The influence of niche and neutral processes on a neotropical anuran metacommunity

Abstract

One of the most important questions in ecology is the relative importance of local conditions (niche processes) and dispersal ability (neutral processes) in driving metacommunity structure. Although many studies have been conducted in recent years, there is still much debate. We evaluated the processes (niche and neutral) responsible for variation in anuran composition in 28 lentic water bodies in southeastern Brazil. Because anurans depend heavily on environmental conditions, we hypothesized that environmental variables (niche processes) are the most important drivers of community composition. Additionally, as anurans have limited dispersal abilities, and the study region presents harsh conditions (high forest fragmentation, low rainfall and long dry season), we expected a lower, but significant, spatial signature in metacommunity structure, due to neutral dynamics. We used a partial redundancy analysis with variation partitioning to evaluate the relative influence of environmental and spatial variables as drivers of metacommunity structure. Additionally, we used a recently developed spatial autocorrelation analysis to test if neutral dynamics can be attributed to the pure spatial component. This analysis is based on predictions that species abundances are independent but similarly spatially structured, with correlograms similar in shape. Therefore, under neutral dynamics there is no expectation of a correlation between the pairwise distance of spatial correlograms and the pairwise correlation of species abundances predicted by the pure spatial component. We found that the environmental component explained 21.5%, the spatial component 10.2%, and the shared component 6.4% of the metacommunity structure. We found no correlation between correlograms and correlation of abundances predicted by the pure spatial component (Mantel test = −0.109, P = 0.961). In our study, niche-based processes are the dominant process that explained community composition. However, neutral processes are important because spatial variation can be attributed to pure neutral dynamics rather than to missing spatially structured environmental factors.

Effects of Grazing Management and Cattle on Aquatic Habitat Use by the Anuran Pseudopaludicola mystacalis in Agro-Savannah Landscapes

“…Despite our predictions that landscape variables would be less important than the structural variables in predicting the abundance of calling males, we found distance to the nearest aquatic habitat to be a very important predictor in our models. This variable has already been considered important for anuran metacommunity structure in the same region [ 55 ] and, indeed, Pseudopaludicola mystacalis was strongly influenced by this variable in previous work (referred to as Pseudopaludicola falcipes 1 in Prado et al [ 55 ]). P .…”

The complex roles of space and environment in structuring functional, taxonomic and phylogenetic beta diversity of frogs in the Atlantic Forest

“…Spatial structure of communities can be the outcome of two principal sources and could not be unambiguously interpreted: environmental predictors that are themselves spatially structured, or spatial autocorrelation [ 7 , 16 ]. In the last few decades it has come to be acknowledged that patterns of diversity may be structured simultaneously by stochastic (neutral) and by niche-based processes at different spatial scales [ 16 , 17 ]. Thus, in order to understand how ecological communities are structured, it has become imperative to investigate, simultaneously, whether spatial and environmental predictors regulate diversity patterns of communities, and if they do so, then how.…”

“…In Brazil, they exhibit a high species diversity, with 1026 species recorded [ 18 ], and show both broad and narrow patterns of geographic distribution [ 19 ]. This variation in distributional patterns of anurans is widely considered to be a result of ecological, spatial and evolutionary mechanisms, such as environmental control and dispersal limitation [ 20 , 17 ]. It is assumed that these patterns can be explained by the extensive phenotypic and behavioural variability of the group, as well as their complex life cycle and permeable skin [ 21 – 23 ].…”

“…It is assumed that these patterns can be explained by the extensive phenotypic and behavioural variability of the group, as well as their complex life cycle and permeable skin [ 21 – 23 ]. The occurrence of tadpoles in particular is recognized to be affected by habitat variables such as canopy cover, pond vegetation structure and pH [ 17 , 24 , 25 ].…”

Evidence of stochasticity driving anuran metacommunity structure in the Pantanal wetlands

“…However, a weak influence of local environmental variables has also been reported, together with an effect of dispersal limitation associated with strong dependence on hydrological connections (De Bie et al, 2012). Therefore, spatial processes due to dispersal limitation also play an important role on the dynamics of anuran metacommunities (Landeiro, Waldez & Menin, 2014;Prado & Rossa-Feres, 2014a;Provete et al, 2014). In the same way, the spatial arrangement of habitat patches and the permeability of the surrounding terrestrial matrix may influence dispersal success of amphibians and, consequently, the occurrence and abundance of many species (Richter-Boix, Llorente & Montori, 2007;Werner et al, 2007a;Landeiro, Waldez & Menin, 2014).…”