Theses and Dissertations at Montana State University (MSU)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/732
Browse
3 results
Search Results
Item Effects of mountain pine beetle on elk habitat and nutrition in the Elkhorn Mountains of Montana(Montana State University - Bozeman, College of Letters & Science, 2018) Cascaddan, Brent Morris; Chairperson, Graduate Committee: Robert A. GarrottMountain pine beetle (Dendroctonus ponderosae, MPB) outbreaks have become increasingly prevalent in western North America, resulting in ecological changes in pine forests that have important implications for wildlife populations and habitat. The potential effects of MPB-caused tree mortality on ungulate populations and habitat are relatively unstudied, and the possibility exists for both beneficial changes to ungulate habitat such as increased production of forage (i.e., forage availability) through the opening of the forest canopy and negative impacts such as accelerated phenology of herbaceous plants that may reduce forage quality. Using data collected during 2015 - 2017 in MPB-impacted National Forests in west-central Montana, I quantified the effects of MPB outbreaks on elk summer forage resources and use. To accomplish this objective, I 1) evaluated differences in herbaceous plant communities between mature uninfested lodgepole pine stands and two temporal classes of MPB-impacted forest stands (i.e., lodgepole pine cover classes: mature uninfested, old infested: > or = 10 years old, recent infested: <10 years old), 2) evaluated differences in elk summer forage availability and herbaceous vegetation quality, and 3) compared current elk use of lodgepole cover classes (2015 - 2017) to a previous elk telemetry study conducted during 1980 - 1991 before the MPB epidemic. I found that herbaceous forage plant communities did not differ in plant species composition but did differ in forage abundance in each cover class. Forage abundance was significantly different between cover classes and was highest in the old-infested cover class, and lowest in the mature uninfested cover class. The dominant phenology stage of forage species did not change across cover classes by a biologically meaningful amount, but herbaceous quality differed across cover classes, however the amount of difference was small. During the 2015 - 2017 study, elk used all three lodgepole pine cover classes in proportion to how much of each cover class was available. Elk use of lodgepole pine during the 1980 - 1991 study was approximately double what was estimated to be available and suggests elk are using the beetle-killed forest less than prior to infestation. My results indicate MPB does not negatively affect elk nutrition during later summer (July and August), and active management of beetle-killed forest is not necessary for the benefit of elk during this time period, but may be needed for improving elk habitat in other ways during other times of year.Item Demographic responses of woodpeckers in relation to a mountain pine beetle epidemic in the Elkhorn Mountains of Montana(Montana State University - Bozeman, College of Letters & Science, 2015) Dresser, Matthew Alan; Chairperson, Graduate Committee: Jay J. RotellaMountain pine beetle (Dendroctonus ponderosae; MPB) epidemics in coniferous forests of western North America have recently increased in size and severity, which affects wildlife habitat. Development of meaningful habitat-conservation strategies therefore requires information on wildlife population responses to mountain pine beetle. Over nine years (2003-2006, 2009-2013), we monitored 355 nests of 5 woodpecker species: American three-toed woodpecker (Picoides dorsalis), hairy woodpecker (P. villosus), downy woodpecker (P. pubescens), red-shafted northern flicker (Colaptes auratus cafer), and red-naped sapsucker (Sphyrapicus nuchalis) in the Elkhorn Mountains of Montana. In our study area, a MPB epidemic began in 2006 and peaked in 2008. We investigated the relationships between daily survival rate (DSR) and metrics of epidemic severity and timing (epidemic period, annual and cumulative estimates of tree-mortality, and red squirrel [Tamiasciurus hudsonicus] counts) while accounting for other potentially important covariates identified in previous studies (temperature, precipitation, time within the breeding season, nest height, diameter at breast height of the nest tree, and nest-tree species). Additionally, we examined trends in densities of hatched nests concurrent with the epidemic. In general, we found little support for a relationship between DSR and variables that described MPB epidemic timing and severity. Red-naped sapsucker was the only species to show a relationship between DSR and a MPB-related variable (cumulative tree-mortality). In contrast, densities of hatched nests for American three-toed, hairy, and downy woodpeckers increased following the epidemic, whereas, nest densities for red-naped sapsucker did not change. We found stronger support for nest survival relationships with covariates unrelated to the MPB epidemic (temperature, nest height, diameter at breast height of the cavity tree), but even these relationships were only weakly supported. As is commonly the case for cavity-nesting birds, nest survival was relatively high, leaving little room for covariate relationships. Our findings suggest that woodpecker populations tend to relate positively with MPB epidemics, although these relationships may often be the result of numerical increases in nest densities rather than functional increases in nest survival rates.Item Avian community response to a mountain pine beetle epidemic(Montana State University - Bozeman, College of Letters & Science, 2011) Mosher, Brittany Ann; Chairperson, Graduate Committee: Jay J. RotellaRecent epidemics of mountain pine beetles (Dendroctonus ponderosae) will fundamentally alter forests of the Intermountain West, impacting management decisions related to fire, logging, and wildlife conservation. We evaluated effects of a recent mountain pine beetle epidemic on site occupancy dynamics of 49 avian and one mammal species in forests dominated by ponderosa pine (Pinus ponderosa) on the Helena National Forest, Montana. Point count data were collected during the avian breeding seasons (May-July) of 2003-06 (pre-epidemic) and again during 2009-10 (during epidemic). We used a Bayesian hierarchical model that accounts for detection probability to obtain occupancy estimates for rare species as well as common ones. We used one model to investigate changes occupancy for all species with respect to the timing of the beetle outbreak and then used a second model to determine whether the relationships seen were associated to changes in snag density. Results show that 30% of species exhibited strong short-term associations between occupancy probability and the occurrence of the beetle epidemic and 12% of species exhibited strong short-term associations between occupancy probability and snag density. Predictions were partially met, as we saw short-term increases in occupancy probability for beetle-foraging species, decreases for some foliage-gleaning canopy insectivores, and intermediate amounts of change for many ground and shrub insectivores. While short-term ecological changes caused by a mountain pine beetle outbreak were associated with changes in occupancy rates for individual species, the overall species richness of native avifauna was unaffected. Though further study over a longer period of time will be necessary to understand the complete dynamics of this disturbance, our results suggest that well-planned salvage operations after beetle outbreaks could also maintain suitable habitat for successfully breeding avian species.