Rare species research

Rare species publication list

 

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Energetics of an apex predator, the cheetah

Hurricanes, islands, and the Miami blue

Recovery of the St. Francis' satyr

Population genetics of African golden moles

Mouse invasions on Gough Island

 

I have always had a keen appreciation for wild things. My birdwatching hobby in particular has taken me to different continents, and the various corners of many countries. I even lived on an uninhabited island for thirteen months following my appreciation for wildlife. Now it seems I have made a career out of saving wild things.

 

Energetics of an apex predator, the cheetah

 

Top-level mammalian predators facing energetic constraints are vulnerable to extinction because they are subjected to environmental restrictions to their distributions and biotic conditions restricting their food intake. This is especially true for the cheetah, the world’s fastest land mammal. Due to their large bodies and high-speed hunting, cheetahs endure an energetically costly lifestyle. Notably, they achieve momentary metabolic scopes of 50x resting metabolic rate when hunting, which is greater than that of any other extant mammal known. The ability to achieve such extraordinary power outputs is supported by their exceptionally large hearts, lungs, livers and muscular bodies, all of which increase energetic load. They also have high core body temperatures (sometimes reaching 41C when hunting) which force them to rest because of critically high brain temperatures. These factors suggest that only short chases during cooler periods of the day may be attempted. Cheetahs thus operate under particularly intense physiological and energetic demands. Energy demands also differ markedly depending on satiation. Importantly, hunting motivation increase as animals get hungrier, so that energy requirements peak when their energy reserves are lowest, producing a downward spiral of energy deficit. As well as physiological constraints, various ecological limitations occur through intra-guild competition. First, cheetahs are often forced to hunt in areas with lower prey densities than those occupied by stronger competitors. Second, they hunt during the day rather than at night to avoid confrontation with other larger predators, even though this may exacerbate potential for overheating. Third, they lose as much as 10-14% of their prey items through kleptoparasitism. Collaborating with Michael Scantlebury and the South African Wildlife Research Expedition of Global Vision International (GVI), and funded by grants from the Royal Society and the Natural Environment Research Council (NERC), our cheetah project have three main objectives. First, we aim to quantify daily activities and food intake of free-ranging cheetahs, and their interactions with other predators. Second, we aim to determine the daily energy expenditure of free-ranging cheetahs using the doubly labelled water technique. Third, using this data, we will calculate behaviour-specific energy expenditures. Our results will provide an understanding of how energetic limitations affect species vulnerability. This work is conducted in the Kgalagadi Transfrontier Park (Botswana/South Africa) and Karongwe Private Game Reserve (South Africa).

 

 

Hurricanes, islands, and the Miami blue

 

The Miami Blue (MBB) is one on the most imperiled butterflies in the world. First described in 1943, the species was once widespread throughout its range in coastal areas of southern Florida. However, the use of insecticides, invasive plants displacing food plants, and habitat loss through urban development reduced the range and populations of the MBB so much that by the 1980s the species was extirpated from mainland Florida, and after Hurricane Andrew in 1992 presumed globally extinct. Since then two new populations have been discovered within Florida’s Lower Keys: one population in 1999 within Bahia Honda State Park (now presumed extinct) and another seemingly healthy population in 2007 on Marquesas Keys. Despite the imperiled status of the MBB, quantitative biological data is very limited for the remaining population. We are also unsure how mosquito control, invasive species, the weather, climate change, and demographic stochasticity influence the remaining population. To ensure the continued persistence of this critically endangered species, there is an urgent need to gain a better understanding of the biology and population status of the MBB. Working with the United States Fish and Wildlife Service, our aims are to (a) quantify the current distribution and habitat requirements of MBB; (b) conduct a comprehensive population survey; (c) provide estimates for population size, abundance and detectability per island; and (d) provide a meaningful and repeatable protocol for future monitoring at appropriate spatial scales.

 

 

Recovery of the St. Francis' satyr

 

I am part of a team that, in partnership with the United States Department of Defense (DoD), design and implement recovery plans for the federally endangered St. Francis’s Satyr butterfly. First discovered in 1983, its known global range is restricted to Ft. Bragg located within the Sandhills region of southern North Carolina (USA). Here they live as several subpopulations in a shifting mosaic of semi-permanent, early-successional wetlands typically situated in riparian areas subjected to disturbances such as beaver activity and fire. However, both beaver populations and fire have been suppressed over the last century, drastically reducing the amount of suitable habitat and subsequently also St. Francis’ satyr population sizes. Over the last few decades, both beaver populations and fire have been restored as ecosystem processes on Ft. Bragg, providing opportunities for St. Francis’ satyr population recovery. Yet, despite extensive surveys, few new colonies have been found in recent years. Moreover, while already limited in their distribution, some previously healthy St. Francis’ satyr subpopulations are currently in decline as once-suitable habitat transitions toward late-successional stages. My interest revolves around using species distribution models to find suitable but unoccupied butterfly habitat, and connectivity modeling to prioritize reintroduction areas.

 

 

Population genetics of African golden moles

 

Golden moles are surely a contender for Africa’s most elusive group of mammals. They are also highly threatened: the 2007 IUCN Red List of Threatened Species lists considers 10 of the 18 known South African golden mole species as threatened. Three more species are considered near threatened and one require more information for assessment (i.e. data deficient), which leaves only four South African species of least conservation concern according to IUCN criteria. Three other Golden Mole species are known elsewhere in Africa – two of them lacking data for evaluation. Undoubtedly, the survival of South Africa’s golden moles hangs in a balance and more data is urgently needed to enable us to make informed decisions as to their survival. Between 2003 and 2005 (part-time) and 2006/2007 (full-time), I spent a considerable amount of time with Nigel Bennett and Sarita Maree (from the MRI) in the field surveying golden moles. During this time I recorded numerous new golden mole localities, and possibly even a few new species; genetic samples are currently being analyzed. Genetic samples will also provide us with information on population structure, gene flow and reproduction of golden moles, within and between species. I am proud to say that I also managed to collect chromosome samples from a third of South Africa’s golden mole species - which any mole expert will tell you is no mean feat.

 

 

Mouse invasions on Gough Island

 

Gough Island is a subantarctic island and UK overseas territory situated in the South Atlantic Ocean. The island possesses an extraordinary wealth of unique biodiversity and has being called the world’s most important seabird island. Not surprisingly, it has been afforded UNESCO World Heritage Site status. In 2000/2001, the first ornithologists to stay on the island for a year discovered that introduced mice are annihilating the island’s bird population (and likely also other biodiversity). This behavior was captured on camera during the second bird expedition in 2002/2003. Working for the Royal Society for the Protection of Birds (RSPB, United Kingdom) and Percy Fitzpatrick Institute (PFIAO) at the University of Cape Town (South Africa) Marie-Hélène Burle and I then spent 13 months (2005/2006) on Gough Island gathering data to determine the feasibility of eradicating the mice in an effort to save the island’s unique wildlife. In addition, we also conducted bird monitoring, as well as various other research activities that included stable isotopes, energetics and genetics. In addition, as conservation officer for the year, I oversaw waste management, eradication of invasive grasses, and the first seal survey in 23 years.

 

 

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