Plethodon Albagula Research Articles

Shifting rivers and stationary ground: biogeographic history of slimy salamanders on an isolated bluff in the Mississippi River floodplain

AbstractGeographic barriers are integral to the processes of dispersal and vicariance, but some barriers, such as rivers, may vary spatiotemporally, potentially affecting biodiversity patterns in significant ways. Fountain Bluff is an isolated upland in the Mississippi River floodplain along the Illinois‐Missouri border, USA. The Mississippi River presently runs on the west side of Fountain Bluff, but the course ran on the east side prior to the Illinois glacial stage (~150 000 years ago). The northern slimy salamander (Plethodon glutinosus) occurs to the east in Illinois, whereas the morphologically similar western slimy salamander (Plethodon albagula) occurs to the west in Missouri. We used mitochondrial and nuclear DNA sequences to determine the species identity of slimy salamanders on Fountain Bluff and test whether they originated via vicariance (P. albagula) or dispersal (P. glutinosus). We found that slimy salamanders on Fountain Bluff are P. glutinosus, which supports the hypothesis that they originated via dispersal from the river bluffs ~6 km to the east. Divergence time estimates corroborated that dispersal likely occurred after the westward diversion of the Mississippi River. The shifting courses of large rivers have had important impacts on biodiversity through the creation and removal of geographic barriers as well as by facilitating passive dispersal across riverine barriers.

Population level differences in thermal sensitivity of energy assimilation in terrestrial salamanders

Thermal adaptation predicts that thermal sensitivity of physiological traits should be optimized to thermal conditions most frequently experienced. Furthermore, thermodynamic constraints predict that species with higher thermal optima should have higher performance maxima and narrower performance breadths. We tested these predictions by examining the thermal sensitivity of energy assimilation between populations within two species of terrestrial-lungless salamanders, Plethodon albagula and P. montanus. Within P. albagula, we examined populations that were latitudinally separated by >450km. Within P. montanus, we examined populations that were elevationally separated by >900m. Thermal sensitivity of energy assimilation varied substantially between populations of P. albagula separated latitudinally, but did not vary between populations of P. montanus separated elevationally. Specifically, in P. albagula, the lower latitude population had a higher thermal optimum, higher maximal performance, and narrower performance breadth compared to the higher latitude population. Furthermore, across all individuals as thermal optima increased, performance maxima also increased, providing support for the theory that “hotter is better”.

Revisiting Burton and Likens (1975): Nutrient Standing Stock and Biomass of a Terrestrial Salamander in the Midwestern United States

Animals found in high densities can have significant influence in nutrient cycles of ecosystems. For example, frogs have been known to influence nutrient cycles in tropical forests. However, research understanding the influence of vertebrates in nutrient cycles of North American forest is limited. It has been found that the biomass of terrestrial salamanders (family Plethodontidae) is higher than that of birds, small mammals, and deer in a New Hampshire forest, and recent studies have found prior estimates of terrestrial salamander densities are likely lower than current estimates using sampling and analysis frameworks to account for imperfect detection. A re-evaluation of the impact plethodontid salamanders could have on forest nutrient cycles is therefore justified. We quantified the degree to which a completely terrestrial, lungless salamander (Plethodon albagula; Western Slimy Salamander) constitutes a standing stock of limiting nutrients in a Missouri, USA forest ecosystem. We utilized values of whol...

Prescribed fire alters surface activity and movement behavior of a terrestrial salamander

AbstractPrescribed fire has become a commonly used forest management tool for reducing the occurrence of severe wildfires, decreasing fuel loads and reestablishing the historic ecological influences of fire. Investigating population‐level wildlife responses to prescribed fire is important for evaluating the effects of fire management on animals, but in order to predict and simulate wildlife responses to potential management actions, mechanistic studies that elucidate individual‐level responses are also necessary. We used radio‐frequency identification to investigate individual‐level responses of western slimy salamanders Plethodon albagula to prescribed fire. We compared the salamander home‐range sizes [minimum convex polygons (MCP)], movement behaviors, and activity levels before and after prescribed fire using a randomized block experiment. We initiated the study at three plots in 2011, and added two new plots in 2012. We captured, tagged and released ≥38 salamanders at each plot from May 2011–May 2012 (total N = 205). We recorded 918 total recaptures of 142 unique salamanders; 31% of tagged salamanders were never recaptured. Across all years and treatments, only 14% of relocations were surface‐active (i.e. visually confirmed) salamanders; the others were underground. Following prescribed fire, the surface‐active proportion of recaptures was nearly seven times greater in control versus burned areas, which indicates that P. albagula respond to post‐prescribed fire conditions by spending more time belowground. We did not find evidence of direct mortality of salamanders from fires; the proportion of known‐alive individuals did not differ between treatments. Maximum daily displacement was 43.3% higher among burn‐area than control‐area salamanders, and MCP varied in a similar pattern; this may indicate salamanders were attempting to find more hospitable microenvironments or other resources, such as prey. Together, these individual‐level observations corroborate our findings from a population‐level study of a congeneric terrestrial salamander and contribute to our understanding of the behavioral mechanisms underlying population dynamics.

Spatial variation in water loss predicts terrestrial salamander distribution and population dynamics.

Many patterns observed in ecology, such as species richness, life history variation, habitat use, and distribution, have physiological underpinnings. For many ectothermic organisms, temperature relationships shape these patterns, but for terrestrial amphibians, water balance may supersede temperature as the most critical physiologically limiting factor. Many amphibian species have little resistance to water loss, which restricts them to moist microhabitats, and may significantly affect foraging, dispersal, and courtship. Using plaster models as surrogates for terrestrial plethodontid salamanders (Plethodon albagula), we measured water loss under ecologically relevant field conditions to estimate the duration of surface activity time across the landscape. Surface activity time was significantly affected by topography, solar exposure, canopy cover, maximum air temperature, and time since rain. Spatially, surface activity times were highest in ravine habitats and lowest on ridges. Surface activity time was a significant predictor of salamander abundance, as well as a predictor of successful recruitment; the probability of a juvenile salamander occupying an area with high surface activity time was two times greater than an area with limited predicted surface activity. Our results suggest that survival, recruitment, or both are demographic processes that are affected by water loss and the ability of salamanders to be surface-active. Results from our study extend our understanding of plethodontid salamander ecology, emphasize the limitations imposed by their unique physiology, and highlight the importance of water loss to spatial population dynamics. These findings are timely for understanding the effects that fluctuating temperature and moisture conditions predicted for future climates will have on plethodontid salamanders.

Six New Host Records forMesocestoidessp. Tetrathyridia (Cestoidea: Cyclophyllidea) from Amphibians and Reptiles of Arkansas, U.S.A

ABSTRACT: Forty-two individual amphibians and 37 reptiles from Arkansas, U.S.A., were examined for tetrathyridia of the cyclophyllidean cestode genus, Mesocestoides. The following herpetofauna were found to be infected with encapsulated or free tetrathyridia of this tapeworm, 1 of 25 (4%) spotted salamanders, Ambystoma maculatum; 1 of 17 (6%) western slimy salamanders, Plethodon albagula; 1 of 21 (5%) 5-lined skinks, Plestiodon fasciatus; 1 of 5 (20%) black racers, Coluber constrictor priapus; 1 of 10 (10%), western rat snakes, Pantherophis obsoletus; and 1 of 1 (100%) eastern garter snake, Thamnophis sirtalis sirtalis. We report 6 new host records for Mesocestoides sp., including the fifth and sixth report of this parasite from caudate amphibians of the world. This is also only the second time this tapeworm has been reported from snakes of the genus Thamnophis.

Ecological resistance surfaces predict fine‐scale genetic differentiation in a terrestrial woodland salamander

Landscape genetics has seen tremendous advances since its introduction, but parameterization and optimization of resistance surfaces still poses significant challenges. Despite increased availability and resolution of spatial data, few studies have integrated empirical data to directly represent ecological processes as genetic resistance surfaces. In our study, we determine the landscape and ecological factors affecting gene flow in the western slimy salamander (Plethodon albagula). We used field data to derive resistance surfaces representing salamander abundance and rate of water loss through combinations of canopy cover, topographic wetness, topographic position, solar exposure and distance from ravine. These ecologically explicit composite surfaces directly represent an ecological process or physiological limitation of our organism. Using generalized linear mixed-effects models, we optimized resistance surfaces using a nonlinear optimization algorithm to minimize model AIC. We found clear support for the resistance surface representing the rate of water loss experienced by adult salamanders in the summer. Resistance was lowest at intermediate levels of water loss and higher when the rate of water loss was predicted to be low or high. This pattern may arise from the compensatory movement behaviour of salamanders through suboptimal habitat, but also reflects the physiological limitations of salamanders and their sensitivity to extreme environmental conditions. Our study demonstrates that composite representations of ecologically explicit processes can provide novel insight and can better explain genetic differentiation than ecologically implicit landscape resistance surfaces. Additionally, our study underscores the fact that spatial estimates of habitat suitability or abundance may not serve as adequate proxies for describing gene flow, as predicted abundance was a poor predictor of genetic differentiation.

Individual (co)variation in thermal reaction norms of standard and maximal metabolic rates in wild‐caught slimy salamanders

Summary Standard metabolic rate (SMR) and maximal metabolic rate (MMR) are fundamental measures in ecology and evolution because they set the scope within which animals can perform activities that directly affect fitness. In ectotherms, both SMR and MMR are repeatable over time when measured at a single ambient temperature (Ta). Many ectotherms encounter variable Ta from day to day and over their lifetime, yet it is currently unknown whether individual differences hold across an ecologically relevant range of Ta (i.e. thermal repeatability; RT). Moreover, it is possible that thermal sensitivity of SMR and MMR are important individual attributes, and correlated with one another, but virtually nothing is known about this at present. We measured SMR and MMR across an ecologically relevant Ta gradient (i.e. from 10 to 25 °C) in wild‐caught salamanders (Plethodon albagula) and found that RT was significant in both traits. SMR and MMR were also positively correlated, resulting in a lower RT in absolute and factorial aerobic scopes (AAS and FAS). We found significant individual differences in thermal sensitivity for both SMR and MMR, but not for AAS and FAS. The intercept (at Ta = 0 °C) and the slope of the thermal reaction norms were negatively correlated; individuals with low MR at low Ta had a higher thermal sensitivity. Finally, individuals with a high thermal sensitivity for SMR also had high thermal sensitivity for MMR. Our results suggest that natural selection occurring over variable Ta may efficiently target the overall level of – and thermal sensitivity in – SMR and MMR. However, this may not be the case for metabolic scopes, as the positive correlation between SMR and MMR, in addition to their combined changes in response to Ta, yielded little individual variation in AAS and FAS. Our results support the idea that organisms with low metabolism at low Ta have a high metabolic thermal sensitivity as a compensatory mechanism to benefit in periods of warmer environmental conditions. Hence, our study reveals the importance of considering within‐individual variation in metabolism, as it may represent additional sources of adaptive (co)variation.

Sampling of Terrestrial Salamanders Reveals Previously Unreported Atypical Color Morphs in the Southern Red-backed Salamander Plethodon serratus

Atypical color morphs have been described in many species of salamander, but few descriptions are quantitative, and none address those found in the Southern Red-backed Salamander, Plethodon serratus. In 2010 and 2011, we conducted 5 weekly rounds of diurnal leaf litter and natural cover object searches per season (Spring and Fall) in the Ozark Mountains of South central Missouri, U.S.A., with a total of 800 individual 3 × 3 m plots searched. We found 1876 Plethodon serratus (Southern Red-backed Salamander), 20 P. albagula (Western Slimy Salamander), and four Eurycea longicauda melanopleura (Dark-sided Salamander). Of the 1876 P. serratus encountered, all but six exhibited the red-backed phase. Atypical color morphs included the lead-backed phase (n = 2, including a gravid female), the silver-backed (grey stripe) phase (n = 1), a ghost-backed (white stripe) phase (n = 1) and the hypomelanistic phase (n = 2). The majority of salamanders were found in leaf litter, followed by woody cover and rocks. Two adults of P. serratus were encountered in burrows of cicada nymphs. We encountered only 3 of the 4 color morphs described for P. cinereus, the sister species of P. serratus, but added two color morphs to the list known for P. serratus. We expect that additional surveys for P. serratus in other parts of their range will help determine whether color morph frequency varies between populations and habitat as it does for P. cinereus.

Fine-Scale Habitat Associations of a Terrestrial Salamander: The Role of Environmental Gradients and Implications for Population Dynamics

Environmental gradients are instrumental in shaping the distribution and local abundance of species because at the most fundamental level, an organism’s performance is constrained by the environment it inhabits. In topographically complex landscapes, slope, aspect, and vegetative cover interact to affect solar exposure, creating temperature-moisture gradients and unique microclimates. The significance of the interaction of abiotic gradients and biotic factors such as competition, movement, or physiology has long been recognized, but the scale at which these factors vary on the landscape has generally precluded their inclusion in spatial abundance models. We used fine-scale spatial data relating to surface-soil moisture, temperature, and canopy cover to describe the spatial distribution of abundance of a terrestrial salamander, Plethodon albagula, across the landscape. Abundance was greatest in dense-canopy ravine habitats with high moisture and low solar exposure, resulting in a patchy distribution of abundance. We hypothesize that these patterns reflect the physiological constraints of Plethodontid salamanders. Furthermore, demographic cohorts were not uniformly distributed among occupied plots on the landscape. The probability of gravid female occurrence was nearly uniform among occupied plots, but juveniles were much more likely to occur on plots with lower surface temperatures. The disconnect between reproductive effort and recruitment suggests that survival differs across the landscape and that local population dynamics vary spatially. Our study demonstrates a connection between abundance, fine-scale environmental gradients, and population dynamics, providing a foundation for future research concerning movement, population connectivity, and physiology.

Spatial and temporal patterns of water loss in heterogeneous landscapes: using plaster models as amphibian analogues

Water balance is critical to survival, growth, and performance of many terrestrial organisms because it can influence foraging time, limit dispersal, and curtail courtship activities. Water loss can vary in time and space across the landscape, and can also be modulated by behavior. Amphibians are particularly sensitive to water loss because their skin provides little to no resistance to evaporative water loss. Our study sought to quantify rates of water loss across a heterogeneous landscape using plaster of Paris models as analogues for the Western Slimy Salamander (Plethodon albagula Grobman, 1944). Models were validated within a controlled laboratory setting prior to field deployment, and were shown to approximate rates and magnitudes of water loss observed in living salamanders. In the field, we tested both adult- and juvenile-sized models, and found that juvenile-sized models lost water at a greater rate under all contexts. The rates of water loss measured at night (1.5%/h–4.5%/h) was nearly half of those measured during the day (2%/h–10%/h). Rates of water loss were greatest on ridges with southwestern aspects during the day (5%/h–10%/h) and lowest in ravines with northeast aspects at night (1.50%/h–3.75%/h). The results of spatial and temporal patterns of water loss corroborate field observations of salamander activity patterns and distribution across the landscape, providing a physiological mechanism driving fine-scale habitat use and distribution. Although we tested plaster models as analogues for salamanders, this approach should be generalizable to other amphibian taxa, providing an efficient means of measuring rates of water loss in the field under biologically meaningful contexts.

Development of microsatellite loci for the western slimy salamander (Plethodon albagula) using 454 sequencing

Terrestrial salamanders of the genus Plethodon are closely tied to abiotic environmental habitat features and are particularly sensitive to land use and habitat change. To better understand the effects of land use and habitat fragmentation on population genetic characteristics, we screened 137 primers developed from 454 sequence libraries, and developed 27 microsatellite primers for the western slimy salamander, Plethodon albagula. Twenty-two of these primers cross-amplified in P. shermani. These new loci will be invaluable tools to study habitat variables affecting gene flow, population genetic structure, and genetic diversity across heterogeneous landscapes.

Effects of experimental forest management on a terrestrial, woodland salamander in Missouri

Successful multi-use planning for forested landscapes requires an understanding of timber management effects on wildlife species. Lungless, woodland salamanders depend on forested habitats and are sensitive to changes in temperature and moisture associated with many forestry practices. Additionally, woodland salamanders are territorial and have relatively low vagility, making it unlikely that they can successfully migrate to more favorable habitat when the surrounding forest is harvested. Therefore, we examined the abundance of the Western Slimy Salamander, Plethodon albagula, in an experimentally manipulated forest in central Missouri. We used artificial cover object searches to compare salamander abundance in three replicate treatments that were clear-cut then burned to reduce maple regeneration, clear-cut and not burned, partially harvested, and un-manipulated control forest. We captured a total of 300 Western Slimy Salamanders between April 2007 and September 2011. We found significantly fewer salamanders in the burn and clear-cut treatments compared with the partial and control treatments. We also found a lower proportion of juveniles and had fewer recaptures in the burn and clear-cut than in the partial and control treatments. Consistent with other studies of woodland salamanders, our results suggest that for at least the first 7years post-harvest, clear-cutting is detrimental to woodland salamander populations. This initial reduction in abundance combined with the further reduced proportion of juveniles may have longer lasting effects even as the forest regenerates. Finally, it appears that timber harvest resulting in limited canopy thinning may be compatible with maintaining populations of Western Slimy Salamanders in Missouri.

Reproduction and Age Composition of a Population of Woodland Salamanders (Plethodon albagula) After a Prescribed Burn in Southwestern Arkansas

We studied a population of Plethodon albagula inhabiting an abandoned mine in Garland County, Arkansas, to test whether variables such as fecundity, diameter of egg, total number of eggs produced, and total number of clutches were influenced by precipitation or prescribed burning. We also compared ratios of juveniles to adults during summer, a period when P. albagula sought refuge in the mine, to determine if prescribed burning influenced certain life stages more than others. Comparing years before and after burning and accounting for the influence of precipitation, we did not detect a significant effect of the prescribed burn on any reproductive variable. However, we did discover a decline in some reproductive variables 1.5 years post-burning. There also was no decline in the ratio of juveniles to adults before or after the burn. Prescribed burning in the inactive season did not affect reproduction or age composition of the population of P. albagula.

Morphological Variation among Populations of the Western Slimy Salamander on the Edwards Plateau of Central Texas

We conducted a morphometric analysis on Western Slimy Salamanders, Plethodon albagula, from each of the five mitochondrially defined groups that occur on the Edwards Plateau of central Texas. Although several groups are similar in body size and/or shape, multivariate analyses do find significant differences among groups, and several groups have clear differences for one or several characters. Thus, for several between-group comparisons, the morphological data are consistent with the mitochondrial data in arguing for cryptic lineages of slimy salamanders on the Edwards Plateau. These results demonstrate that despite the common interpretation of morphological conservatism in plethodontids, detailed morphometric studies can be used in taxonomic and evolutionary investigations of these salamanders. Lastly, male central Texas P. albagula are found to have a larger mean body size than females; this pattern of sexual size dimorphism (SSD) is reverse from that observed in nearly all other plethodontids with SSD.

Reptile and Amphibian Responses to Restoration of Fire‐Maintained Pine Woodlands

Abstract Fire‐maintained woodlands and savannas are important ecosystems for vertebrates in many regions of the world. These ecosystems are being restored by forest managers, but little information exists on herpetofaunal responses to this restoration in areas dominated by shortleaf pine (Pinus echinata). We compared habitat characteristics and herpetofaunal communities in restored pine woodlands to relatively unmanaged, second‐growth forests in the Ouachita Mountains of western Arkansas, USA. We found woodland restoration with periodic burning affected species differently; some species benefited, some species appeared negatively affected, but most species did not respond clearly either way. Overall reptile captures were significantly (p = 0.041) greater in pine‐woodlands than in unrestored forest; one species of snake and three species of lizards were captured more often in woodlands than unrestored forests. Among anurans, we found no significant difference in captures between woodlands and unrestored forests for any species. Among salamanders, we captured western slimy salamanders (Plethodon albagula) almost exclusively in unrestored forest, but captures of other species did not differ between the two treatments. Historically, the Ouachita region likely consisted of a mosaic that included both fire‐maintained habitats (woodlands, savannas, and prairies) and areas of denser forest on mesic sites that were less likely to burn. Consequently, landscapes that retain both open woodlands and denser, less‐intensely burned forest (in the form of unharvested greenbelts or separate stands) would likely promote and maintain a greater diversity of herpetofauna.

Diet of Western Slimy Salamander, Plethodon albagula (Caudata: Plethodontidae), from Two Mountain Ranges in Arkansas

We identified stomach contents of 80 Plethodon albagula (Western Slimy Salamander) from two mountain ranges in Arkansas (Ozark and Ouachita) to examine if regional differences in diet occur. Museum specimens from 1985 to 2005 were used from locations throughout each mountain range. Although a wide variety of prey were found in stomachs, Hymenoptera: Formicidae and Coleoptera: Carabidae were found to be the most important food items in the diet of P. albagula. Ants and beetles constituted 85% abundance of their total diet (79.6% Ozark and 90.1% Ouachita) and 52.2% of their total biomass (42.6% Ozark and 64.1% Ouachita). Seventy-eight and 87% of individuals examined from the Ozark and Ouachita Mountains, respectively, consumed ants (65% total, 83% for animals with food items in their stomachs), whereas 55% in the Ozarks and 58% in the Ouachitas consumed at least one family of beetle. Occurrence and biomass of prey items that did not include ants and beetles showed P. albagula to be a euryphagic predator, with 9.7% of diet being comprised of other prey types (27.3% biomass). Furthermore, importance values indicate ants were the most important prey item for P. albagula in both the Ozark and Ouachita samples, with carabid beetles (Ozark) and all beetles (Ouachita) being second most important. Jaccard Index indicated Ozark and Ouachita specimens shared 80% similarity in diet. Our data suggest P. albagula in Arkansas have high dependence upon ants and beetles, yet appears to be an opportunistic and euryphagic predator.

Phylogeographic Structure and Color Pattern Variation among Populations of Plethodon albagula on the Edwards Plateau of Central Texas

Texas populations of slimy salamanders are isolated from other members of the Plethodon glutinosus complex and are currently placed in the species P. albagula with populations from the Ozark Plateau and Ouachita Mountains of Missouri, Oklahoma, and Arkansas. We sequenced a portion of the mitochondrial protein-coding gene ND4 for 52 P. albagula from 25 localities in Texas and one locality in Missouri. Bayesian MCMC analysis identified five parapatric lineages of Plethodon in Texas. Several morphologically distinctive populations are phylogenetically embedded within the Texas radiation. Additional studies of the interactions among the lineages identified in this study will be necessary to resolve their taxonomic status.

Seasonal Use and Selection of Caves by Plethodontid Salamanders in a Karst Area of Arkansas

From December 1998 through May 2000, seasonal use and selection of caves by salamanders were documented in 93 small caves in Crawford County, Arkansas. Caves were surveyed seasonally between winter 1998–1999 and spring 2000, and the numbers and species of all salamanders present were documented. Cave ambient temperature and relative humidity were recorded. Also, each cave entrance was georeferenced using GPS (Global Positioning System) and landscape-level variables around each entrance were quantified using ArcView GIS (Geographic Information System) data layers. Using salamander and ArcView data, relations between salamander occurrence based upon landscape-level variables (dominant overstory vegetation, geology, slope, aspect, solar radiation and distance to perennial stream) and cave characteristics (ambient temperature, relative humidity, cave length and entrance size) were examined. Six species of salamanders were found during the survey. Eurycea lucifuga (cave salamander), Plethodon albagula (western slimy salamander) and P. angusticlavius (Ozark salamander) were commonly observed. Eurycea lucifuga salamanders were active in caves during spring, summer and autumn. Plethodon albagula were most frequently encountered during the summer and P. angusticlavius were most frequently encountered during spring surveys. Few salamanders of any species were detected during winter surveys. The use of caves by the various species of salamanders was influenced by the landscape-level variables and cave characteristics. However, cave ambient temperature and relative humidity appear to have the most influences of salamander use of caves. Both E. lucifuga and P. albagula were significantly more likely to be found in caves with cooler temperatures in summer and higher relative humidities in autumn. In addition to these factors, the probability of finding E. lucifuga significantly decreased with increasing distance to permanent streams, whereas P. albagula was significantly more likely to be found in caves with south and west facing aspects, especially during summer and autumn surveys. There were no significant patterns for P. angusticlavius use of caves. Seasonal and spatial patterns of cave use by salamanders were primarily influenced by environmental (temperature and relative humidity) factors and the ecological requirements of the salamanders.

FECUNDITY, REPRODUCTIVE ECOLOGY, AND INFLUENCE OF PRECIPITATION ON CLUTCH SIZE IN THE WESTERN SLIMY SALAMANDER (PLETHODON ALBAGULA)

We investigated the reproductive ecology of the western slimy salamander (Plethodon albagula) in an abandoned mine shaft in the Ouachita National Forest of south-central Arkansas. The mine habitat provided an opportunity to observe nesting behavior, quantify reproductive output, and evaluate the influence of precipitation on fecundity for a population of P. albagula that utilize this particular mine shaft to brood and defend egg clutches. We collected reproductive data on 372 clutches between 1982 and 2004. There was no relationship between the number of eggs per egg clutch versus egg size; snout–vent length, body mass, and tail length were not correlated with clutch size. Thirteen females were found to exhibit nest site fidelity, and 10 females exhibited nest securing. Neither nest site fidelity nor nest securing was found to influence reproductive output by females. The amount of precipitation one year prior to oviposition was correlated with the average number of eggs per clutch. It appears, therefore,...