Cross-scale effects of habitat fragmentation on local biodiversity and ecosystem multifunctionality in a fragmented grassland landscape

Anthropogenic habitat fragmentation has become the main threat to terrestrial ecosystems worldwide. However, the impacts of habitat fragmentation at different spatial scales on biodiversity and ecosystem functions remain uncertain. Based on 130 fragmented grassland landscapes in the agro-pastoral ecotone of northern China, we investigated the hierarchical effects of habitat fragmentation at landscape and patch scales on plant, soil bacteria, and soil fungi diversity and ecosystem multifunctionality in local sample sites. We found that increased inter-patch distance within the landscape had the strongest negative effect on plant richness. Decreased habitat amount within the landscape had the strongest negative effect on bacteria richness, fungi richness, and 80% threshold multifunctionality. Decreased patch area and increased patch isolation had the strongest negative effects on 30% and 50% threshold multifunctionality, respectively. Importantly, we found that patch-scale fragmentation mediated the negative effects of landscape-scale fragmentation on biodiversity and ecosystem multifunctionality. And biodiversity had no significant effect on ecosystem multifunctionality.

Synthesis. Our study highlights that both landscape-scale and patch-scale fragmentation decline biodiversity and ecosystem multifunctionality in the agro-pastoral ecotone in northern China, with a significant spatial hierarchical structure. Biodiversity poorly predicts ecosystem multifunctionality in the fragmented grassland landscape.