Thesis
Influences of habitat characteristics on forage resources of Rocky Mountain elk (Cervus canadensis) in north-central Idaho
Washington State University
Master of Science (MS), Washington State University
05/2020
DOI:
https://doi.org/10.7273/000004100
Handle:
https://hdl.handle.net/2376/125056
Abstract
Populations of Rocky Mountain elk (Cervus canadensis) in Idaho have been decreasing since the 1990's. Natural resource organizations seek to determine the cause and opportunities for management. Changes in natural disturbances have altered the abundance of nutritious forage through changes in succession, potentially contributing to elk population declines. We modeled elk forage quantity and quality during summer in relation to stand age, overstory canopy cover, potential vegetation (PV) zone, phenology, and biophysical covariates within North-central Idaho's Clearwater and St. Joe Basins. In summers of 2016-17, we measured overstory and understory characteristics within 359, 0.18-ha macroplots. Using conversions based on double-sampling, we estimated understory vegetation for all plants in each macroplot from estimations of horizontal plant cover (mean pseudo R2 0.63, ranging from 0.25 - 0.99). We collected understory vegetation samples and analyzed them for digestible energy (DE) and digestible protein (DP) content. Using understory biomass, DE and DP content, and prior knowledge of elk diet selection and nutritional constraints, we developed 8 forage resources for elk that differed in how they incorporated forage quality and quantity. We examined the effects of succession on forage resources and compared how different forage resources responded to biogeoclimatic gradients. For most PV zones, overstory canopy cover increased during the first 20 - 50 years before reaching an asymptote. The wetter PV zones increased more rapidly and reached a higher (~ 80%) asymptotic overstory canopy cover than the drier zones (~ 50%). In contrast, the highest abundance of understory vegetation and forage resources in most PV zones occurred during the first 20 years and declined as the overstory closed. Peak understory biomass ranged from 500 - 1,000 kg/ha. We then created models predicting these forage resource metrics, which varied among PV zones (mean R2 ranged from 0.24 - 0.65), with better predictions for wetter PV zones. These predictive models can be used to develop spatially explicit elk nutritional landscapes. Such 'foodscapes' are critical for developing habitat management plans, assessing the drivers of elk density and fitness, and evaluating the effect of past and future disturbances on elk in the Clearwater and St. Joe Basins, Idaho.
Metrics
21 File views/ downloads
68 Record Views
Details
- Title
- Influences of habitat characteristics on forage resources of Rocky Mountain elk (Cervus canadensis) in north-central Idaho
- Creators
- Deborah Suzanne Monzingo
- Contributors
- Lisa Shipley (Advisor) - Washington State University, School of the Environment (CAHNRS)
- Awarding Institution
- Washington State University
- Academic Unit
- School of the Environment (CAS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890786601842
- Language
- English
- Resource Type
- Thesis