Biology subjects

Juen, L.

Publications and source records attributed to Juen, L..

5 recordsLinked to original sources

bioRxiv2026

Taxonomic replacement, but functional stability: taxonomic-functional decoupling in Amazonian streams from an Indigenous territory

Biodiversity patterns in tropical freshwater ecosystems remain unevenly understood, particularly in high-integrity regions such as Indigenous territories. In this study, we assessed taxonomic and functional beta diversity of Ephemeroptera, Plecoptera, and Trichoptera (EPT) in Amazonian streams located within the Panara Indigenous Territory, Brazil. We evaluated the relative contributions of local environmental variables, spatial processes, and landscape context to beta-diversity patterns. We disentangled the roles of replacement and richness differences across taxonomic and functional dimensions. EPT larvae were sampled in 31 streams during the dry season. Beta diversity was quantified using Sorensen-based dissimilarity indices, and functional dissimilarity was calculated from seven ecological traits using Gower distances. Taxonomic beta diversity was dominated by genus replacement and was jointly structured by local habitat variables and spatial components, indicating the combined influence of environmental filtering and dispersal limitation. In contrast, functional beta diversity was higher than taxonomic beta diversity and was predominantly structured by richness differences, with significant effects of local environmental variables but no detectable influence of spatial processes. This pattern indicates a decoupling between taxonomic and functional dimensions, suggesting high levels of functional redundancy among EPT genera across streams. Our findings demonstrate that Amazonian streams within Indigenous territories provide key systems for understanding community assembly processes under low levels of direct anthropogenic disturbance. By revealing contrasting mechanisms underlying taxonomic and functional beta diversity, this study underscores the importance of integrating multiple facets of biodiversity and reinforces the role of Indigenous territories as strategic landscapes for safeguarding Amazonian freshwater biodiversity.

ecology↗

bioRxiv2026

Environmental and spatial drivers shape Odonata diversity in an Amazonian Indigenous Territory

Amazon streams are increasingly threatened by land-use change, yet Indigenous Territories represent some of the most effective areas for maintaining habitat integrity and ecological processes in these systems. Understanding how local environmental conditions, landscape context, and spatial structure interact to shape biodiversity within these territories is essential for advancing conservation strategies. Here, we evaluated the relative influence of local habitat, landscape, and spatial predictors on Odonata diversity and identified species-specific ecological thresholds within an Indigenous Territory in the southern Brazilian Amazon. Adult Odonata were sampled in 31 first- to third-order forested streams in the Panara Indigenous Territory, Xingu River basin. Local habitat variables were the main drivers of Odonata community structure, indicating that local habitat integrity and physical stream characteristics strongly influence assemblage composition. In contrast, Zygoptera suborder were primarily structured by spatial predictors, suggesting stronger dispersal limitations and fine-scale spatial processes. Anisoptera suborder showed no significant community-level associations with the predictors, reflecting their broader ecological tolerance and higher dispersal capacity. Our results demonstrate that even within highly conserved Indigenous Territories, subtle environmental gradients and spatial structure shape Odonata assemblages and define ecological thresholds. By integrating community-level and species-specific approaches, this study provides robust evidence of the role of Indigenous lands in sustaining freshwater biodiversity and highlights the value of Odonata as indicators for monitoring ecological integrity in Amazonian streams.

ecology↗

bioRxiv2026

Mapping research on Indigenous peoples, traditional knowledge, and biodiversity conservation in the Amazon: gaps and Indigenous knowledge co-production

O_LIIndigenous peoples play a central role in biodiversity knowledge and conservation, yet their participation in scientific research remains underrepresented. Understanding how Indigenous peoples, traditional knowledge, and Indigenous territories are portrayed in the scientific literature is essential for developing more equitable and culturally grounded conservation strategies. C_LIO_LIWe conducted a bibliometric analysis of 94 articles on biodiversity conservation in the Amazon, published between 1997 and 2025, indexed in Scopus and Web of Science. We examined temporal trends, geographic distribution, institutional leadership, Indigenous co-authorship, focal ecosystems and taxa, and the main contributions attributed to Indigenous peoples. Indigenous perspectives were integrated into this analysis through a participatory approach. C_LIO_LIScientific production increased after 2010. Research leadership remains concentrated in institutions from the Global North, even though Brazil, Ecuador, and Peru were the most frequently studied countries. Indigenous co-authorship was identified in only 6.4 % of the studies. Most studies focused on plants, mammals, and birds, whereas aquatic environments and groups such as insects, amphibians, and reptiles received comparatively less attention. The main contributions attributed to Indigenous peoples were related to community-based monitoring and management (41.48%) and cultural practices and traditional ecological knowledge (38.19%). C_LIO_LIThese findings show that Indigenous peoples are widely recognized as knowledge holders and conservation actors, but are still rarely included as authors or research partners. Our study highlights persistent geographic, epistemic, and collaborative asymmetries in Amazonian biodiversity research. Conservation science and policy will be stronger, fairer, and more effective when they move beyond documenting Indigenous knowledge towards supporting Indigenous leadership, equitable partnerships, and inclusive co-production of knowledge. C_LI

ecology↗

bioRxiv2024

Thorax temperature and niche characteristics as predictors of abundance of Amazonian Odonata

Environmental architecture and body temperature drive the distribution of ectothermic species, especially those with specific ecophysiological requirements or narrow ecological niches. In this study, we evaluated the connection between thorax temperature and niche specialization concerning the abundance and species contribution to the beta diversity of adult Odonata in Amazonian streams, employing the Species Contribution to Beta Diversity (SCBD). Our hypotheses were (i) Odonata species thorax temperature is positively correlated with both morphology (thorax width) and air temperature, and (ii) the thorax temperature of the Odonata assemblage serves as a more influential predictor than niche specialization in determining species abundance and SCBD. We sampled 46 streams in an anthropized landscape in the Northeastern and Southeastern regions of Para state, Brazil. Notably, niche breadth emerged as the variable influencing the abundance and SCBD of the Odonata assemblage. Niche position is a predictor for Odonata SCBD and not suborders, and predictor for abundance, except for Anisoptera. Both suborders exhibited a negative relationship between abundance and thoracic temperature. In summary, our results underscore the necessity of considering both niche and ecophysiological predictors to comprehensively assess the Odonata assemblage in Amazonian streams. This holistic approach has implications for conservation efforts and bioassessment practices, offering valuable insights into the collective response of Odonata as a group.

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bioRxiv2020

Contrasting beta-diversity and functional composition of aquatic insect communities across local to regional scales in Amazonian streams

We investigated how components of beta diversity (i.e., the turnover and nestedness and functional compositional) aquatic insect assemblages change among sites and are influenced by environmental and spatial drivers. For this, we analyzed beta-diversity and functional composition of Ephemeroptera, Plecoptera, and Trichoptera in 16 streams in two Amazonian basins with distinct environmental conditions (the Carajas and Tapajos regions). We performed Multiple regression on dissimilarity matrices (MRM) and Procrustes analysis to test spatial and environmental influences on the taxonomic and functional composition of communities. Community dissimilarity was most related to variations in geographic distance and topography, which highlighted the environmental distances shaping the communities. Variation in functional composition could be mostly attributed to the replacement of species by those with similar traits, indicating trait convergence among communities. Environmental predictors best-explained species replacement and trait congruence within and between the regions evaluated. In summary, among communities with different taxonomic compositions, the high species replacement observed appears to be leading them to have similar community structure, with species having the same functional composition, even in communities separated by both small and large geographic distances.

ecology↗