Grantee Research Project Results
Impacts of Climate Change and Emerging Infectious Disease on AmphibiansEPA Grant Number: FP917192
Title: Impacts of Climate Change and Emerging Infectious Disease on Amphibians
Investigators: Langhammer, Penny Flick
Institution: Arizona State University - Main Campus
EPA Project Officer: Just, Theodore J.
Project Period: August 19, 2010 through August 18, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Global Change
Climate change and infectious disease are two causes implicated in the global loss of biodiversity. Amphibians may be particularly sensitive to both threats, individually and in concert. Chytridiomycosis, an emerging infectious disease of amphibians, has led to the recent decline or extinction of over 100 amphibian species globally. Climate change is also expected to harm many species, through habitat loss and/or physiological stress that affects reproduction. Furthermore, there is evidence from Puerto Rico that these factors may interact to negatively influence species persistence. This research project aims to evaluate how vulnerable frogs are to climate change across the Caribbean, how key disease parameters differ under normal and drought conditions, and whether frog populations currently persisting with endemic chytridiomycosis may face disease-induced extinction if the climate changes. The Caribbean is expected to face increasing periods of drought over the next 50 years.
Chytridiomycosis, an emerging infectious disease of amphibians, has caused the decline or extinction of 100+ amphibian species. Studies in Puerto Rico indicate climate change may elevate the risk of disease-induced extinction for some species. This project assesses the climate change vulnerability of Caribbean frogs and investigates disease transmission and mortality under normal and drought conditions. Data collected on Puerto Rican frogs will be used to model population-level disease impacts.Approach:
This research project involves a synthesis of existing data on Caribbean frog species, namely a set of biological and exposure risk factors, to determine species’ vulnerability to climate change. Subsequently, three lab experiments will be conducted in Puerto Rico to (a) better understand why frogs are more likely to die from chytirdiomycosis under drought conditions, (b) quantify the rates of disease transmission and disease-induced mortality in drought and normal conditions, and (c) assess whether frogs can become infected indirectly through contaminated soil or vegetation. These lab data, along with historical field data, will be used to parameterize a mathematical model of chytridiomycosis that can be used to better understand disease dynamics and evaluate the likelihood of species extinction from disease.Expected Results:
This project will combine laboratory research, field studies, and mathematical modeling to better understand the impacts of global climate change and emerging infectious disease on amphibian biodiversity. Specifically, the lab experiments will clarify why frogs are more likely to die from chytridiomycosis under drought conditions, which has been observed previously. In addition, the experiments will quantify the rate of disease transmission under normal and drought conditions, a key parameter driving disease dynamics, and will possibly show that indirect transmission of the disease occurs. This work is novel for terrestrial frogs that develop directly from eggs to juvenile frogs, bypassing an aquatic larval stage, which occur throughout Latin America and the Caribbean. The mathematical modeling will help clarify the conditions that can lead to population extinction from, or persistence with, chytridiomycosis. Overall, this research will inform the development of specific strategies that facilitate adaptation by Caribbean frogs to global climate change and disease emergence.
Potential to Further Environmental/Human Health Protection:
Amphibians play significant roles in ecosystems as both predators and prey, and they provide many direct benefits to human societies as food, pets, research animals, cultural symbols, and producers of medicinal compounds. Although habitat loss remains the most significant threat to amphibians (and biodiversity) worldwide, many species have declined, some to extinction, from the emerging infectious disease chytridiomycosis. Climate change is likely to interact with this disease to increase the risk of extinction for some species. Understanding this interaction is the first step towards developing policies that adequately respond to threats above and beyond habitat loss.Supplemental Keywords:
climate change, infectious disease, chytridiomycosis, amphibian, Caribbean, Puerto Rico, mathematical modeling,