Assessment of pesticide residues in army cutworm moths (Euxoa auxiliaris) from the Greater Yellowstone Ecosystem and their potential consequences to foraging grizzly bears (Ursus arctos horribilis).

During summer, a grizzly bear (Ursus arctos horribilis) in the Greater Yellowstone Ecosystem (GYE) (USA) can excavate and consume millions of army cutworm moths (Euxoa auxiliaris) (ACMs) that aggregate in high elevation talus. Grizzly bears in the GYE were listed as threatened by the US Fish and Wildlife Service in 1975 and were proposed for delisting in 2005. However, questions remain about key bear foods. For example, ACMs are agricultural pests and concern exists about whether they contain pesticides that could be toxic to bears. Consequently, we investigated whether ACMs contain and transport pesticides to bear foraging sites and, if so, whether these levels could be toxic to bears. In 1999 we collected and analyzed ACMs from six bear foraging sites. ACMs were screened for 32 pesticides with gas chromatography with electron capture detection (GC-ECD). Because gas chromatography with tandem mass spectrometry (GC-MS/MS) can be more sensitive than GC-ECD for certain pesticides, we revisited one site in 2001 and analyzed these ACMs with GC-MS/MS. ACMs contained trace or undetectable levels of pesticides in 1999 and 2001, respectively. Based on chemical levels in ACMs and numbers of ACMs a bear can consume, we calculated the potential of chemicals to reach physiological toxicity. These calculations indicate bears do not consume physiologically toxic levels of pesticides and allay concerns they are at risk from pesticides transported by ACMs. If chemical control of ACMs changes in the future, screening new ACM samples taken from bear foraging sites may be warranted.

The Role of Ecology in Biological Conservation.

The emerging science of conservation biology represents an intersection of elements of ecology, genetics, biogeography, and many traditional applied disciplines such as wildlife management and forestry. Its major concern is providing a valid scientific basis for actions that will slow or stop the accelerating loss of biological diversity worldwide. Ecology's major contributions to conservation biology so far include the equilibrium theory of island biogeography and the theoretical relationship between population size and persistence time. In the future ecologists can contribute their skills to conservation biology in numerous ways; I suggest three in particular. These are investigating the autecology and natural history of rare species, testing hypotheses concerning population viability with carefully designed laboratory and field experiments, and working to establish and implement a national policy for the protection of biological diversity on United States public lands.