Presence Of Salamanders Research Articles

Vegetation cover and occurrence of salamanders in the western Mediterranean.

The Mediterranean region possesses a rich diversity of salamanders, which also exhibit a high degree of ecological diversification. It is assumed that the presence of salamanders is dependent on the level of vegetation cover in terrestrial habitats, but the strength of this association is likely to vary among species. In this study, we investigated the patterns of habitat utilization for Mediterranean salamanders based on 589 records of 33 species. We tested the hypothesis that the association between salamander presence and vegetation density varies among genera or reproductive modes (i.e. terrestrial vs aquatic). The results show that vegetation cover has similar influences on terrestrial and aquatic groups but important differences are identified for lotic and lentic aquatic species. Our findings also indicate that the aquatic lotic, terrestrial, and small-body species deviate significantly from that expected from the background range of variation.

Salamander loss alters litter decomposition dynamics.

Biodiversity loss affects ecosystem functioning. Top down effects of amphibian declines on the trophic food web of the forest floor are poorly understood. Here we quantify and explain the effects of disease-driven loss of salamanders on the dynamics of forest leaf litter. Using paired mesocosms, within a Belgian forest, we tested the effect of fire salamander (Salamandra salamandra) presence on the trophic cascade that results in the decomposition rate of good quality (maple - Acer pseudoplatanus) and poorer quality (oak - Quercus robur) leaf litter, over an 18month period. The presence of salamanders reduced decomposition rate of Quercus litter up to 20%. This was associated with a significantly higher predation rate on detritivores, which altered the functional composition of the invertebrate community. Functional composition analysis of the litter microbiome showed less bacteria associated with leaf litter degradation on the Quercus litter in the presence of salamanders. Salamanders thus influence ecosystem functions through trophic cascades and promote the retention of the leaf litter fraction in poorer quality litter.

Development of a New Habitat Mimicking Tool for Assessing Larval Salamanders in Temperate Forest Streams

Small streams are a high priority for conservation and an important target for biomonitoring. Stream salamanders are a useful indicator for biotic integrity of headwater streams; however, assessing stream salamanders is a challenging endeavor and existing methods can cause habitat disturbance or require expensive equipment. Our goal was to develop an artificial habitat that mimics the natural habitat that salamanders prefer, leading to rapid colonization and that also (1) represents a standardized area and (2) is easy to handle for rapid assessment. After developing a new artificial habitat (the Maloney Salamander Hotel), we tested the device in a variety of streams and compared our method with other techniques. After a series of field tests in a variety of streams through multiple seasons, we found that stream salamanders will colonize the apparatus and that this method yielded results similar or superior to other methods. For efficient and relatively simple assessment, our results indicate that three devices, left in streams for 3 d, should provide a reliable assessment of salamander presence. The device is relatively inexpensive, simple to build, easily handled for efficient deployment and collection, and does not harm the salamanders. We hope the development of this device provides a useful innovation for biological consultants, land managers, and researchers interested in assessing salamander presence in streams.

A salamander's top down effect on fungal communities in a detritivore ecosystem.

The soil decomposer community is a primary driver of carbon cycling in forest ecosystems. Understanding the processes that structure this community is critical to our understanding of the global carbon cycle. In North American forests, soil fungal communities are regulated by grazing soil invertebrates, which are in turn controlled by the predatory red-backed salamander (Plethodon cinereus). The presence of these soil invertebrate taxa is known to exert direct top-down control via selective grazing on saprotrophic fungi, with direct consequences for biogeochemical cycling in soil. We investigated whether the removal of P. cinereus would relieve top-down control on decomposer fungal communities in a tri-trophic mesocosm study. Fungal communities were characterized using metabarcoding and high-throughput DNA sequencing. The β-diversity of fungal communities differed between salamander presence and absence treatments with a strong effect on saprotrophic fungal communities. We concluded that P. cinereus, a mesopredator in the detritivore food chain, exerts a prominent control on the composition and functional diversity of fungal communities in soil through a multi-trophic top-down process. Given their capacity to govern the compositions of soil invertebrates, the activity of these amphibians may be important for regulating ecosystem function and nutrient cycling in temperate forest systems.

Determining threatened species distributions in the face of limited data: Spatial conservation prioritization for the Chinese giant salamander (Andrias davidianus).

The purpose of this study was to determine whether limited occurrence data for highly threatened species can provide useful spatial information to inform conservation. The study was conducted across central and southern China. We developed a habitat suitability model for the Critically Endangered Chinese giant salamander (Andrias davidianus) based on one biotic and three abiotic parameters from single‐site locality records, which represent the only relevant environmental data available for this species. We then validated model quality by testing whether increased percentage of predicted suitable habitat at the county level correlated with independent data on giant salamander presence. We randomly selected 48 counties containing historical records which were distinct from, and independent of, the single‐site records used to develop the model, and 47 additional counties containing >50% predicted suitable habitat. We interviewed 2,812 respondents near potential giant salamander habitat across these counties and tested for differences in respondent giant salamander reports between counties selected using each method. Our model predicts that suitable giant salamander habitat is found widely across central and southern China, with counties containing ≥50% predicted suitable habitat distributed in 13 provinces. Counties with historical records contain significantly more predicted suitable habitat than counties without historical records. There are no statistical differences in any patterns of respondent giant salamander reports in surveyed counties selected from our model compared with the areas of known historical giant salamander distribution. A Chinese giant salamander habitat suitability model with strong predictive power can be derived from the restricted range of environmental variables associated with limited available presence‐only occurrence records, constituting a cost‐effective strategy to guide spatial allocation of conservation planning. Few reported sightings were recent, however, with most being over 20 years old, so that identification of areas of suitable habitat does not necessarily indicate continued survival of the species at these locations.

Seasonality and microhabitat selection in a forest-dwelling salamander.

Many small terrestrial vertebrates exhibit limited spatial movement and are considerably exposed to changes in local environmental variables. Among such vertebrates, amphibians at present experience a dramatic decline due to their limited resilience to environmental change. Since the local survival and abundance of amphibians is intrinsically related to the availability of shelters, conservation plans need to take microhabitat requirements into account. In order to gain insight into the terrestrial ecology of the spectacled salamander Salamandrina perspicillata and to identify appropriate forest management strategies, we investigated the salamander's seasonal variability in habitat use of trees as shelters in relation to tree features (size, buttresses, basal holes) and environmental variables in a beech forest in Italy. We used the occupancy approach to assess tree suitability on a non-conventional spatial scale. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander's terrestrial ecology. Occupancy changed with the annual life cycle and was higher in autumn than in spring, when females were found closer to the stream in the study area. Salamanders showed a seasonal pattern regarding the trees they occupied and a clear preference for trees with a larger diameter and more burrows. With respect to forest management, we suggest maintaining a suitable number of trees with a trunk diameter exceeding 30cm. A practice of selective logging along the banks of streams could help maintain an adequate quantity of the appropriate microhabitat. Furthermore, in areas with a presence of salamanders, a good forest management plan requires leaving an adequate buffer zone around streams, which should be wider in autumn than in spring.

Environmental Characteristics Associated with Settlement of Reintroduced Chinese Giant Salamanders

Captive breeding and reintroduction have been increasingly used to restore endangered amphibians worldwide. Knowing habitat requirements for targeted species will help to enhance post release settlement and contribute to the success of reintroduction projects. To collect critical information on habitat requirements of the poorly documented Chinese Giant Salamanders (Andrias davidianus), we reintroduced 31 juveniles at two streams in central China and monitored them through radio telemetry from May 2013 to September 2014. We recorded 14 environmental variables twice a month (except during winter) at salamander locations and random locations. We also conducted transects systematically along streams to collect data on environmental variables and prey species. Habitat selection by salamanders was examined at two spatial scales: home-range scale and stream-reach scale. At the home-range scale, water quality variables were not different between salamander locations and random locations, although salamanders were found in deeper water, used larger boulders, and were closer to boulders. Regression models confirmed that presence of salamanders was positively associated with boulder size, river depth, and canopy cover but negatively associated with distance to boulders. At the stream-reach level, only the average water velocity was lower within home ranges than out of home ranges; however, no difference was found between core home ranges and out of home ranges. These results showed that large boulders were the most important variable selected by salamanders. Plenty of large boulders in the streams, together with evidences of postrelease growth of salamanders, indicate the two streams likely are providing suitable habitat for salamanders.

Informing recovery in a human-transformed landscape: Drought-mediated coexistence alters population trends of an imperiled salamander and invasive predators

Understanding the additive or interactive threats of habitat transformation and invasive species is critical for conservation, especially where climate change is expected to increase the severity or frequency of drought. In the arid southwestern USA, this combination of stressors has caused widespread declines of native aquatic and semi-aquatic species. Achieving resilience to drought and other effects of climate change may depend upon continued management, so understanding the combined effects of stressors is important. We used Bayesian hierarchical models fitted with 10-years of pond-based monitoring surveys for the federally-endangered Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi) and invasive predators (fishes and American Bullfrogs, Lithobates catesbeianus) that threaten native species. We estimated trends in occupancy of salamanders and invasive predators while accounting for hydrological dynamics of ponds, then used a two-species interaction model to directly estimate how invasive predators affected salamander occupancy. We also tested a conceptual model that predicted that drought, by limiting the distribution of invasive predators, could ultimately benefit native species. Even though occupancy of invasive predators was stationary and their presence in a pond reduced the probability of salamander presence by 23%, occupancy of Sonoran Tiger Salamanders increased, annually, by 2.2%. Occupancy of salamanders and invasive predators both declined dramatically following the 5th consecutive year of drought. Salamander occupancy recovered quickly after return to non-drought conditions, while occupancy of invasive predators remained suppressed. Models that incorporated three time-lagged periods (1 to 4years) of local moisture conditions confirmed that salamanders and invasive predators responded differently to drought, reflecting how life-history strategies shape responses to disturbances. The positive 10-year trend in salamander occupancy and their rapid recovery after drought provided partial support for the hypothesis of drought-mediated coexistence with invasive predators. These results also suggest management opportunities for conservation of the Sonoran Tiger Salamander and other imperiled organisms in human-transformed landscapes.

Contacts with large, active individuals intensify the predation risk of small conspecifics.

Size variation within a population can influence the structure of ecosystem interactions, because ecological performance differs between individuals of different sizes. Although the impact of size variation in a predator species on the structure of interactions is well understood, our knowledge about how size variation in a prey species might modify the interactions between predators and prey is very limited. Here, by examining the interactions between predatory Hynobius retardatus salamander larvae and their prey, Rana pirica frog tadpoles, we investigated how large prey individuals affect the predation mortality of small prey conspecifics. First, in an experiment conducted in a field pond in which we manipulated the presence of salamanders and large tadpoles (i.e., large enough to protect them against salamander predation) with small tadpoles, we showed that in the presence of large tadpoles the mortality of small tadpoles from salamander predation was increased. On the basis of our observations of the activity of individuals, we hypothesized that active large tadpoles caused physical disturbances, which in turn caused the small tadpoles to move, and thus increased their encounter frequency with the predatory salamanders. To test this hypothesis, we conducted a laboratory experiment in small tanks with three players (i.e., one salamander as predator, one small tadpole as focal prey, and either a small or a large tadpole as the prospective movement inducer). In each tank, we manipulated the presence or absence of a movement inducer, and, when present, its size (large or small) and access (caged or uncaged) to the focal prey. In the presence of a large, uncaged movement inducer, the focal prey was more active and suffered from higher predation mortality compared with the other treatments, because the large movement inducer (unlike a small movement inducer) moved actively and, when uncaged, could stimulate movement of the focal prey through direct contact. The results indicated that high activity of large prey individuals and the resulting behavioral interactions with small conspecifics via direct contact indirectly increased the mortality of the small prey.

Bromeliad selection by two salamander species in a harsh environment.

Bromeliad phytotelmata are frequently used by several Neotropical amphibian taxa, possibly due to their high humidity, microclimatic stability, and role as a refuge from predators. Indeed, the ability of phytotelmata to buffer against adverse environmental conditions may be instrumental in allowing some amphibian species to survive during periods of environmental change or to colonize sub-optimal habitats. Association between bromeliad traits and salamanders has not been studied at a fine scale, despite the intimate association of many salamander species with bromeliads. Here, we identify microhabitat characteristics of epiphytic bromeliads used by two species of the Bolitoglossa morio group (B. morio and B. pacaya) in forest disturbed by volcanic activity in Guatemala. Specifically, we measured multiple variables for bromeliads (height and position in tree, phytotelma water temperature and pH, canopy cover, phytotelma size, leaf size, and tree diameter at breast height), as well as salamander size. We employed a DNA barcoding approach to identify salamanders. We found that B. morio and B. pacaya occurred in microsympatry in bromeliads and that phytotelmata size and temperature of bromeliad microhabitat were the most important factors associated with the presence of salamanders. Moreover, phytotelmata with higher pH contained larger salamanders, suggesting that larger salamanders or aggregated individuals might modify pH. These results show that bromeliad selection is nonrandom with respect to microhabitat characteristics, and provide insight into the relationship between salamanders and this unique arboreal environment.

Inducible offences affect predator–prey interactions and life‐history plasticity in both predators and prey

Phenotypic plasticity can have strong impacts on predator-prey interactions. Although much work has examined the effects of inducible defences, less understood is how inducible offences in predators affect predator-prey interactions and predator and prey phenotypes. Here, we examine the impacts of an inducible offence on the interactions and life histories of a cohort of predatory Hynobius retardatus salamander larvae and their prey, Rana pirica tadpoles. We examined larval (duration, survival) and post-metamorphic (size) traits of both species after manipulating the presence/absence of tadpoles and salamanders with offensive (broadened gape width) or non-offensive phenotypes in pond enclosures. Offensive phenotype salamanders reduced tadpole survival and metamorph emergence by 58% compared to tadpole-only treatments, and by over 30% compared to non-offensive phenotypes. Average time to metamorphosis of frogs was delayed by 30% in the presence of salamanders, although this was independent of salamander phenotype. Thus, offensive phenotype salamanders reduced the number of tadpoles remaining in the pond over time by reducing tadpole survival, not by altering patterns of metamorph emergence. Offensive phenotypes also caused tadpoles to metamorphose 19% larger than no salamander treatments and 6% larger than non-offensive phenotype treatments. Pooled across salamander treatments, tadpoles caused salamanders to reach metamorphosis faster and larger. Moreover, in the presence of tadpoles, offensive phenotype salamanders metamorphosed 25% faster and 5% larger than non-offensive phenotype salamanders, but in their absence, neither their size nor larval period differed from non-offensive phenotype individuals. To our knowledge, this study is the first to demonstrate that inducible offences in predators can have strong impacts on predator and prey phenotypes across multiple life stages. Since early metamorphosis at a larger size has potential fitness advantages, the impacts of offensive phenotypes on frog and salamander life histories likely have significant consequences for individuals and populations. Furthermore, increased predation on tadpoles likely causes offensive phenotype individuals to have strong impacts on pond communities. Future studies should examine the fitness consequences of morphological and life-history plasticity across multiple life stages and should address the population and community level consequences of offensive phenotypes.

The Influence of Amphibians on Mosquitoes in Seasonal Pools: Can Wetlands Protection Help to Minimize Disease Risk?

Wetlands provide a variety of services to society; however, their use as breeding habitat by mosquitoes has caused concern that they pose a risk to human health. As mosquito-borne diseases are undergoing a global resurgence, there is a need to better understand the factors that influence mosquito production in wetlands. Seasonal pools offer a model system in which to study mosquito production as they provide breeding habitat for many mosquito species. In the northeastern US, larval spotted salamanders (Ambystoma maculatum) and wood frog tadpoles (Lithobates sylvaticus) are common in pools and may affect mosquito growth and survival through predation or competition. To determine if these species interact, we conducted surveys of pools and found that larval mosquitoes were less abundant in pools with higher densities of larval salamanders. Experiments on mosquito oviposition and survival found that mosquitoes avoided ovipositing in habitats containing larval salamanders and tadpoles and had low survival in the presence of salamanders. These data indicate that predation by larval salamanders may influence the breeding distribution of mosquitoes by imposing selective pressure on ovipositing adults. Therefore, developing measures to protect amphibians in seasonal pools may contribute to controlling mosquito production in wetlands, potentially minimizing disease risk to humans.

Spatial niche of the Italian cave salamander, Speleomantes italicus (Dunn, 1923) (Plethodontidae, Amphibia), in a subterranean system of Central Italy

A study was carried out on the population structure and spatial niche of Speleomantes italicus (Dunn, 1923) in a subterranean system of 10 caves in Umbria (Italy). The studied populations revealed a peak of activity from April to July. The relative abundance of salamanders varied throughout the year and the observed frequencies of individuals differed significantly from expected, confirming a seasonal pattern of activity. Both external and internal temperatures positively influenced the abundance of salamanders inside the caves. This relationship may principally be indirect, and presumably salamander cave activity follows prey temporal distribution patterns, which in turn are also linked to temperature. The presence of salamanders was negatively affected by high levels of air moisture both outside and inside the cave. In summer, salamanders find refuge inside caves because the air moisture outside reaches values incompatible with the physiological requirements of the species. Adults showed a significant tendency to use areas inside the cave that were closer to the entrance when the external climate conditions come in the vicinity of those suitable for the species (increased external relative humidity and decreased external temperature), and the external influence on internal micro‐climate is reduced. Comparisons to other Speleomantes species are also provided.

Habitat relationships of eastern red-backed salamanders ( Plethodon cinereus) in Appalachian agroforestry and grazing systems

Woodland salamander responses to either traditional grazing or silvopasture systems are virtually unknown. An information-theoretic modelling approach was used to evaluate responses of red-backed salamanders ( Plethodon cinereus) to silvopasture and meadow conversions in southern West Virginia. Searches of area-constrained plots and artificial coverboards that were distributed across a gradient of agricultural conversion and grazing intensity, including hardwood silvopastures, hay meadows, forest edges, and reference forests yielded 2823 salamanders between May 2004 and November 2005. Salamander presence and abundance were positively associated with increasing cover of herbaceous vegetation and negatively associated with the intensity of agricultural disturbance. Although salamander presence and abundance appeared to be negatively influenced by agricultural disturbance when compared to reference forest conditions, the occurrence of red-backed salamanders within agriculturally modified habitats indicates this species may be more resilient to forest conversion than previously thought. This study suggests that herbaceous vegetation retained within some agricultural treatments, in combination with artificial cover, may at least partially mitigate the loss of forest canopy for red-backed salamanders.

Trout affect the density, activity and feeding of a larval plethodontid salamander

Summary1. Ecologists have struggled to describe general patterns in the impacts of predators on stream prey, particularly at large, realistic spatial and temporal scales. Among the confounding variables in many systems is the presence of multiple predators whose interactions can be complex and unpredictable.2. We studied the interactions between brook trout (Salvelinus fontinalis) and larval two‐lined salamanders (Eurycea bislineata), two dominant vertebrate predators in New England stream systems, by examining patterns of two‐lined salamander abundance in stream reaches above and below waterfalls that are barriers to fish dispersal, by measuring the effects of trout on salamander density and activity using a large‐scale manipulation of brook trout presence, and by conducting a small‐scale laboratory experiment to study how brook trout and larval two‐lined salamanders affect each other's prey consumption.3. We captured more salamanders above waterfalls, in the absence of trout, than below waterfalls where trout were present. Salamander density and daytime activity decreased following trout addition to streams, and salamander activity shifted from aperiodic to more nocturnal with fish. Analysis of stomach contents from our laboratory experiment revealed that salamanders eat fewer prey with trout, but trout eat more prey in the presence of salamanders.4. We suggest that as predators in streams, salamanders can influence invertebrate prey communities both directly and through density‐ and trait‐mediated interactions with other predators.

Strategies for Modeling Habitat Relationships of Uncommon Species: An Example Using the Siskiyou Mountains Salamander (Plethodon stormi)

We analyzed environmental relationships of the Siskiyou Mountains salamander, comparing attributes at the landscape, macro- and micro-environmental scales, and the three scales combined, to determine which attributes best predicted salamander presence. Separate analyses were conducted for sites on the north and south sides of the Siskiyou Mountains which basically divide Oregon and California. We sampled 239 randomly selected sites (163 north and 76 south of the Siskiyou Crest), each in ≥ 5 ha of relatively homogeneous forest or post-forest (clearcut) habitat, 75 m from edge, in 7×7 m plots with ≥ 25 % rock cover. Measured attributes at the landscape, macro-, and micro-environmental scales totaled 230 independent variables. Subsets of 122 (North Slope) and 97 (South Slope) variables were used in hierarchical, exploratory, best subsets logistic regression, to determine the best predictors of salamander presence. We tested three analysis strategies: 1) linear relationships only; 2) linear, quadratic, and logistic relationships; and 3) linear, quadratic, and logistic relationships, and interactions among the covariates. The best models of salamander presence consisted of combined landscape, macro- and micro-environmental scale variables; included linear, quadratic, and pseudo-threshold (i.e., log) forms, and included interactions between variables. These models showed positive relationships of salamander presence with site conditions and plant assemblages characterizing old, less disturbed forest with closed canopy, moist, relatively warm microclimates, deep litter, and cobble and boulder-sized rock substrates. Our results suggest that mature to late-seral-forest attributes provide optimal habitat for the Siskiyou Mountains salamander. Stands of mature and older forests evenly distributed and interconnected across the geographical range of this species would likely best insure its long-term viability.

Salamanders in forest-floor food webs: Invertebrate species composition influences top–down effects

Summary The red-backed salamander, Plethodon cinereus, is an abundant predator in northeastern North America, where it is hypothesized to play an important role in the regulation of forest-floor invertebrate communities. We tested the hypothesis that the top–down effects of P. cinereus are influenced by the species composition of invertebrates of the forest-floor. In a month-long microcosm experiment, we compared salamander effects on invertebrate species composition in leaf-litter from two sites that differed in species and size composition of invertebrate detritivores (an urban forest site at which isopods and millipedes were numerous and a rural forest site at which Collembola were the most numerous detritivores, but isopods and millipedes were few). Our results were consistent with our initial hypothesis. The presence of salamanders within microcosms was associated with decreased densities of oribatid mites, pseudoscorpions, isopods and millipedes in comparison to salamander-absent controls, but negative effects of salamanders on isopods and millipedes were most strongly expressed within urban litter microcosms. Salamanders were also associated with a positive, indirect effect, i.e., an increase in density of podomorphic Collembola in comparison to salamander-absent controls, but within urban litter exclusively. Our results suggested that plethodontid salamanders exerted positive, indirect effects through consumption of an intermediate predator, i.e., pseudoscorpions, and macroinvertebrate competitors, i.e., isopods and millipedes, of podomorphic Collembola. We hypothesize that differences in salamander-mediated dynamics between the two litter sources resulted from prey selection by P. cinereus based on differences in prey size and abundance between the rural and urban forest litter.

Assessing Suitability for Conservation Action: Prioritizing Interpond Linkages for the California Tiger Salamander

Abstract: Conservation organizations and public agencies are interested in identifying and prioritizing areas for conservation action, often acquisition or easements. Typically, this requires the use of uncertain data and vaguely defined decision criteria. I developed a decision support system to address these uncertainty issues and assist in evaluating conservation opportunities for the endangered California tiger salamander (Ambystoma californiense) in Santa Barbara, California. Functionally defined planning units were used to aggregate data on land suitability, land cover change, salamander presence, and movement risk along potential linkages between breeding ponds. I used a fuzzy‐logic‐based inference engine to evaluate the planning units and rank the relative suitability of interpond linkages for conservation action. The sensitivity of the rankings was considered with respect to uncertainty in salamander occurrence data and the relationship between land‐cover‐change threats and site suitability. All linkages were substantially degraded, but five areas were consistently identified with high relative suitability for conservation action despite differences in assumptions and uncertainty in biological data. The combination of functionally defined planning units and a fuzzy‐logic‐based decision support system provides a general framework for considering the suitability of sites for conservation action.

SUBSTRATE CUES INFLUENCE HABITAT SELECTION BY SPOTTED SALAMANDERS

Identifying the cues used by spotted salamanders (Ambystoma maculatum) to select forested habitat may provide insight into their habitat requirements and preferences. Environmental factors, such as temperature and moisture, are consistently important factors in explaining the magnitude and timing of annual breeding migrations and are important characteristics of quality terrestrial habitat. These factors, however, may not be used to select terrestrial habitat because microclimate gradients are minimal when salamanders are migrating. To test whether substrates provide cues for habitat selection, we presented juvenile and adult spotted salamanders with a choice between substrates collected from forest or grassland. Further, we presented adults with a choice between litter and a combination of soil and litter collected from forest or grassland. We recorded substrate selection initially and at 3-min intervals for 60 min. Salamanders tended to select the forest substrate more than the grassland substrate in all 4 experiments. Overall, juveniles (88%) selected forest soil more than adults (70%). Adults initially selected forest soil (80%), but the response declined with time. However, when we presented soil and litter in combination, salamanders hid under the litter, and the selection of forest substrate (70%) did not decline with time. The establishment of cues influencing habitat selection provides mechanistic information that may be used to predict habitat selection under scenarios of anthropogenic habitat alteration. Our results suggest that substrate characteristics may influence the presence of salamanders within various habitat types.

Leaf litterbags: Factors affecting capture of stream-dwelling salamanders

Many standardized techniques are used to monitor terrestrial salamanders, but fewer protocols have been tested for inventorying stream-dwelling salamanders, especially larvae. One new method uses artificial refugia (leaf litterbags) placed in shallow streams. Totest the utility of litterbags, we sampled three transects of 6 litterbags each (2 large, 2 medium, and 2 small) placed in five small, medium, and large streams in Great Smoky Mountains National Park, an area of high aquatic salamander diversity. We captured 690 larval, juvenile, and adult stream-dwelling salamanders of 11 different species from June to November 2000 in the 90 litterbags. Large and medium-sized litterbags were most effective at sampling salamanders in small streams, but all bag sizes worked equally well in medium and large streams. The number of salamanders captured varied seasonally,with most captures in June and July. The depth of bag submergence significantly influenced litterbag use by adult and larval salamanders, but had no effect on juvenile salamanders. Although the technique was effective for determining the presence of many salamander larvae, variation in the numbers of individuals captured and the inability to relate captures to overall abundance make it impossible to monitor trends without considerable additional effort. The ease of deployment and non-destructive methodology suggest that litterbags could be useful in determining salamander presence during inventory programs, especially when the time to sample a large number of sites is limited.