Local and Regional Aspects of Habitat Quality Jointly Affect the Biodiversity of Ephemeral Ponds

The biodiversity of local communities is likely affected by both local habitat quality and by the quality of the landscape surrounding the locality. In pond environments, habitat quality may be affected by the kind of leaf litter present because leaf species differ in the kind of habitat structure they provide and the rate at which they release nutrients into the water. Landscape quality could affect diversity as well; some landscapes provide a richer pool of potential colonists. In addition, the plant community surrounding ponds could alter the influence of habitat selection: animals may prefer to colonize ponds that have litter which matches that kind of litter typically produced by plants in the surrounding landscape (e.g. if organisms are adapted to the litter types in the habitats where they occur). We conducted a split-plot randomized block experiment to examine how both landscape and local scale properties, and their interaction, affect biodiversity within temporary pond communities in eastern NC. We manipulated both the kind of landscape in which artificial ponds were located (open-canopy grassland, pine forest, and hardwood forest) and the leaf species (sedge, pine, or maple) present in artificial ponds. Ponds were open to colonization by amphibians and aquatic insects during the summer of 2010. We surveyed organisms in the ponds on a monthly basis and did a complete census of each pond at summer's end.   The kind of plant community (landscape) had consistent, strong effects on biodiversity throughout the experiment: ponds in open-canopy landscapes supported more species and different kinds of species than ponds in forested systems. Litter type affected biodiversity in the monthly catch-and-release samples, with more species in sedge treatments than pine treatments. We also found evidence from the monthly samples to suggest biodiversity was enhanced to a greater extent in open canopy ponds when litter from open canopy environments was present but that biodiversity in closed canopy environments was affected less by the kind of litter present. Our results highlight the importance of the terrestrial matrix surrounding ponds on biodiversity within the ponds, and it could aid conservation efforts aimed at maintaining the unique biodiversity of temporary ponds.  M.S