Nest predation is one of the principle constraints on bird breeding success, accounting for 20 to 80% of all nest failures. It can be exacerbated by anthropogenic factors and the resultant increased predation pressure has caused the decline of numerous bird species worldwide. Identifying management strategies to reduce nest predation is consequently a priority for biodiversity conservation. Many lethal and non-lethal methods of predator control can be ineffective, unethical, time-consuming and expensive to implement. An alternative is the use of Conditioned Food Aversion (CFA), a method by which animals are deliberately induced to avoid nests following consumption of eggs treated with an illness-inducing toxin. Previous studies suggest that this technique is effective but many have been subject to several methodological flaws that limit their applicability. Here I employ an improved experimental design that uses both spatial and temporal controls and incorporates quantification of predator identity and abundance. By so doing the resultant effects can be attributed to CFA treatment with higher certainty. In the Berg River Estuary, South Africa, nest losses of the Kittlitz's Plover (Charadrius pecuarius) are high due to Pied Crow (Corvus albus) nest predation. I used this common plover as a model species to test whether CFA can be used as a conservation management tool to reduce nest predation. I used a field experiment to assess whether provisioning quail eggs treated with carbachol, an illness-inducing chemical, resulted in reduced nest predation. To assess the effects of treatment, nest survival data for both artificial plover nests containing quail eggs and natural Kittlitz's plover nests, as well as predator abundance were compared across three experimental phases (pre-treatment, treatment and post-treatment) and according to treatment type (carbachol versus water).

The use of poison by farmers to control livestock predators is a major threat to vulture populations across Africa. In Namibia, there is now some understanding of poison use on commercial farms, but the situation in the communal farmlands is still poorly understood. Using a series of 36 questions, I interviewed 367 communal farmers to assess the prevalence of poison use across the north-west, north and eastern communal land. I found that 18% (SE 2.8) of farmers had killed a predator in the last year and 1.7% (SE 2.1) used poison to do so. I mapped the probability of poison use across the communal regions surveyed and found that poison use is predicted to be higher (up to 7% of farmers using poison) in some areas of the upper north-west. In contrast to previous research, those living adjacent to protected areas did not experience greater losses to predators and as a result were not more inclined to use poison. I found that those using poison are more likely to own greater numbers of livestock, particularly large livestock. Overall, my study suggests that poison use is approximately 12 times lower in the communal areas than on commercial farms. A number of farmers expressed that it is dangerous to use poison on communal land as the risk of non-target impacts is much higher where the land is not fenced and is communally used. Nonetheless there are communal farmers who are using poison and this poses a risk to already threatened vulture populations. Lastly, I did a survey to look at the farmers' local knowledge about vultures, their attitudes towards them and any cultural value that vultures hold. Overall vultures were viewed positively by farmers. The cultural use of vulture parts appeared fairly uncommon, with 9.5% of farmers reporting that they knew of uses. Many farmers indicated that the cultural use of vulture parts was something practiced by previous generations. Feathers were the most commonly used part, mainly for decorations and making arrows. From my assessment, it appears that anthropogenic threats to vultures in communal areas are fairly low. The cultural use of vulture body parts is rare. In addition, poison is used but this practice is not nearly as common as it is on commercial farms. Since poison can have such devastating impacts on vulture populations, I nonetheless advise that reactive and preventative measures are put in place to reduce poisoning and minimise the impact when poison is used. The identified 'hotspots' of poison use will assist local authorities to focus their poison mitigation efforts.

Includes bibliographical references / Climate change poses a major threat to living organisms, with maximum temperatures expected to continue to rise over the next few decades. Hot desert environments are particularly at risk because they experience high environmental temperatures, scarce vegetation, low productivity and unpredictable water sources. Endotherms such as birds face the challenge of maintaining a stable body temperature while avoiding dehydration. This study was carried out in the southern Kalahari, in South Africa's Northern Cape, where about 50% of bird species (36 species) depend on free-standing drinking water. Livestock farms within this area provide artificial water points, which benefit birds as well as livestock. This study determined the role of shade and cover in the use of these artificial water points by birds. An experiment was conducted at six waterholes using the Before-After, Control-Impact (BACI) design. After an initial baseline was established, three waterholes were shaded while the other three were left unshaded. Camera traps were used to record the pattern and intensity of water use by bird species at different times of the day and at varying air temperatures. A total of 36 bird species drank at the water holes, but data analysis was confined to the ten most abundant species. Of the ten, six species responded to the presence of shade/cover, with four species reacting positively (Cape Glossy Starling Lamprotornis nitens , Red - headed Finch Amadina erythrocephala , Black - throated Canary Serinus atrogularis , and Laughing Dove Spilopelia senegalensis ), four showing no significant change in drinking patterns, and two showing a decrease in visitor numbers when the site was shaded (Cape Turtle - Dove Streptopelia capicola, Namaqua Dove Oena capensis). This suggests that providing shade at waterholes is not a universal solution to the problem of increasing heat stress experienced by birds coming to drink. Certain species such as the Laughing Doves and Cape Turtle-Doves avoided waterholes during the warmest time of the day while the Namaqua Doves were frequent visitors at this time. However, the Laughing Dove took advantage of the shade provided at midday (warmest temperatures) as their numbers increased. The Red-headed Finch and Black-throated Canary also increased at water holes with temperature irrespective of the time of day. These patterns imply that the provision of shade modifies the behavior of some bird species in response to predation risk or heat stress. These species utilized shade at different times of day and with varying intensities as temperatures rose.

Recreation and ecotourism activities are growing in demand worldwide, especially in biodiversity hotspots. Protected area managers may seek to introduce novel activities in order to generate revenue. However, disturbance effects brought about through encounters between humans and wildlife can have negative consequences, which conflict with conservation goals. De Hoop Vlei is a large coastal lake within the De Hoop Nature Reserve. It is a Ramsar site as well as a key feature of a BirdLife Important Bird Area (IBA). Proposals for motorized boat tours and kayak tours on the vlei have been made, for which this study provides an impact assessment. Repeated counts were performed in order to characterize the waterbirds present during the high water level conditions required for boating. Birds were concentrated in areas with aquatic vegetation and shallow water, mainly along the vlei's western shoreline and southern and northern ends. Two routes were designed for boat tours that would minimize disturbance by avoiding these areas as well as breeding sites. Count data were also used to revise the Ramsar and IBA assessments, which underestimated the site's conservation value. Boat tours were monitored to estimate the number of birds disturbed, and to measure agitation distances (ADs) and flight initiation distances (FIDs) in response to the boat as well as a kayak. Post-disturbance recovery was investigated, as was the likelihood of habituation using a space-for-time substitution at a site with regular boat traffic. Boat tours did not typically disturb more than 10% of birds present at the vlei, and largely avoided disturbing species of conservation concern. Responses to the kayak were more severe than to the boat, which is most likely due to the similar speeds of the two boats are similar and the kayak is more easily perceived as a threat due to its shape and stealth, the presence of a paddler, and the consistent paddling motion. Post-disturbance recovery of species was slow and incomplete after an hour, meaning that there are likely costs for foraging opportunities and breeding if important areas are disturbed. Most species did allow a closer approach at the site with regular boating, but AD did not differ between them for most species. From these results it would be dangerous to assume that habituation will mitigate against disturbance impacts. Recommendations made included that kayak tours should not be permitted. Boat tours, with correct management, can be conducted in a manner that will not be too disruptive to birds. This study is the first to document such a large difference in responses of birds to two differing boat types, and is a rare example of disturbance of birds being studied in an African context.

Abstract The Rudd's Lark Heteromirafra ruddi is a globally threatened species with a fragmented population occurring in one of the world's most poorly-protected biomes, the grasslands. This, together with its endemism to the Highveld of South Africa and climate envelope modelling which predicts a dramatic reduction in its available habitat, places the species firmly in the cross-hairs of extinction risk. This thesis aims to gain a better understanding of Rudd's Lark population trends, habitat preference and threats in one of its most important remaining core sites in the grasslands around Wakkerstroom, Mpumalanga Province, which are under private ownership and used predominantly for grazing. My objectives were, first, to determine whether the species has declined in the Wakkerstroom area since a survey conducted in 2002 by David Maphisa. Second, to determine what habitat variables predict Rudd's Lark incidence, whether there has been a change in its available habitat and in farm management practices, and whether the species has changed in its habitat selection since the previous survey. Finally, I aimed to investigate whether other grassland birds (particularly other threatened grassland endemics) also respond to fine-scale habitat variation and share habitat preference with the Rudd's Lark. I found both absolute lower numbers of Rudd's Larks (5 transects with Rudd's Lark present down from 9 in 2002; 9 individuals down from 32), and a lower probability of encounter (significantly lower in the case of individuals). Seven transects had been lost to crop production, two of which formerly contained Rudd's Larks. Forb and dead vegetation cover had significantly increased at a coarse scale, but vegetation variables did not explain any significant variation in Rudd's Lark incidence at either a fine or a coarse scale within 2016. However, Rudd's Larks appear to be occupying subtly different habitat now compared to 12 years ago: lark territories surveyed in 2016 had less bare ground and more but shorter grass cover than in 2002. Most farmers reported warmer conditions in recent years and that burning generally took place between August and October, matching the analysis of remotely-sensed fire data from the past ten years and implying that destructive late-season fires are not common. Correspondingly, I found that burning regimes did not predict Rudd's Lark incidence. Among other threatened grassland species, Yellow-breasted Pipits showed a clear preference for taller grass and higher altitudes, unlike Rudd's Larks which showed no detectable preferences. In summary, direct loss of grassland habitat through conversion to crops appears to be a pressing threat to Rudd's Larks, although the species has also declined within the remaining area of grassland habitat. The specific drivers of this decline remain unclear given that the observed changes in grassland structure since 2002 do not correspond with Rudd's Lark habitat selection. Taken together, these findings are very concerning given that the Wakkerstroom area is considered to be one of the last remaining core sites for the species, and call its IUCN threat status of globally Vulnerable into question. A priority for future research will be to understand what limits Rudd's Larks to its current pockets of occupancy within its remaining apparently suitable grassland habitat, and whether increasing grassland fragmentation will accelerate its decline. Key words: fire, grassland, habitat selection, Heteromirafra ruddi, IUCN status, rangelands, Rudd's Lark, threatened species, transects

Global average temperatures are predicted to increase by as much as 5ᵒC by 2100. Therefore, it is imperative to identify how species are affected by temperature increase to ensure that proper conservation and management of wildlife can be implemented. Species which already live in warmer climates, such as deserts, may provide the first clues to the impacts of increasing temperatures. Birds represent an ideal indicator because research has shown that rising temperatures affect their behaviour, including foraging and provisioning of young, thereby reducing reproductive success. However, it remains unclear whether this results from physiological constraints on behaviour, from declining food availability and or access to prey items at high temperatures. In this study, I aimed to identify how temperature affects the foraging and provisioning behaviour of wild Fork-tailed Drongos, Dicrurus adsimilis, when supplemental food is provided. Additionally, I aimed to identify how nestling growth rates change with temperature. The results of two supplemental feeding experiments indicated that as temperatures increased, adults significantly reduced their willingness to forage, reduced provisioning to offspring and exhibited increased rates of heat dissipation behaviour. Furthermore, when provisioning nestlings, adult drongos consumed a larger proportion of supplementary food at higher air temperatures, and provisioned less. This suggests that they suffer greater provisioning costs at such times. Surprisingly, despite finding several negative effects of temperatures on adults' willingness to forage and provisioning, there was only a weak and non-significant effect of temperature on nestling growth rates. This suggests that adults may be able to compensate for reduced foraging at high temperatures. My study shows that the increased thermoregulatory costs of activity at high temperatures can constrain foraging and provisioning, even when food remains abundant. However, whether this impacts the fitness of current offspring or parents future reproductive success remains unclear.

Research on island biodiversity has played an integral part in our understanding of speciation, biogeography, and adaptive radiations. The islands of the Caribbean provide an ideal location to study evolutionary hypotheses because of their proximity to species-rich mainland source areas while being sufficiently isolated to preserve an endemic biota. Most of the more than 1,000 Caribbean reptile and amphibian species occur nowhere else and are typically restricted to a single island. However, anthropogenic pressures resulting in habitat loss and degradation threaten biodiversity, leading to the loss of undescribed and unstudied species. Few studies have been conducted on the phylogenetic relationships and biogeography of Neotropical forest lizards (Diploglossidae) because of the rarity of most species. Before my work, there were 3 recognized genera and 53 species of these lizards, found in Middle America, South America, and on Caribbean islands. I gathered and analyzed sequence DNA of 3,232 genes and 642,775 aligned base pairs in 30 currently recognized diploglossid species and conducted phylogenetic, phylogenomic, biogeographic, ecological, and morphological analyses. I found that Neotropical forest lizards are older and more species-rich than previously thought. Based on this, I described 2 new subfamilies, 4 new genera, and 18 new species. I also resurrected four genera and elevated 17 subspecies to the species level. The family Diploglossidae now contains three subfamilies, 12 genera, and 91 species. I assigned all 59 Caribbean celestine species to IUCN Redlist threat classes, with the primary threats being habitat loss and introduced predators Of these, fifteen species (25%) are Critically Endangered, seventeen species (29%) are Endangered, one species (2%) is Vulnerable, and twenty-six (44%) are Least Concern. Four of the Critically Endangered species are extinct, or possibly extinct. Four of the Critically Endangered species are extinct, or possibly extinct. My biogeographic analyses indicate that forest lizards reached the Caribbean islands by at least two dispersal events, in the Oligocene and Miocene, likely by floating on flotsam from northern South America. Past and present ocean currents facilitated these initial dispersal events and subsequent dispersals among Caribbean islands. Finally, I assigned the species of Neotropical forest lizards to six different ecomorph classes based on ecology, morphology, and statistical analyses. Several of these ecomorphs appear multiple times in my phylogeny, indicating that convergent evolution has occurred within the family. / Biology

Scientists have long been interested in mechanisms that increase and decrease biodiversity on Earth and the effects they have on organisms’ interactions and functions. Global biodiversity loss is now outstripping accumulation and far exceeds expected background levels and has drawn comparisons to previous mass extinctions. The ongoing Holocene–Anthropocene extinctions differ from prior biodiversity loss, because humans have been directly implicated as major drivers of current loss—overexploitation, habitat modification and destruction, climate variability, spread of pathogens, and invasion by exotic species. Biodiversity change and especially loss can alter ecological assemblages irreversibly, which consequently can change the direction and magnitude of key ecosystem functions that organisms, including humans, rely on. Therefore, it is increasingly important to develop methods for quantifying and understanding phenomena linked to biodiversity change. In my dissertation, I develop methods to: (1) assess risk of a global-scale invasion of a pest species, (2) predict host associations for a generalist pest species, and (3) develop models to understand extinction dynamics within a clade of conservation interest. In my first chapter, I developed a framework and used it to assess a rapidly spreading regional U.S. grape pest, the spotted lanternfly planthopper (Lycorma delicatula; SLF), to spread and disrupt the global wine market. I found that SLF invasion potentials are aligned globally because important viticultural regions with suitable environments for SLF also heavily trade with invaded U.S. states. For my second chapter, I estimated host plant associations for SLF with phylogenetic imputation and predicted SLF host associations for the U.S. Many known and predicted high association host species are found in the uninvaded Midwest, Southeast, and West Coast as well as the Mid-Atlantic and Northeast, where SLF is present. Should SLF spread further, these regions are likely to experience impacts to resident trees. For my third chapter, I proposed a method for detecting three non-random extinction models and used the imperiled Caribbean lizard genus Leiocephalus as a case study to test it. Past extinctions showed directional loss of larger Leiocephalus species. However, future predicted extinctions are random for body size but show stabilizing extinction of species with either smaller or larger limb and tail lengths. Shifting extinction for Leiocephalus may occur because of changing pressures that now include anthropogenic habitat loss. Altogether, these studies attest to the value of developing and evaluating approaches to describe biodiversity dynamics in the Anthropocene. / Biology

Conservation biology is primarily concerned with the amelioration of species decline. The Yellow-footed Rock-wallaby (Petrogale xanthopus xanthopus) is a medium sized Macropod that inhabits the semiarid rangelands of South Australia and New South Wales. Its conservation status is Vulnerable C2a(i). In this study, population modelling, spatially explicit habitat modelling and Population Viability Analysis (PVA) have been used to better understand the factors that affect the abundance and distribution of the P. x. xanthopus in South Australia. The processes that drive the population dynamics of a species operate at different scales. As such this research involves a collection of several inter-related and scale-specific empirical studies that provide insights about the population dynamics of P. x. xanthopus. Each of these studies captures environmental, demographic and behavioural process acting on the population at different scales. These include the analysis of relative abundance data derived from an aerial census, mark recapture sampling of demographic parameters in relation to rainfall patterns and a collection of habitat models derived at different scales using presence-absence data. Spatially explicit PVAs enable the population dynamics of a species to be modelled in space and time. Using these data, a PVA is conducted to explore and rank the importance of the factors that threaten this species and help guide their future monitoring and management. Movement is also a key issue when considering problems such as isolation and inbreeding. Given that little is known about the dispersal behaviour of this species, a range of different dispersal behaviours are also simulated in the PVA using random and non-random mating algorithms, to estimate the potential for inbreeding. / Thesis (PhD)--University of South Australia, 2004.

<p>Within the San Francisco Bay Area, Western Snowy Plovers (<i>Alexandrinus nivosus nivosus</i>) nest and winter in former salt ponds. They face a number of threats including human-altered habitats and high levels of predation by mesopredators and raptors. The South Bay Salt Pond Restoration Project (the Project) is a large wetland restoration project that will change and potentially eliminate Snowy Plover habitat in the region. As the Project returns salt ponds to tidal wetland, there will be less of the dry, flat, and sparsely vegetated habitat that plovers need for breeding and wintering habitat. A greater understanding of the specific microhabitat requirements for high quality plover foraging sites is needed. In particular, it is important for managers to understand what constitutes high quality wintering habitat for Snowy Plover numbers. This study assessed the characteristics at sites where Snowy Plovers winter in former salt ponds, especially habitat traits related to promoting plover foraging. Analysis of plover foraging habitat showed that plovers were associated with increasing plant height, water cover, and distance from perches and levees. This information is designed to inform restoration and management decisions in efforts to meet Snowy Plover recovery goals in the South San Francisco Bay. </p>