<p> Non-habituated coyotes (<i>Canis latrans</i>) avoid direct interactions with humans. Reliance on human food sources has been linked to gradual habituation, a precursor to conflict and attacks on domestic pets and humans. Diet and activity patterns of urban coyotes inhabiting natural fragments in Long Beach, CA were monitored through scat collection and camera trapping over a year (Aug 2016 &ndash; Aug 2017). Local urban coyotes are relying predominately on natural foods, with an increase in mammalian prey in the wet season and an increase in vegetation and insect consumption in the dry season. Anthropogenic items, food and food related inedible items, appeared in 14% of scats overall, with no significant seasonal change. Cat remains were found in 14% of scat samples, but only triggered cameras once throughout the 2,857 camera nights of the study. Coyote activity was centered on nights in both seasons, with greater dawn activity in the dry season, indicating an avoidance of peak human activity. This reliance on natural foods and avoidance of human activity reduces the opportunities for human-wildlife conflicts in our local area.</p><p>

<p> Culverts are ubiquitous in urban and natural environments, installed to provide road access and erosion control, but often impact fish movements in freshwater habitats. Effects of culverts on marine and estuarine fish are not well-studied. This study aimed to understand the potential impacts of a culvert, which connects a large tidal bay and a coastal lagoon, on the movements of several species of fish. Habitat characteristics of both sites were analyzed to better understand these movements, including water parameters, sediment characteristics, and zooplankton, benthic macroinvertebrate, and small fish communities. The two habitats differed in terms of temperature, salinity, dissolved oxygen, zooplankton abundance, and community composition of zooplankton, benthic macroinvertebrates, and small fish. The culvert and associated grate limited large fish from moving between the two habitats likely due to body size and other morphological characteristics. Removing this barrier and replacing it with an open channel would increase connectivity between these two habitats which could improve trophic quality in the lagoon habitat and increase functionality overall.</p><p>

<p> Rivers in semi-arid regions are highly sensitive and pressured yet can support diverse assemblages of species. In central New Mexico, the Rio Grande (River) is the lifeblood of the Middle Rio Grande Valley (MRGV), a semi-arid region which maintains large urban and agricultural centers and is also the principal wintering area for the Rocky Mountain Population of greater sandhill cranes (<i>Antigone canadensis tabida</i>). Human-induced environmental change has transformed the MRGV and habitat availability prompting concerns for the population. To address these concerns, I investigated dietary and behavioral responses of sandhill cranes to the collection of features that function as winter habitat. In Chapter 1, I demonstrated a novel application of stable isotopes to evaluate dietary reliance of sandhill cranes on corn subsidies provisioned by natural resource agencies, estimated rates of carbon isotope incorporation in tissues of sandhill cranes, and estimated tissue-derived winter arrival dates of sandhill cranes. I found subsidized corn was the primary dietary component of sandhill cranes, rates of carbon isotope incorporation in sandhill crane tissues differed predictably by metabolic activity, and estimated tissue-derived arrival dates on wintering grounds approximated actual arrival dates. In Chapter 2, I advanced a hierarchical Bayesian framework for overcoming challenges and improving analysis of behavioral data frequently generated in animal behavior studies and used behavioral observations of sandhill cranes as a case study. In Chapter 3, I estimated energetic and temporal availability of corn subsidies and seasonal energy requirements of sandhill cranes. I found seasonal energetic requirements of the population are likely satisfied by corn subsides but not without strategic planning. In Chapter 4, I examined how current landscape and riverine configuration influenced patterns of diel habitat selection by sandhill cranes. Sandhill cranes avoided sources of anthropogenic disturbance, relied heavily on managed public land resources, and selected roosting locations in the Rio Grande with a wider channel, interspersion of sandbars and shallow water, and low channel bank vegetation. My research suggests sandhill cranes have coped with alterations that have led to current conditions in the MRGV, however, habitat-related resources will need to be managed adaptively as drivers of environmental change will undoubtedly influence future circumstances. </p><p>

<p> My study was designed to determine how different thermal defense strategies and the intensity of high temperature challenges might affect demographic and physiological performance of limpets on rocky shores. Found together in the high intertidal zone, <i>Lottia scabra</i> employs a constitutive thermal defense strategy, whereas <i>L. austrodigitalis</i> has an inducible one. I measured loss and growth rates of both species as a function of average daily maximum temperature exposure in the field, and respiration rates for field-collected and lab-acclimated individuals under benign conditions in the lab before and after exposure to one of five peak temperatures (14, 24, 28, 32, or 36 &deg;C) during a 4.5-hour simulated low tide. <i>L. scabra</i> was relatively unaffected by exposure to high temperatures, whereas <i>L. austrodigitalis</i> exhibited significant increases in loss rates from experimental plates, decreases in growth rates, and increases in oxygen consumption, consistent with activation of the heat shock response.</p><p>

<p> <i>Arundo donax</i> is a rhizomatous perennial grass that invades riparian habitats and replaces native riparian vegetation. The galling wasp, <i> Tetramesa romana</i> (Hymenoptera: Eurytomidae), was selected for evaluation as a biocontrol agent of <i>A. donax</i> in 2009. However, knowledge is scarce on which factors influence host selection and oviposition in <i> T. romana.</i> Through my observations I documented distinct behavioral steps preceding emergence leading to oviposition in <i>T. romana,</i> and elicited an investigatory response in <i>T. romana</i> from plant volatiles extracted from <i>A. donax.</i> My results indicated that <i>T. romana</i> does use a chemical cue as a factor in host selection, but it is likely not the result of a species-specific constituent. Evidence from my study revealed that <i>T. romana</i> may use a physical cue in selecting a host as well. <i>T. romana</i> preferred round glass rods over flat glass slides, indicating that shape is an important factor in host acceptance.</p>

Seabirds are an important link between their marine feeding areas and their terrestrial breeding environments, transporting both marine-derived nutrients and contaminants to land via their excreta, feathers and carcasses. The importance of seabird-derived nutrients is particularly apparent in nutrient poor regions like the Canadian High Arctic, where biological oases form in the area surrounding a colony. While providing the nutrient subsidies that shape the terrestrial ecosystem of many Arctic sites, seabirds may focus contaminants into their nesting sites at potentially toxic levels. Here, we investigated the impact of a large northern fulmar (Fulmarus glacialis) colony on nearby ponds spanning a broad gradient of seabird influence at Cape Vera, Devon Island. Nutrient concentrations were significantly higher in ponds receiving guano than in reference ponds. The ponds closest to the cliffs, and thus receiving the highest seabird subsidies, were the most contaminated, and in some cases exceeded Canadian Sediment Quality Guidelines for the Protection of Aquatic Life for As, Cd and Zn. This study demonstrates that seabirds can transport contaminants bioaccumulated from the ocean and funnel them into receptor sites to potentially toxic levels thousands of kilometers from industrial centers.

Small temperate lakes are under increasing pressure from a number of anthropogenic sources, including but not limited to: habitat alteration, invasive species, climate change, and pollution. In Gatineau Park, Quebec, Canada small temperate lakes have been demonstrated to be under threat from introduced piscivores, among other potential stressors. Here, I assessed the historical impact of four introduced piscivores on minnow, small fish and total fish species richness for a set of small Gatineau Park lakes. Fish community data were obtained from two previously published studies and a lake survey conducted in the summers of 2006 and 2007. I used a modified Control/Impact study design and repeated measures analysis of variance to test the hypothesis that introduced piscivores negatively affect species richness over time. My results strongly demonstrate that piscivores have had a negative effect on minnow and small fish species richness over time, whereas total fish species richness was unaffected. Assuming that these introduced piscivores pose a risk to the parks small temeprate lakes, I then assessed what lake characteristics best predict piscivore invasion risk. To do this, I estimated invasion risk employing two different analytical approaches for a total of 42 small lakes located in Gatineau Park using current and historical data collected in 1971, 1981, 1991 and 2006. Bootstrapped logistic regression was used to predict historical occurrence, and whether or not a lake was invaded/not invaded over time using predictor variables that included lake anthropogenic, spatial-isolation, and morphometric factors. For both logistic regression analyses, lake area and small fish species richness were found to be excellent predictors of piscivore invasion risk and historical occurrence, while lake spatial-isolation factors were also found to be excellent predictors of piscivore historical occurrence. The bootstrapped models with the most support based on Akaike's Information Criterion corrected for small sample size (AICc) were then used to identify lakes at greatest risk for future invasion. My results support the contention that introducing top predators into novel aquatic environments has detrimental impacts on native fish communities, and that these impacts are not always immediately obvious, but are indeed discernable over time. In conclusion, I make specific recommendations to guide the conservation and management of small temperate lake ecosystems.

<p> Community ecology investigates questions related to the density, growth/decline and movements of species over time in given geographical regions. This study investigated similar questions regarding communities of endemic bat species in Connecticut. White-nose syndrome (WNS) has recently killed millions of bats in New England, yet few large-scale conservation efforts have occurred in Connecticut and few data have been published on the status of Connecticut bats post-WNS. This study aimed to: 1) survey bats persisting in WNS regions to document whether changes have occurred in species biodiversity, richness, distribution and habitat use; and 2) measure seasonality effects from summer through pre-hibernal months. Bat presence and activity were recorded using bat detectors set in grassland and forested habitats, near bodies of water and near anthropormorphic and geologic structures across Connecticut. Bioacoustics data have been analyzed by using Sonobat^&copy; software. Combined, these data show that bat activity varies significantly across habitat type (p = 0.02) and over seasons (p = 0.05). Additionally, these data provide insight regarding relationships between individual species, and clumped species groups, with habitat types and across seasons. Ultimately, these data show how bat communities have changed over time in a post-WNS environment. Combined, these data can help drive future wildlife conservation, outreach, education and management practices.</p><p>

<p> Information about population dynamics, life history variation, and connectivity patterns of threatened cutthroat trout (<i>O. clarkii</i> spp.) is critical for effective management and restoration. The Lahontan cutthroat trout (<i>O. c. henshawi;</i> LCT) is classified as threatened under the Endangered Species Act due to widespread extirpations across its range, and is at increased risk due to drought, habitat fragmentation, and climate change. This study was conducted in the Summit Lake Basin, NV (USA), which has a population of LCT that resides in Summit Lake and its tributary stream network. The objectives of this research were to (1) examine the population dynamics of stream- and lake-dwelling LCT in the context of drought, (2) quantify the amount of stream-resident versus adfluvial life histories in an adfluvial spawning tributary, and (3) identify the level of population connectivity between stream-resident and adfluvial components of the population. Chapter 1 shows that stream-dwelling trout were more resilient to drought disturbance and that drought refugia in the stream contribute to their resilience. Chapter 2 provides evidence for stream-residency in addition to high population connectivity across the lake and stream environments that is likely to increase in high flow years. While LCT and other cutthroat species have innate characteristics that allow them to persist in dynamic and harsh environments, this research highlights the importance of drought refugia and landscape connectivity to the long-term persistence and viability of co-occurring adfluvial and stream-resident fish.</p><p>

Antibiotic-producing microorganisms can gain a selective advantage by inhibiting nearby competing species. However, despite their genetic potential, natural isolates often make only small amounts of antibiotics and laboratory evolution can lead to loss rather than enhancement of antibiotic production. We sought to understand selection for antibiotic production in natural and engineered ecosystems. We show that, due to competition with antibiotic resistant cheater cells, increased levels of antibiotic production can actually decrease the selective advantage to producers. Competing fluorescently-labeled Escherichia coli colicin producers with non-producing resistant and sensitive strains on solid media, we found that while producer colonies can greatly benefit from the inhibition of nearby sensitive colonies, this benefit is shared with resistant colonies growing in their vicinity. Experimentally varying the amount of production shows a peak in selection for producers, reflecting a trade-off between benefit gained by inhibiting sensitive competitors and loss due to an increased contribution to resistant cheater colonies. A simple model, which accounts for such local competitive and inhibitory interactions, recapitulates the finding that the advantage of producers varies non-monotonically with the amount of production. These results help explain the low level of antibiotic production observed for natural species, and can help direct laboratory evolution experiments selecting for increased or novel production of antibiotics. / Systems Biology