Vicente Villalobos1,2, Nelson Valdivia2, Gabriel 3, Stacy Ballyram4, Günter Försterra5, Alexis Catalán6, Vreni Häussermann5
1Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Germany - 2Universidad Austral de Chile, Chile - 3Concordia University, Canada - 4Fundacion San Ignacio del Huinay, Chile- 5Pontificia Universidad Católica de Valparaíso, Chile - 6Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Chile
Understanding how community assembly processes vary across spatial scales and environmental gradients is key to predicting species coexistence and informing conservation priorities. Beta-diversity represents the spatial variation in biodiversity and is intimately linked to processes ranging from fully niche-based to neutral assembly processes. Here we investigated the beta-diversity patterns of rocky subtidal macrobenthic assemblages in two environmentally contrasting fjords of Chilean Patagonia and across three spatial scales and dimensions within each fjord: vertical scale (subtidal depth; 0 – 21 m), fine horizontal (within fjord sections; 1 - 10 km) and broad horizontal (between fjord sections; 10 - 100 km). We applied generalized dissimilarity models (GDMs) to analyse three underlying processes that shape ecological communities: density-independent responses to abiotic conditions (salinity and temperature), dispersal (geographical distances and depth), and stochasticity (beta-null deviations) on beta-diversity expressed as Bray-Curtis dissimilarities. Stochastic and dispersal processes dominated beta-diversity along horizontal gradients, particularly at larger spatial scales, while environmental filters consistently contributed to beta-diversity along depth gradients. The southern fjord presented higher community variation in line with higher environmental heterogeneity. Stochastic processes dominate the northern fjord, suggesting a greater influence of habitat homogenization. These results emphasize the scale-dependent nature of assembly processes in fjord ecosystems and underscore the importance of incorporating multiple spatial dimensions into biodiversity assessments.
Biography
Vicente Villalobos is a Chilean marine biologist and a PhD candidate at the Alfred-Wegener-Institute in Germany. His research focuses on understanding the causes and consequences of biodiversity, particularly the mechanisms driving community assembly processes and their implications for ecosystem functioning. Vicente’s current work explores how the diversity of hard bottom macro-benthic communities influences the functionality of biogeochemical cycles of Chilean Patagonian fjords ecosystems.