularly following periods of drought and major hydrological changes such as the construction of the Kiira Power Station, which altered the outflow regime at Jinja (Kull 2006 ). Lowered water levels exposed swampy shorelines, leading to drought, decomposition, and eventual colonization by terrestrial vegetation. This process, coupled with subsequent water level rises during the wet season, can create ideal conditions for vegetation mats to dislodge and form floating islands. Human activity also plays a role. Encroachment into former wetland areas for agriculture or settlement weakens the structural integrity of swamp margins. When seasonal rains return, wave action may break off entire sections of swamp, particularly where vegetation is sparse or heavily disturbed. Understanding the patterns and drivers of floating island formation on Lake Victoria is critical. Projected changes in rainfall intensity due to climate variability may influence both the frequency and distribution of floating islands. It is therefore essential to assess: the trends of occurrence of floating islands, which areas of the lake are most prone to island formation, how far these islands can travel, and their ecological and socioeconomic impacts. Floating islands may obstruct fishing routes, damage fishing gear, and disrupt transport in local communities. At the same time, their potential to support biodiversity or serve as tourist attractions is worth exploring. However, the extent to which they impact livelihoods either positively or negatively remains poorly understood and merits further interdisciplinary research. Our findings align with such mechanisms, suggesting that seasonal fluctuations in rainfall followed by storm events likely triggered the detachment and mobility of this island. In addition to the primary island, we recorded 14 static floating islands and 4 smaller drifting ones in Sengerema, Mwanza region, and 7 in Geita regions, ranging in size from 0.4 to 36 acres (Table 1 ). This confirms a broader presence of floating island dynamics in Lake Victoria’s Nzera Bay. Table 1 Total number, size, status and vegetation types of floating islands present in Nzera Bay, Lake Victoria. Region Island status Total number of islands Location (village) Perimeter (km) Area (m 2 ) Vegetation type Mwanza Floating and drifting 3 Kahunda (present study) 1.2 71426 Swamp and marshes Katwe 0.27 4246.81 Marshes dominated by Cyperus papyrus Rukobe 0.34 6260 Swamp (with very tall trees) and marshes dominated by Cyperus papyrus Disappeared/drifted away 1 Fragmented away 2 Existing (floating, not drifting) 14 Rukobe 2.35 149009 Swamp and marshes Rukobe 1.3 67063 Swamp and marshes Rukobe 2.2 124351 Swamp and marshes Rukobe 1.97 158984 Swamp and marshes Rukobe 0.58 14618 Marshes dominated by Cyperus papyrus Rukobe 1.39 68509 Marshes dominated by Cyperus papyrus Rukobe 0.27 3422 Marshes dominated by Cyperus papyrus Rukobe 1.4 68836 Marshes dominated by Cyperus papyrus Rukobe 0.32 4467 Marshes dominated by Cyperus papyrus Rukobe 0.39 5057 Marshes dominated by Cyperus papyrus Rukobe 0.21 2465 Marshes dominated by Cyperus papyrus Rukobe 0.53 8583 Marshes dominated by Cyperus papyrus Rukobe 0.41 5454 Marshes dominated by Cyperus papyrus Rukobe 0.8 10357 Marshes dominated by Cyperus papyrus Geita Existing (floating but not drifting) 7 Lwezera 0.96 61521 Marshes dominated by Cyperus papyrus Lwezera 1.48 119133 Marshes dominated by Cyperus papyrus Vegetation Types and Species Composition A total of 27 plant species from 11 families were recorded on the floating island, dominated by emergent macrophytes and swamp vegetation (Table 2 ). The dominant families were Cyperaceae, Poaceae, and Moraceae (Figs. 1 & 2 ). The three most common species were: Cyperus papyrus (papyrus sedge), Typhacapensis (bulrush) and Miscanthus procera (giant grass) (Plate 6). These species formed dense mats with extensive rhizome systems, promoting structural cohesion and buoyancy. Such interlocking rhizomes are well-documented to stabilize floating wetlands (Denny 1993 ; Kansiime et al. 2007 ). Notably, the island hosted three tree species: Syzygium cordatum , Ficus capreifolia , and Ficus bubu , indicating that the soil mat was deep and stable enough to support larger woody vegetation (Plate 2 and 6).This matches conditions observed in long-established floating marshes, where increased biomass and trapped sediment allow succession from emergent marsh to swamp forest (Mitsch and Gosselink 2015 ; Junk et al. 2013 ). Unfortunately by the time we arrived, all trees from the wondering floating island had been cleared for traditional and cultural use, including witchcraft. A rare ground orchid, Eulophia angolensis , listed in CITES Appendix II, was also recorded highlighting the island’s conservation significance. These findings demonstrate that floating islands, though mobile, can harbor diverse and sometimes threatened species. In terms of vegetation structure, two major island types were identified in Nzera Bay: Floating and Marshland Islands dominated by sedges, reeds, and ferns. These were more buoyant and moved more frequently due to lower biomass density; and Floating Swamp Forest Islands containing trees like Voacanga africana and Pycnanthus angolensis , with trees up to 10 m tall (e.g. Plate 7). These islands were heavier and moved slowly or remained stationary. This variation in vegetation structure significantly affects island dynamics. Light, sedge-dominated mats are easily dislodged, while forested islands show greater inertia, a pattern consistent with global observations (Ondari et al. 2023 ; Gippel 2020 ). Table 2 Checklist of plant species identified from the floating island located south of Kahunda village, Sengerema, Mwanza, Tanzania 15th to 21 May, 2022. SN Species name Family name Author Habit/Life form 1 Cissampelos pereira Menispermaceae L. Herb 2 Cyperus alticulatus Cyperaceae L. Sedge 3 Cyperus exaltatus Cyperaceae Retz. Sedge 4 Cyperus payrus Cyperaceae L. Sedge 5 Dissotis rotundifolia Melastomataceae (Sm.) Triana Shrub 6 Eichhornia crassipes Pontederiaceae (Mart.) Solms Herb 7 Eulophia angolensis Orchidaceae (Rchb. f.) Summerh. Herb 8 Ficus bubu Moraceae Warb. Tree 9 Ficus capreifolia Moraceae Delile Tree 10 Fuirena pubescens Cyperaceae (Poir.) Kunth Sedge 11 Fuirena umbellate Cyperaceae Rottb. Sedge 12 Leersia hexandra Gramineae Sw. Grass 13 Miscanthus procera Gramineae Grass 14 Nephrolepis undulata Oleandraceae (Afzel. ex Sw.) J.Sm. Herb 15 Pentas zanzibarica Rubiaceae (Klotzsch) Vatke Herb 16 Pistia strutiotes Araceae L. Herb 17 Pluchea ovalis Compositae (Pers.) DC. Herb 18 Polygonum senegalense Polygonaceae Meisn. Herb 19 Pycnanthus angolensis Myristicaceae (Welw.) Warb. Tree 20 Striga asiatica Scrophulariaceae (L.) Ku Herb 21 Syzygium cordatum Mytraceae (Hochst.) Tree 22 Thelypteris confluens Thelypteridaceae (Thunb.) Morton Herb 23 Tristemma mauritianum Melastomataceae J.F.Gmel. Herb 24 Triumfetta brachyceras Tiliaceae K.Schum. Herb 25 Typha capensis Typhaceae (Rohrb.) N.E. Br. Reed 26 Urena lobata Malvaceae L. Herb 27 Voacanga Africana Apocynaceae Stapf Tree Species of Conservation Concern Among the 27 plant species recorded on the floating island, Eulophia angolensis (Orchidaceae) was identified as a species of conservation concern. It is listed under CITES Appendix II, highlighting its vulnerability to overharvesting and habitat disturbance. The presence of this ground orchid on a drifting island underscores the potential role of floating islands as refugia for threatened flora (CITES 1997 ; Redhead-Milne 1952 ). In addition, Syzygium cordatum and Ficus spp., though not classified as endangered, are ecologically significant for wetland stability and as habitats for various fauna. The conservation value of such species-rich islands suggests a need for protective management, even when the islands themselves are transient. Floating islands may provide mobile sanctuaries for biodiversity, much like floating bogs in temperate systems (Mitsch and Gosselink 2015 ). However, their movement also exposes sensitive species to human exploitation, as seen when villagers harvested trees from the Kahunda floating island for timber, medicinal use and cultural beliefs including witchcraft. Soil Type and Animal Fauna Associated with the Floating Island Soil analysis revealed a soft, black, organic-rich top layer mixed with partially decomposed plant material (Plate 8a) with no signs of sediments. The top layer averaged 98.3% organic matter, while the bottom layer, more decomposed, averaged 96% values consistent with floating wetland mats reported in other large lakes (Junk et al. 2013 ). The high organic content likely contributed significantly to buoyancy, allowing the island to support trees, reptiles, and other fauna. Faunal observations included: 1) Reptiles: Monitor lizards and green snakes were frequently sighted, indicating the island provides terrestrial-like habitats. 2) Birds: Several bird species were observed nesting, suggesting that the island also serves as a breeding ground (Plate 8b). And 3) Invertebrates: Gastropods and bivalves were common in the peripheral wetland zones. These findings affirm that floating islands contribute to habitat heterogeneity and support multiple trophic levels. Their role in nutrient cycling and biodiversity maintenance has also been highlighted in wetland ecosystems globally (Howard-Williams and Gaudet 1985 ; Timberlake et al. 1993 ). Movement and Impacts of the Floating Island Using GIS tracking and satellite imagery, the island’s trajectory was reconstructed in three stages: 1) Detachment – between 15th and 20th April 2022, from a wetland near Kasheka. 2) Intermediate Stop – near Kahunda village from 21st to 23rd April. And 3) Final Drift – to a position south of Kahunda by 27th April 2022. The estimated drift distance was approximately 15 km, influenced by changes in wind and rainfall. These movements corroborate findings by Azza ( 2006 ) and Ondari et al. ( 2023 ), who reported that floating islands can drift several kilometers depending on wind intensity and biomass composition. However, the island’s mobility also presents economic and logistical challenges: 1) Navigation Hazards; its path was aligned with ferry routes, posing a threat to MV Tegemeo and other transport vessels. 2) Cage Farming Risks; the calm Nzera Bay is ideal for aquaculture, yet floating islands may physically damage cages or disrupt water flow. And 3) Fisheries Disruption; long-line fishing and beach seines are impeded when floating islands block access or entangle nets. If not managed, such islands could become floating barriers to blue economy initiatives in the Lake Victoria basin (Kansiime et al. 2007 ; Gippel 2020 ). Cultural Beliefs and Values Associated with the Floating Island Interviews with community members revealed a rich tapestry of cultural meanings linked to floating islands. Though villagers acknowledged the natural origin of the island, many interpreted its sudden appearance as a supernatural omen or a sign of witchcraft. This reflects a dual belief system where empirical and spiritual interpretations coexist. Key cultural insights include: medicinal use; plants from floating islands, especially Syzygium cordatum and Voacanga africana , are believed to have healing properties; ritual spaces; certain islands are considered sacred and used for performing traditional rituals; and symbolism; some elders likened a person wandering aimlessly due to mental illness to a “floating island,” drifting without anchorage. These findings align with earlier ethnobotanical studies (Timberlake et al. 1993 ) and suggest that floating islands serve as both ecological and cultural heritage assets. However, the harvesting of entire trees from the island also reflects socioeconomic pressures, especially in areas where forest resources have been depleted. Understanding and integrating these local perceptions into lake management frameworks is essential for developing community-supported interventions and avoiding conflict. Conclusion Floating islands have been observed on Lake Victoria before and are likely to reoccur for as long as environmental conditions allow for landmasses to detach from the mainland. Their recurrence reflects underlying hydrological and ecological processes rather than superstition or unexplained forces. This study documents a rare ecological and cultural phenomenon: the appearance and movement of a massive floating island in Nzera Bay, Lake Victoria. The island, which measured over 7 hectares and supported trees, marsh vegetation, and wildlife, detached from the wetland near Kasheka village in April 2022. Its mobility was influenced by a combination of environmental triggers particularly strong winds and elevated water levels following a period of drought corroborating similar observations from other African and global freshwater systems. The floating island was ecologically diverse, hosting 27 plant species including one orchid ( Eulophia angolensis ) of conservation concern, and provided refuge to birds, reptiles, and aquatic invertebrates. The soil, rich in organic matter, contributed to its buoyancy and stability, allowing it to support even large trees. Cultural interviews revealed deep-rooted local beliefs tied to floating islands, ranging from sacred uses to traditional medicine and myths. Despite their ecological significance, floating islands also pose practical challenges to fisheries, navigation, and aquaculture especially cage farming. Their dynamic nature highlights the need for regular monitoring and adaptive management, particularly in economically strategic areas like Nzera Bay. This study contributes to a growing understanding of floating island formation, movement, biodiversity, and socio-cultural relevance, offering insights for sustainable lake and wetland management in East Africa and beyond. The study recommends establishment of monitoring programs of floating islands, including the i mplementation of GIS-based satellite monitoring in collaboration with local environmental authorities to track island movement and identify potential threats to navigation and fisheries infrastructure. The study also proposes development of management guidelines and protocols for safe removal, harvesting, or stabilization of islands, including the use of bulldozers or community-led vegetation removal where feasible. This will p romote the sustainable use of vegetation for organic composting by encouraging communities to harvest papyrus and other biomass from floating islands for organic manure production, mat weaving, or eco-friendly packaging, creating livelihood opportunities. The government should help to integrate cultural knowledge into the Lake Governance Frameworks recognize and incorporate indigenous beliefs and practices related to floating islands into environmental education, community engagement, and lake management strategies and support research on floating islands dynamics and on how on how climate variability affects wetland stability and floating island formations in Lake Victoria. Declarations Acknowledgement: This study was supported by the University of Dar es Salaam through the office of the Deputy Vice Chancellor Research. The authors declare that no funds, grants, or other support were received during the preparation of this manuscript Competing interest: The authors declare that no competing interest is associated with this publication. Ethical considerations were observed. This research was done under the University of Dar es Salaam moral regulation. Authors contribution: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Prosper L. Mfilinge, Mwita J. Chacha and Baraka Sekadende. The first draft of the manuscript was written by Prosper L. Mfilinge and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data Availability: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. References PhD Thesis, Wageningen University, The Netherlands. CITES (1997). Convention on International Trade in Endangered Species of Wild Fauna and Flora. World Conservation Monitoring Centre, Cambridge, UK. Denny P (1993). Wetlands of Africa. In: Whigham DF, Dykyjová D and Hejny S (Eds.), Wetlands of the World 1: Inventory, Ecology and Management. Kluwer Academic Publishers, Dordrecht, pp. 1–128. Flores A, Rendón R (2011). The Floating Islands of Lake Titicaca. Journal of Cultural Geography, 28(2), 157-170. 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Oliver MK, McKaye KR (1982) Floating Islands: A Means of Fish Dispersal in Lake Malawi, Africa. Copeia 1982(2), 748-754. Ondari O, Awange J, Song Y and Kasedde A (2023).Understanding the spatial–temporal patterns of floating islands impacting the major dams of the White Nile. RS 15(4): 985. Redhead-Milne E (Ed.) (1952–continuing). Flora of Tropical East Africa. Royal Botanic Gardens, Kew. Timberlake J, Nobanda N, Mapaure I (1993) Vegetation survey of the communal lands: North and West Zimbabwe. Kirkia 14: 171–270. White F (1983) The Vegetation of Africa: A Descriptive Memoir to Accompany the UNESCO/AETFAT/UNSO Vegetation Map of Africa. UNESCO, Paris. Wetzel RG (2001) Limnology: Lake and River Ecosystems (3rd ed.). Academic Press. Plate 1 To 8 Plate 1 To 8 are available in the Supplementary Files section. Additional Declarations No competing interests reported. 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Mfilinge","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYFACxgcHHhgAafYGBgkitTAbHEgAaeE5ANPCTFgLQwKIlkggUou52GHGAwkFd+z6Jd8Y3vyZwyDP38B/+AM+LZazkxmADnuWPHN2jrE17zYGwxkHmBkM8GkxuJ1/AKjlcLLB7RwzacZtDIwbgA5LwK8FbMvhZPubZ8wkf25jsAdpOUCMFjsDCR4zCaDDEoFaGBuI8MvhBIkzacVAv0gkzzjMbIxPB4O5dDLzhw9/Dtvztx/eePPnNhvb/vbGx3hDDBY2iVC3SBCOSZgWewLqRsEoGAWjYCQDAM0HSPdP1rmwAAAAAElFTkSuQmCC","orcid":"","institution":"University of Dar es Salaam","correspondingAuthor":true,"prefix":"","firstName":"Prosper","middleName":"L.","lastName":"Mfilinge","suffix":""},{"id":486082405,"identity":"f1047f8b-d5da-4c6a-bb8c-c36377f83041","order_by":1,"name":"Mwita J. Chacha","email":"","orcid":"","institution":"University of Dar es Salaam","correspondingAuthor":false,"prefix":"","firstName":"Mwita","middleName":"J.","lastName":"Chacha","suffix":""},{"id":486082407,"identity":"e35aba3b-dc4a-43a8-b4f6-a01e0e5c21c7","order_by":2,"name":"Baraka Sekadende","email":"","orcid":"","institution":"Ministry of Livestock and Fisheries","correspondingAuthor":false,"prefix":"","firstName":"Baraka","middleName":"","lastName":"Sekadende","suffix":""}],"badges":[],"createdAt":"2025-07-13 14:38:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7113959/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7113959/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86975535,"identity":"93bf5115-c844-4b6f-9f08-6d4787933d54","added_by":"auto","created_at":"2025-07-17 21:15:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":52825,"visible":true,"origin":"","legend":"\u003cp\u003ePlant families and number of individual species recorded from the floating island.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7113959/v1/c4076f77068545a1187c1bf2.png"},{"id":86975511,"identity":"6229631a-3dce-48b6-883c-80229bc46418","added_by":"auto","created_at":"2025-07-17 21:15:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":40868,"visible":true,"origin":"","legend":"\u003cp\u003eDiversity of species in each life form/habit recorded from the floating island.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-7113959/v1/7e64651e39dab01135774a5f.png"},{"id":95951688,"identity":"30f7b7ae-3a5b-43d8-be0f-6d7d04517f8d","added_by":"auto","created_at":"2025-11-14 19:38:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":955449,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7113959/v1/d8f71828-c8c3-4c04-8694-646918f377cc.pdf"},{"id":86976123,"identity":"9f942388-38d9-45b2-b0eb-b6b8b6b9ecc1","added_by":"auto","created_at":"2025-07-17 21:31:27","extension":"doc","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":6179840,"visible":true,"origin":"","legend":"","description":"","filename":"Plate1To8.doc","url":"https://assets-eu.researchsquare.com/files/rs-7113959/v1/1570f808e681e4c707c356e9.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"Floating Island of Trees and Myths: The Rare 2022 Nzera Bay Event in Lake Victoria","fulltext":[{"header":"Introduction","content":"\u003cp\u003eLake Victoria, the largest tropical lake in the world, is fringed by extensive wetlands that play a vital ecological role in biodiversity support and ecosystem functioning. These wetlands, comprised mainly of papyrus swamps, floating mats, and rooted marshes, serve as critical habitats for aquatic plants, fish, birds, reptiles, and invertebrates (Denny \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Howard-Williams and Gaudet \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1985\u003c/span\u003e; Kansiime et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). The lake\u0026rsquo;s wetland zones are categorized into two primary types: rooted systems anchored in terrestrial margins and floating systems formed by dense vegetative mats (Kansiime and Nalubega \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; White \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1983\u003c/span\u003e). Floating mats, such as those dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e and \u003cem\u003eMiscanthidium\u003c/em\u003e spp., often extend over the water column and are held afloat by interlaced rhizome networks and trapped organic matter (Redhead-Milne \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1952\u003c/span\u003e; Kassenga \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1997\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGlobally, floating islands have been documented across diverse freshwater systems. For instance, Lake Titicaca in Peru is home to over 70 artificial floating islands constructed by the Uros people using buoyant reeds for habitation and tourism (Flores and Rend\u0026oacute;n \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Additionally, floating treatment wetlands\u0026mdash;engineered systems mimicking natural islands\u0026mdash;have been used since the 1980s to enhance freshwater restoration and water quality in lakes and ponds (Headley and Tanner \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile floating islands are a known phenomenon in Lake Victoria, their occurrence is usually limited to small-scale papyrus rafts, locally known as \"Lutende.\" However, in April 2022, an exceptionally large and forested floating island unexpectedly appeared in Nzera Bay near Kahunda village, Tanzania. This unusual event, involving a 7.1-hectare island with trees, emergent macrophytes, and animal life, sparked public attention and scientific curiosity. Unlike typical papyrus patches, this island supported entire ecological communities, including \u003cem\u003eSyzygiumcordatum\u003c/em\u003e, \u003cem\u003eFicus\u003c/em\u003e spp., and reptiles like monitor lizards.\u003c/p\u003e\u003cp\u003eThe formation and dislodgment of such large floating islands remain poorly understood. Past studies (Azza \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Gippel \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Ondari et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) suggest that combinations of drought, fluctuating water levels, sediment decomposition, and extreme wind events may weaken wetland root systems, leading to detachment. However, empirical data on such mechanisms in the Lake Victoria basin are scarce. Floating islands have also been implicated in obstructing ferry routes, damaging cage farming operations, and affecting fishery activities (Kansiime et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Gippel \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eCulturally, floating islands hold diverse meanings among communities living around Lake Victoria. Local beliefs associate them with supernatural forces, medicinal uses, and sacred rituals (Timberlake et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). Yet, these socio-cultural dimensions remain undocumented in scientific literature. In response to this unprecedented event, a multidisciplinary research team was tasked to investigate the floating island. The key objectives of this study were to: examine the ecological and climatic factors contributing to the detachment of the island, map and track its movement using GIS and remote sensing tools, identify plant species and vegetation types across the island, analyze the soil composition associated with the island's buoyancy, and assess traditional beliefs, cultural values, and community perceptions surrounding the island. This study contributes to the growing body of literature on floating island dynamics, integrating ecological, spatial, and anthropological insights to inform management strategies in large lake ecosystems.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cem\u003eStudy Area and Survey Coverage\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe study was conducted in Nzera Bay, located on the southwestern shore of Lake Victoria, Tanzania. The focal point was a massive floating island that appeared near Kahunda village in Sengerema District, Mwanza Region, 2\u0026deg;24\u0026apos;27.95\u0026quot; S and 32\u0026deg;03\u0026apos;32.12\u0026quot; E. The lake, situated at an elevation of 1,134 m above sea level, spans an area of 68,000 km\u0026sup2; and supports rich aquatic biodiversity and livelihoods across its basin (Kassenga \u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e). Nzera Bay, protected from strong waves by surrounding islands such as Maisome and Rubondo, is particularly known for its calm waters and dense marshlands (White \u003cspan class=\"CitationRef\"\u003e1983\u003c/span\u003e) (Plate 1).\u003c/p\u003e\n\u003cp\u003eFieldwork was undertaken between 15th and 21st May 2022, covering five shoreline villages: Kahunda, Kasheka, Katwe, Nyamimina, and Nzera. Additional static and drifting islands in Mwanza and Geita regions were also surveyed to contextualize the floating island\u0026rsquo;s scale, vegetation, and structure.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMethodological Approach\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA multidisciplinary approach was adopted, combining field ecology, GIS and satellite tracking, botanical classification, soil sampling, and socio-cultural interviews.\u003c/p\u003e\n\u003cp\u003ei) Desktop Review\u003c/p\u003e\n\u003cp\u003eA preliminary literature review was conducted to gather global and regional insights on floating island dynamics, vegetation composition, detachment mechanisms, and socio-economic impacts. Sources included academic papers, GIS archives, and satellite datasets from Sentinel-2 and Google Earth.\u003c/p\u003e\n\u003cp\u003eii) Field Survey and Island Morphometry\u003c/p\u003e\n\u003cp\u003eIsland morphometry was determined by boating around its perimeter using a handheld GPS receiver (Garmin eTrex32x) to capture spatial coordinates. The area was calculated in ArcGIS Pro using a polygon tool. Island thickness (soil layer depth) was measured at 8 transect points using a 2-meter corer. Water depth beneath the island was also recorded.\u003c/p\u003e\n\u003cp\u003eiii) Vegetation Identification\u003c/p\u003e\n\u003cp\u003eA line-transect method was applied to identify plant species across the island. Vegetation types were classified physiognomically (e.g., marshes, swamps, woody patches). Plant specimens that could not be identified in the field were collected, pressed, and sent to the University of Dar es Salaam Herbarium for formal identification. Endemic and conservation status was verified using the IUCN Red List (2022), CITES Appendices, and the List of East African Plants (LEAP \u003cspan class=\"CitationRef\"\u003e1996\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eiv) Soil Sampling\u003c/p\u003e\n\u003cp\u003eSoil cores were extracted from both the center and periphery of the island for analysis of composition and buoyancy properties. Samples were analyzed for organic content using loss-on-ignition (LOI) methods. Soil color, texture, and stratification were documented in the field.\u003c/p\u003e\n\u003cp\u003ev) Wildlife Observation\u003c/p\u003e\n\u003cp\u003eDirect observations were made to record vertebrate and invertebrate species present on the island. This included gastropods, birds, reptiles (e.g., monitor lizards), and snakes. Photographic documentation supported species identification.\u003c/p\u003e\n\u003cp\u003evi) GIS Tracking and Movement Mapping\u003c/p\u003e\n\u003cp\u003eUsing sequential satellite images from April to May 2022, the island\u0026rsquo;s movement was mapped in ArcGIS. Movement was analyzed in three phases: (i) detachment from origin near Kasheka, (ii) stop near Kahunda village, and (iii) final drift to current position. Cloud cover, wind speed, and rainfall patterns were overlaid to correlate meteorological conditions with the island\u0026rsquo;s mobility.\u003c/p\u003e\n\u003cp\u003evii) Cultural Assessment\u003c/p\u003e\n\u003cp\u003eSemi-structured interviews and focus group discussions were held with elders, fishers, local leaders, and traditional healers. Respondents were selected purposively to provide historical and cultural context. Topics included traditional beliefs, medicinal uses, ritual practices, and community perceptions of floating islands.\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eData Analysis\u003c/h2\u003e\n \u003cp\u003eDescriptive statistics were used to summarize morphometric, vegetation, and soil characteristics. Plant species diversity was analyzed using species richness and frequency distribution by family. Organic matter content was expressed as percentage ash-free dry weight. Satellite data were georeferenced and processed in ArcGIS Pro and QGIS to map trajectories and generate visual overlays of movement phases. Qualitative data from interviews were thematically analyzed to extract common beliefs, uses, and cultural narratives related to the island. Content was triangulated across respondents to ensure reliability and cultural sensitivity.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003e\u003cstrong\u003eFormation, fragmentation and movement of islands\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMorphometric assessment of the floating island at Kahunda (Plate 2), revealed an area of approximately 71,426 m\u0026sup2; (7.1 ha), with a perimeter of 1.2 km and soil thickness ranging from 1.5 m at the edges to 4 m at the center. The average thickness was 2.0 m, composed of soft, black organic-rich soil with a mean organic content of 98.3% ash-free dry weight. Such high organic matter concentration is known to enhance buoyancy, allowing large vegetated islands to float intact even with considerable biomass (Mitsch and Gosselink \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eSatellite image analysis confirmed the island\u0026rsquo;s detachment between 15\u0026ndash;20 April 2022 from a wetland near Kasheka village (Plate 3). It subsequently drifted to a temporary stop near Kahunda village (21\u0026ndash;23 April) and reached its maiden location just south of Kahunda by 27 April (Plate 4 and 5a\u0026amp;b), where it remained until June 2024, the northwest original front position of the island points southeast, indicating that the island could have been spinning while moving. Thereafter the island drifted towards south west of Nzera Bay near the shores of Mnyala village where it is currently located (Personal commun. from fisheries officers). These movements correlated with strong winds, reported to have reached\u0026thinsp;~\u0026thinsp;40 km/h, and heavy rainfall events, which likely dislodged the island by increasing water levels beneath the wetland mat (Azza \u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e; Ondari et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eSimilar floating phenomena have been documented globally such as in the White Nile Basin (Ondari et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e) and Australia\u0026rsquo;s Pirron Yallock Lake (Gippel \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e) often attributed to climatic variability and hydrological pulses. In northeastern Mexico, the sinkhole known as \u003cem\u003eZacat\u0026oacute;n\u003c/em\u003e is famous for its 15 floating islands, driven by subterranean activity beneath limestone landscapes (Morse \u0026amp; Keeler, \u003cspan class=\"CitationRef\"\u003e2000\u003c/span\u003e). Closer to East Africa, Oliver and McKaye (\u003cspan class=\"CitationRef\"\u003e1982\u003c/span\u003e) documented floating islands on Lake Malawi, which often originate from swamp vegetation dislodged by strong winds and waves during the rainy season. Similar cases have been recorded in Florida and other temperate wetlands (Kadlec and Wallace \u003cspan class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eAll these findings point to the fact that floating islands typically form under specific environmental conditions. They are composed primarily of loosely bound organic soils, intertwined root systems, and a mosaic of aquatic and upland plant species. Seasonal water level changes are a key trigger. During dry periods, vegetation at the shoreline grows over desiccated sediments and stabilizes them with roots. When water levels rise again especially during heavy rains these mats become buoyant, lifting entire chunks of soil and vegetation into the water column (Mitchell and Gumbricht \u003cspan class=\"CitationRef\"\u003e1993\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eIn addition, gases produced by microbial decomposition within organic-rich lake sediments may contribute to the buoyancy of detached material. Specifically, methane and other gases (carbon dioxide (CO2), and potentially hydrogen sulfide (H2S) produced during anaerobic decomposition of organic matter) can become trapped within sediment layers and within biofilms, creating bubbles that can contribute to the overall buoyancy of the island and potentially causing them to detach from the sediment. This process can lead to the formation of floating mats or other detached material in the water column. Wind and wave action further break down weakened sections of the shoreline, particularly in lakes with fluctuating water levels and high fetch exposure (Wetzel \u003cspan class=\"CitationRef\"\u003e2001\u003c/span\u003e). Over time, plants establish themselves on these floating mats, stabilizing them and sometimes allowing the formation of semi-permanent islands.\u003c/p\u003e\n\u003cp\u003eLake Victoria provides a suitable environment for such phenomena including the rare 2022 Nzera Bay event in Lake Victoria. Other reports indicate that the lake has experienced marked water level fluctuations, particularly following periods of drought and major hydrological changes such as the construction of the Kiira Power Station, which altered the outflow regime at Jinja (Kull \u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e). Lowered water levels exposed swampy shorelines, leading to drought, decomposition, and eventual colonization by terrestrial vegetation. This process, coupled with subsequent water level rises during the wet season, can create ideal conditions for vegetation mats to dislodge and form floating islands.\u003c/p\u003e\n\u003cp\u003eHuman activity also plays a role. Encroachment into former wetland areas for agriculture or settlement weakens the structural integrity of swamp margins. When seasonal rains return, wave action may break off entire sections of swamp, particularly where vegetation is sparse or heavily disturbed.\u003c/p\u003e\n\u003cp\u003eUnderstanding the patterns and drivers of floating island formation on Lake Victoria is critical. Projected changes in rainfall intensity due to climate variability may influence both the frequency and distribution of floating islands. It is therefore essential to assess: the trends of occurrence of floating islands, which areas of the lake are most prone to island formation, how far these islands can travel, and their ecological and socioeconomic impacts.\u003c/p\u003e\n\u003cp\u003eFloating islands may obstruct fishing routes, damage fishing gear, and disrupt transport in local communities. At the same time, their potential to support biodiversity or serve as tourist attractions is worth exploring. However, the extent to which they impact livelihoods either positively or negatively remains poorly understood and merits further interdisciplinary research.\u003c/p\u003e\n\u003cp\u003eOur findings align with such mechanisms, suggesting that seasonal fluctuations in rainfall followed by storm events likely triggered the detachment and mobility of this island. In addition to the primary island, we recorded 14 static floating islands and 4 smaller drifting ones in Sengerema, Mwanza region, and 7 in Geita regions, ranging in size from 0.4 to 36 acres (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). This confirms a broader presence of floating island dynamics in Lake Victoria\u0026rsquo;s Nzera Bay.\u003c/p\u003e\n\u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eTotal number, size, status and vegetation types of floating islands present in Nzera Bay, Lake Victoria.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRegion\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eIsland status\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTotal number of islands\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLocation (village)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePerimeter (km)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eArea (m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVegetation type\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"19\"\u003e\n \u003cp\u003eMwanza\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eFloating and drifting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" rowspan=\"3\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKahunda (present study)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71426\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp and marshes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKatwe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4246.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6260\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp (with very tall trees) and marshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDisappeared/drifted away\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFragmented away\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"14\"\u003e\n \u003cp\u003eExisting (floating, not drifting)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" rowspan=\"13\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e149009\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp and marshes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67063\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp and marshes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e124351\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp and marshes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e158984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSwamp and marshes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14618\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68509\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3422\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68836\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4467\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5057\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2465\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8583\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5454\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRukobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10357\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eGeita\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eExisting (floating but not drifting)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" rowspan=\"2\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLwezera\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61521\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLwezera\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e119133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMarshes dominated by \u003cem\u003eCyperus papyrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eVegetation Types and Species Composition\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA total of 27 plant species from 11 families were recorded on the floating island, dominated by emergent macrophytes and swamp vegetation (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The dominant families were Cyperaceae, Poaceae, and Moraceae (Figs. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e \u0026amp; \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The three most common species were: \u003cem\u003eCyperus papyrus\u003c/em\u003e (papyrus sedge), \u003cem\u003eTyphacapensis\u003c/em\u003e (bulrush) and \u003cem\u003eMiscanthus procera\u003c/em\u003e (giant grass) (Plate 6). These species formed dense mats with extensive rhizome systems, promoting structural cohesion and buoyancy. Such interlocking rhizomes are well-documented to stabilize floating wetlands (Denny \u003cspan class=\"CitationRef\"\u003e1993\u003c/span\u003e; Kansiime et al. \u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eNotably, the island hosted three tree species: \u003cem\u003eSyzygium cordatum\u003c/em\u003e, \u003cem\u003eFicus capreifolia\u003c/em\u003e, and \u003cem\u003eFicus bubu\u003c/em\u003e, indicating that the soil mat was deep and stable enough to support larger woody vegetation (Plate 2 and 6).This matches conditions observed in long-established floating marshes, where increased biomass and trapped sediment allow succession from emergent marsh to swamp forest (Mitsch and Gosselink \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e; Junk et al. \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e). Unfortunately by the time we arrived, all trees from the wondering floating island had been cleared for traditional and cultural use, including witchcraft.\u003c/p\u003e\n\u003cp\u003eA rare ground orchid, \u003cem\u003eEulophia angolensis\u003c/em\u003e, listed in CITES Appendix II, was also recorded highlighting the island\u0026rsquo;s conservation significance. These findings demonstrate that floating islands, though mobile, can harbor diverse and sometimes threatened species.\u003c/p\u003e\n\u003cp\u003eIn terms of vegetation structure, two major island types were identified in Nzera Bay: Floating and Marshland Islands dominated by sedges, reeds, and ferns. These were more buoyant and moved more frequently due to lower biomass density; and Floating Swamp Forest Islands containing trees like \u003cem\u003eVoacanga africana\u003c/em\u003e and \u003cem\u003ePycnanthus angolensis\u003c/em\u003e, with trees up to 10 m tall (e.g. Plate 7). These islands were heavier and moved slowly or remained stationary.\u003c/p\u003e\n\u003cp\u003eThis variation in vegetation structure significantly affects island dynamics. Light, sedge-dominated mats are easily dislodged, while forested islands show greater inertia, a pattern consistent with global observations (Ondari et al. \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e; Gippel \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eChecklist of plant species identified from the floating island located south of Kahunda village, Sengerema, Mwanza, Tanzania 15th to 21 May, 2022.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSpecies name\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFamily name\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAuthor\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHabit/Life form\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCissampelos pereira\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMenispermaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eL.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCyperus alticulatus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyperaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eL.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSedge\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCyperus exaltatus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyperaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRetz.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSedge\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCyperus payrus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyperaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eL.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSedge\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eDissotis rotundifolia\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMelastomataceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Sm.) Triana\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eShrub\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eEichhornia crassipes\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePontederiaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Mart.) Solms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eEulophia angolensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOrchidaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Rchb. f.) Summerh.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eFicus bubu\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoraceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWarb.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTree\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eFicus capreifolia\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoraceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDelile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTree\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eFuirena pubescens\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyperaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Poir.) Kunth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSedge\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eFuirena umbellate\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyperaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRottb.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSedge\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eLeersia hexandra\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGramineae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSw.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrass\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eMiscanthus procera\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGramineae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrass\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eNephrolepis undulata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOleandraceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Afzel. ex Sw.) J.Sm.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePentas zanzibarica\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRubiaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Klotzsch) Vatke\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePistia strutiotes\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAraceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eL.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePluchea ovalis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCompositae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Pers.) DC.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePolygonum senegalense\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePolygonaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMeisn.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePycnanthus angolensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMyristicaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Welw.) Warb.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTree\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eStriga asiatica\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eScrophulariaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(L.) Ku\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eSyzygium cordatum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMytraceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Hochst.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTree\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eThelypteris confluens\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThelypteridaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Thunb.) Morton\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eTristemma mauritianum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMelastomataceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eJ.F.Gmel.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eTriumfetta brachyceras\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTiliaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eK.Schum.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eTypha capensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTyphaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Rohrb.)\u0026nbsp;N.E. Br.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReed\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eUrena lobata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMalvaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eL.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHerb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eVoacanga Africana\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eApocynaceae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStapf\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTree\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSpecies of Conservation Concern\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAmong the 27 plant species recorded on the floating island, \u003cem\u003eEulophia angolensis\u003c/em\u003e (Orchidaceae) was identified as a species of conservation concern. It is listed under CITES Appendix II, highlighting its vulnerability to overharvesting and habitat disturbance. The presence of this ground orchid on a drifting island underscores the potential role of floating islands as refugia for threatened flora (CITES \u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e; Redhead-Milne \u003cspan class=\"CitationRef\"\u003e1952\u003c/span\u003e). In addition, \u003cem\u003eSyzygium cordatum\u003c/em\u003e and \u003cem\u003eFicus\u003c/em\u003e spp., though not classified as endangered, are ecologically significant for wetland stability and as habitats for various fauna. The conservation value of such species-rich islands suggests a need for protective management, even when the islands themselves are transient. Floating islands may provide mobile sanctuaries for biodiversity, much like floating bogs in temperate systems (Mitsch and Gosselink \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). However, their movement also exposes sensitive species to human exploitation, as seen when villagers harvested trees from the Kahunda floating island for timber, medicinal use and cultural beliefs including witchcraft.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSoil Type and Animal Fauna Associated with the Floating Island\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eSoil analysis revealed a soft, black, organic-rich top layer mixed with partially decomposed plant material (Plate 8a) with no signs of sediments. The top layer averaged 98.3% organic matter, while the bottom layer, more decomposed, averaged 96% values consistent with floating wetland mats reported in other large lakes (Junk et al. \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e). The high organic content likely contributed significantly to buoyancy, allowing the island to support trees, reptiles, and other fauna.\u003c/p\u003e\n\u003cp\u003eFaunal observations included: 1) Reptiles: Monitor lizards and green snakes were frequently sighted, indicating the island provides terrestrial-like habitats. 2) Birds: Several bird species were observed nesting, suggesting that the island also serves as a breeding ground (Plate 8b). And 3) Invertebrates: Gastropods and bivalves were common in the peripheral wetland zones. These findings affirm that floating islands contribute to habitat heterogeneity and support multiple trophic levels. Their role in nutrient cycling and biodiversity maintenance has also been highlighted in wetland ecosystems globally (Howard-Williams and Gaudet \u003cspan class=\"CitationRef\"\u003e1985\u003c/span\u003e; Timberlake et al. \u003cspan class=\"CitationRef\"\u003e1993\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMovement and Impacts of the Floating Island\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eUsing GIS tracking and satellite imagery, the island\u0026rsquo;s trajectory was reconstructed in three stages: 1) Detachment \u0026ndash; between 15th and 20th April 2022, from a wetland near Kasheka. 2) Intermediate Stop \u0026ndash; near Kahunda village from 21st to 23rd April. And 3) Final Drift \u0026ndash; to a position south of Kahunda by 27th April 2022. The estimated drift distance was approximately 15 km, influenced by changes in wind and rainfall. These movements corroborate findings by Azza (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e) and Ondari et al. (\u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e), who reported that floating islands can drift several kilometers depending on wind intensity and biomass composition.\u003c/p\u003e\n\u003cp\u003eHowever, the island\u0026rsquo;s mobility also presents economic and logistical challenges: 1) Navigation Hazards; its path was aligned with ferry routes, posing a threat to MV \u003cem\u003eTegemeo\u003c/em\u003e and other transport vessels. 2) Cage Farming Risks; the calm Nzera Bay is ideal for aquaculture, yet floating islands may physically damage cages or disrupt water flow. And 3) Fisheries Disruption; long-line fishing and beach seines are impeded when floating islands block access or entangle nets. If not managed, such islands could become floating barriers to blue economy initiatives in the Lake Victoria basin (Kansiime et al. \u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e; Gippel \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCultural Beliefs and Values Associated with the Floating Island\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eInterviews with community members revealed a rich tapestry of cultural meanings linked to floating islands. Though villagers acknowledged the natural origin of the island, many interpreted its sudden appearance as a supernatural omen or a sign of witchcraft. This reflects a dual belief system where empirical and spiritual interpretations coexist. Key cultural insights include: medicinal use; plants from floating islands, especially \u003cem\u003eSyzygium cordatum\u003c/em\u003e and \u003cem\u003eVoacanga africana\u003c/em\u003e, are believed to have healing properties; ritual spaces; certain islands are considered sacred and used for performing traditional rituals; and symbolism; some elders likened a person wandering aimlessly due to mental illness to a \u0026ldquo;floating island,\u0026rdquo; drifting without anchorage. These findings align with earlier ethnobotanical studies (Timberlake et al. \u003cspan class=\"CitationRef\"\u003e1993\u003c/span\u003e) and suggest that floating islands serve as both ecological and cultural heritage assets. However, the harvesting of entire trees from the island also reflects socioeconomic pressures, especially in areas where forest resources have been depleted. Understanding and integrating these local perceptions into lake management frameworks is essential for developing community-supported interventions and avoiding conflict.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eFloating islands have been observed on Lake Victoria before and are likely to reoccur for as long as environmental conditions allow for landmasses to detach from the mainland. Their recurrence reflects underlying hydrological and ecological processes rather than superstition or unexplained forces. This study documents a rare ecological and cultural phenomenon: the appearance and movement of a massive floating island in Nzera Bay, Lake Victoria. The island, which measured over 7 hectares and supported trees, marsh vegetation, and wildlife, detached from the wetland near Kasheka village in April 2022. Its mobility was influenced by a combination of environmental triggers particularly strong winds and elevated water levels following a period of drought corroborating similar observations from other African and global freshwater systems.\u003c/p\u003e\u003cp\u003eThe floating island was ecologically diverse, hosting 27 plant species including one orchid (\u003cem\u003eEulophia angolensis\u003c/em\u003e) of conservation concern, and provided refuge to birds, reptiles, and aquatic invertebrates. The soil, rich in organic matter, contributed to its buoyancy and stability, allowing it to support even large trees. Cultural interviews revealed deep-rooted local beliefs tied to floating islands, ranging from sacred uses to traditional medicine and myths. Despite their ecological significance, floating islands also pose practical challenges to fisheries, navigation, and aquaculture especially cage farming. Their dynamic nature highlights the need for regular monitoring and adaptive management, particularly in economically strategic areas like Nzera Bay. This study contributes to a growing understanding of floating island formation, movement, biodiversity, and socio-cultural relevance, offering insights for sustainable lake and wetland management in East Africa and beyond.\u003c/p\u003e\u003cp\u003eThe study recommends \u003cb\u003eestablishment of monitoring programs of floating islands, including the i\u003c/b\u003emplementation of GIS-based satellite monitoring in collaboration with local environmental authorities to track island movement and identify potential threats to navigation and fisheries infrastructure. The study also proposes \u003cb\u003edevelopment of management guidelines and\u003c/b\u003e protocols for safe removal, harvesting, or stabilization of islands, including the use of bulldozers or community-led vegetation removal where feasible. This will p\u003cb\u003eromote the sustainable use of vegetation for organic composting by\u003c/b\u003e encouraging communities to harvest papyrus and other biomass from floating islands for organic manure production, mat weaving, or eco-friendly packaging, creating livelihood opportunities.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eThe government should help to integrate cultural knowledge into the Lake Governance Frameworks\u003c/strong\u003e\u003cp\u003erecognize and incorporate indigenous beliefs and practices related to floating islands into environmental education, community engagement, and lake management strategies and support research on floating islands dynamics and on how on how climate variability affects wetland stability and floating island formations in Lake Victoria.\u003c/p\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u0026nbsp;\u003c/strong\u003eThis study was supported by the University of Dar es Salaam through the office of the Deputy Vice Chancellor Research. \u003cem\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interest:\u003c/strong\u003e The authors declare that no competing interest is associated with this publication. Ethical considerations were observed. This research was done under the University of Dar es Salaam moral regulation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contribution:\u003c/strong\u003e \u003cem\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Prosper L. Mfilinge, Mwita J. Chacha and Baraka Sekadende. The first draft of the manuscript was written by Prosper L. Mfilinge and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/em\u003e\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eData Availability:\u0026nbsp;\u003c/strong\u003e\u003cem\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/em\u003e\u003c/h4\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePhD Thesis, Wageningen University, The Netherlands.\u003c/li\u003e\n\u003cli\u003eCITES (1997). Convention on International Trade in Endangered Species of Wild Fauna and Flora. World Conservation Monitoring Centre, Cambridge, UK.\u003c/li\u003e\n\u003cli\u003eDenny P (1993). Wetlands of Africa. In: Whigham DF, Dykyjov\u0026aacute; D and Hejny S (Eds.), Wetlands of the World 1: Inventory, Ecology and Management. Kluwer Academic Publishers, Dordrecht, pp. 1\u0026ndash;128.\u003c/li\u003e\n\u003cli\u003eFlores A, Rend\u0026oacute;n R (2011). The Floating Islands of Lake Titicaca. Journal of Cultural Geography, 28(2), 157-170.\u003c/li\u003e\n\u003cli\u003eGippel CJ (2020). Hydrological management of a lake with floating islands near PirronYallock, Victoria, Australia. J. Environ. Manage 260: 110149.\u003c/li\u003e\n\u003cli\u003eHeadley TR, Tanner CC (2012) Constructed wetlands with floating emergent macrophytes: an innovative stormwater treatment technology. Crit Rev Environ Sci Tech, 42(21), 2261-2310.\u003c/li\u003e\n\u003cli\u003eHoward-Williams C, Gaudet JJ (1985) The structure and functioning of African swamps. In: Denny P (Ed.), Ecology and Management of African Wetland Vegetation. Dr. Junk Publishers, Dordrecht, pp. 11\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eIUCN (2022) The IUCN Red List of Threatened Species. Version 2022-1.www.iucnredlist.org (Accessed 10 March 2025).\u003c/li\u003e\n\u003cli\u003eJunk WJ, An S, Finlayson CM, Gopal B, Květ J, Mitchell SA, Mitsch WJ, Robarts RD (2013) Current state of knowledge regarding the world\u0026rsquo;s wetlands and their future under global climate change. Aquat Sci 75(1): 151\u0026ndash;167.\u003c/li\u003e\n\u003cli\u003eKadlec RH, Wallace SD (2009) Treatment Wetlands (2nd ed.). CRC Press.\u003c/li\u003e\n\u003cli\u003eKansiime F Nalubega M (1999) Wastewater treatment by a natural wetland: the Nakivubo swamp, Uganda. PFW 12: 91\u0026ndash;99.\u003c/li\u003e\n\u003cli\u003eKansiime F, Saunders MJ, Loiselle SA (2007) Functioning and dynamics of wetland vegetation of Lake Victoria: an overview. Wetlands Ecol Manage. 15(6): 443\u0026ndash;451.\u003c/li\u003e\n\u003cli\u003eKassenga GR (1997) A descriptive assessment of the wetlands of the Lake Victoria Basin in Tanzania. Resour Conserv Recycl 20(2): 127\u0026ndash;141.\u003c/li\u003e\n\u003cli\u003eKull D (2006) Connections between recent water level drops in Lake Victoria, dam operations and drought. International Rivers Network.\u003c/li\u003e\n\u003cli\u003eLEAP (1996). List of East African Plants (LEAP) Database. National Museums of Kenya, Nairobi.\u003c/li\u003e\n\u003cli\u003eMitsch WJ, Gosselink JG (2015) Wetlands, 5th Ed., John Wiley \u0026amp; Sons, New York.\u003c/li\u003e\n\u003cli\u003eMitchell D, Gumbricht T (1993) Simulation of the formation of floating vegetation mats in tropical lakes. Ecol Model 69(1-2), 85\u0026ndash;98.\u003c/li\u003e\n\u003cli\u003eMorse JW, Keeler M (2000) The Karst Lakes of Mexico. National Geographic Research Reports.\u003c/li\u003e\n\u003cli\u003eOliver MK, McKaye KR (1982) Floating Islands: A Means of Fish Dispersal in Lake Malawi, Africa. Copeia 1982(2), 748-754.\u003c/li\u003e\n\u003cli\u003eOndari O, Awange J, Song Y and Kasedde A (2023).Understanding the spatial\u0026ndash;temporal patterns of floating islands impacting the major dams of the White Nile. RS 15(4): 985.\u003c/li\u003e\n\u003cli\u003eRedhead-Milne E (Ed.) (1952\u0026ndash;continuing). Flora of Tropical East Africa. Royal Botanic Gardens, Kew.\u003c/li\u003e\n\u003cli\u003eTimberlake J, Nobanda N, Mapaure I (1993) Vegetation survey of the communal lands: North and West Zimbabwe. Kirkia 14: 171\u0026ndash;270.\u003c/li\u003e\n\u003cli\u003eWhite F (1983) The Vegetation of Africa: A Descriptive Memoir to Accompany the UNESCO/AETFAT/UNSO Vegetation Map of Africa. UNESCO, Paris.\u003c/li\u003e\n\u003cli\u003eWetzel RG (2001) Limnology: Lake and River Ecosystems (3rd ed.). Academic Press.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Plate 1 To 8","content":"\u003cp\u003ePlate 1 To 8 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Floating Island, Lake Victoria, Nzera Bay, Wetlands, Kahunda Village","lastPublishedDoi":"10.21203/rs.3.rs-7113959/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7113959/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFloating islands are not unique to Lake Victoria. Their recurrence reflects underlying hydrological and ecological processes linked to seasonal variability in lake water levels, which can facilitate their detachment and mobility, rather than superstition or unexplained forces. In April 2022, a rare and unusual large floating island appeared in Nzera Bay, Lake Victoria, near Kahunda village, captivating the Tanzanian public and prompting scientific investigation. Unlike typical papyrus mats, this island supported large trees, marshes, emergent macrophytes, and diverse fauna, including birds and reptiles. A multidisciplinary team was formed to investigate the island\u0026rsquo;s origin, composition, movement, and cultural significance. Field surveys and GIS-based satellite tracking revealed that the island detached from wetland vegetation near Kasheka village between 15\u0026ndash;20 April 2022, likely due to a combination of persistent strong winds, waves and elevated water levels following prolonged drought and heavy rains. Morphometric analysis estimated the island\u0026rsquo;s area at 7.1 hectares, with an average soil thickness of 2 meters. Vegetation surveys identified 27 plant species, including three tree species and a ground orchid of conservation concern (\u003cem\u003eEulophiaangolensis\u003c/em\u003e). Soil samples showed high organic content, suggesting buoyancy-enhancing decomposition processes. Ethnographic interviews highlighted traditional beliefs, medicinal uses, and ritual practices linked to floating islands. Although floating islands contribute ecological benefits, their movement poses threats to navigation, fisheries, and cage farming in their path. This study provides scientific insights and offers management recommendations, including harvesting for organic compost and spatial monitoring, to mitigate potential impacts in Lake Victoria.\u003c/p\u003e","manuscriptTitle":"Floating Island of Trees and Myths: The Rare 2022 Nzera Bay Event in Lake Victoria","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-17 21:15:21","doi":"10.21203/rs.3.rs-7113959/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"82e89f6c-f43f-4908-88e1-cb1d8a1e5b03","owner":[],"postedDate":"July 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-14T19:38:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-17 21:15:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7113959","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7113959","identity":"rs-7113959","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}