Recipient Organization
UNIVERSITY OF MONTANA
COLLEGE OF FORESTRY AND CONSERVATION
MISSOULA,MT 59812
Performing Department
College of Forestry and Conservation
Non Technical Summary
Many elk populations in western Montana are declining at the same time as wolf recovery, leading to simplistic conclusions that wolves are causing declines while completing ignoring the role of habitat, and in particular changes in forest harvest and fire. Our project aims to understand the changes in forage and habitat, and how these affect elk calf survival, adult female body condition, to enable the forest service to continue to meet its mandate for providing recreational opportunities and habitat for ungulates and other wildlife. The research breakdown is approximately a 50/50 split between basic and applied research.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
There is almost no more contentious current wildlife management issue in the state of Montana than the effects of recovering wolves on elk. The decline of many western Montana elk populations and calf recruitment has seemingly occurred at the same time as wolf recovery in several populations. This coincidence has lead casual observers and state politicians alike to conclude that wolf predation is the leading cause. This simplistic 'top-down' interpretation of wolf predation driving elk populations completely ignores decadal-scale changes in habitat for ungulate species like elk. Habitat includes forage, but also security cover from both human and non-human predation, and many areas in western Montana have undergone significant changes in the last several decades, for example in declining forestry, changes in fire, and increasing forest succession and shrub encroachment. However, what is unknown and as yet completely underappreciated in the recent controversies about elk declines is the role that these habitat changes have had on elk populations. For example, in the Bitterroot valley, commercial forestry has declined in the last several decades at the same as a surge in recent fires, but all of this is set against a backdrop of increasing invasive species such as knapweed and forest succession and shrub encroachment because of a long-history of fire suppression. Recent interest in stewardship contracting, for example, could be guided by implications of our research. Furthermore, our research will contribute to improved working relationships between Montana Fish, Wildlife and Parks (MFWP), the USFS, and local recreational sportsman's groups in support of forest harvest plans to benefit wildlife. The broad objectives of this project are to understand how bottom-up forest and habitat factors affect contrasting population dynamics in two adjacent elk herds in the Bitterroot valley. Our first objective, therefore, is to understand differences in forest stand age (forestry and fire), forage biomass, and seasonal phenology of forage productivity between these two contrasting units over time. Building on this descriptive and comparative understanding of forage/habitat differences between the two units, our second objective will be to understand elk resource selection for forage and forest stand age. We will determine adult (and calf) female elk resource selection using 20 GPS radiocollared elk in each elk population unit/year, for a total of 60 elk over the three years/unit. Our third objective will be to then test for the consequences of these differences in habitat and resource selection between elk populations on elk calf survival and adult female body condition, and ultimately, population dynamics. We will capture and radio-collar 30 neonatal elk calves/year in each population unit for 3-years, and estimate body condition and pregnancy status for 20 adult female elk in each population per winter to test for the nutritional consequences of habitat differences 6 between the two population units.
Project Methods
We will use a comparative study design between the East Fork (HD 270) and West Fork (HD 250) elk herds. The East Fork (EF) area is a relatively more open habitat, fewer fires, a greater degree of forest harvest, more agricultural activity, and a limited the number of wolves. The West Fork (WF), in contrast, has more fires, fewer forest harvests, and limited agriculture, while the densely forested habitat and proximity to Idaho wilderness areas results in a higher density of wolves. Thus, we predict that elk in the East Fork will have relatively better body condition resulting from more favorable habitat conditions, lower overwinter mortality, lower rates of predation, and higher recruitment than elk in the West Fork. To understand forage and habitat differences between the WF and EF, we will use a combination of field vegetation sampling, remote sensing vegetation indices, and landcover data. We will then combine the landcover-based predictions from field vegetation sampling with remotely-sensed measures of vegetation productivity during our study to quantitatively test for differences in landcover types, elk forage biomass and habitat, and growing season dynamics differences between the two study areas. Next, we will determine adult (and calf) female elk resource selection as a function of landcover types, forest and fire stand age, and growing season dynamics using 20 GPS radiocollared (LOTEK) elk in each elk population unit. Adult female elk will be captured by helicopter and fitted with VHF/GPS collars programmed to record locations in 2-hour intervals. Twenty adult female elk in the East Fork and 20 adult female elk in the West Fork will be captured February 2011, 2012, and 2013. We will estimate resource selection using resource selection function (RSF) modeling. RSF models are a powerful way to examine the factors influencing the distribution of species, and have been used to examine elk resource selection for forestry, fires, wolves, and human factors across western North America. Adult survival will be monitored bi-weekly and causes of mortality recorded. Calves will be captured via helicopter and ground crews 1-6 days post birth and ear-tagged with VHF transmitters equipped with mortality sensors. We will attempt to capture all calves of marked cows, as well as calves of unmarked females. Thirty calves in the East Fork and 30 calves in the West Fork will be captured from the each summer 2011-2013. Mortalities will be investigated and causes of mortality recorded. To ensure an adequate sample of live calves entering the winter period, we will capture a second batch of calves in Oct. and reapply transmitters from summer calves that did not survive. This will allow us to test the novel hypothesis that while most summer mortality is caused by bears, winter mortality is caused by wolves. We will test for differences in body condition, adult female survival, and calf survival between and their relationships to the various differences in habitat and forage measures between the two study areas using statistical modeling.