Large predators, prey carcasses, resource pulses, and heterogeneity in terrestrial ecosystems

TitleLarge predators, prey carcasses, resource pulses, and heterogeneity in terrestrial ecosystems
Publication TypeThesis
Year of Publication2008
AuthorsBump JK
AdvisorPeterson RO, Vucetich JA
Academic DepartmentForest Resources and Environmental Science
DegreeDoctor of Philosophy
Number of Pages173 p.
UniversityMichigan Technological University
CityHoughton, MI
Thesis TypePhD Dissertation

A large ungulate carcass is a significant concentration of premium resources. Understanding the flow of resources from carcasses and what factors influence carcass distribution is important to comprehending links between food-webs and ecosystem processes. This dissertation explores the ecological legacy of large ungulate carcasses in terms of their effects on soil nutrients, microbial communities, and plant quality and growth. The influence of large predators on the spatial distribution of carcasses was also explored. These studies took place across three large predator-prey systems (wolf-moose, -elk, and -deer) and employed experimental and observational analyses. Prey carcasses, whether or not they were well-utilized by predators and scavengers, created significant nutrient pulses to soils at carcass sites that lasted 2-4 growing seasons postmortem. These changes altered microbial communities and increased plant tissues quality and growth at carcass sites relative to paired control sites. Positive feedback mechanisms likely enhanced carcass effects because carcass sites become focal points for other species. The spatial distribution of carcasses was highly clustered, with carcass density depending on mortality type (wolf-killed versus starvation). Carcass density shifted significantly over time and carcass distribution was influenced by the predatory behavior of large carnivores. The chemical and physical changes at carcass sites create resource pulses and disturbances that contribute to ecosystem heterogeneity. Large predators influence ecosystem heterogeneity through carcass distribution and are thereby mechanistically linked to the maintenance of biodiversity.