Placing biodiversity and ecosystem functioning in context: environmental perturbations and the effects of species richness in a stream field experiment

摘要: Greater biodiversity is often associated with increased ecosystem process rates, and expected to enhance the stability of functioning under abiotic stress. However, these relationships might themselves be altered by environmental factors, complicating prediction effects species loss in ecosystems subjected In boreal streams, we investigated two perturbations on three related indices functioning: leaf decomposition, detritivore processing efficiency (LPE) growth. Replicate field enclosures containing leaves assemblages were exposed liming nutrient enrichment, raising pH levels. Both treatments constitute for our naturally acidic nutrient-poor streams. We also varied richness density. The diversity manipulations similar magnitude, but whereas decomposition 18% 8% following respectively, reduced (6%), LPE (19%) growth (12%). effect was negative trait-independent complementarity, indicating interspecific interference competition. These interactions apparently alleviated both enriched limed enclosures, as complementarity became less negative. density monocultures, benefits intra-specific aggregation that outweighed costs competition, dilution probably contributed lowered mixtures. Finally, most mixtures relative monocultures. results demonstrate how changes regulate consequences anthropogenically perturbed ecosystems, highlight potential influences functional stability. Additionally, positive study opposite previous laboratory observations, further illustrating importance context biodiversity-ecosystem relationships.