Below I describe the projects that I am currently pursuing. These projects are either ongoing or in preparation.
Puma Predation on Sheep in the Region of Torres del Paine National Park and UNESCO Biosphere Reserve, Magallanes, Chile: Conserving Top Predators and Local Livelihoods
The purpose of this project is to promote sustainable ranching amidst an environment of wildlife conservation.
Ranchers and pumas have been competing with one another in southern Chile for nearly 150 years. Adjacent to Torres del Paine National Park (TdP), on a string of ranches informally called the “Line of Fire”, the greatest incidence of sheep predation by pumas, and puma hunting by ranchers, in the Magallanes region occurs. The lack of governmental oversight with regard to this problem has engendered increasing frustration among ranchers to the point where pumas have been hunted within TdP. Yet, preliminary results from our research questions the incidence of puma predation on sheep because the majority of hunted pumas do not contain sheep remains in their stomachs. However, in contrast to these data, ranchers report a 36% loss of sheep/year due to puma predation – a total loss of nearly US$2.8 million/year.
In light of the potential emerging markets in the United States for the sale of sheep meat, and the potential negative publicity associated with long-term carnivore eradication policies, it behooves the Chilean Government and ranching sector to arrive at a sustainable solution to this escalating rancher-puma conflict. According to the USDA, the consumption of sheep meat in the U.S. approximates 170,000 tons/year. While the U.S. produces only 80,000 tons, approximately the same amount is imported from New Zealand and Australia in order to satisfy internal demand. The opportunity for Chile to enter the US market is auspicious due to: (1) inconsistent production in Australia and New Zealand because of unfavorable climatic conditions, and (2) the excellent sanitary/health conditions of Chilean sheep (e.g., no antibiotics and very few problems with disease). Since 52% of sheep in Chile are produced in the Magallanes Region, the possible entrance of Chile into the U.S. sheep market could prove to be very lucrative (Mercado de la carne Ovina. Boletin "Mercados Agropecuarios, 2007).
Within our study area (Line of Fire ranches), we are collecting ecological and economic data that will serve as the foundation of a conservation initiative. Politically, we have the interest and involvement of local stakeholders, including ranchers (local and regional), park officials (CONAF; the Chilean National Ministry of Forests and Parks), agricultural officials (SAG; Chilean Agriculture and Livestock Service), university administrators (Univ of Magallanes), and a non-profit foundation within Torres del Paine National Park (AMA Torres del Paine). Therefore, we believe that we are well-positioned for success.
To provide local stakeholders with a comprehensive action plan that will enable them to make informed decisions regarding puma management. Furthermore, we will suggest stewardship practices - - based upon puma ecology - - that will likely reduce puma predation on livestock. We envision this project as a stepping stone to a more comprehensive plan of action for puma management and improved stewardship throughout Magallanes.
A geographic analysis of 2nd generation rodenticide resistance among commensal rodents in New York
The anticoagulant rodenticide warfarin was introduced in Europe to combat rodent pests in the early 1950s. Within only a decade however, resistance to warfarin, as a first generation anticoagulant was observed in Norway Rats, Rattus norvegicus, in Scotland, and was subsequently documented across Europe, the United States, Australia, and Japan.
Because warfarin resistance reduces the efficacy of rodent pest management, more potent second-generation anticoagulant rodenticides were developed during the 1970s and 1980s. Yet resistance to these compounds was also reported soon after their introduction. This may pose potential public health risks to humans because rodent control in most cities around the world rely heavily on the use of these rodenticides, yet the commensal mice and rats harbor numerous pathogens and zoonotic diseases as well as being linked to asthma and indoor allergies.
Urbanization has likely influenced the frequency and geographic pattern of rodenticide resistance among rats and mice. The New York metropolitan area is the most populous in the US, yet resistance of mice and rats to second- generation rodenticides in New York City has not been investigated. Given the unrelenting application of second- generation rodenticides during the past 25-30 years, there is an urgent need to assess the degree and geographic distribution of second -generation rodenticide resistance should it exist among the commensal rodents of New York City. These data are crucial for the development of more efficient and cost effective control protocols, especially considering that in 2003 approximately $13,000,000 was spent on rodent pest control.
Therefore, we are collaborating with the New York City Department of Health and Mental Hygiene to conduct a DNA-based field investigation of the frequency and geographic pattern of second generation rodenticide resistance in rats and mice along an urban-rural gradient from New York City to eastern Long Island. We will collect DNA samples by trapping mice and rats from 30 locations (300 mice/150-200 rats), 3 locations in Manhattan and the outer boroughs (N=15), and 5 locations in eastern, central, and western Long Island (N=15). We will then sequence the rodent VKORC1 gene - the critical gene in which mutations confer rodenticide resistance - in order to assess the frequency and geographic distribution of rodenticide resistance. Our primary objectives are to investigate: 1) the frequency of 2nd generation rodenticide resistance, and 2) the influence of varying levels of urbanization on the geographic pattern of 2nd generation rodenticide resistance in the New York City area.
Two additional longer-term prospects are considered important for our study: (1) in-depth analyses using “next generation” DNA sequencing to potentially reveal the zoonotic potential of the commensal rodents; and, (2) the incorporation of genomic tests of selection to identify possible additional genes involved in warfarin resistance other than VKORC1. This approach should reveal loci that could then be examined for a role in the treatment response of humans to warfarin, which is also the most commonly used anticoagulant pharmaceutical (i.e., Dicoumerol) in human medicine.
Genetic variation and movement of Florida Burrowing Owls
Despite the long-term scientific interest in the Florida Burrowing Owl, the majority of research has focused on reproductive ecology and natural history. While important, virtually nothing is known about other crucial aspects of their ecology including population genetic structure and movement. Because mobility and dispersal are inextricably linked to population genetic structure, highly vagile organisms such as birds should exhibit minimal amounts of genetic differentiation across populations compared to less mobile species, which include many mammals and amphibians. Physical barriers and even behavioral differences among highly mobile species, however, can limit movement to the point where gene flow ceases and populations exhibit increasing levels of homogeneity and differentiation from one another due to inbreeding. The limited dispersal of burrowing owls within a patchy matrix of suitable habitat makes this species an excellent candidate for investigating the forces driving population genetic structure in this declining species. Only by increasing our understanding of the geographic distribution of genetic variation of burrowing owls in Florida will strides be made in improving conservation and management strategies for this “Species of Special Concern.”
The utilization of molecular markers in Camelids: population/conservation implications
My colleagues and I are investigating genetic diversity and long‑term viability of vicuñas in the Apolobamba National Management Area (ANMIN-A), Bolivia. Since 1998, wild vicuñas have been captured, shorn for their fine wool, and released on an experimental basis in the Apolobamba National Integrated Natural Management Area. Although vicuñas are not intentionally harmed, the stress associated with capture and shearing may disrupt their social structure by separating young animals from their mothers, by causing shifts in territorial boundaries or changes in habitat use, and/or by altering behavior. Changes in behavior and distribution due to capture and shearing may also reduce adult female fecundity and increase juvenile and/or adult mortality. In addition to the potential problems associated with capture and shearing, this population revealed the lowest levels of genetic variation at both mitochondrial and nuclear loci when compared to three other vicuña populations in Bolivia and Chile. While ANMIN-A is the largest vicuña population in Bolivia (containing 72% of all vicunas in protected areas in Bolivia, and nearly 20% of all vicuñas in the country), it is also the most isolated population in Bolivia. The numerous problems associated with reduced genetic variation in natural populations of animals, due to small effective population size, are well documented and include: inbreeding, lowered resistance to infectious diseases and parasites, reduced survival, and increased probability of extinction. Utilizing blood samples from vicuñas collected during the capture and shearing process, we will:
- document and evaluate the possible detrimental effects of the current program of economic utilization of vicuñas in ANMIN-A on individual behavior and social structure by combining census, behavioral, and molecular genetic data,
- survey levels of genetic variation and infer demographic history by utilizing mtDNA and microsatellite markers,
- generate independent estimates of the effective population size (Ne) employing both demographic and genetic data, and
- conduct a Population Viability Analysis of this vital population using demographic, environmental, and genetic data.
Individual identification, mating patterns, and population structure of Darwin’s Rhea in southern Chile
Except for anecdotal observations, the mating system of Darwin’s Rhea has been poorly studied. The mating system can be considered to be both polygynous and polyandrous. Males build nests, mate with and incubate the eggs of several females, and raise young. After depositing their eggs in a males’ nest, however, adult females will then mate with another male. We propose that adult males may not always raise their own young because of this serial polyandry.
Amplifying DNA from feathers and membranous tissue on the inside of eggshells will allow us to utilize novel approaches to study various aspects of the ecology of the Darwin’s Rhea-a species that up to now has been extremely difficult to study. I will investigate the reproductive strategies of adults, as well as dispersal and individual movements. By collecting feathers in the field, and genotyping them against all known individuals, I will generate movement histories for each individuals. This approach, used in conjunction with behavioral data, will ultimately increase our understanding of the mating system of this fascinating and under-studied species.
Invitation to collaborate
I wish to emphasize that these research topics are just a few examples of questions that interest me. My research endeavors are broad and are certainly not limited to these topics of inquiry. I am excited about exploring a wide range of questions and to collaborate with students and the diverse faculty in the Department of Biology at Hofstra University.