Multiscale patterns of ground-dwelling spider (Araneae) diversity in Northern Canada

Patterns of diversity and their determinants are dependent on spatial scale. Integrating data collected on a local scale with larger-scale questions is a challenging and necessary step to improving our understanding of diversity patterns and influencing factors. Partitioning diversity was used to examine spider (Araneae) diversity patterns on multiple spatial scales in Northern Canada. Arctic environments are interesting in this context because harsh local conditions can influence regional patterns. As part of the Northern Biodiversity Program, ground dwelling spiders were sampled in a standardized way in 12 sites with comparable habitats. The nested sampling design had three spatial scales: local, regional and continental. We compared diversity patterns of each component (α, β and γ) and consistency of patterns at each scale using the partition software. Gradients of diversity were found at the regional and continental scales even when species composition followed a random distribution at local scale. Each region showed different patterns of alpha and beta diversity suggesting that glacial history or climate can influence large pattern of diversity.