Concern for a worldwide decline in amphibian populations was initially voiced in 1989 at the First World Congress of Herpetology held in England. At this meeting, participants presented scientific papers and exchanged personal accounts of amphibian declines and disappearances. In 1998 an international meeting of experts convened by the National Science Foundation concluded that significant amphibian declines have occurred in protected areas not subjected to obvious changes in habitat, such as national parks, wildlife refuges, and wilderness areas. Based on the information presented at these and similar meetings, scientists concluded that the numbers and geographic extent of the reports indicated that the situation should be approached as a potential environmental crisis.

Amphibians are considered good indicators of general ecosystem health because of their close association with various aquatic habitats and sensitivity to different environmental stresses. Habitat destruction has been shown to cause amphibian declines, but little is known about the effects of deforestation, highway construction, urban development, and other habitat changes. Additionally, little is known about the role that other potential stressors (e.g., contaminants, introduced species, climate change, ultraviolet radiation, disease, atmospheric deposition, etc.) might play in influencing declines.

In response to these concerns, the President and Congress in 2000 directed Department of the Interior (DOI) agencies to undertake a national amphibian research and monitoring initiative (ARMI). Measuring, understanding, and responding to the effects of environmental change upon the Nation's amphibians is a daunting task that cannot be done by any single agency. For success there must be effective cooperation within DOI and with other organizations, agencies, academic scientists, and, particularly, the States.

The USGS can provide scientific leadership for this effort because the Agency serves as the research arm of the DOI, has a long history of employing research scientists who have pioneered studies on amphibian sampling techniques, toxicology, and health-related issues, and has a nationwide organization that oversees other national monitoring programs. The USGS has identified four goals for the Program:

	Provide the first nationwide assessment of the current distribution and status of amphibian populations
	Understand the scope and severity of amphibian declines throughout the U.S.
	Determine the causes for declines
	Provide essential scientific information to support effective management actions to arrest or reverse declines.

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P	rogram Design

One of the greatest challenges to developing a national monitoring plan is the highly regional nature of amphibians in North America. Amphibians occupy diverse habitats that require specialized sampling techniques. No single technique is capable of sampling amphibians across the country, and the factors affecting amphibians vary regionally. This diversity argues for a highly regionalized approach to amphibian monitoring and research. However, it is also important to integrate these regional programs in a way that allows for a national synthesis and for analysis at a wide range of spatial scales.

The USGS has organized the ARMI Program around a pyramid conceptual model to achieve regional and national assessments of status and trends (Figure 1). Extensive and necessarily coarse analyses are being carried out at the national level (the base of the pyramid), while intensive efforts, geared towards population monitoring and research (including egg counts, population estimates, demographic studies, and other detailed population-scale work), are underway at a relatively small number of sites (the apex of the pyramid). The mid-level of the pyramid is where most of the analysis and reporting occur in ARMI, and is targeted at identifying questions related to potential stressors, and whether additional data related to those stressors can and should be collected.

Important elements incorporated at the mid-level of the pyramid conceptual model center around amphibian monitoring and include:
 

	A defined range of inference. Investigators delineate the geographic range of inference, divide it into sampling units, and select a subset of units to sample via a probabilistic scheme. This includes decisions on species to monitor and habitat data to collect and analyze as covariates.
	Development of regionally meaningful response variables that can be integrated at a national level. Currently, one such response variable is being tested: proportion of sites (or area) occupied (PAO). Regional investigators will produce annual estimates of PAO and PAO variance for a subset of species of their choosing for each midlevel monitoring area.
	Disease screening as an integral part of data collection. Data are being collected at each mid-level monitoring area.

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Environmental Conditions Monitoring

Also incorporated at the mid-level of the pyramid conceptual model are efforts to measure and monitor environmental conditions such as:
	Collection of water data.
	Characterization of habitat conditions.

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Stressors and Causal Research. Research to date indicates that a host of environmental variables including climate change, competition, contamination, disease, habitat destruction, parasitism, predation, and ultraviolet radiation may cause amphibian population declines or malformations. It is likely that amphibians are subject to combinations of these stressors, and that the combinations vary by region and time. Physical and fiscal limitations of ARMI preclude monitoring for all potential stressors at all amphibian monitoring locations, but to the extent possible, the ARMI Program will link collection of statistically robust amphibian monitoring data with environmental data to support covariate analyses into potential causal relationships.

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Protocols Development. Due to the diversity of amphibians, habitats, and risk factors, development of methods and protocols for an integrated program is complex. Existing methods have been adapted and new protocols developed to meet Program goals. Adaptation, development, and testing of protocols is one form of product that ARMI provides to interested users. Protocol development currently falls under eight categories: 1) amphibian monitoring, 2) stressors monitoring, 3) trend analysis and correlation, 4) population, landscape, and stressors modeling, 5) geospatial applications, 6) management decision support tools, 7) database management structure, input, and output, and 8) metadata.

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National Databases.

ARMI has a set of national databases that are managed by different ARMI participants and/or USGS Centers. Conceptually, these databases can be linked, and over time ARMI is implementing the linkages physically.
	Metadatabase – The Research and Monitoring Metadatabase contains a tabular synopsis of apex-, mid-, and base-level field activities conducted by ARMI regional investigators and partners. The database is currently being implemented in the ARMI web tool for online querying.
	Field Database – The National Field Database stores amphibian field survey data from monitoring areas and includes information on sampling methods, observed species, habitat, water chemistry, and additional variables. The database was designed to store current monitoring data, while maintaining flexibility to incorporate future data collections under revised protocols and survey methods.
	Health and Disease Database – The Health and Disease Database contains results from clinical analyses of amphibian specimens sent to the National Wildlife Health Center from ARMI and other field investigators.
	Parameters Database – The Parameters Database is emerging from an effort to build a repository for statistical metrics calculated from mid-level and apex-level field measurements.
	Geospatial Layers Database – The Geospatial Layers Database is a collection of numerous data layers that support mapping, environmental modeling, and multivariate analyses to study amphibian-landscape interactions. The data layers have been standardized for display and distribution through the ARMI web tool.
	Amphibian Atlas Database – The ARMI National Atlas for Amphibian Distributions contains data on amphibian occurrence (species range distributions) for all species currently recognized in the United States. For each species, the database includes information on counties or subcounties of occurrence, availability of voucher information, and a listing of the sources used to compile the data. Information sources include literature, museum, and validated observational records (Lannoo and others, 2005). The ARMI Atlas was created not only to identify where amphibians occur in the United States, but also to identify potential gaps in our knowledge of amphibian distributions. The Atlas is also enabled for display in the ARMI web tool. *Lannoo, M.J., ed., 2005, Amphibian declines: The conservation status of United States species: University of California Press, Berkeley, California, 1,094 p.

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Analysis and Reporting. A variety of analyses are being conducted to assess the status and trends of amphibian populations, determine biotic and abiotic stressors, and improve understanding of the relationships between amphibians and environment. The results are used for regional and national syntheses, to provide feedback for determining whether changes in protocols, monitoring strategies, and/or research activities should be considered, and as input for decision support tools for land managers and policymakers. Reports include descriptions of field and laboratory activities, status and progress reports, methods and protocol documentation, field survey raw data and summaries, environment-amphibian association studies, summaries of stressors research and findings, and administrative summaries regarding operational challenges and integration of partners. [View ARMI publications]

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Partnerships. This is a critical component of the ARMI Program, as no agency has sufficient resources for sole implementation of a national assessment and monitoring program for amphibians. The U.S. Fish and Wildlife Service, the National Park Service, and the Bureau of Land Management also have requirements for understanding the status and trends of amphibians to make management and policy decisions. Other federal partners, such as the U.S. Environmental Protection Agency, USDA Forest Service, and USDA Natural Resources Conservation Service also utilize the information collected by the USGS to make decisions about environmental regulations, land management, conservation incentive policies, and landowner education needs.