1 |
Large carnivore recolonization of Eastern North America: habitat connectivity and human dimensionsWinkel, Brianna M 01 September 2021 (has links)
Cougars (Puma concolor) have been recolonizing Midwestern North America over the past 2 decades with >950 cougar confirmations east of established populations. Management and public interest in habitat suitability and connectivity east of current cougar range have grown as confirmations increase and models predicting habitat connectivity and population viability for the Midwest show potential for breeding populations. However, although long-range dispersal and recolonization continues, no studies have assessed potential habitat associated with cougars throughout their historical range in eastern North America. I used ArcGIS, the Analytical Hierarchy Process, and geospatial data to model cougar habitat and potential dispersal corridors in eastern North America. The total amount of potential habitat was >2,400,000 km2 and mean patch size was 257,500 km2. Patches of habitat ranged in size from 3,868 km2 (Ozark Mountains) to >2,490,850 km2 (central and eastern Canada) with ≤53,643 km of dispersal corridors connecting patches. With cougars potentially recolonizing areas previously devoid of large carnivores, public acceptance of management efforts is pivotal for the success of their recolonization. However, targeted surveys assessing public perceptions and knowledge of cougars and red wolves (Canis rufus), who have faced similar extirpation in the Southeastern United States are limited. I mailed 20,000 questionnaires and 2,000 follow-up postcards to residents near areas of potential red wolf and cougar habitat in the Southeastern United States in 2020. I used cumulative link models to gauge the associations between sociodemographic predictor with respondent’s knowledge and attitude towards large carnivores. Total response rate was 4.6% with the majority of respondents identifying as male (53.6%), having a 4-year degree or above (54.1%), and 57 ± 16 (SE) years of age. Respondents’ knowledge and attitudes towards large carnivores were largely positive (≥63% positive) with higher education, older age, and current livestock ownership being largest predictors for responses. Attitudes towards red wolves were largely driven by knowledge of red wolves while attitudes towards cougars were primarily driven by livestock ownership. Livestock owners (71.5%) were concerned about safety of livestock in large carnivore habitat, and most respondents (61%) did not trust their local agency to effectively manage large carnivore populations. My research provides a foundation for wildlife managers to develop informed plans, educational programs, and policy decisions for potentially recolonizing large carnivore populations.
|
2 |
Habitat composition and restocking for conservation of the white-backed woodpecker in SwedenStighäll, Kristoffer January 2015 (has links)
In Sweden, intense human land use, especially forestry, has led to profound changes in the landscape over time, especially within the forest ecosystems. A consequence of this is that several specialist species have become endangered. One group of specialists is the woodpeckers. The middle spotted woodpecker became extinct in Sweden in 1982 and the white-backed woodpecker is today Sweden’s most critically endangered forest-living bird. The white-backed woodpecker is dependent on old deciduous forests, rich in dead wood. The woodpecker is areademanding and hence one of the best indicators or umbrella species for biodiversity in this region. A long-term goal within the conservation of the species is to be able to make more accurate predictions of what is needed in the species habitat to establish a viable population, both in terms of composition of landscape and breeding territories. In addition to earlier studies better tools are needed for measuring the distribution of suitable and potential habitats and finding faster ways of creating optimal habitats. In an attempt to secure the future existence of the white-backed woodpecker in Sweden, restocking of birds are carried out. This presupposes availability of suitable habitats as well as strong enough landscape. Due to intense forestry the presumption for the species is, as stated above, alarming. Comparing the different populations around the Baltic Sea and Norway, great differences but also similarities can be seen, in landscape as well as in territory composition. It seems that fragmentation of foraging patches as well as amount of dead deciduous wood within the breeding territory is critical matters. Grey alder stands in Sweden should have high priority in conservation of habitat for the species. / <p>Funding agency: Swedish Society for Nature Conservation (SSNC)</p>
|
3 |
A Biogeographic Analysis of the Socially Polyphenic Spider <em>Anelosimus studiosus</em> in East Tennessee.Linville, Brent 01 May 2011 (has links) (PDF)
Microclimates associated with environmental and geographic factors directly affect the ability of an organism to survive in a particular area. Survival is affected by: predator/prey abundance, temperature, relative humidity. A group of organisms that are particularly prone to habitat sensitivity are web-building spiders, because building the web commits them to a particular site for a period of time. Anelosimus studiosus is a small (~8 mm) Theridiid spider that exhibits varying degrees of sociality: a subsocial phenotype and a social phenotype. Population densities of A. studiosus vary significantly among seemingly suitable habitats within its range in east Tennessee. I conducted a large-scale survey of east Tennessee lake systems to establish connections between spider presence and geographic features such as aspect, slope and elevation. These geographic features were shown to have a strong impact on overall spider density.
|
4 |
Descriptions, Ecological Associations and Predictive Species Distribution Models of New Species of Psilochalcis Kieffer (Hymenoptera; Chalcididae) Occurring in Utah's Eastern Great BasinPetersen, Mark J. 18 April 2023 (has links) (PDF)
The genus Psilochalcis, of the Family Chalcididae, was originally described in 1905 by Kieffer. Mainly considered an Old-World taxon, the first North American Psilochalcis were not identified until 1981 by Grissell and Schauff. Little is known about the species distributions, biologies and ecological relationships of these parasitic wasps. This dissertation describes research conducted in central Utah setting arrays of Malaise traps in 4 different habitat types common to the Great Basin at three separate locations. A result of this sampling revealed a high abundance of multiple species of Psilochalcis wasps, particularly from one location and two habitat types. Chapter 1 describes three new species of Psilochalcis wasps namely; P. adenticulata Petersen, P. minuta Petersen, and P. quadratis Petersen. A review of all North American Psilochalcis species explains their distribution in Utah and throughout the surrounding western United States. A taxonomic key for all North American Psilochalcis species is given. Chapter 2 examines the seasonal abundance of P. minuta and P. quadratis and their associations with two common Great Basin habitat types. Both species show their highest abundance from late June through early August. Their peak abundance is shown to change dependent on the environmental conditions of temperature and precipitation. Psilochalcis minuta is significantly associated with pinyon/juniper (Pinus edulis or P. monophylla and Juniperus osteosperma) and P. quadratis is significantly associated with cheatgrass (Bromus tectorum). Chapter 3 describes the building of species distribution models for P. minuta and P. quadratis using a maximum entropy (Maxent) approach. Ten environmental variables were used to predict areas of optimal suitable habitat for each species. Multiple predicted sites were field sampled to test each model's effectiveness. Psilochalcis minuta occurred at nearly 90% of predicted sites, and P. quadratis occurred at 50% of predicted sites. Both species occurred at some non-predicted sites in other habitat types. Model analyses and field-testing results show the P. minuta model to be reliable in predicting areas of probable species occurrence, while the P. quadratis model is much less reliable in doing so. Aspect and fire disturbance show the highest percent contribution to both species' models. Slight differences in variable percent contribution between models suggest these species have sympatric distributions. Soil and slope are more important predictors of optimal suitable habitat for each species. Maintaining integrity between model predictions and field testing gave insights into other factors contributing to probable occurrence of Psilochalcis species.
|
Page generated in 0.064 seconds