Biology subjects

Altermatt, F.

Publications and source records attributed to Altermatt, F..

At least 19 recordsLinked to original sources

bioRxiv2026

Small habitat patches can be the largest contributors to urban biodiversity across taxonomic groups

AimAs cities densify and expand, the careful planning and design of green spaces are essential for supporting urban biodiversity. Here, we evaluate the relative contribution of habitat patches of varying size, quality, and connectivity to urban biodiversity and assess environmental factors driving differences in species richness and community composition. LocationZurich, Switzerland. Time period: 2008-2018.Major taxa studied: Invertebrates, vertebrates, and trees. MethodsWe analyzed species occupancy data from 452 habitat patches. We quantified alpha, beta, and gamma diversity, assessed species-area relationships, and applied generalized dissimilarity modelling to test the role of patch area, connectivity, and habitat quality--proxied through environmental variables, including vegetation complexity, water presence, and forest isolation--in shaping community composition. ResultsAlpha diversity increased significantly with area, although small patches (usually < 5 ha) disproportionately contributed to beta diversity. Per unit area, groups of small patches yielded higher gamma diversity than equivalent areas of large patches, particularly for trees and invertebrates. Community composition was strongly influenced by patch area, with effects mediated by vegetation complexity, water, and isolation, with responses differing among taxa. Main conclusionsSmall habitat patches play a critical role in enhancing overall urban biodiversity. They increase species richness through cumulative area effects and promote community turnover (mediated by environmental heterogeneity). Maintaining networks of small patches alongside large green spaces is therefore key to conserving biodiversity in urban landscapes.

ecology↗

bioRxiv2025

Changing seasonality and phenology mediate the effects of migration across meta-ecosystems

Migration is a ubiquitous process that links ecosystems with distinct seasonal dynamics, transferring biomass and species interactions across space. Despite being widely altered by global change, studies commonly overlook the interaction of seasonal characteristics and bidirectional migration on species coexistence and biomass production across meta-ecosystems. We developed a mathematical model to study how migration interacts with key characteristics of seasonality--amplitude of variation and length of summer--to influence migrant persistence, consumer coexistence, and biomass production. Our findings demonstrate that seasonal characteristics mediate the effect of migration on coexistence and biomass production across meta-ecosystems. However, the effects strongly depend on migration timing: phenological mismatches can reduce biomass at local and meta-ecosystem scales and lead to the extinction of migratory and non-migratory consumers. Our study highlights how migration and seasonality interact to shape community structure and ecosystem function across scales, emphasizing the importance of system-level approaches for studying ecological outcomes of global change.

ecology↗

bioRxiv2025

Complementarity of ecosystem types drives landscape-wide productivity in North America

Landscape mosaics with a greater diversity of ecosystems tend to be more productive, mirroring the well-established relationship between species diversity and productivity observed in plot-scale biodiversity experiments. However, the mechanisms driving this effect at the landscape scale remain unclear. Here, we analyze a 15-year time series of satellite-derived primary productivity across over 50,000 landscape plots that vary in ecosystem composition. Our results demonstrate that more diverse landscapes are more productive and more predictable under environmental stress, especially drought. Using statistical partitioning, we show that these diversity effects are primarily driven by complementarity, with productivity gains that are broadly shared among ecosystem types rather than being dominated by a few. The specific ecosystem types that contributed most to landscape functioning varied regionally, but their role in driving mixture productivity remained unaffected by drought. These findings extend biodiversity theory to the landscape scale, emphasizing the critical role of higher-order diversity in shaping ecosystem function and informing landscape management.

ecology↗

bioRxiv2025

Positive effects of landscape diversity on vegetation productivity at the kilometer scale

AO_SCPLOWBSTRACTC_SCPLOWBroad evidence suggests a positive relationship between local species richness and ecosystem functioning 1,2. However, Earths terrestrial surface is formed by a mosaic of different habitats, which constitutes a higher level of diversity known as landscape diversity. Recent studies indicate that landscape diversity can also promote ecosystem functions, including primary productivity, but the underlying mechanisms and relevant spatial scales remain poorly understood 3,4. Here, we combine satellite remote sensing of vegetation productivity with high-resolution land cover data to investigate the effects of landscape diversity on ecosystem functioning across different spatial scales. Using a plot network covering North America, we find that the observed landscape-wide effects cannot be explained by local-scale interactions along ecosystem interfaces. In a subsequent, global-scale analysis, we instead demonstrate that landscape diversity effects are most strongly associated to landscape diversity at a spatial scale of a few kilometers. This association holds across continents and climatic zones, indicating that this pattern is universal. Our investigation therefore suggests that effective land management and biodiversity conservation strategies must integrate both local species richness and higher-level organizational diversity, such as landscape diversity, to ensure robust ecosystem functioning.

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bioRxiv2025

Spatial Biodiversity Indicators and a Composite Index for Conservation Prioritization in Switzerland

Spatially explicit indicators that quantify to which extent landscapes support biodiversity are essential for guiding evidence-based conservation planning. Here, we present a 25-meter resolution dataset for Switzerland, encompassing three key biodiversity indicators-- Complementarity, Extinction Risk, and Ecological Connectivity--developed across 17 major taxonomic groups, using habitat suitability maps for approximately 7,500 individual species. These three indicators capture (1) the contribution of landscapes to taxonomic, functional, and phylogenetic diversity, (2) species vulnerability to extinction and (3) ecological connectivity. Outputs are provided for both terrestrial and aquatic realms, including versions adjusted for species richness, and integrated into composite indices. In total, 272 spatial layers were produced and made openly accessible. Relationships among the three indicators were analyzed to assess their distinct contributions, and expert-based validations were performed to evaluate their ecological plausibility and relevance for conservation applications. This dataset provides a robust foundation to support spatial planning and conservation decision-making in Switzerland and can be used as a blueprint for analogue integration in other countries.

ecology↗

bioRxiv2025

Food-web coupling by mobile consumers has individual to ecosystem level effects

Mobile consumers serve as a ubiquitous link, coupling the dynamics and functions of different ecosystems, ranging from diel-vertical migration of zooplankton to seasonal movements of large ungulates. Despite mounting theoretical interest, experimental tests of the effects of consumer mobility in meta-ecosystems are virtually non-existent. Here, we used an experimental microcosm system to investigate how mobile consumers (Daphnia magna) mediate ecosystem biomass, community structure, and their own fitness by coupling spatially distinct aquatic ecosystems composed of two different protist communities. We found that consumer mobility significantly influenced the effect of consumption on ecosystem biomass and the growth and reproduction of the consumers, themselves. However, the direction and magnitude of these effects depended on community composition in the connected ecosystem. Further, we found consumer mobility consistently promoted the coexistence of a competing local species, regardless of community composition in the connected ecosystem. Our findings underscore the profound role of consumer mobility in shaping individual to ecosystem-level dynamics while emphasizing a strong mediating effect of community composition across the landscape.

ecology↗

bioRxiv2025

Biodiversity modulates the size-abundance relationship in changing environments

Organismal abundance tends to decline with increasing body size. Metabolic theory links this size structure with energy use and productivity, postulating a size-abundance slope of -0.75 that is invariant across environments. We tested the robustness of this relationship across gradients of protist species richness (1-6 species), temperature (15-25 {degrees}C), and time. Using replicated microcosms, we provide an empirical test of how temperature and biodiversity jointly shape the cross-community scaling relationship (CCSR). While our results support the expected of slope -0.75, we also found interactive effects showing the relationship is not invariant. Warming altered abundance scaling with size depending on richness; in high-richness communities, temperature favoured small protists, steepening the CCSR slope. These context-dependent responses emerged over time, suggesting a role of size-dependent species interactions in shaping responses to environmental change. Our findings demonstrate that cross-community size scaling is not fixed but shifts dynamically with ecological context.

ecology↗

bioRxiv2025

Extracting massive ecological data on state and interactions of species using large language models

The contemporary ecological crisis calls for integration and synthesis of ecological data describing the state, change and processes of ecological communities. However, such synthesis depends on the integration of vast amounts of mostly scattered and often hard-to-extract information that is published and dispersed across hundreds of thousands of scientific papers, for example describing species-specific interactions and trophic relationships. Recent advancements in natural language processing (NLP) and in particular the emergence of large language models (LLMs) offer a novel, and potentially revolutionary solution to this persistent challenge, for the first time creating the opportunity to access and extract virtually all data ever published. Here, we demonstrate the transformative potential of LLMs by extracting all types of biological interactions among species directly from a corpus of 83,910 scientific articles. Our approach successfully extracted a network of 144,402 interactions between 36,471 taxa. Performance analysis shows that the model exhibits a high sensitivity (70.0%) and excellent precision (89.5%). Our approach proves that LLMs are capable of carrying out complex extraction tasks on key ecological data on a very large scale, paving the way for a multitude of potential applications in ecology and beyond.

ecology↗

bioRxiv2025

Tracking the phenology of riverine insect communities using environmental DNA

Aquatic insects are iconic and ecologically highly relevant inhabitants of riverine ecosystems. They are also often the target of monitoring programs to assess the ecological status of these lotic habitats. Environmental DNA (eDNA) techniques have been widely and successfully implemented to investigate freshwater insects and other macroinvertebrates. Commonly, such monitoring is conducted at one or two timepoints per year, despite the known strong seasonality and phenology of aquatic insects. Here, we assessed if and how eDNA can capture the temporal changes of the orders Ephemeroptera (mayflies), Plecoptera (stoneflies), Trichoptera (caddisflies) and Diptera (true flies). We carried out eDNA sampling at roughly monthly intervals from April to October at 25 sites across a whole river catchment in the northeastern part of Switzerland. We found pronounced, cyclic phenological trends in all orders but Trichoptera: the communities diverged from spring to summer and then in fall gradually returned closer to the spring state. The four orders exhibited different predominance in gains or losses of species detection throughout this time interval. Lastly, we found that field replicates, despite showing a relatively high local stochasticity, were able to provide a more complete assessment of aquatic communities and could thus be used as a proxy for the frequency of observation of a species through the seasons. In fact, this approach yielded comparable temporal patterns to the ones extracted from the Global Biodiversity Information Facility (GBIF). Overall, our findings demonstrate that eDNA techniques can be used to reveal intra-annual dynamics of aquatic insects. Given the current necessity to assess and monitor the biodiversity status of ecosystems, we therefore show that eDNA methods are a viable option to obtain a deeper understanding of the structuring of freshwater communities over time.

ecology↗

bioRxiv2024

A global synthesis on land-cover changes in watersheds shaping freshwater detrital food webs

Anthropogenic land-cover changes are among the most pressing global threats to both aquatic and terrestrial ecosystems, jeopardising biodiversity and the critical connections between these systems. Resource flows and trophic interactions intricately link aquatic and terrestrial ecosystems, with terrestrial-derived detritus playing a foundational role in supporting aquatic food webs. These detrital inputs form essential cross-ecosystem linkages, underpinning key ecological processes and providing vital resources for aquatic communities. Yet, little research has focused on how land-cover changes cascade across this linkage. To better understand how land-cover changes in the watershed influence freshwater detrital food webs, we conducted a meta-analysis of field studies reporting the effects of vegetation changes on freshwater detrital consumers and organic matter decomposition. The results from 144 studies, reporting 1235 comparisons, showed that, overall, land-cover changes in the watershed vegetation, especially through harvest and land-use conversion, have negative effects on aquatic biodiversity and ecosystem processes. These vegetation changes reduced diversity, abundance, and biomass across multiple trophic levels in freshwater detrital food webs. Studies examining multiple organism groups most often observed negative responses across multiple trophic levels, suggesting that the land-cover changes negatively affected multiple detrital food web components simultaneously. Our results also show that outcomes of restoration of watershed vegetation were context-dependent, and no clear trend of improvement was visible. Therefore, conservation of natural riparian and catchment vegetation are key to maintain freshwater ecosystem processes and aquatic biodiversity worldwide, and more efficient and evidence-based restoration measures are urgently needed. As our global synthesis shows that direct human-induced alterations of vegetation type in watersheds have significant negative effects on freshwater detrital food webs, there is a pressing need to consider cross-ecosystem consequences of land-cover changes in conservation and ecosystem management.

ecology↗

bioRxiv2024

Biodiversity and riparian forests are mutual biological drivers of ecosystem functions in temperate and tropical streams

Fluxes of energy, matter, and organisms sustain linkages and functions within and between ecosystems. Yet, how biological drivers influence interactions and functions at the interface between aquatic and terrestrial environments (i.e., aquatic-terrestrial ecosystem functions) locally and across regions has received little attention. To test the relative importance of biological drivers on multiple aquatic-terrestrial ecosystem functions, we subsidised local terrestrial detritus in forested and non-forested stream sites in a temperate and tropical region. We also manipulated leaf litter diversity (horizontal biodiversity of resources) and macroinvertebrate access (vertical biodiversity of consumers). We measured secondary production of aquatic fungi, in-stream leaf litter nitrogen loss, and decomposition rates. The simultaneous provision of all three ecosystem functions (i.e., multifunctionality) was positively driven by vertical biodiversity and riparian forests in both regions. In both tropical and temperate streams, nitrogen loss was associated with vertical biodiversity. Decomposition rates were also enhanced by vertical biodiversity and linked to other ecosystem functions. These results reveal strong and consistent effects of biodiversity and riparian forests on aquatic-terrestrial ecosystem functions in freshwater detrital food webs in both temperate and tropical headwater streams. Thus, disentangling the drivers of ecosystem functions in these systems requires an understanding of underlying mechanisms beyond ecosystem borders.

ecology↗

bioRxiv2024

eDITH: an R-package to spatially project eDNA-based biodiversity across river networks with minimal prior information

O_LIEcological and ecosystem monitoring is rapidly shifting towards using environmental DNA (eDNA) data, particularly in aquatic systems. This approach enables a combined coverage of biodiversity across all major organismal groups and the assessment of ecological indices. Yet, most current approaches are not exploiting the full potential of eDNA data, largely interpreting results in a localized perspective. In riverine networks, by explicitly modelling hydrological transport and associated DNA decay, hydrology-based models enable upscaling eDNA-based diversity information, providing spatially integrated inference. To capitalize from these unprecedented biodiversity data and translate into space-filling biodiversity projections, a streamlined implementation is needed. C_LIO_LIHere, we introduce the eDITH R-package, implementing the eDITH model to project biodiversity across riverine networks with minimal prior information. eDITH couples a species distribution model relating a local taxons eDNA shedding rate in streamwater to environmental covariates, a mass balance expressing the eDNA concentration at a rivers cross-section as a weighted sum of upstream contributions, and an observational model accounting for uncertainties in eDNA measurements. By leveraging on spatially replicated eDNA measurements and minimal hydromorphological data, eDITH enables disentangling the various upstream eDNA sources, and produces space-filling maps of a taxons spatial distribution at any chosen resolution. eDITH is applicable to both eDNA concentration and metabarcoding data, and to any taxon whose DNA can be retrieved in streamwater. C_LIO_LIThe eDITH package provides user-friendly functions for single-run execution and fitting of eDITH to eDNA data with both Bayesian methods (via the BayesianTools package) and non-linear optimization. An interface to the DHARMa package allows model validation via posterior predictive checks. Necessary preliminary steps such as watershed delineation and hydrological characterization are implemented via the rivnet package. We illustrate eDITHs workflow and functionalities with two case studies from published fish eDNA data. C_LIO_LIThe eDITH package provides a user-friendly implementation of eDITH, specifically intended for ecologists and conservation biologists. It can be used without previous modelling knowledge but also allows customization for experienced users. Ultimately, eDITH allows upscaling eDNA biodiversity data for any river globally, transforming how state and change of biodiversity in riverine systems can be tracked at high resolution in a highly versatile manner. C_LI

ecology↗

bioRxiv2023

Terrestrial land cover shapes fish diversity in major subtropical rivers

Freshwater biodiversity is critically affected by human modifications of terrestrial land use and land cover (LULC)1,2. Yet, knowledge of the spatial extent and magnitude of LULC-aquatic biodiversity linkages is still surprisingly limited, impeding the implementation of optimal management strategies3. Here, we compiled fish diversity data across a 160,000-km2 subtropical river catchment in Thailand characterized by exceptional biodiversity4 yet intense anthropogenic alterations5, and attributed fish species richness and community composition to contemporary terrestrial LULC across the catchment. We estimated a spatial range of LULC effects extending up to about 20 km upstream from sampling sites, and explained nearly 60 % of the variance in the observed species richness, associated with major LULC categories including croplands, forest, and urban areas. We find that integrating both spatial range and magnitudes of LULC effects is needed to accurately predict fish species richness. Further, projected LULC changes showcase future gains and losses of fish species richness across the river network and offer a scalable basis for riverine biodiversity conservation and land management, allowing for potential mitigation of biodiversity loss in highly diverse yet data-deficient tropical to sub-tropical riverine habitats.

ecology↗

bioRxiv2023

Riparian forests shape trophic interactions in detrital stream food webs

Freshwater and terrestrial biodiversity is linked through resource flows. For example, subsidies from the riparian vegetation form the base of food webs in small streams. Despite the key role of detritivores in these food webs, consequences of altered resource availability and riparian vegetation type on their trophic strategies are largely unknown. Therefore, we experimentally tested direct and indirect effects of riparian vegetation type on trophic interactions and dietary imbalances of detritivores. We used stoichiometric and isotopic differences between consumers and resources as functional measures of trophic link strength. Our results show that the lack - compared to the presence - of riparian forests directly affected both stoichiometric and isotopic differences in detrital food webs, yet with diverging patterns between resources and consumers, ultimately leading to aquatic-terrestrial decoupling. Consequently, our findings demonstrate that riparian forests are essential for aquatic food webs by influencing both organisms and interactions networks.

ecology↗

bioRxiv2023

Evolutionary origin of morphologically cryptic species imprints co-occurrence and sympatry patterns

AimMorphologically cryptic species are an important part of global biodiversity, yet it remains unclear how these species contribute to and integrate into communities at different geographic scales. It is especially unclear at which scales they co-occur, and if and how their ranges overlap. To adequately protect biodiversity, an accurate understanding of the underlying processes and adequate level of protection is needed, in particularly for often overlooked cryptic species. QuestionWe analyzed patterns of syntopies (local co-occurrences) and sympatries (range overlap) to test how the evolutionary origin of cryptic species shapes biodiversity patterns at different geographic scales. We hypothesized i) that syntopies are more common among phylogenetically deeply divergent cryptic species than among close relatives, and ii) that sympatries are an outcome of phylogenetic relatedness and dispersal, with range size as a proxy of dispersal ability. LocationWestern Europe. TaxonSubterranean amphipod crustaceans of the polyphyletic Niphargus rhenorhodanensis species complex. MethodsUnilocus species delimitations (PTP, ASAP), calibrated multilocus phylogenetic analyses, co-occurrence analyses using a probabilistic model, generalized linear models (GLM). ResultsThe studied species complex comprises 37-48 molecular operational taxonomic units (MOTUs) from nine different clades. Syntopies are random or less frequent than expected, implying an insufficient between-MOTU differentiation allowing stable coexistence. GLM suggested that age of divergence does not predict species sympatries, although they emerge more frequently among MOTUs from different clades. By contrast, sympatries emerge when at least one MOTU disperses over a large geographic range. Biodiversity rich regions were found at the foothills of the Alps, the Jura and the Central Massif, regardless the inference method. Main conclusionsBiodiversity patterns of the herein studied species complex are driven mainly by dispersal and reflect geographic circumstances of speciation. While species richness on a local scale may be the outcome of competition and dispersal, regional biodiversity patterns emerged through biogeographic history on a clade-level.

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bioRxiv2022

The structure of Lepidoptera-plant interaction networks across clades, life stages, and environmental gradients

AimIntegrate biogeographic and ecological knowledge to understand the spatial-structural patterns of plant-insect interaction networks at the landscape scale. LocationThe 36,000 km2 German state of Baden-Wurttemberg, Central Europe. MethodsWe integrated extensive data of Lepidoptera-plant occurrences and interactions to inferentially construct local interaction networks across Baden-Wurttemberg, considering in total 3148 plant and 980 Lepidoptera species, covering butterflies, Noctuid moths, Geometrid moths and Bombycoid moths. We quantified clade- and life-stage-specific network structures and related these features to GIS-informed environmental conditions, thereby revealing the spatial (environmental) patterns and potential drivers of networks structural variation across the landscape. ResultsSpanning the same environmental gradients, Lepidoptera clades and life stages can form various interaction structures with food plants and exhibit distinct spatial-structural patterns. For all major Lepidopteran groups, except Geometrid moths, potential diet across life stages tended to broaden toward low-elevation farmlands. The larval and adult networks of butterflies became less modular with farmland coverage; the same for adult Noctuid moths, but the inverse for adult Geometrid moths. With increasing elevation, the larval and adult networks of Noctuid moths became less and more modular, respectively, whereas Geometrid adult networks became more modular. While the adult dietary niche of butterflies was more overlapped at low elevation, those of Noctuid and Geometrid moths further associated with land cover and were more overlapped toward low- and high-elevation farmlands, respectively. Main conclusionsEnvironmental factors and biotic interactions together shape ecological communities. By particularly accounting for species-interaction contexts, we revealed the spatial-structural patterns of Lepidoptera-plant networks along geo-climate and land-cover gradients, where the shaping mechanisms likely include both evolutionary (e.g., resource-consumer co-evolution) and ecological (e.g., competitive exclusion) processes and are specific to Lepidopteras clade or life stage. Such biogeographical structural patterns provide ecological and conservation implications at both species and community levels, and can indicate the potential response of Lepidoptera-plant communities to environmental changes.

ecology↗

bioRxiv2022

Fewer non-native insects in freshwater than in terrestrial habitats across continents

AimBiological invasions are a major threat to biodiversity in both aquatic and terrestrial habitats. Insects represent an important group of species in freshwater and terrestrial habitats, and they constitute a large proportion of non-native species. However, while many non-native insects are known from terrestrial ecosystems, it remains unclear how they are represented in freshwater habitats. Comparisons of the richness of invaders relative to the richness of native species between freshwater and terrestrial habitats are scarce, which hinders syntheses of invasion processes. Here, we used data from three regions on different continents to determine whether non-native insects are under- or overrepresented in freshwater compared to terrestrial assemblages. LocationEurope, North America, New Zealand MethodsWe compiled a comprehensive inventory of the native and non-native insect species established in freshwater and terrestrial habitats of the three study regions. We then contrasted the richness of non-native and native species among freshwater and terrestrial insects for all insect orders in each region. Using binomial regression, we analysed the proportions of non-native species in freshwater and terrestrial habitats across the three regions. ResultsIn most insect orders living in freshwater, non-native species were under-represented, while they were over-represented in a number of terrestrial orders. This pattern occurred in purely aquatic orders as well as in orders with both freshwater and terrestrial species. Overall, the proportion of non-native species was significantly lower in freshwater than in terrestrial species. Main conclusionsDespite the numerical and ecological importance of insects among all non-native species, non-native insect species are surprisingly rare in freshwater habitats, and this pattern is consistent across the three investigated study regions. We briefly review hypotheses concerning species traits and invasion pathways that are most likely to explain these patterns. Our findings contribute to a growing appreciation of drivers and impacts of biological invasions.

ecology↗

bioRxiv2022

Modelling eDNA transport in river networks reveals highly resolved spatio-temporal patterns of freshwater biodiversity

O_LIThe ever-increasing threats to riverine biodiversity call for the development of novel approaches for a complete assessment of biodiversity across highly resolved spatial, temporal and taxonomic scales. Past studies on riverine biodiversity patterns were often restricted to spatially scattered data, focused on specific taxonomic groups, and disregarded the temporal dimension, preventing a universal understanding of relationships between biodiversity and stream size across spatial, temporal and taxonomic scales. Recent advances in the joint use of environmental DNA (eDNA) data and novel mechanistic models for eDNA transport in river networks have the potential to uncover the full structure of riverine biodiversity at an unprecedented spatial resolution, hence providing fundamental insights into ecosystem processes and offering a basis for targeted conservation measures. C_LIO_LIHere, we applied a mechanistic model (i.e., the eDITH model) to a metabarcoding dataset covering three taxonomic groups (fish, invertebrates and bacteria) and three seasons (spring, summer and autumn) for a 740-km2 Swiss catchment, sampled for eDNA at 73 sites. C_LIO_LIUsing the mechanistic model, we upscaled eDNA-based biodiversity predictions to more than 1900 individual reaches, allowing an assessment of patterns of - and {beta}-diversity across seasons and taxonomic groups at a space-filling, fine scale over the whole network. C_LIO_LIWe found that both predicted - and {beta}-diversity varied considerably depending on both season and taxonomic group. Predicted fish -diversity increased in the downstream direction at all seasons, while invertebrate and bacteria -diversity either decreased downstream or was not significantly related to position within network, depending on the season. Spatial {beta}-diversity was mostly found to be decreasing in the downstream direction, and this was the case for all seasons for bacteria. Temporal {beta}-diversity was mostly found to be increasing downstream. In general, genus richness values predicted by the model were found to be higher than those obtained by directly analyzing the eDNA data. Overall, stream size (subsumed by drainage area) was generally a poor predictor of patterns of predicted - and {beta}-diversities. Conversely, riverine biodiversity is shaped by a complex interplay of environmental variables, abiotic and biotic factors, which need be taken into account for a correct assessment of its structure. C_LI

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