¿Blanco, negro o escala de grises? Determinación de la contribución relativa del nicho ecológico y la teoría neutral en los ensambles de especies

Abstract

According to the niche theory, species assemblies should reflect biotic and abiotic local conditions. In turn, the neutral theory of biodiversity stands that species are equivalent and that local species assembly is the product of colonization and extinction rates. After some years of debate, nowadays, ecologists agree that purely niche or neutral assemblies rarely occur in nature and, in turn, that the rule are assemblies somewhere in the middle. A niche assembly is the product of interspecific interactions or environmental forcing, while a neutral assembly is derived from intrinsic population dynamics (e.g., colonization and extinction rates). The beta-diversity concept (it has various definitions, but all of them share the idea of a link between local [alpha] and regional [gamma] diversity, and, thus, refers to the heterogeneity in species composition between places or times) has become particularly popular during the last decade. It is used to analyze a great variety of systems in different ways. In particular, it gained attention as a tool to differentiate niche- vs neutral-based species assembly. This could be easily addressed using ad hoc neutral models. A pure neutral assembly should exhibit a variability in species composition similar to that expected by randomly selecting species from the regional pool (gamma diversity) for each sample (alpha diversity). The more deviant from the variability expected by chance, the more niche-based assembly. We have greatly expanded our knowledge of the factors that promote one or the other type of assembly. However, there is still much more to elucidate, like how neutral vs. niche assembly is influenced by the interaction between factors, spatio-temporal relationships or if there are scale-dependent variations. In this review, we analyze the potential uses and methodologies associated with this emerging topic in community ecology and discuss some related and interesting scientific questions that remain unanswered. https://doi.org/10.25260/EA.18.28.1.0.622