Papers & Reports Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians
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Authors: Cayuela H, Valenzuela-Sanchez A, Teulier L, Martinez-Solano I, Lena JP, Merila J, Muths E, Shine R, Quay L, Denoel M, Clobert J, Schmidt BR | Date: 2020-02 | Outlet: The Quarterly Review of Biology | Format: .PDF
Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations and affects evolutionary processes by shaping patterns of gene flow. For these reasons, dispersal has received considerable attention from ecologists, evolutionary biologists, and conservationists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades researchers have taken an ever-increasing interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography, genetic, and the conservation of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal.
Papers & Reports ACRIS BLANCHARDI (Blanchard's Cricket Frog). Predation.
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Authors: Maldonado BR, Glorioso BM, Kidder RP | Date: 2020-06 | Outlet: Herpetological Review 51(2):296 | Format: .PDF
A natural history note describing predation of a Blanchard's Cricket Frog by a wolf spider at an elevated height.
Papers & Reports Changes in capture rates and body size among vertebrate species occupying an insular urban habitat reserve
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Authors: Stanley TR, Clark RW, Fisher RN, Rochester CJ, Root SA, Lombardo KJ, Ostermann-Kelm SD | Date: 2020-06-29 | Outlet: Conservation Science and Practice 2020;e245. | Format: .PDF
Long-term ecological monitoring provides valuable and objective scientific information to inform management and decision making. In this paper we analyze 22 years of herpetofauna monitoring data from the Point Loma Ecological Conservation Area (PLECA), an insular urban reserve near San Diego, California. Our analysis showed that counts of individuals for one of the four most common terrestrial vertebrates declined, whereas counts for other common species increased or remained stable. Two species exhibited declines in adult body length, whereas biomass pooled over the five most common species increased over time and was associated with higher wet season precipitation. Although the habitat and vegetation at PLECA have remained protected and intact, we suspect that changes in arthropod communities may be driving changes in the abundance, growth, and development of insectivorous lizards. This study underscores the value of long-term monitoring for establishing quantitative baselines to assess biological changes that would otherwise go undetected.
Papers & Reports Pseudacris ornata
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Author: Glorioso BM | Date: 2010 | Outlet: Catalogue of American Amphibians and Reptiles | Format: .PDF
An in-depth species account of the ornate chorus frog (Pseudacris ornata).
Papers & Reports Growth, survival, longevity, and population size of the Big Mouth Cave Salamander (Gyrinophilus palleucus necturoides) from the type locality in Grundy County, Tennessee, USA
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Authors: Niemiller ML, Glorioso BM, Fenolio DB, Reynolds RG, Taylor SJ, Miller BT | Date: 2016 | Outlet: Copeia 104(1):35-41 | Format: .PDF
Salamander species that live entirely in subterranean habitats have evolved adaptations that allow them to cope with perpetual darkness and limited energy resources. We conducted a 26-month mark–recapture study to better understand the individual growth and demography of a population of the Big Mouth Cave Salamander (Gyrinophilus palleucus necturoides). We employed a growth model to estimate growth rates, age at sexual maturity, and longevity, and an open population model to estimate population size, density, detectability, and survival rates. Furthermore, we examined cover use and evidence of potential predation. Individuals probably reach sexual maturity in 3–5 years and live at least nine years. Survival rates were generally high (>75%) but declined during the study. More than 30% of captured salamanders had regenerating tails or tail damage, which presumably represent predation attempts by conspecifics or crayfishes. Most salamanders (>90%) were found under cover (e.g., rocks, trash, decaying plant material). Based on 11 surveys during the study, population size estimates ranged from 21 to 104 individuals in the ca. 710 m² study area. Previous surveys indicated that this population experienced a significant decline from the early 1970s through the 1990s, perhaps related to silvicultural and agricultural practices. However, our data suggest that this population has either recovered or stabilized during the past 20 years. Differences in relative abundance between early surveys and our survey could be associated with differences in survey methods or sampling conditions rather than an increase in population size. Regardless, our study demonstrates that this population is larger than previously thought and is in no immediate risk of extirpation, though it does appear to exhibit higher rates of predation than expected for a species believed to be an apex predator of subterranean food webs.
Papers & Reports Feeding times of Amphiuma tridactylum at Reelfoot Lake, Tennessee
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Authors: Glorioso BM, Niemiller ML, Cobb VA | Date: 2010 | Outlet: Journal of the Tennessee Academy of Science 85(3-4):87-90 | Format: .PDF
Feeding activity times were determined for Amphiuma tridactylum in a roadside slough adjacent to Reelfoot Lake in northwestern Tennessee. Twenty-nine A. tridactylum were captured using baited deep-water crawfish nets, with more than half of the captures being large adults. Despite the majority (82.4%) of trapping effort being concentrated in daytime hours, 82.7% of A. tridactylum captures were at night. Capture rates during nighttime hours were more than 25 times greater than during daytime capture rates. Though nocturnal, the mid-day captures indicated that A. tridactylum may exit their burrows during the day. This study also provides an alternative trapping method for Amphiuma, in which feeding times can be accurately determined.
Papers & Reports AMBYSTOMA MACULATUM (Spotted Salamander). REPRODUCTION.
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Authors: Glorioso BM, Waddle JH, Hefner J | Date: 2012 | Outlet: Herpetological Review 43(4):627-628 | Format: .PDF
This is a note on reproduction in Spotted Salamanders (Ambystoma maculatum) describing clutch sizes and several instances of inadvertant passive integrated transponder tag loss by tagged females via oviposition.
Papers & Reports Nocturnal arboreality in snakes in the swamplands of the Atchafalaya Basin of south-central Louisiana and Big Thicket National Preserve of southeast Texas
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Authors: Glorioso BM, Waddle JH | Date: 2017-03-29 | Outlet: The Journal of North American Herpetology 2017(1):11-18 | Format: .PDF
The southeastern United States is home to a diverse assemblage of snakes, but only one species, the Rough Greensnake (Opheodrys aestivus), is considered specialized for a predominantly arboreal lifestyle. Other species, such as Ratsnakes (genus Pantherophis) and Ribbonsnakes/Gartersnakes (genus Thamnophis), are widely known to climb into vegetation and trees. Some explanations given for snake climbing behavior are foraging, thermoregulation, predator avoidance, and response to flood. Reports of arboreality in snake species typically not associated with life in the trees (such as terrestrial, aquatic, and even fossorial species) usually come from single observations, with no knowledge of prevalence of the behavior. Here, we report on arboreality of snake species detected during 8 years of night surveys in the Atchafalaya Basin of south-central Louisiana and 5+ years of night surveys in Big Thicket National Preserve in southeast Texas. We recorded a total of 1,088 detections of 19 snake species between the two study areas, with 348 detections above ground level (32%). The Rough Greensnake and Western Ribbonsnake (Thamnophis proximus) accounted for nearly 75% of total arboreal detections among the two study areas. However, with one exception, all snake species detected more than once between both study areas had at least one arboreal detection. These observations demonstrate that snakes with widely varying natural histories may be found in the trees at night, and for some species, this behavior may be more common than previously believed.
Papers & Reports Effects of Snowpack, Temperature, and Disease on Demography in a Wild Population of Amphibians
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Authors: Muths E, Hossack BR, Grant EHC, Pilliod DS, Mosher BA | Date: 2020-06 | Outlet: Herpetologica | Format: .PDF
Understanding the demographic consequences of interactions among pathogens, hosts, and weather conditions is critical in determining how amphibian populations respond to disease and in identifying site-specific conservation actions that can be developed to bolster persistence of amphibian populations. We investigated population dynamics in Boreal Toads relative to abiotic (fall temperatures and snowpack) and biotic (the abundance of another anuran host and disease) characteristics of the local environment in Wyoming, USA. We used capture-recapture data and a multi-state model where state is treated as a hidden Markov process to incorporate disease state uncertainty and assess our a priori hypotheses. Our results indicate that snowpack during the coldest week of the winter is more influential to toad survival, disease transition probabilities, and the population-level prevalence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) in the spring, than temperatures in the fall or the presence of another host. As hypothesized, apparent survival at low (i.e., <25 cm) snowpack (0.22 [CI: 0.15–0.31]) was lower than apparent survival at high snowpack (90.65 [CI: 0.50–0.78]). Our findings highlight the potential for local environmental factors, like snowpack, to influence disease and host persistence, and demonstrate the ecological complexity of disease effects on population demography in natural environments. This work further emphasizes the need for improved understanding of how climate change may influence the relationships among pathogens, hosts, and their environment for wild animal populations challenged by disease.