However, it should be remarked that sample size was relatively small in this latter analysis (112 juveniles observed), and this may have limited statistical power, compared to the previous analyses. The black points represent the medians, the grey boxes represent the second and third quartiles. The spring salamander (Gyrinophilus porphyriticus) is a species of salamander in the family Plethodontidae It is found in Canada and the United States. Such presence of juveniles also in suboptimal microhabitats has been observed also in other species of cave salamanders (Ficetola, Pennati & Manenti, 2013), and may allow juveniles to exploit more superficial environments, where they can find more food. The deepest sectors always showed lower light than the superficial ones. thank you in advance for your patience and understanding. The results of the previous models may be affected by imperfect detection. The dorsal coloration varies from salmon or light brownish to pink or reddish. S1A and S1B). Surveys were conducted during day-time. The record length is 8.06 in (20.5 cm). Raoul Manenti conceived and designed the experiments, contributed reagents/materials/analysis tools, wrote the paper, reviewed drafts of the paper. Prescribed fire and timber harvest effects on terrestrial salamander abundance, detectability, and microhabitat use ... and microhabitat use. We used niche equivalency tests to assess whether salamanders select sectors with similar environmental features in different months, after taking into account differences for the availability of microhabitat conditions (Broennimann et al., 2012). Caves are often described as stable environments (Romero, 2012), but their features and the distribution of their inhabitants shows strong fluctuations through the year, particularly in the superficial sectors. For all models, Variance Inflation Factor was <5, confirming lack of collinearity issues (Fox, 2002). Different processes may determine changes in species-habitat association: individuals may prefer different habitat typologies in different periods, or they may be forced to occupy a different habitat in order to follow the changing environment. We used a likelihood ratio test to assess the significance of terms in the best-AICc model. Seasonal change led to thermal inversion inside caves: from late autumn to early spring temperature increased with depth, while from late spring to early autumn temperature decreased in the deep sectors (Fig. Effects of food restriction across stages of juvenile and early adult development on body weight, survival and adult life history, Predicting to new environments: tools for visualizing model behaviour and impacts on mapped distributions. Its skin is orange/red with random black spots. An analysis with. In cohabitation trials, we predicted earthworms would exclude salamanders from high quality microhabitat (beneath artificial COs), resulting in salamanders using high quality microhabitat less frequently when paired with an earthworm than when alone. This indicates that juveniles may trade-off microclimatic optima for food availability (Vlachos et al., 2014). Conversely, if adults only were analyzed, none of similarity tests were rejected (Table 5). based on availability of microhabitat conditions (Smith & Grossman, 2003) or a ... For example, larger Gryonophilus porphyriticus (spring salamander) salamanders have greater predatory influence on Eurycea cirrigera (southern two-lined salamander) (Gustafson, 1994). This is likely the case for juveniles. Our study explores the complexity of habitat use patterns under variable conditions, and highlights difficulties in determining habitat selection processes. In subterranean environments microclimatic features are often considered to remain approximately stable, giving organisms the opportunity to inhabit caves constantly. Underground environments suffer constant food scarcity (Romero, 2009), but juveniles require consistent food supply in order to grow and reach maturity. To assess the robustness of habitat models to imperfect detection, we also repeated the GLMM analysis by comparing two contrasting periods seasons: January–February and June–July. This standardized technique allows to verify the presence of species in an area during a defined time (Crump & Scott Jr, 1994; Jung et al., 2000). This suggests that tolerance for suboptimal abiotic conditions may change through time, depending on the required resources. Actually, most of equivalency tests were not significantly different from random expectations, indicating that the species consistently selected the same microhabitat. Common use cases In the long term, temporal variation for habitat association in a given species may also occur due to evolution of novel adaptations (Nogués-Bravo, 2009; Stigall, 2012). Most Cope's giant salamanders become sexually mature in the larval stage. S2), they can only find such conditions in the deepest sectors of caves, in which temperature is relatively warm during winter, and coolest during summer. The difficulty of extrapolating regression results and linear relationships beyond the limits of environmental gradients tested is a major issue in ecological modelling (Randin et al., 2006; Zurell, Elith & Schroder, 2012). Juveniles were more frequent in sectors with high humidity and abundant M. menardi spiders; furthermore the effect of month, and the interactions humidity-month and temperature-month were significant (Tables 3C and 4C). As lungless salamanders exchange gasses mainly through their skin, and the efficiency of this skin function increases with high level of moisture (Spotila, 1972), during the cold season the individuals could be more tolerant to low humidity because of their lower respiration needs. nymphs also were important predictors of salamander microhabitats. We also included the time of survey (hour and minute in which we began the survey) as an additional independent variable. The use of habitat models to evaluate factors determining species distributions is becoming increasingly prevalent in ecological research (Peterson et al., 2011; Warren, 2012; Stein, Gerstner & Kreft, 2014). monticola), and spring salamanders (Gyrinophilus p. porphyriticus). Not detecting a species during a survey does not necessarily mean that species is absent, as most species have detection probability <1 (MacKenzie et al., 2006). However, under certain circumstances, individuals may select conditions that are closer to their physiological limits (Kearney et al., 2013). However, such “ideal” conditions are rarely available in the real world, and species have to deal with environmental variability, which causes frequent changes of habitat conditions and resources availability (Seebacher & Alford, 1999; Araújo et al., 2010; Fredericksen, 2014). The nominate subspecies, G. p. porphyriticus, occupies the remainder of the geographical range of this species. Enrico Lunghi conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper. In principle, the “optimal” habitat of a species should match species requirements for multiple parameters, ranging from metabolism to water balance and food availability. Although many studies have shown negative effects of anthropogenic disturbances on woodland salamanders, such as timber harvest and tree canopy removal, (Petranka et al., 1993; Ash and Bruce, … Enrico Lunghi is representing the Association Natural Oasis as President. G. p. dunni is distributed through the southern portion of the Blue Ridge Province and the Piedmont from southwest North Carolina to eastern to central Alabama. , Its natural habitats are temperate forests, rivers, swamps, freshwater marshes, freshwater springs, inland karsts, and caves. Pacific giant salamander larvae (Dicamptodon tenebrosus) inhabit headwater streams and are sensitive to heavy sedimentation and stream degradation. The dependent variables were three major features of cave microclimate: (A) internal temperature, (B) internal humidity and (C) illuminance. Counts of E. naufragia on the surface were made monthly or bimonthly at Swinbank Spring near Georgetown, Williamson County, Texas, over a period of 1 year. Research Article Prescribed Fire and Timber Harvest Effects on Terrestrial Salamander Abundance, Detectability, and Microhabitat Use KATHERINE M. O’DONNELL,1,2 Division of Biological Sciences, University of Missouri, 105 Tucker Hall, Columbia, MO 65211, USA FRANK R. THOMPSON III, Northern Research Station, U.S.D.A. Sector and cave identity were included as random categorical factors. Therefore, in the following winter, acquiring energy is a major priority for juveniles. For this study, we surveyed a 260 m section of Bagley Trail Brook, beginning 200 m from its confluence with the second-order Hubbard Brook main stem. In the analysis of juveniles, only the interaction between season and temperature remained significant (Table S1C, Figs. NewScientist.com: Salamanders formed new species despite interbreeding, https://en.wikipedia.org/w/index.php?title=Spring_salamander&oldid=921556000, Creative Commons Attribution-ShareAlike License, This page was last edited on 16 October 2019, at 12:29. During these two intervals we observed 112 salamanders in winter and 257 salamanders in summer. cinereus on salamander microhabitat use and foraging behavior. Cave salamanders are able to exploit the whole cave; therefore, if salamanders just require optimal abiotic conditions they can remain in farthest sectors where suitable microclimate is more stable. S1E and S1F). Similar to other giant salamander species, most activity is probably nocturnal and much time is spent in subterranean microhabitats. In a natural field experiment, conducted on salamander populations from “non-invaded” and “pheretimoid invaded” sites in Ohio, salamanders and earthworms shared cover objects ~60% less than expected. The abundance of Meta menardi spiders was considered as a biotic variable. are lungless salamanders. Furthermore, differences in habitat association patterns may occur through two distinct, non-exclusive processes: the species may select different habitats across their life-time (selection change hypothesis), and environmental features may change through time (environmental change hypothesis). The model assuming constant detection probability across sectors showed a lower AIC value (AIC: 53.3) than the model assuming that detection probability is related to distance from the entrance (AIC: 53.9). Three-m sectors approximately correspond to the home range of Hydromantes during their hypogean activity (Salvidio et al., 1994). Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander’s terrestrial ecology. Salamanders were most com- monly found in shallow (<10 mm), slowly moving (usually <10 cm/s) water with medium-sized rocks (65-256 mm diameter), moderate degrees of embeddedness (about 50%), … Outside caves, we registered air temperature (accuracy: 0.1 °C) and humidity (accuracy: 0.1%) using a thermo-hygrometer Lafayette TDP92, in a shaded area 5–10 m from the entrance. Furthermore, the significant interaction between month and depth indicated that the humidity gradient was not constant through the year (Tables 1B and 2B). Corresponding Author. They are known to rub heads as part of courtship behavior. We merged data from two-months periods respectively into winter (January–February) and summer (June–July), and repeated the analyses using the same variables of the best-AICc models obtained from the analyses of full dataset. Despite repeated calls for mechanistic modelling (Kearney & Porter, 2009), correlative habitat models remain the most frequently used approach. Nevertheless, the few studies analyzing the seasonal variation in the distribution of European cave salamanders (Salvidio et al., 1994; Vignoli, Caldera & Bologna, 2008) did not test whether habitat selection changes through time. When necessary resources are inversely correlated along environmental gradients, habitat choice will be the results of a trade-off between the multiple requirements of a species. The light line from eye to nostril is bordered below by gray pigment, but the markings are not always conspicuous. If salamanders always select the same optimal temperature (about 10–15 °C; Fig. 2A and 2B). Means (2000) described an assemblage of plethodontid salamanders that inhabit the steephead ravines of the coastal plain that included southern two-lined salamanders, red salamanders (Pseudotriton ruber), and either Apalachicola dusky salamanders (D. 3). Standard approaches to the analysis of detection probability assume that sites are closed to changes in the state of occupancy for the duration of sampling (MacKenzie et al., 2006). Results were nearly identical in the analysis of adults-only (Table S1B; Figs. We used as independent variables: Month of survey, Time in which the survey began, Depth of sector, External Temperature, External Humidity and interaction between Month and Depth (Prof : M). Scarce access to food resources during juvenile stages poses major constraints on development, and may have prolonged consequences and even impact lifetime fitness (Wong & Kölliker, 2014). Adults were associated with the wettest microclimates, while juveniles were present in apparently more stressful sectors as they were also present in sectors with lower humidity and less suitable temperatures. Complex models with AICc values higher than the simpler, nested models were not considered as candidate models (Richards, Whittingham & Stephens, 2011). In other words, apparent changes in species-habitat relationships (e.g., positive relationship with temperature in winter and negative relationship in summer) occurred because the habitat occupied by salamander remained the same, but environmental gradients changed through the time. Parameters related to microclimatic change of caves through the year: best-AICc models. However, this explanation is unlikely: previous studies explicitly testing this hypotheses have found evidence that juveniles are not displaced by adults (Ficetola, Pennati & Manenti, 2013), while behavioral analyses suggested lack of competition for territories (Berti & Corti, 2010). Pairs of months for which the species-habitat relationships were not equivalent (after Bonferroni’s correction: Atti del Museo Civico di Storia Naturale di Trieste, Polymath: An Interdisciplinary Arts and Sciences Journal, Proceeding of The Royal Society of London Series B, Proceedings of the National Academy of Sciences of the United States of America PNAS, Biochemistry, Biophysics and Molecular Biology, PeerJ (Life, Biological, Environmental and Health Sciences), PeerJ - General bio (stats, legal, policy, edu), Seasonal variations in scorpion activities (Arachnida: Scorpiones) in an area of Caatinga vegetation in northeastern Brazil, Insect overwintering in a changing climate, Assessing the utility of statistical adjustments for imperfect detection in tropical conservation science, Relazione del progetto: difesa del territorio in, Distribution, ecology and conservation of, Modelling distribution of habitats required for different uses by the same species: implications for conservation at the regional scale, Seasonal use and selection of caves by plethodontid salamanders in a Karst area of Arkansas, Measuring ecological niche overlap from occurrence and spatial environmental data, Use of twilight zones of caves by plethodontid salamanders, Role of temperature in determining relative abundance in cave twilight zones by two species of lungless salamander (family Plethodontidae), Mass gained during breeding positively correlates with adult survival because both reflect life history adaptation to seasonal food availability, Comparison of two non-lethal methods for dietary studies in terrestrial salamanders, Measuring and monitoring biological diversity: standard methods for Amphibians, Models for estimating abundance from repeated counts of an open metapopulation, Habitat selection by juvenile black-capped vireos following independence from parental care, Predicting the potential distribution of the beaded lizard and identification of priority areas for conservation, The art of modelling range-shifting species, Do cave salamanders occur randomly in cavities? Cave and sector identity were considered as random categorical variables, as they shows a typical combination of variables (both biotic and abiotic) independently from their position and location. 2E and 2F). 2C). Actually, in our study caves, the potential prey richness (calculated as the summed N of species of Araneae (excluding M. menardi) and Diptera, as these taxa are the major food items for cave salamanders (Vignoli, Caldera & Bologna, 2006; Crovetto, Romano & Salvidio, 2012)) quickly decreases with depth (generalized linear model with Poisson error, taking into account month of survey: B ± SE = − 0.024 ± 0.006, χ12=201.3, P < 0.0001). The peculiar physiology of plethodontids forces these salamanders to live within very narrow typologies of habitat. Plethodontid salamanders ar e characterized by having. In summer, adults were associated with the most humid sectors; however, they showed a clear preference for the most humid sectors also in February (Fig. The order of cave survey was chosen randomly, and the time interval between successive visits was 9–45 days. Results for December were not reported due to small sample size. First, newborns Hydromantes normally hatch at the end of summer (Lunghi et al., 2014). Juvenile Blue-spotted and Jefferson salamanders have light-blue flecking that might be mistaken for the silvery-gray flecking of juvenile Marbled Salamanders, For equivalency tests, salamander occurrences from different months were pooled and then randomly split in two datasets, maintaining the same number of occurrences of the original datasets; Schoener’s D was then calculated. 2 and Table 5). Multiple, non-exclusive explanations are possible for such selection change. Analyses (see results) showed a per-visit detection probability of 0.75, i.e., two surveys allow to ascertain presence/absences with 94% confidence (Sewell, Beebee & Griffiths, 2010). The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers): University of Florence approved the project by regular department’s application and we followed our institutional guidelines. Width of plots is proportional to the number of sectors showing such microclimate condition. Spring Salamanders can also be found under stones and logs near stream edges (Wild Portraits, 2000). Relationships between species and their habitats are not always constant. Furthermore, all cave abiotic features (temperature, humidity and light) followed the variation of external conditions, which indeed were the major cause of fluctuations of internal microhabitats. PeerJ promises to address all issues as quickly and professionally as possible. They have a fairly slender build and a light-colored ridge running from the eye to the tip of the snout.Coloration varies from salmon to yellowish brown with hints of red, and quite often there is a mottled or cloudy appearance with small dark spots. Forest Service, 202 Natural Resources Building, Columbia, MO 65211, USA Due to their particular physiology, they need a narrow combination of environmental characteristics, and actively search places with suitable microclimatic conditions (cold temperature and high moisture; Spotila, 1972; Camp & Jensen, 2007. The interior of each cave was divided into sectors of 3-m length, starting from the entrance and extending to the deepest explored area: our exploration was conducted until the end of the caves, or until the deepest sector reachable without speleological equipment. We used as independent variables: internal humidity (Humid), Month of survey, illuminance (Lux), The dependent variables were the presence of (A) Species, (B) Adults only and (C) Juveniles only. There is also an isolated colony in Hamilton County, Ohio. We assessed the pattern and role of niche variation along a hybrid zone, by investigating differences in microhabitat selection between terrestrial cave salamander species (Hydromantes Do cave features affect underground habitat exploitation by non-troglobite species? Season strongly affected the presence of salamanders; furthermore, we detected a significant interaction between temperature and season; the interaction between humidity and season was marginally not significant (Table S1A). All individuals were immediately released at the collection point. In these rainy nights of early spring, salamanders migrate to ponds to breed. During these two seasons, salamanders were generally associated with sectors in which microclimate was different from outdoor climate conditions: in fact, they were associated with the most humid and cold sectors during summer, while in winter they preferred relatively warm sectors (Figs. First, we used habitat models to identify the relationships between the distribution of salamanders and microhabitat features, evaluating if the pattern of microhabitat association is constant through time. Movements between superficial and deep sectors are more frequent during spring and autumn (Lanza et al., 2006), thus we assumed that occupancy was relatively stable within these periods. You can also choose to receive updates via daily or weekly email digests. The authors declare there are no competing interests. We Five best AIC models relating salamander distribution to environmental features. ext (external humidity), Time (hour of survey). In a good salamander year, hundreds of these critters will be in the edges of ponds, seemingly dancing in the water. Low environmental temperature reduces metabolism in ectotherms, which limits oxygen needs. We focused on univariate rather than multivariate tests because we were interested on variation of habitat selection due to change of specific variables (Saupe et al., 2014). How should detection probability be incorporated into estimates of relative abundance? For each continuous variable, the regression coefficient is reported if the variable is included into a given model. Surface density was not correlated with amount of rainfall, but microhabitat choice was so correlated: the percentage of salamanders under rocks and logs increased and the percentage in the leaf litter decreased with decreasing rainfall. For 12 months (from January 2013 to December 2013) we monitored 15 caves occupied by Hydromantes italicus in the North of Tuscan Apennines (Central Italy, between 43°52′42″N, 11°07′18″E and 43°59′51″N, 10°13′48″E). We used the MacKenzie & Kendall (2002) approach to test detection probability of cave salamanders, on the basis of data collected in 22 sectors from three different caves. There also may be a dark line above the white line, often conspicuous. 1B). This procedure was repeated 300 times to assess whether niche similarity was significantly lower than expected by chance. 2A and 2B). predictions regarding potential changes to species distribu-tion or ecology. Some studies have shown that cave salamanders are associated with caves having specific environmental features, such as low temperature, high humidity and presence of prey (Ficetola, Pennati & Manenti, 2012; Lunghi, Manenti & Ficetola, 2014), but these studies have been often performed during summer, when outdoor conditions are particularly unsuitable for salamanders, and abundance in cave is highest. Katherine M. O'Donnell. Detection probability of salamanders within sectors was high (detection probability ± SE: 0.75 ± 0.12). Like all members of the family Plethodontidae these salamanders have a nasolabial groove. 1C). Cave environments are dominated by few, simple environmental gradients, such as light, depth, temperature, humidity and food availability (Romero, 2009), affording simplistic habitat characterization. 2F). Although deforestation is a potential threat, the spring salamander occurs in many protected areas and is not listed as threatened in the IUCN Red List.. If you are following multiple publications then we will send you Reproduction in long-tailed salamanders is not well documented. The subspecies G. p. danielsi and G. p. dunni can be 5–7.5 in (13–19 cm). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The Shenandoah Salamander is generally found within moist microhabitats in otherwise dry talus areas on the very tops of Shenandoah's mountains . The spotted salamander (Ambystoma maculatum) is a large (adults are, on average, 6 to 7 inches long with some individuals reaching 9 inches), distinctively colored (dark gray or blue-black on its back with two, full body length rows of round, orange or yellow spots) salamander found on our Nature Trail. Universität Trier Fachbereich VI Raum- und Umweltwissenschaften Biogeographie, Campus I, Gebäude N Universitätsring, Museo di Storia Naturale dell’Università di Firenze, Sezione di Zoologia “La Specola,”, Dipartimento di Bioscienze, Università degli Studi di Milano, Dipartimento di Scienze dell’Ambiente e del Territorio e di Scienze della Terra, Università degli Studi di Milano-Bicocca, Laboratoire d’Ecologie Alpine (LECA), Université Grenoble-Alpes, This is an open access article distributed under the terms of the. However, caves are not closed systems, and environmental characteristics within caves can change over time due to external influences (Romero, 2009). Efficient exploitation of seasonal peaks of food resources may be a key of fast development during the first years. Description: Spring salamanders are one of the largest stream salamanders in our region (5 - 7.5 in; 12 - 19 cm). We flagged trees every 5 m along the stream for accurate estimation of salamander capture locations. Both selection changes and environmental changes may influence the possibility of predicting species distribution in different time periods. Individuals showed differences in their response to abiotic features, which resulted in a different distribution of salamanders inside caves (Ficetola, Pennati & Manenti, 2013). and will receive updates in the daily or weekly email digests if turned on. Second, we assessed whether the temporal variation in microhabitat occurs because the species selects different environmental features through the year, or because habitat features are affected by seasonal variation (i.e., we evaluated the support of the environmental changes vs. selection change hypotheses). Among amphibians, plethodontid salamanders represent a very interesting study case. For temperature and humidity, the trend of the respective external feature is also shown, represented by a continuous red line. The white line from eye to nostril, bordered below by a conspicuous black or dark brown line, is distinctive. The most superficial cave sectors are the ones with driest microclimate (Table 2), but show the highest abundance of prey. Humidity inside caves was strongly related to external humidity, month, depth and to the time of survey. However, incident light increased in summer and during periods characterized by low humidity (Fig. Maintenance of subsurface microhabitats and microclimates are essential to their survival because they have a very limited period of surface activity in the spring and fall when Such fluctuations mostly affect areas near the entrance of caves (twilight zone) and can strongly influence cave communities (Ficetola, Pennati & Manenti, 2013; Camp et al., 2014; Lunghi, Manenti & Ficetola, 2014). The analysis of detection probability was repeated twice: assuming constant detection across sectors, and assuming that detection probability is related to distance from cave entrance. This analysis was performed on four months (January, February, June and July) showing contrasting patterns of habitat association (see results), and during which we do not expect major movements among cave sectors (i.e., within these intervals the quasi-equilibrium assumption is more likely to be hold than when seasonal migrations occur). The aim of this study was analyzing the variation through time of species-habitat association in the Italian cave salamander (Hydromantes italicus). 1A). Females lay 60 to 110 eggs on the undersides of rocks in water and leave after laying. Best AIC models explaining the variation in microhabitat features of caves. 2016, Ficetola et al. The following information was supplied regarding the deposition of related data: Raw data can be found in the Supplemental Information. We used the Akaike’s Information Criterion corrected for small sample size (AICc) to identify the combination of parameters that better explain the variation of microclimatic features inside caves (Stephens et al., 2007). The specific name, porphyriticus, is Latin from Greek, meaning the color of porphyry, a purple stone, and this salamander has also been called the purple salamander. Salamanders were detected throughout the year with 13% of detections in winter, 39% in spring, 30% in summer and 18% in autumn months. Juveniles were associated with the coldest sectors during winter and with warmer sectors during spring (Fig. At the time of surveys, in each sector we recorded four parameters known to influence cave salamanders. Adults were more abundant in sectors with low light and abundant M. menardi (Tables 3B and 4B). Inferring patterns and dynamics of species occurrence, The distribution of cave twilight-zone spiders depends on microclimatic features and trophic supply, Predicting the past distribution of species climatic niches, Ecological niches and geographic distributions. First, we used generalized linear mixed models (GLMM) assuming binomial error to identify the relationships between the presence of salamanders and environmental features (air temperature, humidity, illuminance and spider abundance) of each sector, throughout the 12 months of sampling. Beside some differences in habitat selection between adults and juveniles, a strong interaction between temperature, humidity and time of survey was consistently observed in most analyses (Tables 3, 4 and Fig. Salamanders have already attained the adult color pattern. Larvae can get very large and typically have a grey or brown base color and blocky heads with squared-off noses. Understanding patterns of woodland salamander microhabitat use is important for predicting their response to natural and anthropogenic disturbances such as land use and climate change. All applicable institutional and/or national guidelines for the care and use of animals were followed. Conversely, in this study, salamanders during summer were associated to more humid sectors than in winter. For instance, many species show seasonal activities, and select different environments depending on the activities performed (e.g., nesting, foraging, wintering) (Seebacher & Alford, 1999; Brambilla & Saporetti, 2014). Note: You are now also subscribed to the subject areas of this publication 2E). Salamanders were associated to relatively cold and humid sectors in summer, but not during winter. Immobility times for Shenandoah salamanders averaged 5.9 s (range 1–36 s) and were significantly lower from times for seven other species of eastern Plethodon . For both categorical variables and interactions, + indicates their presence into the model. Salamanders were more tolerant for low-humidity habitats than during winter (Fig. According to the selection change hypothesis, a given species may be associated with different environmental features in different time periods and/or life stages. Furthermore, significant interactions between month and temperature and between month and humidity indicated different microhabitat selection patterns among months (Table 4A). During winter a positive relationship between temperature and depth was observed, while the relationship became negative during the warm months (Fig. The spring salamander (Gyrinophilus porphyriticus) is a species of salamander in the family Plethodontidae It is found in Canada and the United States. Typos, corrections needed, missing information, abuse, etc. Immobility times for Shenandoah Salamanders averaged 5.9 s (range 1–36 s) and were significantly lower from times for seven other species of eastern Plethodon. Internal temperature was strongly related to external temperature and humidity, month, depth and interaction between month and depth: all variables except depth were significant (Tables 1A and 2A). We used linear mixed models (LMM) to analyze the temporal variation of cave microhabitat. Equivalency of species-habitat relationships (measured as Shoener’s D) observed in different months. Nevertheless, juveniles were more tolerant to dry sectors during late winter, when food demand was highest. The Eastern Backed salamander occurs in the northeast corner of TN, while the identical Southern Red-backed Salamander occurs in southeast corner of TN.. days during spring and summer, even during seven-day periods without rain. We quantified seasonal patterns of microhabitat use by larval southern two-lined salamanders (Eurycea cirrigera) and microhabitat availability in two Georgia Piedmont streams from April 2000 to April 2001. The model assuming constant detection probability across sectors showed a lower AIC value (AIC: 53.3) than the model assuming that detection probability is related to distance from the entrance (AIC: 53.9). This species is found in cool springs and mountain springs, but is also likely to be found in any wet depression beneath logs, stones, or leaves in the surrounding forest. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander's terrestrial ecology. 2D). To assess whether the habitat selection pattern is constant through time, we included the interactions between sampling month and environmental features. For instance, salamanders tended to be associated to the coldest and wettest sectors of caves, but this pattern was not evident during late winter/spring (Figs. Therefore, in certain months, young salamanders exploit superficial sectors with more stressful abiotic conditions, but they receive enough food input from the outdoor environment to offset the risk. TypoMissing or incorrect metadataQuality: PDF, figure, table, or data qualityDownload issuesAbusive behaviorResearch misconductOther issue not listed above. Are niche-based species distribution models transferable in space? Furthermore, Meta spiders are associated with areas showing high invertebrate abundance, and have been proposed as an indicator of prey abundance in cave environments (Manenti, Lunghi & Ficetola, in press). The trade-offs between tolerance and resources requirement are major determinant of such variation. We used mixed models and niche similarity tests to assess whether species-habitat relationships remain constant through the year. The similarity of the habitat selection pattern in two distinct seasons was assessed using Schoener’s D, a metric of niche similarity (Warren, Glor & Turelli, 2008; Saupe et al., 2014). The red salamander (Pseudotriton ruber) is a species of salamander in the family Plethodontidae endemic to the eastern United States. Unmarked: an R package for fitting hierarchical models of wildlife occurrence and abundance, An R and S-PLUS companion to applied regression, Thermal regulation and habitat use of the eastern box turtle in southwestern Virginia, I can’t define the niche but I know it when I see it: a formal link between statistical theory and the ecological niche, Predicting species distribution: offering more than simple habitat models, Evaluation of terrestrial and streamside salamander monitoring techniques at Shenandoh National Park, Mechanistic niche modelling: combining physiological and spatial data to predict species ranges, Balancing heat, water and nutrients under environmental change: a thermodynamic niche framework, A review of systematics, taxonomy, genetics, biogeography and natural history of the genus. The peculiar features of both caves and plethodontid salamanders make them an excellent system for species-habitat association studies. Air temperature, humidity and incident light (illuminance, measured using a Velleman DVM1300 light meter, minimum recordable light: 0.1 lux) represented the abiotic conditions of caves, which influence metabolism, water balance and activity (Kearney et al., 2013). Such models help understanding the factors determining species occurrence, and may allow predicting potential areas of occupancy, with important consequences for planning adequate conservation actions (Domíguez-Vega et al., 2012; Bogaerts et al., 2013). The cool habitats that the salamander requires are only at these higher elevations. Such models are based on the assumptions that species presence is associated with favorable environmental features (species-habitat association) (Godsoe, 2010). 1A). From late winter until spring, juveniles were associated with sectors characterized by lower humidity, while during summer this apparent preference shifted in favor of most humid sectors (Fig. ing of niche evolution, but information on microhabitat differences between paren‐ tal species and hybrids is extremely scarce for animal populations. Seasonal variation in microhabitat of salamanders: environmental variation or shift of habitat selection? For example, the average number and wholesale value of Western Tiger Salamander larvae in South Dakota wetlands was estimated at 35,625 and $1,614 per hectare, respectively, in 1989 (Carlson and Berry 1990) and Collins (1981) notes that in 1968 2.5 million salamander larvae were sold as bait on the lower Colorado River area alone. Salamanders were detected throughout the year with 13% of detections in winter, 39% in spring, 30% in summer and 18% in autumn months. (2014), we preferred performing analyses using standard mixed models, while verifying that low detection probability did not bias our results. In practice, selection of the same habitat resulted in regression coefficients that were remarkably different among seasons (Fig. Preliminary surveys performed in 2012 indicated the presence of H. italicus at all sites. The analysis was performed on all individuals together and for each age category (juveniles only and adults only). salamanders, this study also has opportunity to contribute to the understanding of Van Dyke’s salamander, ... Amphibian Microhabitat Study (SAMS) and their Riparian Ecosystem Management Study (REMS). We used visual encounter surveys to assess the presence/absence of H. italicus and M. menardi spiders in each sector. However, cave salamanders quickly modify their occupancy patterns throughout the year in response to environmental variation (Briggler & Prather, 2006; Camp & Jensen, 2007; Vignoli, Caldera & Bologna, 2008), and therefore violate the closed population assumption. We categorized a salamander as moving away from a good microhabitat if it was migrating out of upland forest, whereas a salamander migrating out of the old field (poor canopy cover) or out of the red maple swamp (poorly drained soil) was considered to be moving from a poor microhabitat (Downs, 1989; Windmiller, 1996). First, the temperature gradient showed a clear inversion through the seasons (Fig. Spring Salamanders are semi-aquatic, spending a majority of their time in springs, wet caves, and cool, clear mountain brooks (Tenn. Aquarium, 1998). No doubt, the strong seasonal variation of salamander distribution was mostly dictated by the fluctuations of microhabitats. However, seasonality is a pervasive feature of natural environments, highlighting the importance to always take into account the potential seasonal variation and considering the interactions between the requirement of individuals and the variability of habitats. Actually, the end of winter may be a particularly important period, as in this period many invertebrates end their winter latency (Bale & Hayward, 2010). Hatching occurs four to six weeks later. In principle, only sampling the whole spectrum of potential habitat conditions may allow a full reconstruction of habitat preferences, but this is not feasible in the real world, because the available environmental gradients generally cover a limited range of conditions (Soberon & Nakamura, 2009; Elith, Kearney & Phillips, 2010). In each graph, colored plots represent sectors located at different distance from the entrance (from 3 to 21 m). Analyses of habitat associations generally assume that species are at quasi-equilibrium with the environment, but this assumption may not always hold (e.g., during dispersion or contraction phases) (Saupe et al., 2014). The violin plots for temperature are available in. Such variation may occur over both short (e.g., variation of vegetation cover or temperature among the seasons) and longer timescales (e.g., climate change, habitat degradation) (Saupe et al., 2014). However, patterns of species-habitat association may be not consistent during time. Microhabitat showed strong seasonal variation, with the highest variability in the superficial sectors. See, The area of violin plots represents the distribution of cave sectors according to microclimate feature. Model selection and model averaging in behavioural ecology: the utility of the IT-AIC framework, Macroevolutionary consequences of profound climate change on niche evolution in marine molluscs over the past three million years, Movement and microhabitat use of a terrestrial amphibian (, Optimising biodiversity assessments by volunteers: the application of occupancy modelling to large-scale amphibian surveys, Niches and distributional areas: concepts, methods, and assumptions, Role of temperature and water in the ecology of lungless salamanders, Environmental heterogeneity as a universal driver of species richness across taxa, biomes and spatial scales, A call for statistical pluralism answered, Using ecological niche modelling to evaluate niche stability in deep time. no more than one email per day or week based on your preferences. Our promise We conducted repeated area-constrained surveys to examine variation in salamander microhabitat use of terrestrial salamanders in relation to season, year, and weather conditions. ext (external temperature), Hum. The average sampling effort was of 7.5 min/sector. The generic name, Gyrinophilus, means "tadpole lover" and refers to the long period of time it spends as a gilled larva before maturing. These updates will appear in your home dashboard each time you visit PeerJ. Internal variables are (A) temperature, (B) humidity and (C) illuminance (lux). This suggests a higher tolerance for dry sectors during winter, and supports the selection change hypothesis. Nevertheless, habitat preferences and requirements may change across seasons, as in the case of juveniles that select microhabitats with slightly different conditions in different times (Figs. Most of variation in species-habitat relationships was likely caused by the seasonal variation of temperature and humidity. We showed that such trade-off may be not constant with time or life stage, as both species priorities and habitat features may change across time. We monitored multiple caves in Central Italy through one year, and monthly measured biotic and abiotic features of microhabitat and recorded Italian cave salamanders distribution. Adults were associated with relatively cold sectors during summer, while in winter they were associated with warmer sectors (Fig. As a consequence, the relationships between microclimatic conditions and salamanders were not constant with time: in summer individuals tended to select the coldest, most humid sectors of caves, while the relationship was different during winter months (Fig. For these sectors, two surveys were performed 9–14 days apart, therefore we assumed constant occupancy in this interval and estimated detection probability using single-season closed population occupancy models with the unmarked package in R (Fiske & Chandler, 2011). We also considered the interaction between depth and month of survey. 1A). 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. I looked at levels of sedimentation within and between plots in a headwater stream, and salamander use of substrate types to determine if they were selecting against sediment. Seasonal variation also occurs for the distribution of cave spiders but was not analyzed here as it will be the focus of a separate study. "Following" is like subscribing to any updates related to a publication. We thank two reviewers for constructive comments on a previous version of this manuscript. As detection probability was imperfect, we repeated the analysis by focusing on the comparison between two contrasting seasons (winter/summer), in which migration of salamanders is probably limited. Nevertheless, particularly in the analysis of humidity with juveniles, tests of niche equivalency between late winter and summer months were consistently rejected (Table 5). If all individuals were pooled, salamanders were associated with the darkest sectors. Cave salamanders (genus Hydromantes) may live both in surface and subterranean environments, but must move underground during the arid and hot Mediterranean summer, when the surface conditions become hot and dry (Lanza et al., 2006; Ficetola, Pennati & Manenti, 2012). The deepest sectors showed high stability of humidity through time, while fluctuations due to external variation were evident in sectors nearby the cave entrance. The dorsal coloration can be clear reddish, salmon, or orange-yellow marked with black or brown spots or flecks. The equivalency test was repeated for the two environmental variables (temperature and humidity) for which habitat models suggested differences among months. In principle, it might be also possible that in certain periods juveniles are forced to move toward suboptimal areas because of competition with adults. These sectors represent the area in which microclimate variability is higher; at 21 m illuminance was constantly 0 lux. Spatial niche of the Italian cave salamander, Home range and foraging habitat selection by breeding lesser kestrels (Falco naumanni) in Greece, Environmental niche equivalency vs. conservatism: quantitative approaches to niche evolution. Therefore, following recommendations by Banks-Leite et al. During surveys, for each cave we recorded monthly environmental data both inside and outside caves. 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. Presence of H. italicus was strongly related to month, and was generally associated with sectors characterized by high humidity, low light and abundant M. menardi spiders (Tables 3A and 4A). Existing studies indicate that multiple physical habitat characteristics can affect the abundance and distribution of larval stream salamanders. Approaches assuming open populations also exist but, in this study case, their implementation would require assumptions on population dynamics for which no data were available (Dail & Madsen, 2011). The observation of H. italicus was strongly related to time of survey. Since six pairwise tests were performed for each group and for each variable, significance values were corrected using sequential Bonferroni’s correction (Rice, 1989). These caves were surveyed in late June-early July: during this interval, Hydromantes movements among sectors are expected to be limited (Lanza et al., 2006). Placing a log upside down can destroy the microhabitat found below. On the one hand, Meta spiders are major predators of juvenile salamanders (Lanza et al., 2006). According to the environmental change hypothesis, temporal variation that exists for the many biotic and abiotic features can affect species distribution (Kearney et al., 2013). Dodd (1989) determined the length of time salamanders remained immobile when disturbed in the field by close approach, through disturbance of nearby microhabitat, or when touched. While this influence was strongest in the first meters of the caves, it remained clearly detectable at depths >20 m (Fig. Furthermore, species are easily detectable inside the delimited cave environments (Ficetola, Pennati & Manenti, 2012), allowing a reliable identification of occupied and unoccupied sectors. Spatial and temporal variability in microhabitat use greatly inﬂuence individual detectability, which is always a challenge for terrestrial salamanders. In addition to insects, worms, and other small invertebrates, the fairly large spring salamander may also consume smaller stream dwelling salamanders such as two-lined and dusky salamanders. Study species.—Gyrinophilus porphyriticus is in the See Ficetola, Pennati & Manenti (2013) for additional details on the recording of cave features. Differences in habitat use are jointly determined by environmental variation through time, and by changes in the preferred habitat. Its distribution ranges from southern Quebec to northern Alabama and extremely northeast Mississippi. Internal light incidence was related to depth and external humidity (Tables 1C and 2C). They use cutaneous respiration, and for that reason, must live in moist habitats (Petranka 1998). You can add specific subject areas through your profile settings. Individuals often require different resources depending on their life stage, and thus must shift their habitat selection to exploit different environments to satisfy their needs (Cox & Cresswell, 2014; Dittmar et al., 2014; Webb et al., 2014). Specifically, in winter periods salamanders were associated with warmest sectors, while in summer periods they were associated with coldest and most humid sectors (Figs. Furthermore, the negative consequences of low humidity may be stronger in summer. The SAMS study program is an attempt to characterize microhabitats of ... spring season of 2003. The distribution range of G. p. danielsi is the southern Appalachian Mountains and the adjacent Piedmont from North Carolina to Alabama.