Predicted effects of climate change on the spatial distribution of soil nematodes at a regional scale

Abstract

Soil biodiversity is essential for the provision of ecosystem services, yet the response of belowground communities to climate change remains unclear and poorly integrated into conservation policies. In soil, nematodes are recognized as bioindicators of soil health and function. In this study, we aimed to assess the current distribution and potential shifts in nematode communities across the North of Portugal, considering the climate forecasts. A total of 406 soil samples were collected throughout the region in different land-use types (agriculture, forests, pastures and urban areas), in a stratified sampling design, from which soil nematodes were extracted and identified through morphological characters. Species distribution models were created using ensemble approaches to predict their distribution under current and future climate conditions. Our results show that slope, agriculture cover and precipitation were the most important drivers of nematode distributions. Model projections under three future climate Shared Socioeconomic Pathways (SSP1, SSP3, SSP5) for 2041–2070 suggest a decline in nematode richness in 58.10% of the region, particularly in the northwest. Trophic groups responded differently: omnivores, fungivores and herbivores substantially reduced their distribution, while bacterivores expanded their range. Results suggest that protected areas buffer species loss and foster richness gain across all climate scenarios, although their effectiveness remains uncertain. This study highlights the importance of protecting belowground communities and their functions in the face of climate change. Integrating soil biodiversity into policy planning will contribute to build resilient ecosystems under global change.