Diversity metrics of spider communities associated with an understorey plant in tropical rain forest fragments

Human activities change the biodiversity of ecological communities in at least three dimensions: ecologically, taxonomically and functionally. Gathering information on these three dimensions allows the improvement of biodiversity assessments and the increased understanding of anthropogenic impact on natural communities. In this study, we analysed the spider community associated with the tropical plant Heliconia aurantiaca in two contrasting habitat types: continuous forest and forest fragments in south-eastern Mexico. We examined the foliage, stems and bracts of H. aurantiaca individuals in both habitats. We categorized each spider species according to its behavioural and functional traits. We analysed ecological diversity using Hill numbers, taxonomic distinctness and functional diversity using the FRic index. Overall, we collected a total of 110 spiders, of which 44 individuals from 29 species were found in continuous forests, with 66 individuals from 36 species in forest fragments. We found greater ecological diversity in continuous forest than in fragments. In contrast, we found lower functional diversity in continuous forest than in fragments. Taxonomic diversity showed no significant difference between habitats. Forest fragmentation affected the biodiversity of spiders by disrupting species composition and function, which may lead to other ecological changes such as predator-prey interactions and other aspects of ecosystem functioning.