Correlates of zooplankton beta diversity in tropical lake systems.

Paloma M Lopes,Ludgero C G Vieira,Steven A J Declerck,Luis M Bini,Vinicius F Farjalla,Francisco A Esteves,Fabio A Lansac-Toha,Reinaldo L Bozelli,Claudia C Bonecker,Frédéric Guichard

doi:10.1371/journal.pone.0109581

Abstract

The changes in species composition between habitat patches (beta diversity) are likely related to a number of factors, including environmental heterogeneity, connectivity, disturbance and productivity. Here, we used data from aquatic environments in five Brazilian regions over two years and two seasons (rainy and dry seasons or high and low water level periods in floodplain lakes) in each year to test hypotheses underlying zooplankton beta diversity variation. The regions present different levels of hydrological connectivity, where three regions present lakes that are permanent and connected with the main river, while the water bodies of the other two regions consist of permanent lakes and temporary ponds, with no hydrological connections between them. We tested for relationships between zooplankton beta diversity and environmental heterogeneity, spatial extent, hydrological connectivity, seasonality, disturbance and productivity. Negative relationships were detected between zooplankton beta diversity and both hydrological connectivity and disturbance (periodic dry-outs). Hydrological connectivity is likely to affect beta diversity by facilitating dispersal between habitats. In addition, the harsh environmental filter imposed by disturbance selected for only a small portion of the species from the regional pool that were able to cope with periodic dry-outs (e.g., those with a high production of resting eggs). In summary, this study suggests that faunal exchange and disturbance play important roles in structuring local zooplankton communities.

Highlights

Beta diversity, that is, the change in species composition between habitat patches, is directly related to local or alphadiversity and to regional or gamma-diversity [1,2]
We examined the effect of seasonality and disturbance on zooplankton communities by calculating the local contribution to beta diversity (LCBD) as a measure of ecological uniqueness of each lake in terms of species composition [33]
Environmental heterogeneity, seasonality and spatial extent had no significant effect on beta diversity (Table 1)

Summary

Introduction

That is, the change in species composition between habitat patches, is directly related to local or alphadiversity (i.e., number of species within a particular habitat) and to regional or gamma-diversity (i.e., diversity in the different habitats within a region) [1,2]. Understanding the mechanisms underlying beta diversity is one of the main goals in community ecology and interest in this area has increased substantially in the last decade [3,4,5]. Both deterministic and stochastic processes may affect beta diversity patterns. Deterministic processes are based on niche theory and assume that environmental filtering and biotic interactions play major roles in shaping local community composition. According to this theory, species have different ecological requirements, determining different responses to environmental gradients [6]. It is increasingly recognised that these processes shape the community structure simultaneously [8]

Methods

Results

Conclusion