Theses and Dissertations at Montana State University (MSU)
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Item Plant-pollinator network assembly after wildfire(Montana State University - Bozeman, College of Letters & Science, 2018) Simanonok, Michael Peter; Chairperson, Graduate Committee: Laura BurklePlant-pollinator networks are threatened by anthropogenic influence due to habitat loss, changing fire regimes, climate change and other factors. Furthermore, we have little current knowledge for how species interactions and processes like pollination assemble and recover post-disturbance. Studying the mechanisms by which plant-pollinator interactions assemble in a post-disturbance landscape, particularly across gradients of disturbance intensity and successional time, would greatly help in building foundational ecological knowledge regarding the assembly of species interactions as well as provide specific information to aid conservation and management. Therefore, we investigated plant-pollinator network assembly after wildfire, between mixed- and high-severity burns and across time-since-burn, and we asked i) how do network structure and the network roles of persistent species vary ii) how does wildfire change the nutritional landscape of available floral pollen quality and how does that influence bumble bee foraging and nutrition, and iii) how do nesting and floral resources affected by wildfire influence wood-cavity-bee nesting success and richness? Our study design involved four wildfires from the Absaroka Mountains of southwest Montana, USA, which included a range of burn severities as well as a 1-25 year chronosequence of time-since-burn sampled primarily from 2014 to 2016. Bees were sampled via hand netting and nesting boxes alongside floral census transects and pollen sampling to assess metrics important to plant-pollinator network assembly, available floral pollen quality, bumble bee nutrition, and wood-cavity-nesting bee nesting success. The primary findings are that i) plant-pollinator network structure does not dramatically shift with burn severity or time-since-burn, nor do the network roles of persistent species, ii) available floral pollen quality and bumblebee nutrition are limited by high-severity burns, and iii) burn severity has little effect on the nesting success of wood-cavity-nesting bees. The conclusions that follow these results are mainly that i) evidence of constant structure and low variance of species' roles provides evidence for preferential attachment over opportunistic attachment in assembling plant-pollinator networks post-disturbance, ii) varied species composition between mixed- and high-severity burns may mean that bumble bees are nutritionally limited in high-severity burns, and iii) nesting resources do not appear to strongly limit nesting success or richness of wood-cavity-nesting bees.Item An assessment of the usefulness of winter wheat for nesting dabbling ducks in North and South Dakota(Montana State University - Bozeman, College of Letters & Science, 2014) Skone, Brandi Renee; Chairperson, Graduate Committee: Jay J. RotellaThe Prairie Pothole Region (PPR) of North America is highly valuable for breeding waterfowl, however over the last century has been predominantly converted to some form of agriculture. With the recent increase in economic value of some cash-crops and the potential to lose highly valuable nesting habitat in the Conservation Reserve Program (CRP), there has been interest in evaluating alternative farming practices to provide additional breeding habitat for waterfowl. We evaluated and compared daily survival rates (DSR) of nests in winter wheat to nests in perennial cover and examined the number of hatched nests per hectare in each habitat to put habitat-specific estimates of nest survival in perspective. We studied nest survival of duck nests (Anas spp.) in winter wheat (n=1,170) and perennial cover (n=3,041) in the PPR of North and South Dakota on 13 to 19, 10.36-km 2 sites each year between 2010 and 2012. . We used an information-theoretic approach to develop and evaluate a set of competing models based on covariates of interest and what has been established important in the waterfowl nest-survival literature. Our top model included a set of covariates that were either highly or moderately supported in all of the models that received substantial amounts of support from the data. Across all species, we found evidence that nest survival was at least as high in winter wheat as in perennial cover, and for several species, estimated nest-survival rates were higher in winter wheat. Nest survival also varied by year and study area, was positively related to nest age and vegetation density, and was negatively related to the number of wetland basins and the proportion of cropland in the landscape. Our estimates for hatched nests per hectare were twice as high in perennial cover compared to values for winter wheat fields. However, estimates for fields of winter wheat were 6.5 times higher than estimates in spring wheat fields. Our results provided evidence that winter wheat could be a useful tool for wildlife managers seeking to add nesting habitat in landscapes used for modern agriculture.Item Common Loon nesting ecology in Northwest Montana(Montana State University - Bozeman, College of Letters & Science, 2006) Paugh, Justin Isaac; Chairperson, Graduate Committee: Jay J. RotellaCommon Loons (Gavia immer) are found across the northern continental United States and in Canada and Alaska. The common loon is long lived, with delayed breeding maturity and low fecundity. Surveys indicate Montana's Common Loon population remains stable, but lakeshore development and watercraft recreation are increasing. While the effects of these changes are unclear, research investigating reproductive success over a gradient of habitat conditions, at multiple spatial scales is lacking. The objectives of this research were to investigate vital rates and the relationships between daily nest survival, chick survival and environmental covariates across multiple spatial scales. I monitored seventy-nine Common Loon nesting attempts and the fates of sixty-five Common Loon chicks during two field seasons in Montana. The strongest predictor of nest survival was the type of breeding territory occupied by loons. Loon nests on small lakes (<60 acres) showed the highest nest survival, followed by nests established on large lakes (>60 acres) occupied by a single breeding pair. The lowest nest survival occurred on large lakes (>60 acres) occupied by two or more breeding pairs.Item 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.Item Influence of local and landscape characteristics of Prairie Dog colonies on Burrowing Owl nest ecology in South Dakota(Montana State University - Bozeman, College of Letters & Science, 2008) Bly, Kristy Lee Sydney; Chairperson, Graduate Committee: Mark Taper; David Willey (co-chair)In the Great Plains, sylvatic plague (Yersinia pestis), poisoning, and habitat conversion continue to reduce and fragment black-tailed prairie dog (Cynomys ludovicianus) habitat in which burrowing owls (Athene cunicularia) seek shelter and nest sites. Consequently, burrowing owls are experiencing population declines at the periphery of their range. The objective of this research was to evaluate habitat factors affecting a population of burrowing owls at the eastern extent of their range. I modeled hypothesized relationships between nest density (Chapter 2) and colony productivity (Chapter 3) and prairie dog habitat characteristics at two scales on the Bad River Ranches, South Dakota. Colony size, prairie dog and total burrow density, mean nearest neighbor and mean nest-to-colony edge distances, cover of warm-season grasses, and soil texture were variables measured at the colony level. Landscape level variables included the degree of colony isolation and the topographic location of colonies. In Chapter 4, I evaluated the spatial distribution of nests within colonies. Twenty-six prairie dog colonies were surveyed for burrowing owl nests during the 2005 (n =10) and 2006 (n = 16) breeding seasons. I evaluated competing models of nest density using a likelihood cross-validation approach. The model selection results in Chapter 2 suggested the top a priori predictor of nest density was colony size. Nest density was greatest on small colonies (<20 ha) and lowest on large colonies (>40 ha); in contrast, owl numbers were higher on large colonies. Exploratory analysis identified the interaction between cover of bare ground and colony habitat as the best approximating model of nest density. In Chapter 3, competing models of colony productivity were assessed. Although an additive model containing the degree of isolation, habitat, and colony size had a positive effect on colony productivity, exploratory analysis suggested colony size and the degree of isolation had the strongest influence. In Chapter 4, results showed that owls displayed a strong preference for nesting near colony perimeters, but this did not translate to higher productivity. The associations I observed lend support for the value of maintaining prairie dog colonies to ensure the persistence of burrowing owl populations in the Great Plains ecosystem.