Download or read book Short term Relationship of Timber Management and Pacific Giant Salamander Populations and the Response of Larval Stream Amphibian to Predators Under Differing Sediment Levels written by Niels C. Leuthold and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the Pacific Northwest, multiple studies have found negative effects of timber harvest on stream amphibians, but the results have been highly variable and region-specific. In this collection of studies, I examined the short term effect of timber harvest using a field study, and used lab work to examine a potential mechanism for timber harvest effect. Over the last 30 years forest management practices have changed substantially, yet little work examines how modern forest management relates to the abundance or density of stream amphibians. I examined the influences of contemporary forest practices on Pacific giant salamanders as part of the Hinkle Creek paired watershed study. I used a mark-recapture analysis to estimate Pacific giant salamander density at 100 1-m segments spread throughout the basin and then used extended linear models that accounted for correlation resulting from the repeated surveys at sites across years. Density was positively associated with substrate, negatively associate with upstream area drained, and had a weak positive association with fish density, but I found no evidence of an effect of harvest. A Monte Carlo analysis suggested that our results were not sensitive to missing captures at sites with no captures. Pacific Northwest stream amphibians are often negatively associated with sedimentation, but the mechanism underlying this relationship is not clear. One hypothesized mechanism is that the reduced interstitial space that results from sedimentation increases susceptibility of amphibians to predation. I used laboratory mesocosms to test this hypothesis and examine the response of larval Pacific giant salamanders and tailed frogs to cutthroat trout and adult Pacific giant salamander presence under three different levels of sediment. I found amphibian larvae were more visible as sediment level increased and some evidence that larvae were less visible in the presence of fish. Movement decreased in the presence of cutthroat trout, though for tailed frog larvae this effect was marginally significant (p = 0.066). Larvae did not respond to presence of adult Pacific giant salamanders. These patterns are consistent with the hypothesis that sediment affects larval stream amphibians by increasing vulnerability to predation. While both species of larvae actively sought cover in response to fish, I found little evidence that this behavior mitigates the effects of increasing sediment.
Download or read book Measuring the Effects of Increasing Loads of Fine Sediment from Timber Harvest and Road Building on Aquatic Populations of Dicamptodon Tenebrosus pacific Giant Salamander in California s Redwoods written by Seth Pogue and published by . This book was released on 2008 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dicamptodon tenebrosus (Pacific giant salamander) was evaluated for suitability as an indicator of aquatic habitat quality relative to increasing loads of fine sediment from timber harvest and road building. I compared three surrogates of D. tenebrosus population success - biomass per unit area, density, and number of age classes (dependent variables) to two measures of stream sedimentation - RSI, which measures how much of the stream bed becomes mobilized at peak flow, and D50, the median bed particle diameter (independent variables) on 49 streams from three subjective disturbance categories: a control group, a moderate management group, and a high management group. Streams impacted by sediment exhibited fewer surviving age classes, and also significantly less biomass per square meter of pool bottom. These streams were from the moderate and high management categories. Unimpacted streams (control group) exhibited the greatest number of surviving age classes and the highest biomass. This study also presents the first quantitative analysis of D. tenebrosus age class structure. These animals live to be at least twelve years old.
Download or read book Feeding Ecology of Larvae of the Pacific Giant Salamander Dicamptodon Tenebrosus and Their Role as Top Predator in a Headwater Stream Benthic Community written by Michael S. Parker (Professor of biology) and published by . This book was released on 1992 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coexistence of Top Predators in Headwater Streams written by David E. Rundio and published by . This book was released on 2002 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coexistence of multiple predators may have important consequences for the structure and function of communities. Interactions between predators may strongly affect their combined direct and indirect effects on prey populations and lower trophic levels. Predators often have size-structured populations, which may result in intraguild predation characterized by complex trophic and behavioral interactions. Coexistence of multiple predators may strongly depend on antipredator defenses of small size classes that reduce their vulnerability to predation. In Pacific Northwest forested ecosystems, Pacific giant salamanders (Dicamptodon tenebrosus) and coastal cutthroat trout (Oncorhynchus clarki clarki) are the top predators in many perennial headwater streams. Dicamptodon and cutthroat have size-structured populations with roughly corresponding size classes, and interactions between these species appear consistent with intraguild predation. My research objective was to determine the mechanisms contributing to the coexistence of Dicamptodon larvae with cutthroat trout in headwater streams, and the effects of this coexistence on factors related to Dicamptodon fitness. First, I tested for two general types of antipredator defenses of young-of-year Dicamptodon larvae against trout. Larvae were palatable to trout during initial and repeated offerings, which suggests that they may survive few encounters with trout. However, larvae increased refuge use in response to non-visual, chemical cues from trout, which likely reduces the probability of encounters with trout and contributes to their coexistence. Second, I measured the effects of cutthroat trout on Dicamptodon fitness parameters in a field experiment. Dicamptodon survival, growth, and behavior (activity level) did not differ between trout-present and trout-absent pools, although these results were compromised by unexplained gains or losses of larvae from most pools. Antipredator behaviors may promote coexistence of Dicamptodon and cutthroat trout, and may contribute to a complex series of behavioral and trophic interactions affecting lower trophic levels within headwater stream communities.
Download or read book Movement and Demography of Larval Coastal Giant Salamanders Dicamptodon Tenebrosus in Streams with Culverts in the Oregon Coast Range written by Jina P. Sagar and published by . This book was released on 2004 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barriers to the movement of aquatic organisms can increase the genetic and spatial isolation of populations and may decrease the viability of these regional populations. Focus on culvert passage issues has increased as federal agencies attempt to inventory and replace road-crossing stream culverts that are barriers to the movement of anadromous fish. However, the effect of road-crossing culverts on the movement of other aquatic organisms is not known. The coastal giant salamander (Dicamptodon tenebrosus) is an important component of headwater stream communities and their movement may be affected by culverts in the larval aquatic stage. The objectives of this study were to determine the effect of road-crossing culverts on the movement and survival of larval coastal giant salamanders in the Oregon Coast Range. We conducted a mark-recapture study on larval D. tenebrosus 3rd and 4th order streams to: i) determine culvert use and passage by design type (pipe and arch types) relative to reference stream reaches without culverts; and ii) model larval survival and growth by season, age and culvert presence. We assessed the movement of over 2,000 larval D. tenebrosus in 14 streams and found that larvae were highly sedentary. Mean movement distances did not differ with culvert presence. However, a small portion of larvae (20%) moved sufficient distances to assess culvert passage. Larvae moved less frequently through stream reaches with culverts than stream reaches without culverts, suggesting a barrier effect. There was less upstream movement through pipe culverts than arch culverts. Also, there were lower larval densities in pipe culverts, indicating arch culverts provided more larval habitat. Larval density both inside culverts and in the adjacent stream reaches was associated with the presence of large substrates, which may be important in facilitating larval D. tenebrosus movement through culverts. Stream reaches with culverts were associated with higher levels of fine sediments, however, which may reduce the suitability of near-culvert habitats. Survival estimates indicated high selection pressure early in the larval period. Apparent survival was lower in summer, and for first-year larvae in comparison to second/third-year larvae. Larval survival for both age groups was lower in reaches of stream with culverts although this effect was weak. Culvert effects on movement of coastal giant salamander aquatic larvae indicate they can operate as barriers but their effect on survival remains unclear. Culvert replacements that simulate both the natural stream bed and hydraulic conditions would help provide both habitat and passage opportunities for larval D. tenebrosus.
Download or read book Individual Population and Landscape scale Effects of Timber Harvest on the Red legged Salamander Plethodon Shermani written by Grant McClintock Connette and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat loss and alteration are widely recognized as major threats to global biodiversity and the vulnerability of animal species to these disturbance processes can depend on the behavioral responses of individuals to modified landscapes. In response to a changing environment, individuals may either attempt to adapt to changing conditions or disperse to new habitat. At the local scale, the emigration of individuals or changes in activity patterns could lead to reduced counts of animals in ecological studies. At broader spatial scales, organismal movement may enable population rescue or reestablishment after disturbance and maintain demographic connectivity among populations. These complex mechanisms underlying the perceived abundance and distribution of species often requires a careful deconstructing of demographic trends and sampling variation in ecological data. Lungless salamanders (Family Plethodontidae) are extremely abundant in many forest and headwater stream ecosystems of eastern North America. These salamanders breathe across their moist skin surface, making them sensitive to fluctuations in temperature and moisture conditions. Thus, changes in habitat characteristics are known to have a considerable effect on populations of these salamanders. However, studies identifying the behavioral or demographic causes of declines as well as patterns of long-term recovery are critically needed. My dissertation research combined behavioral, population and landscape-scale studies to identify the effects of timber harvest on a lungless woodland salamander (Plethodon shermani). The primary objectives of my research were to 1) to describe the short-and long-term effects of timber harvest on salamander abundance and 2) to determine the behavioral or demographic processes dictating the abundance and distribution of salamanders at both local and landscape scales. To characterize baseline population dynamics of the salamander, P. shermani, I conducted a 5-year capture-mark-recapture study which revealed substantial annual variation in survival, recruitment, and population size under natural conditions. Initial results suggest that differences in recruitment and over-winter survival might be responsible for the lower abundances of terrestrial salamanders in logged areas at the end of this study. In an experimental translocation of salamanders into a timber cut and nearby forest habitat, I found that salamanders respond to differences in habitat quality by altering their movement behavior. This type of behavioral shift might help mitigate the risk of sustaining activity in recently logged forest. In an additional study, I tracked salamanders using a PIT-tag telemetry system in order to identify mortality, rather than emigration or reduced activity, as the likely cause for perceived declines in salamanders immediately following timber harvest. Finally, in a series of landscape-scale surveys, I found that salamander abundance was positively correlated with forest age (i.e., years since harvest), that full population recovery can require greater than 100 years, and that populations of species with greater movement ability may recover faster due to immigration of individuals from surrounding forest. Collectively, these studies identify key behavioral and demographic processes responsible for observed changes in salamander populations and suggest specific strategies for conservation and management.
Download or read book Riparian Vegetation and Larval Pacific Giant Dicamptodon Tenebrosus and Adult Western Redback Plethodon Vehiculum Salamanders in the Oregon Coast Range written by Paula Hayes Graff and published by . This book was released on 2006 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Riparian areas in the Pacific Northwest provide important biotic and abiotic features, such as down wood, moist microsites, and abundant invertebrate prey that benefit aquatic and terrestrial amphibians. Reported high densities of amphibians from streams and riparian areas in the Pacific Northwest highlight their importance in riparian food webs. Amphibians provide an important trophic link between terrestrial and aquatic systems because they may exploit both terrestrial and aquatic prey and in turn they are prey for other vertebrates. In the Oregon Coast Range, riparian vegetation is often more diverse than upland vegetation and there is typically a considerable deciduous component. However, forestry regulations in Oregon require landowners to promote the growth of conifer over deciduous trees in riparian areas to benefit salmonids and other fishes. The goal of our research was to examine associations between the distribution and diets of aquatic and terrestrial amphibians and vegetation in second- and third-order Oregon Coast Range streams and riparian areas. Sites reflected overstory conditions in managed forests of the central Oregon Coast Range, ranging from primarily red alder (Alnus rubra) in the riparian zone to mostly Douglas- fir (Pseudotsuga menziesii). The two most common amphibians detected were the aquatic Pacific Giant Salamander larvae (Dicamptodon tenebrosus) and the terrestrial Western Redback Salamander (Plethodon vehiculum). Our first research objective was to identify habitat characteristics with an emphasis on riparian vegetation, that could be associated with the presence of these two species. We used logistic regression to examine the presence of these salamanders among sites and the information-theoretic approach using Akaike Information Criterion (AIC) methods to compare the strength of evidence of a set of candidate models formed from a priori hypotheses. The highest ranked model explained 95% of the variability of the presence of Dicamptodon tenebrosus larvae among sites and included variables representing percent cover of Douglas- fir, elevation, amount of wood cover, and lithology type. The odds of the presence of D. tenebrosus increased with the percent cover of Douglas- fir over the wetted width of the stream. Two competitive models (
Download or read book Amphibian Conservation written by Rebecca K. Smith and published by Pelagic Publishing Ltd. This book was released on 2014-05-16 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphibian Conservation is the fourth in the series of Synopses of Conservation Evidence, linked to the online resource www.ConservationEvidence.com. This synopsis is part of the Conservation Evidence project and provides a useful resource for conservationists. It forms part of a series designed to promote a more evidence-based approach to biodiversity conservation. Others in the series include bee, bird, farmland and bat conservation and many others are in preparation. Approximately 32% of the 7,164+ amphibian species are currently threatened with extinction and at least 43% of species are declining. Despite this, until recently amphibians and their conservation had received little attention. Although work is now being carried out to conserve many species, often it is not adequately documented. This book brings together and summarises the available scientific evidence and experience relevant to the practical conservation of amphibians. The authors consulted an international group of amphibian experts and conservationists to produce a thorough summary of what is known, or not known, about the effectiveness of amphibian conservation actions across the world. "The book is packed with literature summaries and citations; a veritable information goldmine for graduate students and researchers. It also admirably provides decision makers with a well-researched resource of proven interventions that can be employed to stem/reverse the decline of amphibian populations." -John G Palis, Bulletin of the Chicago Herpetological Society
Download or read book Resistance and Resilience of Stream Salamander Populations to Disturbance written by Steven J. Price and published by . This book was released on 2011 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Urbanization and drought represent two pervasive disturbances that affect animal inhabitants of small, first-order streams. Stream salamanders (Family Plethodontidae) represent the dominant vertebrate group and play important ecological roles in first-order streams, although they have often been neglected in previous studies on the effects of disturbance on system ecosystems. It was hypothesized that urbanization and drought would strongly influence vital rates (e.g., occupancy, abundance, survival, etc.) of salamander populations. One goal of this research was to use a before-after control-impact study design to determine occupancy probabilities and abundances of salamander life stages and species in streams with urbanized catchments, compared to streams with undisturbed catchments. Using both dynamic occupancy models and binomial mixed models, I not only estimated the state variables (i.e., occupancy and abundance), but provided estimates of colonization, survival, and detection while incorporating site-level and survey covariates. Four years post-urbanization, occupancy estimates of larval northern dusky (Desmognathus fuscus), larval and adult southern two-lined salamanders (Eurycea cirrigera) declined by approximately 40%, whereas adult northern dusky salamander occupancy remained stable. Occupancy of salamanders in control streams remained relatively stable over five years. Abundance estimates followed somewhat similar trends, although response-time for salamanders was shown to be more rapid. Abundances of larval dusky and two-lined salamanders were different from control streams one-year after urbanization, whereas adult two-lined salamander and dusky salamander abundances differed from control streams two and three years' post-urbanization, respectively. A second main objective was to use capture-mark-recapture (CMR) data to estimate survival probability, temporary emigration probability and detectability of stream salamanders, with a focus on the northern dusky salamanders. I used Huggins Robust Design to construct a set of a priori candidate models. Strong support was found for models that included month-specific capture probabilities and recapture probabilities, which indicated a strong capture response. Furthermore, I found support for random temporary emigration and location specific survival. Findings suggest that it may be necessary to include survey and population-level parameters in order to estimate survival in stream salamanders. A final objective was to use occupancy and CMR data to examine the response of the northern dusky salamander to drought, specifically the supra-seasonal drought of 2007-2008. I used dynamic occupancy models to estimate salamander occupancy of adult and larval salamanders and Huggins Robust Design to estimate vital rates of adult salamanders. Occupancy of larval salamanders declined by 30% during supra-seasonal drought conditions, yet adult occupancy remained similar to non drought years. Adult temporary emigration rates were twice as high during supra-seasonal drought conditions than during non-drought and typical drought conditions and survival of adults during the supra-seasonal drought was similar to survival during non-drought conditions. These findings suggest persistence of dusky salamanders during drought is due to both between generation and within generation refugium-use strategies.
Download or read book Beyond the Edge written by John A. Crawford and published by . This book was released on 2007 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: While there are many types of habitat loss and degradation (e.g., agriculture, land development), many studies have focused on the impacts of logging on wildlife populations and on ecosystem processes. Little information, however, exists on the effects of logging on amphibians that require streams for reproduction. In order to mitigate the impacts of habitat alteration on stream amphibians, it is necessary to have a clear understanding of the role abiotic and biotic factors play in determining habitat use and abundance. Additionally, we must determine the effects of forest management practices, such as timber harvesting, have on amphibian populations in order to develop alternative management strategies. My data show that core terrestrial habitat use, microhabitat use, and overall stream salamander abundance are dependent on leaf litter depth and soil moisture. Furthermore, as leaf litter depth and soil moisture are reduced as a result of even-aged timber harvesting, the core terrestrial habitat use and abundance of salamanders decrease as a result of fewer microhabitats being available. The decrease in suitable microhabitats available is accompanied by a resulting increase in competition between stream salamander species. Lastly, I found that current USFS regulations for riparian buffer widths are vastly inadequate to protect stream salamander populations from activities such as timber harvesting.
Download or read book Feeding ecology of larvae of the Pacific giant salamander and their role as top predator in a headwater stream benthic community by Michael Steven Parker written by and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Standardized Protocol for Surveying Aquatic Amphibians written by Gary M. Fellers and published by . This book was released on 1995 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Riparian Areas written by National Research Council and published by National Academies Press. This book was released on 2002-10-10 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Download or read book Influence of Multi scale Drivers on Stream Salamander Occupancy Abundance and Reproduction in an Exurban Landscape written by Diana C Macklem and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The number of city-dwelling humans currently exceeds half of the world’s population and is expected to increase in the future (Meyer et al. 2005; Barrett and Price 2014); however, urban development significantly alters the surrounding ecological community. Urbanization increases the amount of impervious surfaces on the landscape, fragments or destroys habitats, produces pollutants and nutrient contaminants, promotes the introduction and invasion of non-native species, increases disease transmission, and alters biotic communities (Allan 2004; Bar-Massada et al. 2014). The manifestation of urbanization in stream ecosystems is a number of consistent symptoms collectively known as urban stream syndrome (Walsh et al. 2005; Hamer and McDonnell 2008). Urban streams typically have flashier hydrographs, increased sediment and pollutant loads, and altered channel morphology and stability (Walsh et al. 2005; Hamer and McDonnell 2008). These ecosystem changes reduce biotic richness, leaving a predominance of tolerant, generalist species in urban streams (Walsh et al. 2005; Hamer and McDonnell 2008). Urbanization currently threatens more than one-third of the world’s known amphibian species (Hamer and McDonnell 2008). Urban development has been linked to reduced amphibian species richness, declines in individual species occurrence and abundance, loss of genetic diversity and population isolation, and altered biotic communities and interactions (Hamer and McDonnell 2008; Barrett and Price 2014). Moreover, salamanders make up a considerable portion of the vertebrate biomass in forest and wetland ecosystems (Burton and Liken 1975; Hamer and McDonnell 2008; Barrett and Price 2014). Thus, severe declines or extirpation of salamander populations will have a substantial influence on nutrient cycling and trophic interactions in the riparian ecosystem (Barrett and Price 2014). In southern New England, reforestation has occurred since the 1850’s along with the establishment of low-density residential communities beginning in the 1920’s (Foster 1992). Reforestation plateaued by the mid-1970’s with forest conversion to residential land use resulting in forest loss during the last 20-30 years in southern New England (Jeon et al. 2014). Today, exurban development, defined as human housing density of 6-25 houses per square kilometer (Hansen et al. 2015), dominates the landscape (Foster 1992; Jeon et al. 2014). Despite exurban development being the fastest growing form of land use in the United States since the 1950’s (Hansen et al. 2005), the range of ecological effects that occur within exurban development are not well understood (Bar-Massada et al. 2014). In southern New England, we are just now beginning to understand how wildlife populations persist over multiple decades in this landscape of second growth forest intermixed with exurban development. Addressing the challenges of urban stream syndrome and amphibian declines will require a basic understanding of species-specific amphibian ecology, identification of multi-scale and interactive drivers of population declines, and a multi-scale approach to management (Hamer and McDonnell 2008; Barrett and Price 2014; Semlitsch et al. 2017). Preventing salamander population declines within exurban development requires identifying what features of an exurban landscape influence population dynamics. Thus, I examined the influence of multi-scale drivers on stream salamander occupancy, abundance, and reproduction in the exurban landscape of eastern Connecticut. Moreover, my thesis addresses a recent call for research that examines species-specific responses to urbanization, focuses on gradients of housing development, and highlights the potential legacy effects associated with housing development (Hamer and McDonnell 2008; Barrett and Price 2014). Connecticut is home to three species of stream-dwelling salamander species. The northern spring salamander, Gyrinophilus porphyriticus, is restricted to a few known locations and thus not included here. I focused on the responses of the other two stream salamander species, Eurycea bislineata and Desmognathus fuscus, to a range of exurban housing development densities and ages.
Download or read book Post wildfire Sedimentation in Saguaro National Park Rincon Mountain District and Effects on Lowland Leopard Frog Habitat written by John T. C. Parker and published by . This book was released on 2006 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Methods to Estimate Population Density of Pacific Giant Salamanders in Small Streams of the Southern Oregon Cascades written by Niels C. Leuthold and published by . This book was released on 2003 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: I compared hand sampling, two-pass multiple removal sampling, mark-recapture and catchability-based population estimates for the Pacific giant salamander (Dicamptodon tenebrosus) at 22 sites in 11 streams of Cascade Mountains of Oregon. Mark-recapture and catchability-based population estimates were not significantly different (p 0.86). Hand sampling and two-pass multiple removal population estimates were not significantly different (p = 0.57). However, mark-recapture and catchability-based estimates were significantly greater than two-pass multiple removal and hand sampling estimates. Hand sampling and multiple removal population estimates were frequently lower than the number of individual Pacific giant salamanders captured by all methods at a site. The catchability of each method differed between streams and within consecutive sites on the same stream. Unacknowledged differences in catchabilities among sites are a potential source of error when using hand-sampling index counts to estimate and compare populations without correcting the estimates for the differences in Pacific giant salamander catchability. Catchability decreased significantly between the first pass of electroshocking and the subsequent recapture pass of electroshocking. This decrease was observed even though the recapture passes were performed the day after the multiple removal electroshocking. A decrease in catchability violates the assumptions of constant catchability for multiple removal population estimates and potentially explains the weaker performance of removal estimates. Hand sampling estimates did not adjust for the proportion of the population captured at each site, and this is probably the cause of their poor performance. The presumption of constant catchability in hand sampling produced biases in the population estimates, because the catchabilities were not constant. In future studies of stream amphibian abundance, catchability needs to be included in population estimation procedures to produce accurate estimates and to allow valid comparisons of population sizes between sites. Catchability models can be used to calibrate less intensive survey methods, such as hand sampling or a single pass of electroshocking, with the results from more intensive mark-recapture methods. Intensive work would be needed to do the calibrations, but afterwards a standard, more convenient method, such as electroshocking or hand sampling, can be used within the ranges of habitat values for which the calibration model is valid.
Download or read book Amphibians of the Pacific Northwest written by Lawrence L. C. Jones and published by Branch Line Video. This book was released on 2005 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Sponsored by: Society for Northwestern Vertebrate Biology, USDA Forest Service"--Title page verso.
