Current Research

Evaluating the Distribution of Introduced Capybaras in Central Florida

Capybaras (Hydrochoerus hydrochaeris) have been observed throughout Florida over the past 15 years, however the Santa Fe River is the only area in Florida where there is believed to be a reproducing population. In this area, there have been multiple observations of herds and juveniles, however little is known about the population size, distribution, or potential impacts. In this study, we are using surveys via boats and 45+ camera traps along the Santa Fe River in an effort to evaluate capybara distribution. We are also collecting water samples from the Santa Fe River and ponds in the surrounding floodplain and using these samples to pilot an environmental DNA study. This allows us to extract DNA from the water samples and use PCR to determine if capybara DNA is present, allowing us to understand if capybaras are utilizing these areas. This information will provide baseline information on this population and help guide future research and management efforts.

 

Comparing Invasion Potential of Introduced Mammals in Florida 

Florida is among the states that has experienced the greatest number of introductions of non-native wildlife species. These introductions threaten native wildlife and ecosystems and are estimated to cost over $500 million annually in mitigation and management costs. Florida is particularly at-risk for species introductions due to the peninsular geography, subtropical climate, large tourism industry, and several major ports of entry. Approximately 20 species of mammals have been introduced into Florida; research is needed to evaluate the invasion and expansion potential of these populations. There are at least seven species of terrestrial mammals in Florida with locally established populations: capybaras (Hydrochoerus hydrochaeris), sambar deer (Cervus unicolor), nutria (Myocastor coypus), Mexican red-bellied squirrels (Sciurus aureogaster), rhesus macaques (Macaca mulatta), vervet monkeys (Chlorocebus sabaeus), and squirrel monkeys (Saimiri sciureus).  In this study, we are using climate envelope models to predict the ability of these species to spread into other areas in Florida and in surrounding states. This information can be used to prioritize use of limited research and management funds.

 

Characterizing Rhesus Macaque Genetics in Central Florida

Approximately 10 rhesus macaques (Macaca mulatta) were introduced in what is today Silver Springs State Park, central Florida, in the 1930s and 1940s in an effort to increase tourism. This population has demonstrated considerable growth and reached ~400 individuals in the initial introduction site by the mid-1980s. From that time until 2012, the population was controlled through a trapping and removal program, but no population control has been implemented for the past ~5 years. From 2011 – 2016, there were ≥38 observations of rhesus macaques in Florida  outside of Silver Springs State Park. It is unknown whether these individuals represent separate introductions, or if they are emigrants from the Silver Springs population. In this study, we present cotton swabs soaked in sucrose to the macaques; the macaques chew the swabs until they lose flavor, then spit out the swabs. We then collect the swabs and extract DNA from the residual macaque saliva. We are using genetic sequencing to characterize the mitochondrial genetic makeup of this population. This will allow managers and researchers to sample any macaque in Florida to determine if it came from the Silver Springs population.

 

Evaluating the Public Threat of the Zoonotic Herpes B Virus from Rhesus Macaques in Central Florida

Rhesus macaques are believed the to be natural host of the Herpes B Virus, meaning infected individuals display few, if any, symptoms. In wild populations, 80% of individuals can test seropositive for the virus, or act as carriers. The threat of transmission of Herpes B Virus from macaques to humans is poorly understood. There are no accounts of a human being infected by a macaque in the wild, despite countless potential infection opportunities (e.g., bites and scratches). However, approximately 50 humans have contracted the virus from macaques in laboratory settings, and about half of these cases were fatal. The reason for this discrepancy – the apparent absence of infections from wild populations but danger of infections from captive individuals – is unknown. Over 600 rhesus macaques were trapped and removed from the areas around the Silver River and Ocklawaha River from 2000 – 2012. Of these, 325 were tested via serology for Herpes B Virus. We are analyzing these data for prevalence of the virus in the rhesus macaque population, and evaluating the impacts of age and sex on prevalence. We are also evaluating whether rhesus macaques in Silver Springs State Park are actively shedding the virus, the state which allows infected individuals to pass the virus to uninfected individuals. To do this, we used the saliva sampling method (described above) during Fall 2015 (breeding season), Spring 2016 (gestation season), and Summer 2016 (lactation season). We used PCR to detect active shedding of the virus from macaque saliva and evaluated whether shedding rates varied across seasons. This information will provide important insight as to the potential public health threat of this introduced macaque population in a public park.

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