Environmental assessment: Evaluation of ungulate impacts to park resources; a research project using exclosures

Bandelier National Monument

Bandelier National Monument was originally established to protect and preserve archeological resources. During the past 60 years, national legislation has expanded that mission to include protection and preservation of natural resources as well. Today, large numbers of elk (Cervus elaphus) and deer (Odocoileus hemionus) are causing visible damage to both cultural and natural resources in the park. Elk numbers have increased dramatically during the last 30 years in and near Bandelier National Monument. Within the park, deer have been reported at habitat-damaging levels since at least the 1950's. Heavy grazing and browsing by elk and deer are apparent on several plant species. Removal of plant material by elk and deer along with associated soil trampling appear to be changing forest and grassland structure, changing habitat compositions, contributing to losses of cultural resources, and magnifying high erosion rates in pinon (Pinus edulis)-juniper (Juniperus spp.) habitats. Significant resource loss may result if the observed trends continue in the future. Before potential actions and alternatives can be identified, however, objective and quantitative information is needed. A study approach using replicated ungulate exclosures and vegetation reference sites is proposed. Measurements at both the exclosures and reference sites will record soil surface cover; tree and scrub cover; grass and forb standing biomass and annual biomass production; forb and shrub reproduction and vigor; and measures of insect, small mammal and bird usage. Population indices for elk and deer will also be determined based on pelletgroup counts. The accumulated data will provide information on the current level of plant utilization by ungulates, damage to plants due to trampling by ungulates, impacts to cultural resources, and effects on insect, small mammal, and bird populations. This information will be used to determine long-term sustainable ungulate population levels relative to the current level.