Substantial long-Term effects of carcass addition on soil and plants in a grassy eucalypt woodland

Abstract

The decomposition of large vertebrate carcasses generates small-scale disturbances characterized by changes in soil chemistry and new opportunities for plant establishment. Yet few studies have examined whether this effect is still evident several years after death, or has consequences for landscape-scale heterogeneity. We examined soil chemistry and plant species richness and composition at 12 kangaroo carcasses (~30 kg initial mass) five years after their initial placement. Each carcass was paired with a nearby "control" site for comparison. We found that soil phosphorus was eight times higher at carcasses than at control sites, but that nitrogen concentration was similar. We also found that plant composition was substantially different between each carcass and control pair, with 80% of carcasses dominated by exotic species (mostly weedy annuals). Notably, overall variability in plant species composition across carcass sites was not different from the variability at control sites, indicating that the colonization of carcasses by weedy species did not have a homogenizing effect on plant assemblages across our study landscape. Our study demonstrates that a localized effect of large vertebrate carcasses on soil and plants was still evident after five years, indicating a state shift in the soil-plant dynamics at a carcass site. However, the effect of carcasses on landscape-scale plant community heterogeneity was minimal because colonization was by weedy plants already present in the landscape.