Microeukaryotic habitat specialists exhibit stronger determinism and biodiversity-nutrient cycling relationship than generalists in a subtropical river.

Abstract

Microeukaryotic generalists and specialists exhibit varying levels of environmental sensitivity, which contribute differently to community dynamics and are important for aquatic ecosystem functioning. However, the community assembly, co-occurrence network, and impacts of microeukaryotic generalists and specialists' diversity on ecosystem functions remain poorly understood in riverine ecosystems. Here, we investigated the microeukaryotic generalists and specialists along a subtropical river. Our results showed that specialists were more controlled by deterministic processes compared with generalists. Co-occurrence network analysis revealed that microeukaryotic specialists were more interconnected and contributed more to maintaining network stability. More importantly, microeukaryotic specialists also played disproportionately important roles in maintaining nutrient cycling. Overall, our results elucidated the different ecological responses of microeukaryotic generalists and specialists and emphasized the important roles of microeukaryotic specialists in maintaining ecosystem stability and functions, thus providing a new perspective to better understand the significance of specialists in riverine ecosystems.

Importance: The underlying community assembly mechanisms and biodiversity-nutrient cycling (BNC) relationships of microeukaryotic generalists and specialists remain unknown in riverine ecosystems. Here, we found that microeukaryotic habitat specialists, compared with generalists, exhibited stronger deterministic processes and contributed more to maintain co-occurrence network stability, suggesting that specialist communities were more vulnerable to environmental disturbances than generalists. Furthermore, we found specialists exhibited stronger BNC relationships, indicating specialists with narrow distribution seem to have greater capacity to support ecosystem functions. Overall, this study expands the current understanding of assembly mechanisms and BNC relationships in microeukaryotic generalists and specialists.