Bottom‐up effects of species diversity on the functioning and stability of food webs

Abstract

Summary1. The importance of species diversity for the stability of populations, communities and ecosystem functions is a central question in ecology. 2. Biodiversity experiments have shown that diversity can impact both the average and variability of stocks and rates at these levels of ecological organization in single trophic-level ecosystems. Whether these impacts hold in food webs and across trophic levels is still unclear. 3. We asked whether resource species diversity, community composition and consumer feeding selectivity in planktonic food webs impact the stability of resource or consumer populations, community biomass and ecosystem functions. We also tested the relative importance of resource diversity and community composition. 4. We found that resource diversity negatively affected resource population stability, but had no effect on consumer population stability, regardless of the consumer's feeding selectivity. Resource diversity had positive effects on most ecosystem functions and their stability, including primary production, resource biomass and particulate carbon, nitrogen and phosphorus concentrations. 5. Community composition, however, generally explained more variance in population, community and ecosystem properties than species diversity per se. This result points to the importance of the outcomes of particular species interactions and individual species' effect traits in determining food web properties and stability. 6. Among the stabilizing mechanisms tested, an increase in the average resource community biomass with increasing resource diversity had the greatest positive impact on stability. 7. Our results indicate that resource diversity and composition are generally important for the functioning and stability of whole food webs, but do not have straightforward impacts on consumer populations.

Trophic complementarity drives the biodiversity–ecosystem functioning relationship in food webs

“…This is congruent with a release from a strong top‐down control of consumers by predators with their extinction. The potentially complex dynamics that are likely to arise when both bottom‐up and top‐down effect are acting (Narwani & Mazumder ) may explain the lower for the removal of consumers than for the removal of predators (Table S1).…”

Producer diversity enhances consumer stability in a benthic marine community

“…; Best et al . ), we are unaware of any experiments testing the effects of producer diversity on the stability of these consumer responses outside of aquatic microcosms (Narwani & Mazumder ) and terrestrial grasslands (Proulx et al . ; Haddad et al .…”

“…; Haddad et al . ; Borer, Seabloom & Tilman ; Narwani & Mazumder ). It remains unclear, however, as to what extent the increased consumer stability observed in grasslands resulted from producer diversity or producer biomass.…”

Plankton Community Stability and Its Relationship with Phytoplankton Species Richness in Lake Nansihu, China

“…The rapid loss of biodiversity has generated great concerns about the influence of diversity on main ecosystem processes, such as productivity and stability [1][2][3][4]. Aquatic ecosystems are unique, and the stabilization of their main organisms, phytoplankton and zooplankton, has been found to be influenced by variations in producer diversity [5,6].…”