Larissa Bailey (Colorado State), USGS, FWS, and SCC volunteers building vernal pools at Patuxent NWR, to adaptively manage for climate change. Photo by: A. Green.
Only a few years ago, amphibians were rarely considered in the development and implementation of management plans. But now, it’s not uncommon to see amphibian populations as the primary targets of management activities.
ARMI scientists conduct research on the impacts of various traditional management actions on amphibians, and have worked with partners to develop and test novel management options specifically to benefit amphibians.
Important decisions are made every day on management and policy that affect multiple wildlife species. ARMI works with its partners in Federal and State agencies to develop processes for structuring their natural resource decisions to achieve their conservation objectives related to amphibians.
ARMI Products on Management
* USGS neither sponsors nor endorses non-USGS web sites; per requirement "3.4.1 Prohibition of Commercial Endorsement."
* PDF documents require Adobe Reader or Google Chrome Browser for viewing.
Integrating Multiple Distribution Models to Guide Conservation Efforts of an Endangered Toad
Authors: Treglia M, Fisher R, Fitzgerald L | Date: 2015-06-30 | Outlet: PloS ONE | Format: .PDF
Species distribution models are used for numerous purposes such as predicting changes in species’ ranges and identifying biodiversity hotspots. Although implications of distribution models for conservation are often implicit, few studies use these tools explicitly to inform conservation efforts. Herein, we illustrate how multiple distribution models developed using distinct sets of environmental variables can be integrated to aid in identification sites for use in conservation. We focus on the endangered arroyo toad (Anaxyrus californicus), which relies on open, sandy streams and surrounding floodplains in southern California, USA, and northern Baja California, Mexico. Declines of the species are largely attributed to habitat degradation associated with vegetation encroachment, invasive predators, and altered hydrologic regimes. We had three main goals: 1) develop a model of potential habitat for arroyo toads, based on long-term environmental variables and all available locality data; 2) develop a model of the species’ current habitat by incorporating recent remotely-sensed variables and only using recent locality data; and 3) integrate results of both models to identify sites that may be employed in conservation efforts. We used Random Forests to develop the models, focused on riparian zones in southern California. We identified 14.37% and 10.50% of our study area as potential and current habitat for the arroyo toad, respectively. Generally, inclusion of remotely-sensed variables reduced modeled suitability of sites, thus many areas modeled as potential habitat were not modeled as current habitat. We propose such sites could be made suitable for arroyo toads through active management, increasing current habitat by up to 67.02%. Our general approach can be employed to guide conservation efforts of virtually any species with sufficient data necessary to develop appropriate distribution models.
Modeling habitat connectivity to inform reintroductions: a case study with the Chiricahua leopard frog
Authors: Jarchow CJ, Hossack BR, Sigafus BH, Schwalbe CR, Muths EL | Date: 2015 | Outlet: Journal of Herpetology | Format: .PDF
Managing a species with intensive tools like reintroduction may focus on single sites or entire landscapes. For vagile species, long-term persistence will require colonization and establishment in neighboring habitats. Thus, both suitable colonization sites and suitable dispersal corridors between sites are required. Assessment of landscapes for both requirements can contribute to ranking and selection of reintroduction areas, thereby improving management success. Following eradication of invasive American bullfrogs (Lithobates catesbeianus) from most of Buenos Aires National Wildlife Refuge (BANWR; Arizona, USA), larval Chiricahua leopard frogs (L. chiricahuensis) from a private pond were reintroduced into three stock ponds. Populations became established at all three reintroduction sites, followed by colonization of neighboring ponds in subsequent years. Our aim was to better understand colonization patterns by the federally-threatened L. chiricahuensis, which could help inform other reintroduction efforts in the region. We assessed the influence of five landscape features on colonization. Using surveys from 2007 and information about the landscape, we developed a habitat connectivity model based on electrical circuit theory that identified potential dispersal corridors, after explicitly accounting for imperfect detection of frogs. Landscape features provided little insight into why some sites were colonized and others were not, results that are likely due to the uniformity of the landscape at BANWR. While corridor modeling may be effective in more complex landscapes, an approach more focused on local habitat is required at BANWR. We also illustrate that existing data, even when limited in spatial or temporal resolution, can provide information useful in formulating management actions.
Animal reintroductions: an innovative assessment of survival
Authors: Muths E, Bailey LL, Watry MK | Date: 2014-06 | Outlet: Biological Conservation xx:xxx-xxx
Quantitative evaluations of reintroductions are infrequent and assessments of milestones reached before a project is completed, or abandoned due to lack of funding, are rare. However, such assessments, which are promoted in adaptive management frameworks, are critical. Quantification can provide defensible estimates of biological success, such as the number of survivors from a released cohort, with associated cost per animal. It is unlikely that the global issues of endangered wildlife and population declines will abate, therefore, assurance colonies and reintroductions are likely to become more common. If such endeavors are to be successful biologically or achieve adequate funding, implementation must be more rigorous and accountable. We use a novel application of a multistate, robust design capture-recapture model to estimate survival of reintroduced tadpoles through metamorphosis (i.e., the number of individuals emerging from the pond) and thereby provide a quantitative measure of effort and success for an “in progress” reintroduction of toads. Our data also suggest that tadpoles released at later developmental stages have an increased probability of survival and that eggs laid in the wild hatched at higher rates than eggs laid by captive toads. We illustrate how an interim assessment can identify problems, highlight successes, and provide information for use in adjusting the effort or implementing a Decision-Theoretic adaptive management strategy.