Biodiversity Increases the Productivity and Stability of Phytoplankton Communities

Abstract

Global biodiversity losses provide an immediate impetus to elucidate the relationships between biodiversity, productivity and stability. In this study, we quantified the effects of species richness and species combination on the productivity and stability of phytoplankton communities subject to predation by a single rotifer species. We also tested one mechanism of the insurance hypothesis: whether large, slow-growing, potentially-defended cells would compensate for the loss of small, fast-growing, poorly-defended cells after predation. There were significant effects of species richness and species combination on the productivity, relative yield, and stability of phytoplankton cultures, but the relative importance of species richness and combination varied with the response variables. Species combination drove patterns of productivity, whereas species richness was more important for stability. Polycultures containing the most productive single species, Dunaliella, were consistently the most productive. Yet, the most species rich cultures were the most stable, having low temporal variability in measures of biomass. Polycultures recovered from short-term negative grazing effects, but this recovery was not due to the compensation of large, slow-growing cells for the loss of small, fast-growing cells. Instead, polyculture recovery was the result of reduced rotifer grazing rates and persisting small species within the polycultures. Therefore, although an insurance effect in polycultures was found, this effect was indirect and unrelated to grazing tolerance. We hypothesize that diverse phytoplankton assemblages interfered with efficient rotifer grazing and that this “interference effect” facilitated the recovery of the most productive species, Dunaliella. In summary, we demonstrate that both species composition and species richness are important in driving patterns of productivity and stability, respectively, and that stability in biodiverse communities can result from an alteration in consumer functioning. Our findings underscore the importance of predator-prey dynamics in determining the relationships between biodiversity, productivity and stability in producer communities.

Effects of Environmental Factors on the Temporal Stability of Phytoplankton Biomass in a Eutrophic Man-Made Lake

“…Ecologists argue that the temporal stability of phytoplankton is positively influenced by its diversity [14,19,[21][22][23][24]. In the present study, we observed that both the temporal mean and variability of many environmental factors had an influence on the temporal stability of phytoplankton.…”

“…McGrady-Steed et al [19] suggested that aquatic microbial communities with higher diversity were more stable (measured as predictability). Corcoran and Boeing [21] found that phytoplankton temporal stability increased with increasing diversity. However, field investigations conducted over the past few years have shown conflicting diversity-stability relationships in phytoplankton communities [24,25].…”

“…In most cases, ecologists mainly focused on the effects of phytoplankton diversity on community stability [19][20][21][22]. Most studies based on artificial phytoplankton communities in the laboratory have shown positive diversity-stability relationships [19,21,23].…”

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

“…Previous studies based on artificial plankton communities in the laboratory have shown positive diversity-stability relationships [26]. Corcoran and Boeing [27] found that phytoplankton temporal stability increased with increasing diversity. McGrady-Steed et al [28] suggested that aquatic microbial communities with higher diversity were more stable (measured as predictability).…”

New scope on the relationship between rotifers and Biomphalaria alexandrina snails

“…These microscopic animals can be either freewheeling or parasitic and known to live in a variety of fresh and salt water environments [10,18] .Rotifers possess wide ecological importance. They represent an important part of the freshwater zooplankton by contributing to nutrient recycling [10,19] . On the other hand, some species of rotifers are associated with organisms in a predator-prey manner [20] .…”