Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Do spawning salmon indirectly influence ungulate space use in the Copper River Delta, Alaska by attracting bears?(Montana State University - Bozeman, College of Letters & Science, 2020) DeFries, Elizabeth Shaw; Chairperson, Graduate Committee: Greg FrancisOne of the key challenges in ecology is understanding the drivers of animal movements and distributions. Here, I used remote camera photography to examine whether the timing of spawning salmon altered ungulate space use due to the presence of bears. Using observational data collection methods, I quantified ungulate and bear presence at individual salmon spawning sites. I then analyzed relationships between bear and ungulate detection data to test for indirect effects between salmon and ungulates by applying linear regression models. A zero-inflated negative binomial model suggested that increases in bear detections are associated with decreases in ungulate detections. Results did reveal little overlap in the timing of ungulate and bear use of stream habitat during salmon spawning times, however, rigorous testing of my hypothesis may be limited by low rates of ungulate detection. Research dedicated to understanding the indirect effects of the timing of salmon spawning in the Copper River Delta can help evaluate the evidence for trophic interactions at various ecosystem levels. It may also offer insights into the potential magnitude the impact salmon has on the prey of large predators, other herbivore densities, plant communities, riparian area morphology, and essential ecosystem functions.Item The influence of sampling design on the characterization of in-stream salmonid habitat(Montana State University - Bozeman, College of Letters & Science, 2019) Clark, Christopher Lee; Chairperson, Graduate Committee: Thomas E. McMahon; Robert Al-Chokhachy (co-chair); Robert Al-Chokhachy, George Pess and Thomas McMahon were co-authors of the article, 'Using continuous surveys to evaluate precision and bias of habitat inferences from different reach-scale sampling alternatives' submitted to the journal 'Canadian journal of fisheries and aquatic sciences' which is contained within this thesis.Pacific salmon have endured widespread population extirpations with some estimates at nearly one third of historical populations. In the western coterminous United States Pacific salmon no longer inhabit upwards of 40% of their historical freshwater range. Reintroducing Pacific salmon has therefore become a common conservation effort. An early step in evaluating potential reintroductions includes quantifying the available habitat, however the quantification, and interpretation of the habitat can be influenced by the sampling design and methods chosen. Reach-based sampling designs have been used extensively to collect fisheries related data; however, few studies have examined how reach-based inferences may be biased, a particular concern given the non-random distribution of factors such as woody debris and the magnitude of site-to-site variability. To address this concern, I collected reach-based habitat data continuously within streams. I then used simulations to resample the streams which were delineated into discrete reaches. During simulations I applied simple random, simple random with unequal probability, and generalized random tessellation stratified sampling designs and chose three habitat attributes that are commonly collected in stream habitat surveys, thought to be important factors for Pacific salmon survival, and expected to be distributed differently across the riverscape. My goal of identifying potential bias and precision under these sampling designs was achieved by summarizing simulations and comparing simulated results across streams, attributes, sampling designs and ultimately the census derived estimate of an attribute. My results indicate the extent of bias and levels of precision varied not only across habitat metrics but also across streams. My analyses suggest the use of reach-based approaches, particularly with low sampling efforts, can result in substantially different estimates of habitat characteristics and erroneous estimates of habitat carrying capacity of fishes.Item Habitat use of juvenile salmonids in Ophir and East Ophir Creeks, Yakutat, Alaska(Montana State University - Bozeman, College of Letters & Science, 1999) Whitton, Kellie SuItem Habitat and juvenile salmonid populations in streams in logged and unlogged areas of southeastern Alaska(Montana State University - Bozeman, College of Letters & Science, 1980) Cardinal, Peter Joseph