Thursday, August 9, 2007 - 2:30 PM

COS 122-4: The living and dead ungulates of Yellowstone National Park: Testing recent surficial bone assemblages as a source of high-quality historical insight

Joshua H. Miller, The University of Chicago

Landscape-scale surficial accumulations of large-mammal bones that accrue over numerous generations are potentially excellent sources of high-quality historical data that are complementary to modern ecological surveys. Information on an animal community’s recent and more distant past is vital for understanding how anthropogenic perturbations have contributed to its current population structure. However, particularly for localities where long-term, multi-generational studies have not been conducted, we must look to other means to acquire the relevant historical data. Recent bone accumulations may provide the necessary historical insight to more adeptly understand current large-mammal populations and make appropriate goals for restoration. Here I use the well-studied ungulate community of Yellowstone National Park (YNP) to test the fidelity with which recent large-mammal bone remains mirror the population structure and habitat utilization of living populations in cold, temperate environments. Transects sampled in four generalized habitats (grasslands, forests, rivers, and lakes) recovered remains from all native ungulate species that breed within YNP. Furthermore, strongly positive relationships between the living community’s rank-order abundances and their representation in the dead remains (Spearman rho ~0.7 to 0.9) illustrate the quality of abundance data. Geographic distributions of bones also conform to species-specific habitat preferences (particularly for bison and pronghorn), and changes in small-scale habitat utilization over the last couple decades among elk are documented by calibrating stages of bone decay to carcasses of known decomposition time. Finally, mountain goats, introduced in the 1990’s, show a predicted absence in the bone sample due to both habitat specificity and a lack of time to incorporate remains into the bone record from small, geographically constrained populations. Although an untapped resource for management and conservation planning, the ecological data contained within recent bone accumulations can provide an historical setting with which to more fully understand the populations (changing or stable) of a living mammal community.