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No abstract available at this time
Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta . Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.
Many species of reptiles and amphibians (herpetofauna) rely on wetlands that are being degraded and lost at a high rate. Characterization of herpetofauna diversity in different wetland types may help guide conservation strategies. However, traditional survey methods often involve sampling within small temporal windows, and the gear deployed may be taxonomically biased, thus, they may fail to accurately characterize species presence/absence and diversity. In contrast, environmental (e)DNA metabarcoding has been shown to effectively survey entire aquatic communities and can provide a useful complement to traditional surveys. The objective of this study was to design and optimize eDNA sampling and laboratory protocols for wetland herpetofauna. Protocols evaluated included different water sampling approaches (point versus transect sampling), seasonality of sampling, and choice of metabarcoding marker (mitochondrial 12S versus 16S rDNA). Samples collected from 10 sites across southern Michigan detected 17 amphibian and five reptile species, including four species of conservation concern ( Ambystoma texanum , Clemmys guttata , Rana palustris , and Sternotherus odoratus ). We observed no difference in the number of species detected between point and transect samples ( p = 0.70), but point sampling required less time ( p = 0.03) and allowed significantly larger volumes of water to be filtered ( p = 1.13e-5). No difference in species richness was observed between the 12S and 16S mitochondrial DNA markers ( p = 0.96). However, a greater number of taxa were identifiable at the species level when using the 16S locus. There was also a significant difference in the number of species detected between early and late summer sampling periods (more species detected in the earlier period; p = 6.31e-6), and some species were only found in the early or late sampling period. Sampling during multiple periods to fully characterize species composition, the use of point sampling, and the 16S mtDNA marker for herpetofauna eDNA metabarcoding studies may increase efficiency and reliability of results.
The biological control agent (tamarisk leaf beetle, Diorhabda spp.) is actively being used to defoliate exotic saltcedar or tamarisk ( Tamarix spp.) in riparian ecosystems in western USA. The Virgin River in Arizona and Nevada is a system where tamarisk leaf beetle populations are spreading. Saltcedar biocontrol, like other control methods, has the potential to affect non-target species. Because amphibians and reptiles respond to vegetation changes in habitat and forage in areas where beetles are active, herpetofauna are model taxa to investigate potential impacts of biocontrol defoliation. Our objectives related herpetofauna abundance to vegetation cover and indices (normalized difference vegetation index, NDVI; enhanced vegetation index, EVI) and timing of biocontrol defoliation. We captured herpetofauna and ground-dwelling arthropods in trap arrays and measured vegetation using remotely sensed images and on-the-ground measurements at 16–21 sites 2 years before (2009–2010) and 2 years following (2011–2012) biocontrol defoliation. Following defoliation, riparian stands (including stands mixed with native and exotic trees and stands of monotypic exotic saltcedar) had significantly lower NDVI and EVI values and fewer captures of marked lizards. Total captures of herpetofauna (toads, lizards, and snakes) were related to higher vegetation cover and sites with a lower proportion of saltcedar. Our results suggest that effects of biocontrol defoliation are likely to be site-specific and depend upon the proportion of native riparian trees established prior to biocontrol introduction and defoliation. The mechanisms by which habitat structure, microclimate, and ultimately vertebrate species are affected by exotic plant biocontrol riparian areas should be a focus of natural-resource managers.
Occupancy patterns of herpetofauna in most tidal freshwater swamps are unknown. Tidal freshwater swamps currently face multiple threats, including salinization, which can influence their associated plant and animal communities. The impacts of salinization to herpetofauna communities in tidal freshwater swamps have not been assessed. To improve predictions regarding these herpetofauna, we conducted surveys in tidal freshwater swamps of the Savannah National Wildlife Refuge located in South Carolina, USA, from March to June, 2016 and 2017, using a variety of methods. Goals included inventorying species, determining communities, examining microhabitat associations, and modeling occupancy to predict the impacts of salinity changes. We detected 8 species of amphibians and 12 species of reptiles in our surveys. Community analyses failed to detect patterns related to measured environmental variables. Species richness and diversity declined along the salinity gradient, but the observed patterns did not match our predictions and may instead be related to site-level heterogeneity. Microhabitat associations were detected for two amphibian species via occupancy analyses. Occupancy and regression analyses indicated soil salinity may be a factor affecting nine species’ occurrences. Amphibian detections may be affected by water depth, pH values, and weather conditions. These results expand our understanding of herpetofauna within an understudied, and threatened, wetland type.
Habitat loss and fragmentation can negatively impact native wildlife and facilitate establishment of introduced species. On islands, introduced species are a primary cause of extinction and can alter community membership through predation or competition for resources. Consequently, elucidating the distribution of introduced and native species can improve understanding of the potential synergistic effects of land use and introduced species on native island species. The island of Saipan in the Commonwealth of the Northern Mariana Islands has a long history of herpetofaunal introductions. However, the distribution of native and introduced herpetofauna on Saipan is poorly understood, and the effects of land use and introduced species on the native herpetofauna are largely unknown. In 2018, we randomly selected sites on Saipan from established island-wide transects and used multiple detection methods, repeated surveys, and single-season occupancy models to account for imperfect detection and construct species distribution models. We investigated the role of biotic and abiotic factors in explaining occupancy and detection of Saipan’s native and introduced herpetofauna. We recorded 2568 observations representing 1 amphibian and 11 reptile species. Introduced species were encountered 3.8 times more frequently and were 33% more broadly distributed than native species. Occupancy for the native forest dwelling species Emoia caeruleocauda and Perochirus ateles was positively associated with elevation and enhanced vegetation index, suggesting that human habitat modification at lower elevations may be reducing their suitable habitat.We found evidence of a range contraction for the imperiled P. ateles and suggest potential avenues for implementing targeted conservation of native herpetofauna.
The Klamath-Siskiyou region of southwest Oregon and northwest California (USA) has some of the most complex landscape mosaics and plant communities in western North America, reflecting its marked diversity of precipitation and topography. With 38 native species of amphibians and reptiles, the Klamath-Siskiyou region has the most species-rich herpetofauna of any similarly sized mountain range in the Pacific Northwest. Although it is a biodiversity 'hot spot,' there are only two endemic species, both salamanders, in the Klamath-Siskiyou region. High diversity is due to the overlap of two major biogeographic groups: the Arcto- (= northern) and Madro- (= southern) Tertiary herpetofaunas. Many of the amphibians in the Klamath-Siskiyou region are restricted to specialized habitats. Much of our knowledge about the biology of the regional fauna is based on studies elsewhere. Distributional surveys and ecological research are needed to address how the herpetofauna responds to timber harvest and other human activities that may reduce populations and increase fragmentation of suitable habitats. Conservation of the region's diverse herpetofauna should emphasize strategies directed at habitat specialists and species at the latitudinal limits of their ranges.
Herpetofauna populations are decreasing worldwide, and the range of wild pigs (Sus scrofa) is expanding. Depredation of threatened reptile and amphibian populations by wild pigs could be substantial. By understanding depredation characteristics and rates, more resources can be directed toward controlling populations of wild pigs coincident with threatened or endangered herpetofauna populations. From April 2005 to March 2006 we used firearms to collect wild pigs (n = 68) and examined stomach content for reptiles and amphibians. We found 64 individual reptiles and amphibians, composed of 5 different species, that were consumed by wild pigs during an estimated 254 hours of foraging. Primarily arboreal species (e.g., Anolis carolinensis) became more vulnerable to depredation when temperatures were low and they sought thermal shelter. Other species (e.g., Scaphiopus holbrookii) that exhibit mass terrestrial migrations during the breeding season also faced increased vulnerability to depredation by wild pigs. Results suggest that wild pigs are opportunistic consumers that can exploit and potentially have a negative impact on species with particular life-history characteristics. ?? 2009 American Society of Mammalogists.
From 1985 through 1990, the herpetofauna of a temporary pond in an uplands longleaf pine sandhills community in north-central Florida was monitored. A drift fence completely encircled the pond. Animals were captured in pitfall traps and marked as they entered and exited the pond basin. I captured 16 155 individuals of 42 species (16 amphibians, 26 reptiles). The species richness, diversity (using Margalef's Diversity Index) and dominance (using the Berger-Parker Index) varied among years. Between 62.5% and 87.5% of the amphibian species and 65% to 81% of the reptile species were captured in any one year. Daily amphibian capture was positively correlated with rainfall, whereas reptile capture was either not correlated or weakly negatively correlated with rainfall. Hydroperiod duration was not correlated with the numbers of either amphibians or reptiles captured. Neither the amphibian nor the reptile community showed any trends in diversity or dominance indices during the course of the study, although both communities were dominated by a few species. However, the species responsible for community dominance changed somewhat as the study progressed. Assessing the results of this study is hampered by the lack of comparable studies elsewhere, expected natural fluctuations of amphibian populations, and a prolonged drought, especially during the latter stages of the study. The herpetological community at Breezeway Pond does not appear to follow theoretical predictions of community response to stress. Temporary ponds are important centres of herpetofaunal biodiversity in uplands sandhills communities. Long-term studies are needed to monitor the composition, structure, and functional interactions of their resident species.
The herpetofauna (amphibians and reptiles) of northwestern forests (U.S.A.) is diverse, and many species are locally abundant. Most forest amphibians west of the Cascade Mountain crest are associated with cool, cascading streams or coarse woody material on the forest floor, which are characteristics of mature forests. Extensive loss and fragmentation of habitat resulted from logging across approximately 50% of old-growth forests in northern California and approximately 80% of stands in Oregon and Washington. There is a complex landscape mosaic and overlap of northern and southern biotic elements in the Klamath-Siskiyou Region along the Oregon and California border, creating a biodiversity hotspot. The region experiences many low-severity fires annually, punctuated by periodic major fires, including the Biscuit fire, the largest in North America in 2002. In the fire's northern portion, severe fire occurred on >50% of stands of young, managed trees but on only about 25–33% of old-growth stands. This suggests that the legacy of timber harvest may produce fire-prone stands. Calls for prescribed fire and thinning to reduce fuel loads will remove large amounts of coarse woody material from forests, which reduces cover for amphibians and alters nutrient inputs to streams. Our preliminary evidence suggests no negative effects of wildfire on terrestrial amphibians, but stream amphibians decrease following wildfire. Most reptiles are adapted to open terrain, so fire usually improves their habitat. Today, the challenge is to maintain biodiversity in western forests in the face of intense political pressures designed to 'prevent' catastrophic fires. We need a dedicated research effort to understanding how fire affects biota and to proactively investigate outcomes of fuel-reduction management on wildlife in western forests.
Mountaintop removal mining is a large-scale surface mining technique that removes entire floral and faunal communities, along with soil horizons located above coal seams. In West Virginia, the majority of this mining occurs on forested mountaintops. However, after mining ceases the land is typically reclaimed to grasslands and shrublands, resulting in novel ecosystems. In this study, we examined responses of herpetofauna to these novel ecosystems 10–28 y postreclamation. We quantified differences in species-specific habitat associations, (sub)order-level abundances, and habitat characteristics in four habitat types: reclaimed grassland, reclaimed shrubland, forest fragments in mined areas, and nonmined intact forest. Habitat type accounted for 33.2% of the variation in species-specific captures. With few exceptions, forest specialists were associated with intact forest and fragmented forest sites, while habitat generalists were either associated with grassland and shrubland sites or were distributed among all habitat types. At the (sub)order level, salamander (Order Urodela) captures were highest at fragmented and intact forest sites, frog and toad (Order Anura) captures were lowest at intact forest sites, and snake (Suborder Serpentes) captures were highest at shrubland sites. Habitat type was a strong predictor for estimated total abundance of urodeles, but not for anurans or snakes. Tree stem densities in grasslands differed from the other three habitat types, and large trees (>38 cm diameter at breast height) were only present at forest sites. Overstory vegetation cover was greater in forested than in reclaimed habitat types. Ground cover in reclaimed grasslands was distinct from forest treatments with generally less woody debris and litter cover and more vegetative cover. It is important to consider the distributions of habitat specialists of conservation concern when delineating potential mountaintop mine sites, as these sites will likely contain unsuitable habitat for forest specialists for decades or centuries when reclaimed to grassland or shrubland.
Previous collections in the Departamento del Beni in tropical Bolivia only hinted at high levels of herpetological biodiversity (Fugler 1986, 1988; de la Riva 1990a; Fugler and de la Riva 1990). Fieldwork (totaling 48 days) in July-August 1988 and September 1987 (dry seasons) and November-December 1990 (wet season) has resulted in collection and identification of 401 amphibian and reptilian specimens from the general area of the Beni Biological Station's (EBB) headquarters at El Porvenir. These collections represent 33 amphibian and 17 reptilian species in 29 genera (14 amphibian, 15 reptilian). The inventory of herpetofauna scientifically documented to occur in the Departamento del Beni is considered to have been increased by 6 amphibian and 10 reptilian species. Specimens that could not be definitively identified (reflecting taxonomic uncertainty and/or probably species new to science) include 3 amphibian species (anurans) and 2 reptilian species (snakes). The EBB harbors the richest savanna for anuran species known in South America.
Noninvasive fecal sampling combined with genetic analysis is a powerful technique allowing the study of elusive or otherwise difficult to monitor species without the need for direct contact. While this method is widely used in birds and mammals, it has never been successfully applied on a large scale in reptiles. The blunt-nosed leopard lizard (Gambelia sila) is an endangered species endemic to the San Joaquin Desert of California. Presently, acquiring data on G. sila for research and management involves more traditional methods such as live capture to obtain tissue samples for DNA analysis, or observation via visual surveys, which are also used for regulatory monitoring in accordance with wildlife agency protocols. Here we describe an innovative approach for gathering additional information, that combines use of conservation detection dogs trained to locate G. sila scat samples with genetic analysis for identifying and distinguishing among sympatric lizard species. We developed two PCR assays that produce fluorescently labelled amplicons of species-specific fragment length for six lizard species in the study area. Using these assays we genetically identifed to species 78% (255 of 327) of samples collected by dog-handler teams across four years. The majority of the genetically identifed samples (82.4%; 210 of 255) were confirmed as originating from G. sila. Beyond the immediate application of these techniques for the study and monitoring of G. sila, our ability to recover usable DNA and to differentiate among a diverse group of lizards highlights the broad potential of our methodology for noninvasive sampling in reptiles.
Anarbys switaki, a species previously known only from Baja California Sur, Mexico, occurs in eastern San Diego and southwestern Imperial Counties in California. In California, specimens tend to have continuous transverse bars on the body, are lighter in color, and more slender in body form than in southern Baja California. California populations appear to be confined to extremely rocky habitats in desert foothill situations between 200 and 600 m. The species appears to be secretive, and occurs in low densities within rock crevices and subterranean cavities. The morphological gap between Anarbylus and Coleonyx species may not warrant generic recognition. Anarbylus is part of a diverse lizard fauna in southern California and occurs in sympatry with 15 lizard species in a small area of southern California.
Quantitative and qualitative samples of amphibian and lizard faunas were taken from forest litter in Costa Rica and compared with similar samples collected in Borneo, the Philippines, and Panama. Animal abundance is about ten times greater in Costa Rican lowland wet forest than in Borneo. Radically different routes and rates of energy flow are postulated to account for the difference. In a series of upland (1010-1425 m) samples in the Philippines, the number of litter lizards and frogs increases with elevation. A single upland (1200 m) Costa Rican sample contains about three times as many animals per 100 m2 as two lowland sites. This increase with altitude correlates well with hypotheses that overall tropical forest productivity is greatest at intermediate elevations. Herpetofaunal densities are greater in wet areas compared to dry sites and flat terrain compared to slopes. These observations are linked to the greater variation and lesser total litter fall in dry sites and/or slopes. The number of species of amphibians and lizards regularly inhabiting the litter is similar in all wet lowland forests studied. Increasing elevation and decreasing rainfall correlate with faunas having fewer species. The former is seen as the result of the differential ability of lowland species to invade uplands, and the latter as a decrease in the kind and duration of frog-spawning sites. Reduced equitability with increasing elevation is principally due to the much greater proportional increase of the commonest species. In the evolution of American and Bornean-Philippine wet lowland faunas, frogs with direct development (Eleutherodactylus) have radiated in the former in the same fashion that skinks have in the latter.
No abstract available at this time
Introduction The U.S. Air Force (USAF) issued funds to the U.S. Geological Survey (USGS) to update the biosecurity plan, create a current (2019) flora and fauna species identification index, and do container evaluations for the presence of potential invasives. The current (2019) biosecurity protocols used for prevention were evaluated, and new biodiversity surveys were completed for terrestrial vegetation and arthropods and included the first formal reptile surveys. Results from field efforts add to existing knowledge and may identify new species arrivals to Wake. One goal of this project was to update and compile established species information for the atoll and create species identification guides for the three taxonomic groups surveyed. We made these flora and fauna species identification guides by compiling results of the recent (2019) and historical surveys. The guides can be used as resident desktop references, as a baseline for assessing future natural resource surveys, and to assist with guiding management actions. We refer herein to biosecurity and integrated pest management plan materials, which we created simultaneously to inform current (2019) biosecurity and to identify some of the top invasive species at Wake. This study was done in cooperation with the USAF, and surveys were performed for the 611th Civil Engineer Squadron Natural Resources Program, ACES PROJECT #YGFZ170002 under agreement number F2MUAA7116GW02 between the USAF and the USGS Western Ecological Research Center.
Abstract not supplied at this time