Theses and Dissertations at Montana State University (MSU)
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Item Conservation guidance for blanding's turtles in northwest iowa(Montana State University, 2021) Howing, Drew Taylor LeeBlanding's turtles (Emydoidea blandingii) are currently threatened or endangered across their range in the United States and Canada due to habitat destruction and fragmentation. In Iowa, a recent survey from 2010 states that they currently reside in only 26 of the original 45 counties they historically inhabited. Due to the habitat differences across their range, developing survey protocols for the prairie pot-hole region of northwest Iowa is needed. Within Dickinson, Clay, and Palo Alto counties of Iowa, Blanding's turtles have been detected historically and contain a greater abundance of wetland habitats than the surrounding counties. The goal of this project was to assess different survey and capture techniques to inform future monitoring programs for Blanding's turtles in this region of Iowa. I used visual rapid assessments and hoop net trapping to detect, capture, and mark Blanding's turtles throughout the 2020 and 2021 field seasons. These surveys and trapping efforts were mostly conducted throughout the month of June, which is later than most literature would recommend due to reduced turtle basking behavior. However, due to the proliferation of submergent vegetation as the summer progressed, it seems likely that the detection of this species could be greater using these methods later into the summer as turtles venture out into more open areas of wetlands. In addition, these methods led to the discovery of multiple viable Blanding's turtle populations and new sites where the species is present. An additional spatial analysis concluded the presence of perennial streams in turtle home ranges which could be an important habitat factor for their existence in the boom-and-bust cycles of the prairie. Further research needs to be conducted using these methods for developing a more robust dataset to determine the effectiveness of this method. Long-term monitoring will be initiated using a field maps survey created by Iowa Lakes Community College students for increasing efficiency of data collection by managers and other professionals that encounter this species. In addition, funding for the purchase of 25 radio transmitters has been received for marking and tracking adult male and female turtles. These data will give a population-level understanding of future conservation action needed for their habitat management.Item Factors affecting duck nesting in the aspen parklands : a spatial analysis(Montana State University - Bozeman, College of Letters & Science, 2003) Howerter, David WilliamItem The influence of landscape characteristics on duck nesting success in the Missouri Coteau Region of North Dakota(Montana State University - Bozeman, College of Letters & Science, 2003) Stephens, Scott Eugene; Chairperson, Graduate Committee: Jay J. Rotella; Mark S. Lindberg (co-chair)Because of the importance of nesting success to avian population dynamics, and the extensive and ubiquitous nature of habitat fragmentation, many studies have attempted to address the relationship between fragmentation and nesting success. However, an overall theory of fragmentation effects on nesting success has remained elusive. First, we reviewed published literature to examine fragmentation effects on nesting success at three spatial scales (i.e., edge, patch, and landscape scales). We identified 86 relevant manuscripts that provided 117 individual tests of hypotheses regarding the effects of fragmentation on nesting success. Fragmentation effects were more likely to be detected if fragmentation was examined at a landscape scale and if research was conducted over several years. Next, we examined the influence of habitat and landscape variables on duck nest survival (n ~ 4200 nests) on 18 10.4-km2 sites in the Missouri Coteau Region of North Dakota. We evaluated competing models of nest survival that considered combinations of habitat features measured at nests, within nesting patches, and at multiple landscape scales. We used generalized non-linear mixedmodeling techniques to model nest survival. Information-theoretic techniques were used to select among competing models. Models that included random effects of individual sites and covariates measured at multiple landscape scales were dramatically better than models that included nest-level, patch-level, or landscape-scale covariates measured at a single spatial scale. Nest survival was positively related to the amount of grassland habitat, negatively related to the wetland density and related to the amount of grassland edge in a complex quadratic manner. Finally, we combined our nest survival model with existing models of mallard pairs using spatially-explicit GIS models and applied them to the entire Coteau region of North and South Dakota to guide conservation programs. Important trade-offs existed between pair density and nest survival; source populations were dominated by low pair-density areas while sink populations were dominated by high and medium pair-density areas. Based on the complex suite of factors influencing nest survival, a unifying paradigm of fragmentation across taxa and habitat types may not exist. Thus, research on the species and habitats of interest may be necessary to guide successful conservation efforts.