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Counts of egg masses have been proposed as a valid state variable for monitoring Wood Frog (Rana sylvatica) populations. Here, we investigate the statistical power of egg mass counts to identify trends in egg mass abundance using computer simulation. We also calculate the expected bias in using the slope of a trend line fit to a time series of egg mass counts as an estimate of trend in abundance. The results of the simulations suggest that a minimum of eight years of monitoring is necessary to achieve high statistical power for monitoring programs that use counts of Wood Frog egg masses as a state variable. In addition, the slope of a trend line fit to a time series of egg mass counts is a biased estimate of trend in abundance. Increasing the duration of monitoring, however, minimizes the bias and improves inference regarding trend. Managers and herpetologists who plan to monitor Wood Frog populations using counts of egg masses should plan on a minimum of eight years of data collection to have high power to detect trends.

Although populations of amphibians are declining worldwide, there is no evidence that salamanders occupying small streams are experiencing enigmatic declines, and populations of these species seem stable. Theory predicts that dispersal through multiple pathways can stabilize populations, preventing extinction in habitat networks. However, empirical data to support this prediction are absent for most species, especially those at risk of decline. Our mark-recapture study of stream salamanders reveals both a strong upstream bias in dispersal and a surprisingly high rate of overland dispersal to adjacent headwater streams. This evidence of route-dependent variation in dispersal rates suggests a spatial mechanism for population stability in headwater-stream salamanders. Our results link the movement behavior of stream salamanders to network topology, and they underscore the importance of identifying and protecting critical dispersal pathways when addressing region-wide population declines.

I examined the population dynamics of a high elevation population of the pond-breeding amphibian Rana luteiventris. Understanding the natural dynamics of this species in relation to environmental variation informs us about the natural history of this species, helps identify how different environmental stressors may impact the population, and may elucidate key processes important to other populations of the same species or other species inhabiting mountain environments.

Non?native fish and bullfrogs (Lithobates catesbeianus) are frequently cited as contributing to the decline of ranid frogs in the western United States, so we hypothesized that non?native species, habitat, or a combination of these relate to the probability of local extinction for northern red?legged frogs (Rana aurora) in Oregon, USA. We also hypothesized that the probability of colonization relates to land use, wetland size, or riparian forest. In a 5?yr study, we found no support for an effect of non?native species on northern red?legged frogs. Instead, probability of local extinction decreased with the extent of emergent vegetation and riparian forest. This finding suggests that managers consider the role of habitat when confronting non?native species problems.

In 2003, southern California experienced several large fires that burned thousands of hectares of wildlife habitats and conserved lands. To investigate the effects of these fires on the reptile and
amphibian communities, we compared the results from prefire herpetofauna and vegetation sampling to two years of postfire sampling across 38 burned and 17 unburned plots. The sampling plots were spread over four vegetation types and four open space areas within San Diego County. Our capture results indicated that burned chaparral and coastal sage scrub plots lost herpetofaunal species diversity after the fires and displayed a significant shift in overall community structure. Shrub and tree cover at the burned plots, averaged across the second and third postfire years, had decreased by 53% in chaparral and 75% in coastal sage scrub. Additionally, postfire herpetofauna community structure at burned plots was more similar to that found in unburned grasslands. In grassland and woodland/riparian vegetation plots, where shrub and tree cover was not significantly affected by fires, we found no differences in the herpetofaunal species diversity or community composition. At the individual species level, Sceloporus occidentalis was the most abundant reptile in these areas both before and after the fires. We saw increases in the net capture rates for several lizard species, including Aspidoscelis tigris, Phrynosoma coronatum, and Uta stansburiana in burned chaparral plots and Aspidoscelis hyperythra and U. stansburiana in burned coastal sage scrub plots. The toad, Bufo boreas, was detected at significantly fewer burned plots in chaparral after the fires. Additionally, we documented decreases in the number of plots occupied by lizards (Elgaria multicarinata), salamanders(Batrachoseps major), and snakes (Coluber constrictor, Lampropeltis getula, Pituophis catenifer, andMasticophis lateralis) in coastal sage scrub and chaparral after the fires. We discuss the individual species results as they relate to such life-history traits as the susceptibility to initial mortality, the response to the altered postfire habitat, and shifts in the availability of potential prey. We foresee that a continued unnatural fire regime will result in a simplification of the southern California reptile and amphibian communities.

We sampled a population of two species of hylid treefrogs using 90 vertical ground-placed PVC pipes of 3 diameters positioned along a 1500-m transect at a forest-open pond ecotone in north-central Florida in order to identify potential capture biases. We recorded 1,981 treefrog observations (778 unmarked, 1,203 recaptures) in 8 months. Our results identified species-specific seasonal and weather-related variation in capture by pipe diameter and pipe location. These biases may limit the usefulness of this sampling technique when monitoring long-term treefrog population status and trends.