abstract: Small-scale fisheries are globally ubiquitous, employing more than 99% of the world’s fishers and providing over half of the world’s seafood. However, small-scale fisheries face many management challenges including declining catches, inadequate resources and infrastructure, and overcapacity. Baja California Sur, Mexico (BCS) is a region with diverse small-scale fisheries; these fisheries are intense, poorly regulated, and overlap with foraging hot spots of endangered sea turtles. In partnership with researchers, fishers, managers, and practitioners from Mexico and the United States, I documented bycatch rates of loggerhead turtles at BCS that represent the highest known megafauna bycatch rates worldwide. Concurrently, I conducted a literature review that determined gear modifications were generally more successful than other commonly used fisheries management strategies for mitigating bycatch of vulnerable megafauna including seabirds, marine mammals, and sea turtles. I then applied these results by partnering with researchers, local fishers, and Mexico’s federal fisheries science agency to develop and test two gear modifications (i.e. buoyless and illuminated nets) in operating net fisheries at BCS as potential solutions to reduce bycatch of endangered sea turtles, improve fisheries sustainability, and maintain fisher livelihoods. I found that buoyless nets significantly reduced mean turtle bycatch rates by 68% while maintaining target catch rates and composition. By contrast, illuminated nets did not significantly reduce turtle bycatch rates across day-night periods, although they reduced mean turtle bycatch rates by 50% at night. Illuminated nets, however, significantly reduced mean rates of total bycatch biomass by 34% across day-night periods while maintaining target fish catch and market value. I conclude with a policy analysis of the unilateral identification of Mexico by the U.S. State Department under section 610 of the Magnusson-Stevens Fishery Conservation and Management Act for failure to manage bycatch of loggerhead turtles at BCS. Taken together, the gear modifications developed and tested here represent promising bycatch mitigation solutions with strong potential for commercial adoption, but fleet-wide conversion to more selective and turtle-friendly gear (e.g. hook and line and/or traps) at BCS, coupled with coordinated international conservation action, is ultimately needed to eliminate sea turtle bycatch and further improve fisheries sustainability. / Dissertation/Thesis / Doctoral Dissertation Biology 2015

This study examines the importance of short-term climate variability when simulating forest succession using ecological process models. A version of the FORSKA2 forest gap model was modified for use with daily climate data and applied along a transect of sites crossing the boreal region in central Canada, including the aspen-parkland and forest-tundra ecotones where impacts of climatic change on forest ecosystems could be particularly significant. The model's sensitivity to forcing with daily climate observations compared to monthly mean and long term averages of monthly mean climate data was investigated. Inclusion of daily climate (minimum and maximum temperature and total precipitation) improved the simulations of key characteristics of present-day forest along the transect, and was particularly important at the ecotones. The results demonstrate that changes in variability associated with future change in mean climate are likely to be important when trying to predict boreal forest responses to projected future climate change. Ideally, the use of projected daily climate data or data based on the statistical characteristics of daily climate is highly recommended for future impact studies. A number of approaches to further improve the functioning of the model are also presented.

<p> As growing human populations put an increasing demand on finite ocean resources, fisheries management tools rely ever more on high quality inputs and a comprehensive understanding of model factors. Stock assessment modeling for South Atlantic (SA) King Mackerel, <i>Scomberomorus cavalla </i>, uses inputs such as abundance indices, growth parameters, and fisheries landings. However, one underlying assumption in this modeling system is there are measurable connections among life stages. A juvenile abundance index developed from the SEAMAP-SA Coastal Trawl Survey (CTS) is presumed to represent ecological recruitment. Very weak correlations to other life stage proxies suggested a deficiency with the juvenile abundance index accuracy and indicated data exploration into the index formulation was needed. Examination of CTS juvenile length frequencies support that the smallest juveniles appear in the summer and spring juveniles are from overwintering of the previous year class. Juvenile abundance indices developed using year class (year in which a fish is spawned) rather than year of sampling (as done for previous assessments) showed substantial differences, in particular lowering AIC values indicating an improvement in model accuracy. Evidence of seasonal and regional variation with CTS juveniles prompted the development of separate age 0 and age 1 indices. Correlations of these indices to fisheries-derived year class strength suggested the age 0 index to be the best indicator of initial juvenile king mackerel abundance while the age 1 index reflects abundance after high early life stage mortality. Data exploration also was conducted for potential environmental variables impacting age 0 and age 1 abundance. Relationships were found between age 0 abundance and freshwater input, the Gulf Stream, hurricane activity, and predator abundance and between age 1 abundance and freshwater input and hurricane activity. This research provides not only valuable baseline knowledge for SA king mackerel juveniles, but also findings pertinent for their management. </p><p>

<p> Conservation of endangered Indiana bats (<i>Myotis sodalis</i>) requires knowledge of regional habitat use patterns. I radio-tracked Indiana bats to roosts and foraging areas to document summer habitat use. Sexes selected different roost trees: reproductive females selected maples, whereas males selected elms and other species, but did not use maples. Distribution models based on environmental correlates revealed that soil series was the strongest contributor to niche models. Females selected roosts in silt loams; males selected roosts in muck, silt loam and fine sandy loams. All bats foraged in habitats over fine sandy and gravelly loams. Male roosts and female foraging areas were found near local water body elevations, though males foraged at higher elevations. The niche models suggest that sexes roost and forage separately, but that ranges for these activities overlap. My findings identify habitats selected by Indiana bats thereby enabling more effective conservation for this endangered species.</p><p>

<p> Mammalian carnivores are a vital component of many ecosystems and can be particularly sensitive to human disturbance, even within protected areas (PAs). Our objective was to understand how human disturbance affects carnivore communities in southern Arizona, U.S.A., by studying habitat occupancy based on data collected using non-invasive methods in three PAs with different levels of human disturbance. We examined the impacts of human disturbance variables and disturbance level on carnivore occupancy, co-occurrence, temporal activity, and habitat associations. Carnivore occupancy varied based on human disturbance variables (i.e., roads, trails, etc.). Edges of PAs appeared to negatively impact occupancy of nearly all carnivore species. We also found that the presence of roads and trails, and not necessarily how much they are used, had a significant negative impact on the occupancy of most carnivore species. Furthermore, the overall level of disturbance within a PA influenced how sensitive carnivores were to human disturbance variables. Carnivores were more sensitive in PAs with higher levels of disturbance and were relatively unaffected by disturbance variables in a PA with low base levels of disturbance. In areas with low levels of disturbance, we found that many carnivore species have lower than expected levels of co-occurrence, which suggests spatial partitioning. As disturbance within an area increased, spatial partitioning became less prominent, and carnivores exhibited higher levels of temporal partitioning within these areas. We found that habitat associations varied among carnivore species, and associations were often different across different scales. We also found evidence of different habitat preferences in protected areas with higher levels of disturbance (e.g., avoidance of water sources). Information on the impacts of human disturbance is important when developing conservation plans, which is especially true for protected areas, given their important role in carnivore conservation, particularly as they are experiencing ever increasing rates of visitation.</p><p>

<p>Billions of dollars have been invested in land protection as a strategy to conserve biodiversity based on the assumption that protected areas buffer species from processes that drive extinction. Increasingly, protected area expansion and connectivity are being incorporated into climate change adaptation strategies to facilitate anticipated shifts in species ranges in response to predicted changes in temperature and precipitation. However, the effectiveness of protected areas at maintaining biodiversity, either by reducing the risk of extinction or facilitating colonization into new areas, has not been well established. In addition, the growing reliance on multiple-use protected areas that allow resource extraction, such as timber harvest and mineral mining, has raised questions about whether multiple-use protected areas are equally beneficial for long-term biodiversity conservation as more strictly protected areas that limit active resource management. In order to address these questions using repeated Breeding Bird Atlas data, I first had to confront the limitations of existing approaches to account for imperfect detection by developing a novel modelling approach to addresses the gap between requirements of other multi-season occupancy models (i.e. repeated sampling) and existing datasets. I then applied that single-visit dynamic occupancy modelling approach to Atlas data in New York and Pennsylvania for 97 species to quantify drivers of colonization and extinction while accounting for imperfect detection in landscapes that varied by type and amount of land cover and area under protection. In general, protected areas increased colonization and lowered extinction probabilities to an increasing degree as both forest cover and neighborhood protection decreased, with particular benefits for forest breeding birds. Both strict and multiple-use protected areas increased colonization and reduced extinction more for mature forest species than early forest species, with the greatest benefits accruing when forest cover was relatively low. These results provided the most comprehensive evidence to date that protected areas can facilitate species persistence by both reducing the risk of extinction and providing attractive colonization sites as species? ranges shift and that biodiversity conservation can be compatible with renewable resource extraction.

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No description available.

Abstract not available.

Selection-cutting is the preferred method of logging in northern hardwood forests, because it is thought to favor the regeneration of valuable, shade-tolerant trees, maximize long-term productivity, and increase the health, quality and economic value of residual trees. Claims have also been made for the ecological sustainability of selection cutting, in particular that it: (a) preserves soil fertility; (b) maintains natural canopy composition; (c) protects plant and animal habitat. I evaluated these claims by studying the effects of selection-cutting on several measures of soil fertility (Ca, Al, Ca/Al molar ratios, pH), canopy composition and tree regeneration, herbaceous layer composition, and structural features related to habitat quality (cavity trees, snags, coarse woody debris) in 55 stands ranging from newly cut to old-growth (not all data overlaps). I found that forest growth after selection-cutting depletes soil solution calcium and lowers soil solution Ca/Al molar ratios, posing a threat to long-term forest health and productivity, particularly at higher elevations and in sites on siliceous bedrock. I found that selection-cut stands dominated by red oak (Quercus rubra) are converting to sugar maple (Acer saccharum) stands, posing a threat to both canopy and herbaceous layer diversity. I found no lasting effects of selection-cutting on herbaceous layer composition, diversity or quality, but I found indirect threats from the conversion of red oak stands to sugar maple and from depletion of soil solution calcium. Finally, I found that current selection-cutting practices generally do not meet published targets for large trees, cavity trees, snags and coarse woody debris, but that they probably could meet those targets with minor changes to cutting practices. I conclude by discussing the implications of these results for the management of northern hardwood forests.