Coastal Aquatic Biodiversity
Recently terrestrial biodiversity has been positively connected to forest age, but data is lacking for freshwater ecosystems. We evaluated hypotheses about spatial patterns of freshwater vertebrates, freshwater invertebrates, and Phytophthora using traditional and/or environmental DNA (eDNA) methods across a gradient of young to old forests. Freshwater vertebrate and invertebrate richness was higher in older forests supporting the intact ecosystem hypothesis likely from greater habitat heterogeneity supporting rare, specialized species. Old forests have more species than young forests, suggesting that activities or events that affect forest age may affect freshwater biodiversity. Functional invertebrate richness was higher in older forests probably owing to their many community roles. Interestingly, higher taxonomic vertebrate richness did not lead to higher functional richness based on the roles of the species detected. There was not a significant pattern for species or functional evenness, except invertebrate functional evenness was higher in younger forests because of similar abundances across species within each watershed with more variability in older forests. Our findings support adding freshwater biodiversity as another ecological role to forests.