Research on Wild Cats

APPLYING MOLECULAR MARKERS TO ECOLOGY, BEHAVIOR, AND POPULATION HISTORY OF WILD CATS IN TEXAS

Researchers: Jan E. Janecka, Michael Tewes, John Young (TPWD), Linda Laack (USFWS), Rodney Honeycutt (TAMU)

Bobcat, ocelot, jaguarundi, and mountain lion are four species of felids present in Texas. Bobcats are abundant throughout the United States and Texas. Mountain lions are distributed throughout the western United States and western and southern Texas. In contrast, ocelots are primarily found in Central and South America and southern Texas. Although jaguarundis are found in Central and South America, their presence in Texas is doubtful. In Texas, the majority of the studies on these cats have focused on habitat use, activity, and diet. There have been few studies on population genetics of these species. Two of the most recent projects were conducted by Chris Walker on ocelot and bobcat (at Texas A&M University with Drs. Tewes and Honeycutt) and Jan Janecka on bobcat (at University of Vermont with Drs. Hirth and Kilpatrick).
We have been collecting scat samples from throughout this region for over 20 years and have a large number of ocelot, bobcat, and mountain lion samples. We are continuing to collect samples with the cooperation of Texas Parks and Wildlife, Wildlife Services, U. S. Fish and Wildlife Service, Welder Wildlife Foundation, and private landowners. This study will examine genetic variation of wild cats in Texas using both microsatellites and mtDNA. We will compare differences in genetic variation, geneflow, and dispersal between the cat species and relate them to known differences in ecology and behavior. This study has four main emphases: 1) examine population structure and patterns in genetic variation, 2) estimate recent fluctuations in population size, 3) combine genetic data with radio-telemetry to examine dispersal and social structure, and 4) compare the differences and similarities between these four cat species.



CONSERVATION GENETICS OF WILD AND CAPTIVE CATS IN THAILAND


Researchers: Jan E. Janecka, Lon I. Grassman, Dr. Whichan Eiadthong (Department of Forest Biology, Kasetsart University, Thailand), Michael Tewes

Population genetics has become an important tool for wildlife conservation and captive breeding programs. The application of genetics to conservation biology has provided critical insight into the status, history, and conservation of threatened populations and captive breeding programs. There is extremely limited ecological information on the clouded leopard, Asiatic golden cat, marbled cat, and leopard cat and no knowledge on population genetics of these species. In addition, Thailand Zoological Parks Organization has clouded leopards, Asiatic golden cats, marbled cats, fishing cats, and leopard cats that have not been genetically analyzed.
Our field research of wild cats in Thailand has resulted in a unique opportunity to examine samples valuable for the study and conservation of these species both in the wild and in captivity. We have also recently approached Thailand Zoological Parks Organization to obtain access to samples from captive cats maintained in membership zoos. We will use microsatellite loci and mitochondrial DNA sequences to: (1) examine genetic erosion that may have occurred in wild and captive clouded leopard and leopard cat due to fragmentation and reductions in population size, (2) provide baseline data on genetic variation of clouded leopard, Asiatic golden cat, marbled cat, and leopard cat in wild and captive populations in Thailand, (3) provide genetic information on captive populations that will be pertinent to breeding and zoo exchange strategies, (4) estimate the level of dispersal and geneflow between Phu Khieo Wildlife Sanctuary and Khao Yai National Park, (5) estimate long-term effective population size (Ne) and recent reductions/expansions of leopard cat, and (6) support and expand a wildlife genetics laboratory at Kasetsart University (Bangkok, Thailand).


ESTIMATING EFFECTIVE POPULATION SIZE USING GENETIC METHODS

Researchers: Jan Janecka, Michael Tewes, John Young (TPWD), Rodney Honeycutt (TAMU)

It is important to monitor effective population size (Ne) because it has a strong effect on genetic variation. Analysis of Ne provides insights into the stability and viability of a population. The Ne of a population is defined as the size of an ideal population that has the same genetic behavior as the study population. Wild populations often violate assumptions made in many genetic models. For example, only a portion of all individuals breed and mating is not random. Due to these violations, Ne is always lower than the actual census population size. Because Ne has predictable effects on genetic variation it can be estimated from genetic data (although estimation can be problematic).
We will use several different models to estimate Ne of mountain lion, bobcat, and ocelot in Texas. Different models will be tested for biologically meaningful estimates against each other. The confidence intervals of different models will be compared. The effects of sample size, number of molecular markers, and types of molecular markers used on different models will also be tested. The goal of this project will be to design methods for estimating Ne of wild cats that is biologically meaningful and informative for management purposes. This project will be done in close cooperation with Texas Parks and Wildlife.


ANALYSIS OF SCAT SAMPLES USING MICROSATELLITES AND MtDNA MARKERS
Researchers: Jan E. Janecka, Michael Tewes, Rodney Honeycutt (TAMU)

Studies on elusive species (such as felids) are often limited by small sample sizes. The time and financial cost of obtaining a large sample is often prohibitive. Invasive studies may also be complicated by the interference effects of capturing animals. However, non-invasive sampling such as collecting scat or hair samples is in some cases a simple and efficient way to obtain wildlife samples. For some cat species such as bobcat, scat is often visible and easy to find, providing researchers with a large sample per unit effort.
Successful genetic analyses have been done on DNA extracted from scat samples. However, several factors complicate DNA analysis of scat. These factors include DNA degradation due to the harsh environment of the digestive track, low amounts of target DNA, and allele drop-out. Despite these difficulties, other researchers have amplified DNA from scat from various species including grey seals (Halichoerus grypus), harbor seals (Phoca vitulina), bears (Ursidae), mountain lions (Puma concolor), and bobcats (Lynx rufus).
This study has several objectives: 1) develop an easily assayed species specific genetic marker for differentiating ocelot, bobcat, jaguarundi, and mountain lion that is efficiently amplified in scat, and 2) identify microsatellites that will provide efficient genotyping of scat samples for mark-recapture or rarefaction estimates of population size. In some areas this may eliminate the need to capture felids for the purpose of obtaining DNA, saving significant amounts of time and financial expenditures.


ESTIMATING POPULATION SIZE AND DISTRIBUTION USING SCAT SURVEYS


Researchers: Jan Janecka, John Young (TPWD), Michael Tewes, Rodney Honeycutt (TAMU)

It is very difficult to estimate population size of elusive carnivores that occur at low densities, such as mountain lion and ocelot. Yet these species are a high management priority in Texas. The size and distribution of populations has to be accurately described to make good management decisions. The latest methods for estimating population size utilize survey schemes that non-invasively sample populations, then use genetic markers to identify individuals, and finally estimate population size from the data using mark-recapture or rarefaction models.
In this project, we will develop scat collection schemes that will effectively sample a population in a representative area. A portion of the cytochrome b sequence will be used for species identification of questionable scat. Individuals sampled will be identified by genotyping scat using a sufficient number of microsatellite loci. Population size will be estimated for the study area using either the rarefaction or mark-recapture model (depending on the survey method). We will test the applicability of this method for estimating population size of mountain lion, ocelot, and bobcat.


HISTORIC GENETIC VARIATION OF WILD CATS IN TEXAS


Researchers: Jan E. Janecka, Michael Tewes, Rodney Honeycutt (TAMU)

Genetic factors must be taken into account for long-term management of threatened populations. To provide more detailed information on population genetics of ocelot and bobcat, this study will examine the temporal continuity of these cats in Texas. We will examine the patterns in genetic variation of historic populations by analyzing museum specimens and compare them to current populations. The effects that population fluctuations in the 20th century have had on genetic variation will be studied.
Ocelot and bobcat museum specimens collected around 1900 will represent historic populations. Samples collected in the 1990's will represent current populations. We will use microsatellite, control region, cytochrome b, and Major Histocompatibility Complex (MHC) markers to address the following objectives: 1) compare historic and current genetic variation, 2) examine the geographic origin of current populations in southern Texas, 3) compare the differences in genetic erosion between neutral markers (microsatellites and mtDNA) and adaptive loci (MHC). We will generate historic baseline data on genetic variation for future studies and monitoring of ocelot and bobcat in southern Texas.
The contradictory evidence and the lack of understanding of the effects of genetic depletion on fitness in wild populations are partly due to the limited number of studies conducted that compare current variation to historic variation. Genetic data from this study will increase our understanding of temporal changes in genetic variation and make an important contribution towards testing current hypotheses on conservation biology and genetics.