Large carnivores face numerous threats, including habitat loss and fragmentation, direct killing, and prey depletion, leading to significant global range and population declines. Despite these threats, leopards (Panthera pardus) persist outside protected areas throughout most of their range, occupying a diverse range of habitat types and land uses, including peri-urban and rural areas. Our understanding of leopard population dynamics in mixed-use landscapes is limited, especially in South Africa, where most research has focused on protected areas. Here I use spatially explicit capture-recapture (SECR) models on camera trap data to estimate how leopard density varies across a mixed-use landscape of protected areas, farmland, and urban areas in the Overberg region of the Western Cape, South Africa. Data were derived from 86 paired camera stations, which collected data for 161 camera trap nights, providing 221 independent leopard captures at 50 camera trap stations. A total of 25 individual leopards were identified, and the best-performing SECR model included the covariate sex on the σ (spatial decay), and a combination of sex, vegetation type and the interaction on λ0 (capture probability), with a density estimate of 0.64 leopards per 100 km2 . Elevation, terrain ruggedness, protected area status and NDVI were all important drivers of leopard density in the region, with leopard density highest on elevated remnants of natural land outside of protected areas. These results are similar to previous research findings in the Western Cape, where high-lying natural vegetation was shown to serve as both a refuge and a corridor for leopard movement in otherwise transformed landscapes. Given the low level of risks to lives and livelihoods posed by leopards in this region, the continued persistence of leopards in this shared landscape is considered high. Education of landowners should still be prioritised to improve tolerance towards leopards in the event of occasional negative impacts (e.g., livestock depredation).

Climate change poses one of the biggest risks to biodiversity globally. Africa is warming at twice the global average rate and African bird species are therefore at risk, particularly in desert environments where they are already operating near physiological limits. Desert air temperatures in the subtropical latitudes will rise by 3°-5°C by the end of the century. When air temperatures are higher than body temperature, birds must use evaporative cooling to avoid hyperthermia. However, evaporative cooling requires water and a tradeoff exists between hyperthermia and dehydration. For drinking species which need open water sources in order to rehydrate, this tradeoff is exacerbated by high operative temperatures on the ground near the water's edge during periods of extreme heat. This study assessed whether providing artificial shade at waterholes can buffer impacts of high temperature by increasing accessibility of water to birds, potentially facilitating persistence of desert bird communities under climate change. I used a before-after control-impact experimental design to test the impact of shade provision on visitation rates, species richness and the timing of visits by desert birds to waterholes in the Tankwa Karoo National Park of South Africa. Providing shade reduced afternoon waterside operative temperatures below lethal limits for many small passerine species and successfully buffered birds' visitation rates to the water's edge during hot periods, although species richness did not change. Overall bird visitation rates to waterholes increased in the afternoon relative to control sites in response to the addition of shade but decreased in the morning, likely due to a perceived/actual predation risk while operative temperatures were low and shade structures provided no thermal benefit. Responses to shade were species-specific, with the overall positive response driven in part by two common species: Grey-backed Sparrow-larks Eremopterix verticalis and Tractrac Chats Emarginata tractrac. Two species (Cape Sparrows Passer melanurus and White-throated Canaries Crithagra albogularis) responded negatively to the provision of shade. There was an observed shift in bird visitation rates from the morning to the afternoon at shaded structures, suggesting temperature as a primary driver in the use of shade. As temperatures increase under climate change, birds may be forced to drink more in the afternoon due to rising water demands for thermoregulation. Shade structures such as those trialed in this study may have the potential to facilitate this shift and keep water accessible to desert birds in the face of temperature increases.

Vultures are highly mobile scavengers that cover vast distances on their daily foraging trips. Vultures display specific spatial and behavioral patterns when feeding on carcasses, and these behaviors are potentially identifiable in the tracks of geographical positioning system (GPS)- tagged birds. Thus, by applying algorithms to classify their movements it may be possible to create a carcass detection system using these spatial signatures. In this study I applied this approach to explore its efficiency in detecting carcasses and describing the diet of 12 GPStagged vultures in Botswana. I tracked five resident vulture species in Botswana using GPStrackers, these were: Cape Vulture (Gyps coprotheres n=2), Hooded Vulture (Necrosyrtes monachus n=2), Lappet faced Vulture (Torgos tracheliotos n=2), African White-backed Vulture (Gyps africanus n=4) and the White-headed Vulture (Trigonoceps occipitalis n=2). I attempted to search as many as possible of the feeding sites identified by the algorithms between January and June 2022. These potential feeding events were ground-truthed to confirm carcass presence. At each investigated site, any carcass found was identified down to species level. The ground-truthed sites constituted 22% (n=109) of all potential feeding sites identified within the study time frame (n=494). Carcasses were recorded at 62% (n=67) of these investigated sites. Carcasses associated with feeding events from all vulture species were located, except for Hooded Vultures. For this species only one site was checked, with no carcass found. At vulture feeding sites, carcasses from a total of ten taxa were identified. These were mainly wild ungulates (84%) with livestock making up a far lower proportion (16%) comprising of cattle (Bos taurus) and donkey (Equus asinus). Elephant (Loxodanta africana) was the most frequently identified taxon in the carcasses (31%; n=21) and was found at feeding sites of all four vulture species. Although sample sizes were relatively small for each species, it appeared that livestock was recorded only at Lappet-faced and White-backed Vulture investigated sites. Furthermore, Cape and White-headed Vultures had wildlife mostly giraffe and elephant at their investigated sites. Potential feeding events were ground-truthed on average 8 ± 8.35 days after the initial identification of the feeding event. The likelihood of detecting a carcass at these sites declined significantly with the amount of time lapsed from initial identification. The intercept of this relationship suggested that at the time of initial identification there was an 85% chance of detecting a carcass. Vegetation biomass at the sites, and the vulture species involved, had no influence on the likelihood of detecting a carcass. My study, on the application of GPS-tracking to understand the diet of a sample of African vultures in Botswana suggests that this technique is a useful approach but requires substantial resources in terms of personnel to investigate the identified feeding events as soon as these events are triggered, to derive a sufficient sample size to characterize the diets of these different vulture species.

<p> As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts with commercial and recreational fisheries. An analysis of strandings of California sea lions, _{Zalophus californianus,} and Steller sea lions, <i>Eumetopias jubatus, </i> from 2006 to 2014, included cause of death, changing ocean conditions, and anthropogenic activity. Causes of death included disease, injury, and human interaction, such as gunshot wounds, fisheries net entanglements and boat strikes. </p><p> Oregon and Washington strandings of California sea lions are primarily adult and subadult males that migrate north from California rookeries, while Steller sea lions are year-round residents and strandings are comprised of males and females of all ages. While the California sea lion population is currently at or near carrying capacity, the Eastern Pacific population of Steller sea lions was designated as Threatened under the Endangered Species Act until October 2013. Understanding impacts to these two pinniped species is vital to implementing effective management and conservation policies.</p><p> Oregon and southern Washington strandings of California sea lions and Steller sea lions from 2006 to 2014 were analyzed spatially using the geographic information system (GIS), and temporally to identify possible correlations with prey availability and human interaction. Strandings were found to follow seasonal patterns from year to year: Steller sea lion strandings were highest from May to July, California sea lions peaked in September, October, and November. There was a correlation between significantly high numbers of strandings and the three largest commercial fisheries in Oregon: Chinook salmon, Coho salmon, and Dungeness crab. </p><p> This analysis provides a format for continuing to monitor primary ecological and anthropogenic drivers of pinniped mortality in Oregon and southern Washington. </p>

<p> This study provides the first assessment of demographic and habitat information for pinto abalone (<i>Haliotis kamtschatkana</i>) in San Diego, California, two decades after the closure of all abalone fisheries in southern California. SCUBA surveys conducted from June 2014 to December 2016 indicate that current low densities (0-0.03 individuals/m²) were far below critical thresholds identified for other abalone species (0.15-0.30 abalone/m²) for successful spawning and recruitment. A broad range of sizes were represented (13-146 mm), however, only 95 individuals were found. Some sites showed significant aggregation of adult (> 50 mm) pinto abalone, 30% of adults had a nearest-neighbor within a critical spawning distance of 2 m, and 65% had a neighbor within 5 m, indicating that at least a small proportion of individuals may be capable of reproducing successfully. Pinto abalone showed a significant preference for boulder habitat at a lower relief (&lt; 10 cm) relative to available habitat&ndash; a preference that may influence aggregation around habitat features and enhance reproduction. The frequency, timing, and broad spatial distribution of these surveys was not sufficient to measure patterns in recruitment or changes in abundance, particularly over a strong El Ni&ntilde;o event that occurred during the study period. There is a critical need for consistent long-term monitoring in southern California to better understand demographic and environmental processes affecting recovery and persistence of populations, particularly at the southern edge of the broad range of pinto abalone.</p><p>

<p>Western Pond Turtles, <i>Emys</i> (<i>Actinemys</i>) <i> marmorata</i>, were captured (n=173) in 2011 (wet year) and 2012&ndash;2013 (successively drier drought years) along upper Coyote Creek, an intermittent stream in central California. Males outnumbered females 2.8:1, juveniles less than 120 mm long made up 26% of captures, growth rates varied among individuals, and little growth occurred in turtles older than 10 years. I radio-tracked turtles from May 2011 through August 2013 to ascertain movements and seasonal habitat use. Males had much larger home ranges than females (means of 2281 m for males and 501 m for females in 2012), and males moved extensively in April and May, during the apparent breeding season. Turtles preferred deep and complex pools, complex runs, and backwaters. Turtles left the stream for upland habitats in late spring and summer as stream flow ceased and pool connectivity was broken. There was substantial variation in departure dates among individuals and between wetter and drier reaches. Mean departure date was 16 August in 2011, but decreased to 20 July in 2012 and 28 June in 2013, as the drought intensified. Upland sites were mostly within 100 m of the stream, beneath dried leaves and/or thatch, and on slopes varying from flat to over 40%. Turtles remained upland for almost seven months in 2011&ndash;2012, although there was much variation. Mean return to stream dates were 27 February (males) and 16 March (females). </p>

<p>The efficacy of intensive rotational targeted grazing (IRTG) for suppression of the invasive shrub, multiflora rose (Rosa multiflora) was investigated in upstate New York. Sheep stocked at high density were rotated through a circuit of enclosures at a frequency of 3-d per enclosure, from May-September, 2011 and 2012. The photosynthetic surface areas (PSA) and vitality of R. multiflora plants were evaluated before (May 2011) and after treatment by grazing (Sept 2011). Changes over time were compared with similar measurements of ungrazed plants. Species richness (S) was estimated in each enclosure before (May) and after (September) treatment. PSA in grazed enclosures declined by 56.8% over the 2011 season and by 62.5% during the 2012 season. One year after ITRG treatment, healthy R. multiflora plants in grazed enclosures had declined by 91% and unhealthy and dead plants had increased by more than 200%. The distributions of healthy, unhealthy and dead plants, in grazed and ungrazed enclosures, though not different before treatment (chi square goodness of fit test; p>0.05?? were different one year later (p<0.001). Mean S in grazed enclosures increased by 27% over the season and by the end of the study, S was 12% higher than ungrazed enclosures. Evidence of stress in R. multiflora (clumping, dwarfing and reddening of leaves) at the end of the 2011 season led me to investigate the possible presence of rose rosette disease (RRD) during 2012. Potential stress was confirmed in plants experiencing leaf reddening. Chlorophyll a concentrations were significantly lower in red than green leaves (Student?s t = 5.20, df=28, p<0.001). Not unexpectedly, Normalized Difference Vegetative Index (NDVI) lso differed in red and green leaves (Student?s t = 2.76, df=32, p<0.01). Green leaves had higher dry weights than red leaves (Student?s t=14.13, df=151, p<0.001). Wool from the sheep, and R. multiflora leaf and petiole samples were collected to determine if the eriophyid mite, Phyllocoptes fructiphilus, a vector for RRD was present. No significant evidence of P. fructiphilus in leaf and petiole (Mean=0.00 N=414 SD=.71) or wool samples (Mean=0.00 N=11 SD=0) was found. This was unexpected, although it would only take one mite to be the vector if that particular mite was carrying the rose rosette virus. Further studies would be required to test whether rose rosette was confirmed in this population. Visual evidence of RRD symptoms were more prevalent in grazed enclosures than ungrazed locations, and a greater decline in grazed enclosures was clear.

<p> This thesis examined avian population dynamics over a four year span (2011-2014) in four forest types in Kings Canyon, Sequoia, and Yosemite National Parks, California. I asked, do bird populations show fluctuations in abundance and species richness depending on early spring snowpack levels in various forest types of the Sierra Nevada? I conducted point transect sampling surveys as part of the Sierra Nevada Network's Inventory and Monitoring bird monitoring program. To calculate local abundances for fourteen common bird species, I modeled detection functions in program Distance 6.2. I also determined species richness for each transect, and finally correlated avian abundance with spring snow depths. None of the common bird species in this study displayed a strong correlation between their abundance and snow depths in any of the four years. Clark&rsquo;s Nutcracker indicated potential for a positive correlation for abundance and snow depth, but this result may have been driven by other factors. With changing climate in the Sierra Nevada expected to increase the variability of snowpack among years, it is crucial to continue studying relationships between bird populations and snowfall in the Sierra Nevada.</p>

No description available.

<p> As the southern sea otter (<i>Enhydra lutris nereis</i>) range expands into northern and southern California, it will encounter estuaries that have been historically occupied by sea otters. Understanding how otters use re-colonized estuarine environments will inform how estuaries might be managed to encourage future sea otter range expansion. This project addressed the question: how do southern sea otters use space in the unique estuarine habitats of Elkhorn Slough? I compared the locations and behaviors of 25 individual sea otters of different status (male, female, and female with pup) among eelgrass, saltmud, saltmarsh, tidal creek, and main channel habitats in Elkhorn Slough. From these data I created a synoptic model to predict space use for resident otters of Elkhorn Slough based on sex, behavior, home range, and habitat distribution. Ninety percent home ranges calculated from the model indicated that females used larger home ranges than males in the slough, but both sexes had smaller home range areas than otters using the rocky outer-coast habitats of the Monterey Peninsula. In Elkhorn Slough, important habitats associated with resting included tidal creeks (for females only) and eelgrass, whereas the main channel was important for foraging behaviors of both sexes. Although using land habitats, sea otters were most likely to be found within 50 m of water. Protection of similar resting and foraging habitats in prey-rich estuaries colonized in the future will promote southern sea otters recovery by allowing them to re-colonize historically important estuarine habitats. </p>