The biodiversity of a habitat patch is predicted to be driven in part by interactions between patch quality and landscape context (i.e. type of regional matrix), but these interactions are rarely explored experimentally. Understanding the interaction between patch quality and matrix context can provide insight into the kind of dynamics that best describe a metacommunity and help predict how the diversity of a patch will respond to environmental change at different scales. We conducted a landscape-scale experiment to examine how regional and local aspects of the terrestrial matrix interact to affect biodiversity within artificial ponds designed to mimic generic features of freshwater ephemeral ponds. We manipulated both the kind of matrix surrounding ponds (open canopy grassland, pine forest, and hardwood forest) and pond quality (three different types of leaf litter substrate). Ponds were left open to natural colonization for three months by aquatic insects and amphibians. The terrestrial matrix had consistent and strong effects on biodiversity throughout the experiment: ponds in open canopy areas had more animal morphotypes than ponds in pine or hardwood forests. Leaf litter type affected biodiversity during the experiment, with more animal morphotypes in ponds with higher quality litter than ponds with lower quality litter, and this effect was stronger in open canopy areas. The effect of leaf litter, however, disappeared by the end of the experiment. Our results suggest that the matrix surrounding patches has strong effects on community dynamics and biodiversity within patches, and conservation efforts aimed at maintaining biodiversity requires simultaneous consideration of both matrix habitats and habitat patches.

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