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Hydrological and biological investigations were done during 2005 and 2006 in cooperation with the U.S. National Park Service at Darwin Falls in Death Valley National Park, Piute Spring in Mojave National Preserve, and Fortynine Palms Oasis in Joshua Tree National Park where discharge from springs or groundwater seeps sustains rare perennial streams in the otherwise arid environment of the Mojave Desert in which surface water is scarce and usually ephemeral. The study collected data on water quantity (discharge), temperature, water quality, and endemic anuran (frog and toad) populations and their health. In addition, a single survey of endemic anuran populations and their health was completed at Rattlesnake Canyon in the Joshua Tree National Park. Results from this study were compared to historical data, and can provide a baseline for future hydrological and biological investigations to evaluate health and sustainability of the resource as well as its response to changing climate and increases in human use.

Data collected from the biological surveys completed for this study were evaluated to document the reproduction, estimate the population, and assess the overall health of each of the endemic anuran species present at the Darwin Falls, Piute Spring, and Fortynine Palms Oasis study areas. Where available, historical biological data also were evaluated.

Studies of the systematics and ecological characteristics of hosts and their parasites require proper identification of both groups. When the parasites associated with a host are not collected
and preserved properly, species- level diagnostic characters (i.e., morphological characters) are usually destroyed. In addition, improper preservation of parasites severely limits,
or more likely prevents, studies based on DNA from those specimens.

One end goal of a study is to analyze and synthesize the data collected in an effort to understand their meaning. Most data from field studies are analyzed in an electronic format, using modern software packages for models and statistics. Consequently, how the data are stored is important and should be considered simultaneously with protocol development. Data definitions and data storage should reflect how the data are collected in the field and how they ultimately will be analyzed.

Here, we describe an alternative to traditional penand-paper data recording. With recent advancements in handheld computers and their software applications, the development and use of electronic forms for recording data (using Personal Digital Assistants, or PDAs), a topic that has only been mentioned briefly in previous literature (e.g., Donnelly and Guyer 1994), has become a reality. Multiple operating platforms for PDAs, including handheld PCs, Pocket PCs, and the Palm OS (see Appendix II), are now on the market. Each one offers mobile, electronic data collection and its associated benefits to investigators in the fi eld. Below, we outline some of the advancements that have been made over the past 10 years in the use of PDAs for recording data, and we compare the benefits of recording field data electronically with those of data entry on paper sheets.

This chapter enumerates the steps required in designing and planning field studies on the ecology and conservation of reptiles, as these involve a high level of uncertainty and risk. To this end, the chapter differentiates between goals (descriptions of what one intends to accomplish) and objectives (the measurable steps required to achieve the established goals). Thus, meeting a specific goal may require many objectives. It may not be possible to define some of them until certain experiments have been conducted; often evaluations of sampling protocols are needed to increase certainty in the biological results. And if sampling locations are fixed and sampling events are repeated over time, then both study-specific covariates and sampling-specific covariates should exist. Additionally, other critical design considerations for field study include obtaining permits, as well as researching ethics and biosecurity issues.

The pervasive and unabated nature of global amphibian declines suggests common demographic responses to a given driver, and quantification of major drivers and responses could inform broad-scale conservation actions. We explored the influence of climate on demographic parameters (i.e., changes in the probabilities of survival and recruitment) using 31 datasets from temperate zone amphibian populations (North America and Europe) with more than a decade of observations each. There was evidence for an influence of climate on population demographic rates, but the direction and magnitude of responses to climate drivers was highly variable among taxa and among populations within taxa. These results reveal that climate drivers interact with variation in life-history traits and population-specific attributes resulting in a diversity of responses. This heterogeneity complicates the identification of conservation ?rules of thumb? for these taxa, and supports the notion of local focus as the most effective approach to overcome global-scale conservation challenges.

Understanding how factors that vary in spatial scale relate to population abundance is vital to
forecasting species responses to environmental change. Stream and river ecosystems are inherently hierarchical, potentially resulting in organismal responses to fine-scale changes in patch characteristics that are conditional on the watershed context. Here, we address how populations of two salamander species are affected by interactions among hierarchical processes operating at different scales within a rapidly changing landscape of the southern Appalachian Mountains. We modeled reach-level occupancy of larval and adult black-bellied salamanders (Desmognathus quadramaculatus) and larval Blue Ridge two-lined salamanders (Eurycea wilderae) as a function of 17 different terrestrial and aquatic predictor variables that varied in spatial extent. We found that salamander occurrence varied widely among streams within fully forested catchments, but also exhibited species-specific responses to changes in local conditions. While D. quadramaculatus declined predictably in relation to losses in forest cover, larval occupancy exhibited the strongest negative response to forest loss as well as decreases in elevation. Conversely, occupancy of E. wilderae was unassociated with watershed conditions, only responding negatively to higher proportions of fast-flowing stream habitat types. Evaluation of hierarchical relationships demonstrated that most fine-scale variables were closely correlated with broad watershed-scale variables, suggesting that local reach-scale factors have relatively smaller effects within the context of the larger landscape. Our results imply that effective management of southern Appalachian stream salamanders must first focus on the larger scale condition of watersheds before management of local-scale conditions should proceed. Our findings confirm the results of some studies while refuting the results of others, which may indicate that prescriptive recommendations for range-wide management of species or the application of a single management focus across large geographic areas is inappropriate.

The Cuban treefrog, Osteopilus septentrionalis, is native to Cuba, the Bahamas, and the Cayman Islands, and is invasive in areas where it has been introduced and established in the Caribbean as well as Hawaii and Florida. Despite repeated occurrences in several states over many years, it was not believed that Cuban treefrogs had successfully established outside of Florida in the mainland United States. From mid-September to mid-November 2017, we captured and removed 367 Cuban treefrogs in just four surveys in New Orleans, Louisiana. The impacts of this population on native treefrogs in this area is unknown but possibly severe as indicated by the paucity of observations of native treefrogs during our surveys. Eradication of this seemingly established population is improbable, but continued surveys will facilitate learning about the ecology and genetics of this novel population.

The arroyo southwestern toad is a specialized and federally endangered amphibian endemic to the coastal plains and mountains of central and southern California and northwestern Baja California. It is largely unknown how long these toads live in natural systems, how their population demographics vary across occupied drainages, and how hydrology affects age structure. We used skeletochronology to estimate the ages of adult arroyo toads in seven occupied drainages with varying surface water hydrology in southern California. We processed 179 adult toads with age estimates between one and six years. Comparisons between skeletochronological ages and known ages of PIT tagged toads showed that skeletochronology likely underestimated toad age by up to two years, indicating they may live to seven or eight years, but nonetheless major patterns were evident. Arroyo toads showed sexual size dimorphism with adult females reaching a maximum size of 12mm greater than males. Population age structure also varied among the sites. Age structure at sites with seasonally predictable surface water was biased toward younger individuals, which indicated stable recruitment for these populations. In contrast, age structures at the ephemeral sites were biased toward older individuals with cohorts roughly corresponding to higher rainfall years. These populations are driven by surface water availability, a stochastic process, and are thus more unstable. Based on our estimates of toad ages, climate predictions of extreme and prolonged drought events could mean that the number of consecutive dry years could surpass the maximum life span of toads making them vulnerable to extirpation, especially in ephemeral freshwater systems. Understanding the relationship between population demographics and hydrology is essential for predicting species resilience to projected changes in weather and rainfall patterns. The arroyo toad serves as a model for understanding potential species responses to long term climatic and hydrologic changes in Mediterranean stream systems. We recommend development of adaptive management strategies to address these threats.

Livestock grazing is an important land use in the western USA and can have positive or negative effects on amphibians. Columbia Spotted Frog (Rana luteiventris) often use ponds that provide water for cattle. We conducted a long-term manipulative study on US Forest Service land in northeastern Oregon to determine the effects of full and partial exclosures that limited cattle access to ponds used by frogs. We found weak evidence of a short-term increase in abundance that did not differ between full and partial exclosures and that diminished with continuing exclusion of cattle. The benefit of exclosures was small relative to the overall decline in breeding numbers that we documented. This suggests that some protection can provide a short-term boost to populations.