Importance & Issues
For the North Coast and Cascades Network, we selected elk for monitoring over several other potential wildlife species or groups of species because of their potentially large influence on ecosystems where they occur and the many agents of change that are expected to influence future elk populations.
Because elk are important agents of ecological change within park ecosystems, reliable information on trends is needed to interpret changes in the health of park ecosystems. Over several decades, there has been recurrent controversy regarding potential ecological effects of overabundant elk on ecological integrity of subalpine meadows in Mount Rainier National Park and of lowland rainforest communities in Olympic National Park.
At Lewis and Clark National Historical Park, we selected elk for monitoring over several other potential wildlife species or groups of species because of their importance to interpreting the Lewis and Clark story, their popularity with the visiting public, their potentially large influence on ecosystems where they occur and the many agents of change that are expected to influence future populations of elk.
- Lewis and Clark National Historical Park
- Mount Rainier National Park
- Olympic National Park
- Monitor trends in elk abundance, distribution, and herd composition in selected subalpine summer ranges in Mount Rainier and Olympic National Parks.
- Monitor trends in elk abundance and distribution in selected low-elevation winter ranges in Olympic National Park.
Monitor trends in relative use and in the proportion of the area occupied by elk in the Fort Clatsop unit of Lewis and Clark National Historical Park.
- Monitor seasonal trends in elk sightings during roadside surveys near the Fort Clatsop unit of Lewis and Clark National Historical Park.
Approach for Mount Rainier and Olympic National Parks
For summer surveys, we monitor trends in the estimated abundance, spatial distribution, bull:cow ratio and cow:calf ratio of elk present in selected subalpine trend count areas during late summer. The surveys are conducted from helicopter between August 15th and September 15th each year. Summer surveys at Mount Rainier are jointly supported by NPS, Muckleshoot Indian Tribe, Puyallup Tribe of Indians, and Washington Department of Fish and Wildlife.
Summer trend count areas correspond with major summer ranges of elk in each park and include open subalpine vegetation; they have been defined by a combination of elevation and forest canopy cover. At Mount Rainier, the trend count areas also coincide with historical survey areas to provide comparative information. To adjust for differing detection rates due to such variables as group size and vegetation where the groups are found, raw counts of elk are converted to abundance estimates through the use of group-specific weighting. The weighting factor for each group will come from a sightability model developed to account for variation in detection probability due to covariates such as group size, vegetative cover, or other covariates.
For spring surveys, we monitor trends in the abundance and spatial distribution of elk using three primary winter range areas of elk in the western rainforest valleys of Olympic National Park: Hoh, South Fork Hoh, and Queets. The floodplains and associated terraces of these three rivers have been the primary survey units for elk monitoring in Olympic National Park for over 25 years. However, due to insufficient funding, the spring surveys were put on hiatus in 2010 and will be reinstated when funding becomes available.
If funding becomes available, the spring surveys will be conducted during the last weeks of winter / first weeks of spring, when forest understory plants on floodplain habitats have begun spring growth, but before leaves on overstory deciduous trees obscure visibility to ground level. The survey window is in March; April surveys are precluded by endangered species restrictions of the marbled murrelet nesting season.
Approach for Lewis and Clark National Historical Park
Relative use and proportion of area occupied (PAO) are two measures from which we infer trends in elk use within the Fort Clatsop unit of the Park. Relative use in this protocol refers to the estimated abundance of elk fecal pellet groups at survey points which are distributed systematically throughout the Fort Clatsop unit. PAO is estimated based on the pattern of survey points where elk 'sign' is detected by either one or both of two independent observers. Estimates of relative use and PAO in the Fort Clatsop unit draws on data coming from elk fecal pellet group surveys at survey points. Monitoring is limited to the winter season due to funding constraints and pellet decay rates.
Ungulate pellet group density can be a reliable index of relative use so long as decay rates and probabilities of detecting pellet groups are comparable across the sampled space or can be estimated. To control for potentially variable decay rates, we clear any elk pellets from surveyed plots in the fall. To estimate pellet group detection probability, we collected double-observer data that was used to develop a statistical model for pellet detection probability.
We monitor the rate at which elk are sighted in roadside surveys on specified routes. The road survey sighting rate is a direct index to the rate that park visitors driving the selected set of roads would be expected to see elk. Although road surveys are standardized, the road survey sighting rate is not a direct measure of elk abundance.
Monitoring results will allow park managers in Mount Rainier and Olympic National Parks to determine whether elk abundance in the surveyed subalpine areas has increased or decreased and to identify changes in herd composition and distribution in those areas. Even though elk populations are protected in these parks, land use, hunting, and predator management programs on lands adjacent to Mount Rainier and Olympic National Parks and increased prevalence of wildlife diseases (e.g., chronic wasting disease, paratuberculosis, and brucellosis) have the potential to influence elk population trends and ecosystem properties within the parks.
The superintendent and staff at Lewis and Clark National Historical Park specifically selected elk monitoring as a useful tool for building community partnerships, monitoring the effects of forest and wetland restoration efforts, highlighting regional habitat and land use planning effects on park resources, and providing the only peer-reviewed data in regional discussions of policies that may influence the Park's elk population. The double-observer method also allowed for a comparison in accuracy between citizen scientists and resource professionals. To date, there is no statistical difference between these volunteers and biologists in their elk pellet detection rate.