Search results for "Limiting similarity"

2016

Ecological communities are structured by competitive, predatory, mutualistic and parasitic interactions combined with chance events. Separating deterministic from stochastic processes is possible, but finding statistical evidence for specific biological interactions is challenging. We attempt to solve this problem for ant communities nesting in epiphytic bird’s nest ferns (Asplenium nidus) in Borneo’s lowland rainforest. By recording the frequencies with which each and every single ant species occurred together, we were able to test statistically for patterns associated with interspecific competition. We found evidence for competition, but the resulting co-occurrence pattern was the opposit…

Plant functional and taxonomic diversity in European grasslands along climatic gradients

2021

Aim European grassland communities are highly diverse, but patterns and drivers of their continental-scale diversity remain elusive. This study analyses taxonomic and functional richness in European grasslands along continental-scale temperature and precipitation gradients. Location Europe. Methods We quantified functional and taxonomic richness of 55,748 vegetation plots. Six plant traits, related to resource acquisition and conservation, were analysed to describe plant community functional composition. Using a null-model approach we derived functional richness effect sizes that indicate higher or lower diversity than expected given the taxonomic richness. We assessed the variation in abso…

Assembly rules of helminth parasite communities in grey mullets: combining components of diversity.

2020

Abstract Organisms aggregate in ecological communities. It has been widely debated whether these associations are explained by deterministic or, in contrast, random processes. The answer may vary, depending on the level of an organisational scale (α, β and γ) and the facet of diversity considered: taxonomic, functional and phylogenetic. Diversity at the level of a sampling unit (i.e. host individual) is the α diversity; β diversity represents the extent of dissimilarity in diversity among sampling units (within a level of an organisational scale, β1; between levels of an organisational scale, β2); and the total diversity of a system is γ diversity. Thus, the combination of facets and levels…

Morphological Similarity and Ecological Overlap in Two Rotifer Species

2013

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentia…

Designing ‘trait-based null model’ approaches to investigate community assembly mechanisms

2014

SPEEAECOLDURGEAPSIéquipe CAPA; During the last decade, many studies have addressed the signature of community assembly processes by assessing the deviation of a functional diversity pattern from that expected in null communities, using a randomization algorithm. The basic principle has been to compare the functional structure of a ‘local community’ with a set of randomly generated communities from a ‘regional species pool’. Specifically, it allows assessing the extent to which species constituting a community are functionally more or less similar than expected under the assumption of a random assembly, thus revealing the influence of assembly processes such as competition or environmental a…