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What is the impact of trait selection in the ecological inferences of habitat filtering and competition?
Tali Guez, Andrea Paz
Understanding the processes shaping species composition and structure in ecological communities has been a growing focus over the past decades. Two processes are suggested to explain community assembly: biotic (e.g., competition) and habitat filtering (environmental constraints). Historically, phylogenetic diversity studies compared observed communities to null models, traits conservatism of traits within phylogenies. Habitat filtering often would result in clustering (underdispersion), where related species with similar traits are selected by environmental constraints, while biotic interactions lead to trait overdispersion, where unrelated species with divergent traits coexist due to niche partitioning.
However, phylogenetic and functional diversity are not necessarily fully correlated and trait convergence/divergence amongst species is not as rare as previously thought. Functional diversity indices, which often pool traits together, are now commonly used to infer those processes. Yet the selection of traits is often based on availability, measurement effort or ecological relevance and thus might introduce biases into the inferences of under/over dispersion.
The project aims to analyze regional amphibian and global tree datasets to explore how trait selection influences conclusions about habitat and biotic filtering. It will involve selecting different groups of traits (randomly, based on ecology, and using different numbers of traits) to create functional diversity maps and compare them to null models of community assembly. We will then compare both the patterns functional diversity distribution and inferences of over/under dispersion. This will allow us to assess how trait selection strategies influence ecological conclusions regarding the distribution of diversity and community assembly processes.
