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Loss of wetlands worldwide has necessitated the creation of wetlands to counteract declines of fauna associated with these habitats. Ephemeral wetlands have been disproportionally lost and hydrology of ephemeral wetlands is challenging to restore. Created wetlands with water control structures may be a viable option. In Western Kentucky, we surveyed three ephemeral wetland types [managed open canopy (MOC), unmanaged open canopy (UMOC), and unmanaged closed canopy (UMCC); managed = created wetlands with water control structures] to estimate amphibian richness and occupancy among wetlands, and estimated abundance of three locally common species: Southern Leopard Frog (Lithobates sphenocephalus), Spotted Salamander (Ambystoma maculatum), and Crawfish Frog (L. areolatus). In addition, we quantified physical characteristics and water quality among wetland types. Managed Open Canopy wetlands had a greater percent of submergent vegetation than both UMCC and UMOC wetlands, shallower depth at 1.0 m from the wetted wetland edge than UMOC wetlands, and were larger than UMCC wetlands. Mean predicted amphibian species richness and occupancy was highest at larger wetlands (0.15–0.78 ha). Occupancy of three common species was not influenced by management. Estimated abundance of L. areolatus, a species of conservation concern, was higher at MOC wetlands, and conversely, A. maculatum abundance was highest at UMCC wetlands. Larger wetlands had higher estimated abundances of L. areolatus and L. sphenocephalus. Our results suggest that created, open canopy wetlands managed for hydroperiod have similar species richness to unmanaged ephemeral wetlands. Furthermore, these managed wetlands provide habitat for a species of concern in Kentucky (i.e., L. areolatus).

Streamside management zones (SMZs), buffers of forest retained along streams when adjacent areas are harvested, are a primary tool for maintaining ecological functions in managed forests. However, few studies have examined the influence of SMZs on salamanders, and none have examined variation in salamander occupancy, species richness, and abundance across a gradient of SMZ widths at a large spatial scale. Further, because previous studies had limited ability to detect responses of uncommon species, little is known about interspecific variation in salamander responses or whether SMZs serve as refuges for terrestrial species during harvesting. To evaluate the role of SMZs in maintaining salamander species, we conducted four replicate surveys at 102 headwater stream sites, spanning a gradient of SMZ widths and adjacent forest stand ages, within the Ouachita Mountains, Arkansas, USA. We used a hierarchical Bayesian community occupancy model to estimate salamander species richness and species-specific occupancy responses to SMZ and overstory characteristics, while accounting for variation in occupancy and detection attributable to site and sampling covariates. Additionally, we used Bayesian binomial mixture models to examine the influence of SMZ width and surrounding stand age on abundance of two stream-associated salamanders [Ouachita dusky salamander (Desmognathus brimleyorum) and many-ribbed salamander (Eurycea multiplicata)] and three terrestrial salamanders [red-backed salamander (Plethodon serratus), slimy salamander (P. glutinosus complex), and Caddo Mountain salamander (P. caddoensis)]. Occupancy, species richness, and abundance increased with increasing SMZ width, but the strength of responses varied among species. Occupancy of uncommon species was highest at sites with wide SMZs, likely because of the need for specific habitat elements (e.g., wetlands, rocky talus). Richness was lowest in SMZs dominated by pine overstory, and lowest in mid-aged stands, consistent with a lagged decrease in richness within SMZs following harvest. Finally, we documented patterns of abundance consistent with the evacuation hypothesis, indicating that salamanders may leave recently harvested areas seeking more suitable habitat and microclimate within SMZs. Collectively, results indicate that SMZs in intensively managed forests can support robust salamander communities, provided managers continue to retain wide SMZs at some key sites across the landscape (i.e., ≥55 m on each side of the stream), a value larger than current Forestry BMP guidelines.

Timber harvesting can influence headwater streams by altering stream productivity, with cascading effects on the food web and predators within, including stream salamanders. Although studies have examined shifts in salamander occupancy or abundance following timber harvest, few examine sublethal effects such as changes in growth and demography. To examine the effect of upland harvesting on growth of the stream‐associated Ouachita dusky salamander (Desmognathus brimleyorum), we used capture–mark–recapture over three years at three headwater streams embedded in intensely managed pine forests in west‐central Arkansas. The pine stands surrounding two of the streams were harvested, with retention of a 14‐ and 21‐m‐wide forested stream buffer on each side of the stream, whereas the third stream was an unharvested control. At the two treatment sites, measurements of newly metamorphosed salamanders were on average 4.0 and 5.7 mm larger post‐harvest compared with pre‐harvest. We next assessed the influence of timber harvest on growth of post‐metamorphic salamanders with a hierarchical von Bertalanffy growth model that included an effect of harvest on growth rate. Using measurements from 839 individual D. brimleyorum recaptured between 1 and 6 times (total captures, n = 1229), we found growth rates to be 40% higher post‐harvest. Our study is among the first to examine responses of individual stream salamanders to timber harvesting, and we discuss mechanisms that may be responsible for observed shifts in growth. Our results suggest timber harvest that includes retention of a riparian buffer (i.e., streamside management zone) may have short‐term positive effects on juvenile stream salamander growth, potentially offsetting negative sublethal effects associated with harvest., Population mean growth curves for Desmognathus brimleyorum under control (unharvested and pre‐harvest; dashed yellow lines) and treatment (post‐harvest; solid indigo lines) conditions. Bold lines represent posterior modes, light lines represent 95% highest posterior density intervals, and the intensity of shading represents the posterior probability density.

With escalating anthropogenic alteration of landscapes worldwide, managed forests are increasingly important as providers of ecosystem services and wildlife habitat. Therefore, it is crucial to maintain a balance between producing forest products and biodiversity conservation. Several studies have reported negative effects of forest management on terrestrial plethodontid salamanders, but fewer have focused on stream‐dwelling species or evaluated mechanisms for shifts in their abundance (e.g., mortality vs. movement). We used a before–after–control–impact design to examine the effects of clear‐cut harvesting on a semi‐aquatic stream‐breeding salamander endemic to the Ouachita Mountains, Desmognathus brimleyorum. We conducted a three‐year capture–mark–recapture (CMR) study at three streams within a managed pine (Pinus spp.) landscape in west‐central Arkansas, USA. Loblolly pine (Pinus taeda) stands surrounding two of the streams were clear‐cut (leaving a 14–21 m wide forested buffer on each side of the stream) midway through the study; the third stream served as a control site and remained unharvested. We estimated apparent survival using open CMR models and compared salamander movement over time and between harvested and control streams. Overall, our models revealed seasonal and temporal variation in salamander survival and abundance, but little evidence for strong immediate effects of timber harvesting on post‐metamorphic salamanders within two years postharvest. However, there was increased salamander movement at sites where forest harvest occurred. Our results suggest that streamside buffers of at least 14–28 m on either side of a stream are effective for minimizing immediate effects of forestry activities on juvenile and adult stream‐dwelling salamanders, when timber harvest occurs in the winter months. These results will inform management decisions aimed at conserving biodiversity and ecosystem integrity in managed forest landscapes while also filling a critical gap in the knowledge of stream salamander demographic parameters.

Background Satellite tags have revolutionized our understanding of marine animal movements. However, tags may stop transmitting for many reasons and little research has rigorously examined tag failure. Using a long-term, large-scale, multi-species dataset, we evaluated factors influencing tracking duration of satellite tags to inform study design for future tracking studies. Methods We leveraged data on battery status transmitted with location data, recapture events, and number of transmission days to probabilistically quantify multiple potential causes of failure (i.e., battery failure, premature detachment, and tag damage/fouling). We used a combination of logistic regressions and an ordinary linear model including several predictor variables (i.e., tag type, battery life, species, sex, size, and foraging region). Results We examined subsets of data from 360 satellite tags encompassing 86,889 tracking days deployed on four species of marine turtles throughout the Gulf of Mexico, Caribbean, and Bahamas from 2008 to 2019. Only 4.1% of batteries died before failure due to other causes. We observed species-specific variation in how long tags remain attached: hawksbills retained 50% of their tags for 1649 days (95% CI 995–1800), loggerheads for 584 days (95% CI 400–690), and green turtles for 294 days (95% CI 198–450). Estimated tracking duration varied by foraging region (Caribbean: 385 days; Bahamas: 356; southern Gulf of Mexico [SGOM]: 276, northern Gulf of Mexico [NGOM]: 177). Additionally, we documented species-specific variation in estimated tracking duration among foraging regions. Based on sensor data, within the Gulf of Mexico, across species, we estimated that 50% of tags began to foul after 83 95% CI (70–120) days. Conclusions The main factor that limited tracking duration was tag damage (i.e., fouling and/or antenna breakage). Turtles that spent most of their time in the Gulf of Mexico had shorter tracking durations than those in the Bahamas and Caribbean, with shortest durations observed in the NGOM. Additionally, tracking duration varied by species, likely as a result of behaviors that damage tags. This information will help researchers, tag companies, permitting agencies, and funders better predict expected tracking durations, improving study designs for imperiled marine turtles. Our results highlight the heterogeneity in telemetry device longevity, and we provide a framework for researchers to evaluate telemetry devices with respect to their study objectives.

For many amphibian species of conservation concern, our understanding of drivers of distribution and abundance are based on data collected at only a few localities. Thus, landscape-scale efforts are needed to better inform management and species conservation. The Streamside Salamander (Ambystoma barbouri) is a global conservation priority because of its restricted geographic distribution and presumed sensitivity to forest loss, yet landscape-scale studies have not occurred. We surveyed a 16-county area in Kentucky (USA) and examined the influence of catchment (forest, agriculture, and urban) and local-scale (water chemistry and sunfish presence) variables on A. barbouri occupancy and abundance. We sampled 80 streams across different land cover types (i.e., 30 agriculture, 34 forested, and 16 urban) over 2 yrs (2017–2018). Within these streams, we identified 56 new localities. Estimated mean occupancy (Ψ = 0.91; credible interval [CI] = 0.76–0.99) was high. Streams with the highest estimated abundances were those without sunfish and containing >50% forested or agricultural land cover within their catchments; urban streams had the lowest estimated abundances. At sites where we did not detect sunfish, there were an estimated 35.25 (95% CI = 32.04–38.67) A. barbouri individuals per 10 m in forested sites, 22.47 (95% CI = 19.86–25.14) in agricultural sites, and 0.66 (95% CI = 0.14–1.59) in urban sites. Water chemistry varied across site types; however, only maximum sodium (β = –0.51, 95% CI = –0.58 to –0.43) was associated with A. barbouri abundance. If managing this species becomes necessary, minimizing urban development within low-order stream catchments should be a priority.

Almost all large rivers worldwide are fragmented by dams, and their impacts have been modeled using the serial discontinuity concept (SDC), a series of predictions regarding responses of key biotic and abiotic variables. We evaluated the effects of damming on anuran communities along a 245‐km river corridor by conducting repeated, time‐constrained anuran calling surveys at 42 locations along the Broad and Pacolet Rivers in South Carolina, USA. Using a hierarchical Bayesian analysis, we test the biodiversity prediction of the SDC (modified for floodplain rivers) by evaluating anuran occupancy and species diversity relative to dams and degree of urbanized land use. The mean response of the anuran community indicated that occupancy and species richness were maximized when sites were farther downstream from dams. Sites at the farthest distances downstream of dams (47.5 km) had an estimated ~3 more species than those just below dams. Similarly, species‐specific occupancy estimates showed a trend of higher occupancy downstream from dams. Therefore, using empirical estimation within the context of a 245‐km river riparian landscape, our study supports SDC predictions for a meandering river. We demonstrate that with increasing distance downstream from dams, riparian anuran communities have higher species richness. Reduced species richness immediately downstream of dams is likely driven by alterations in flow regime that reduce or eliminate flows which sustain riparian wetlands that serve as anuran breeding habitat. Therefore, to maintain anuran biodiversity, we suggest that flow regulation should be managed to ensure water releases inundate riparian wetlands during amphibian breeding seasons and aseasonal releases, which can displace adults, larvae, and eggs, are avoided. These outcomes could be achieved by emulating pre‐dam seasonal discharge data, mirroring discharge of an undammed tributary within the focal watershed, or by basing real‐time flow releases on current environmental conditions.

Wetlands within tallgrass prairie are among the most endangered ecosystems in North America and serve as critical habitat for many sensitive and endemic species. Although loss of these habitats has acutely affected reptiles and amphibians, most prairie restoration initiatives take an ecosystem restoration approach adapted for plant and/or game species, with few focusing particularly on herpetofauna. Limited information exists documenting the population responses of reptiles and amphibians to wetland restoration in tallgrass prairie ecosystems. We used multiple techniques to compare reptile and amphibian communities in recently (2006) restored and unrestored tallgrass prairie and associated wetland habitats at Woolsey Wet Prairie Sanctuary (WWPS), a wetland mitigation site in Northwest Arkansas (USA). We documented 24 reptile and amphibian species and found that Regina grahamii (Graham’s Crayfish Snake) and Lithobates areolatus (Crawfish Frog), both of which are considered species of greatest conservation need in the state, showed preferential use of restored habitat, while common, widespread species did not use restored or unrestored habitat preferentially. Our results demonstrate that restoration of tallgrass prairie and associated wetlands benefits rare and sensitive herpetofauna and highlight two important management considerations: 1) promoting ephemeral (fishless) hydrology, and 2) emphasizing terrestrial movement corridors and critical upland habitat.

Many reptiles and amphibians are gaining recognition as harmful invaders, highlighted by well-known examples such as the Brown Tree Snake (Boiga irregularis), Cane Toad (Rhinella marina), American Bullfrog (Lithobates catesbeianus), and Burmese Python (Python molurus bivittatus). In 2003, an introduced population of Seal Salamanders (Desmognathus monticola) was found in Spavinaw Creek, within the Ozark Plateau of northwest Arkansas. Genetic evidence confirmed an introduction from northern Georgia. Very little is known about the status of this non-native population; thus, the objective of this study was to assess the current distribution and abundance of non-native D. monticola along Spavinaw Creek. We conducted repeated, low-intensity visual surveys along the 30 km extent of Spavinaw Creek in Arkansas and used a hierarchical Bayesian analysis to model the occupancy response of D. monticola and five native salamander species relative to river mile and habitat covariates. We also conducted a short-term clos...

Streamside management zones (i.e., riparian buffers; SMZs) are commonly implemented within managed forests to protect water quality but may also provide habitat for riparian-associated wildlife. Yet, little research has rigorously addressed the value of SMZs for wildlife, particularly for cryptic species such as amphibians and reptiles. Previous studies of herpetofauna within SMZs have focused on one or a few stream-associated species, and questions remain regarding variation among species or guilds and what role SMZs serve toward conservation of herpetofaunal diversity in managed forests. However, recent statistical advances have improved our ability to analyze large multi-species presence-absence data sets, accounting for low detection rates typical for some herpetofaunal species. Our study represents an extensive landscape-scale examination of herpetofaunal communities within SMZs using a multi-species occupancy approach. We conducted four replicate surveys at 102 headwater streams, spanning a gradient of SMZ widths and adjacent forest stand ages, within the Ouachita Mountains, Arkansas, USA. We used a hierarchical Bayesian community occupancy model to estimate species richness and species-specific occupancy responses to SMZ and overstory characteristics, accounting for variation in occupancy and detection attributable to site and sampling covariates. We documented high richness (37 species) within SMZs. Across the herpetofaunal community, occupancy and species richness were consistently positively associated with SMZ width, with maximum predicted richness of 30 species occurring at sites with buffers extending 51 m on either side of the stream. However, we documented considerable variation among groups and species within groups, underscoring the potential for different responses to forest management among taxa. Reptile predicted richness increased more rapidly up to SMZs of ~35 m, whereas maximum salamander predicted richness was not seen until an SMZ width of 55 m. Estimated salamander richness was highest within SMZs embedded in mature managed pine stands and was higher in SMZs comprised of a deciduous or mixed overstory vs. a pine overstory. Compared to salamanders, more anuran species showed high mean estimated occupancy (>75%) at narrower SMZs (

Because resources are finite, female animals face trade-offs between the size and number of offspring they are able to produce during a single reproductive event. Optimal egg size (OES) theory predicts that any increase in resources allocated to reproduction should increase clutch size with minimal effects on egg size. Variations of OES predict that egg size should be optimized, although not necessarily constant across a population, because optimality is contingent on maternal phenotypes, such as body size and morphology, and recent environmental conditions. We examined the relationships among body size variables (pelvic aperture width, caudal gap height, and plastron length), clutch size, and egg width of diamondback terrapins from separate but proximate populations at Kiawah Island and Edisto Island, South Carolina. We found that terrapins do not meet some of the predictions of OES theory. Both populations exhibited greater variation in egg size among clutches than within, suggesting an absence of optimization except as it may relate to phenotype/habitat matching. We found that egg size appeared to be constrained by more than just pelvic aperture width in Kiawah terrapins but not in the Edisto population. Terrapins at Edisto appeared to exhibit osteokinesis in the caudal region of their shells, which may aid in the oviposition of large eggs.

The diamondback terrapin (Malaclemys terrapin) is a species of conservation concern that has experienced noticeable declines throughout its range. Mark–recapture studies have been conducted on terrapins at Kiawah Island, South Carolina, since 1983, and during the early 1990s, this population began to decline. Our objectives were to evaluate current spatial and temporal variation in survivorship and compare current estimates of survivorship with those calculated from 1983 to 1999 in a previous study. We used an 11-year data set (2003 to 2013) in a capture–mark–recapture analysis to estimate the survivorship of terrapins in 5 creeks. Among creeks, annual survivorship estimates ranged from 61% to 82% with no difference between the sexes. Survivorship was lower than that documented for this population in the early 1990s. Recent anthropogenic habitat modification, such as the construction of docks, roads, and housing developments, as well as activities such as crab-trapping, likely play a role in low ...

Natural and sexual selection are frequently invoked as causes of sexual size dimorphism in animals. Many species of turtles, including the Diamond-backed Terrapin (Malaclemys terrapin), exhibit sexual dimorphism in body size, possibly enabling the sexes to exploit different resources and reduce intraspecific competition. Female terrapins not only have larger body sizes but also disproportionately larger skulls and jaws relative to males. To better understand the relationship between skull morphology and terrapin feeding ecology, we measured the in-lever to out-lever ratios of 27 male and 33 female terrapin jaws to evaluate biomechanics of the trophic apparatus. In addition, we measured prey handling times by feeding Fiddler Crabs (Uca pugnax), a natural prey item, to 24 terrapins in the laboratory. Our results indicate that although females have disproportionately larger heads, they have similar in:out lever ratios to males, suggesting that differences in adductor muscle mass are more important...

Oviposition site selection is an important aspect of reproduction for species such as amphibians that breed in dynamic environments. We examined predictors of oviposition site selection of Spotted Salamanders (Ambystoma maculatum) at Cowan's Ford Wildlife Refuge in Mecklenburg County, North Carolina. We conducted egg mass surveys and checked 40 minnow traps for potential predators every 2 days along transects, sampling a subset of all representative habitat within the wetland. Random points were generated for each egg mass to compare microhabitat conditions in areas where egg masses were present versus undetected. We constructed a paired logistic regression model and used Akaike information criterion to rank the associations between oviposition site and water depth, temperature, predator density, and vegetation. Ambystoma maculatum egg mass location was best predicted by deeper water and denser submergent vegetation. Our study suggests that A. maculatum select oviposition sites actively, rather t...

Within urbanized areas, the importance of greenspaces for wildlife has been widely investigated for some animal groups, but reptiles have generally been neglected. To assess the importance of the amount, spatial distribution, and configuration of greenspaces (comprised of terrestrial and aquatic areas), we examined semi-aquatic turtle species richness in urbanized areas. In this study, we sampled turtles from 2010 to 2011 at 20 ponds, including farm (rural) ponds, ponds in urbanized environments, and golf course ponds. We used a hierarchical Bayesian species-richness model to estimate species richness and species-specific occupancy responses to three pond types (rural, golf, or urban) and four landscape measurements of greenspace (i.e., Euclidean nearest neighbor, interspersion juxtaposition, percent of landscape, and connectance), generated in FRAGSTATS. We found that probability of occupancy of four species, Kinosternon subrubrum , Trachemys scripta , Chelydra serpentina , and Pseudemys concinna increased substantially with an increase in connectance of greenspace within 500 m of each pond. When the model examining the configuration of greenspaces was analyzed, estimated species richness was greater at golf ponds as compared to either rural or urban ponds, and richness increased with increasing connectivity of greenspaces. Our results indicate that in golf course ponds can potentially support a greater diversity of semi-aquatic turtle species than rural or urban ponds and thus may be considered superior habitat in suburban environments. In addition, we suggest that maintaining connectivity of greenspaces in suburban areas is important for semi-aquatic turtles and should be considered in urban planning.

Golf courses represent a common type of anthropogenically modified habitat in suburban environments. Golf courses may provide suitable habitat for semi-aquatic animals in suburban areas, yet studies comparing animal abundances in golf course ponds with other pond types in suburban environments are somewhat limited. In this study, we compared turtle abundances in golf course ponds with ponds found in residential areas and ponds found in rural (farm) areas and examined the relationship between turtle abundance and residential land-cover within individual golf courses. We captured turtles in 10 golf course ponds, 5 ponds surrounded by residential development, and 5 ponds located on farms. We estimated abundance and the effects of pond area, pond type (i.e., residential, golf, farm) and percentage of residential development within golf course boundaries. Using binomial mixture models and Bayesian inference, we found that ponds surrounded by residential development had lower abundances of Painted Turt...

Various anthropogenic pressures, including habitat loss, threaten reptile populations worldwide. Riparian zones are critical habitat for many reptile species, but these habitats are also frequently modified by anthropogenic activities. Our study investigated the effects of two riparian habitat modifications – damming and urbanization – on overall and species-specific reptile occupancy patterns. We used time-constrained search techniques to compile encounter histories for 28 reptile species at 21 different sites along the Broad and Pacolet Rivers of South Carolina. Using a hierarchical Bayesian analysis, we modeled reptile occupancy responses to a site’s distance upstream from dam, distance downstream from dam, and percent urban land use. The mean occupancy response by the reptile community indicated that reptile occupancy and species richness were maximized when sites were farther upstream from dams. Species-specific occupancy estimates showed a similar trend of lower occupancy immediately upstream from dams. Although the mean occupancy response of the reptile community was positively related to distance downstream from dams, the occupancy response to distance downstream varied among species. Percent urban land use had little effect on the occupancy response of the reptile community or individual species. Our results indicate that the conditions of impoundments and subsequent degradation of the riparian zones upstream from dams may not provide suitable habitat for a number of reptile species.

An inventory of the Broad River Basin in South Carolina documented distribution and species richness of amphibians and reptiles of the area, focusing primarily on riparian zones. A list of 92 potentially occurring species was assembled for the area. Multiple survey methods were used including active searches, manual anuran calling surveys, and turtle trapping to document the herpetofauna. Using these techniques, 14 anuran, 9 salamander, 7 lizard, 16 snake, and 8 turtle species were documented. Seven of these species were of conservation concern in South Carolina. The Broad River Basin supports a diverse array of amphibian and reptile species associated with both wetland and riverine habitats. As water resources, energy demand, and urbanization continue to increase in the Piedmont region, these baseline data have important implications for conservation and future land management.

Summary 1. Wetlands are ecologically and economically important ecosystems but are threatened globally by many forms of human disturbance. Understanding the responses of wetland species to human disturbance is essential for effective wetland management and conservation. 2. We undertook a study to determine (i) whether anurans can be used effectively to assess the ecological integrity of wetlands affected by groundwater withdrawal and, if so, (ii) what effect increasing urbanization might have on the utility of anurans as wetland indicators. We monitored the intensity of anuran calls at 42 wetlands in south-western Florida throughout 2001–2002 and 2005– 2009. 3. We first validated the use of anurans to assess wetland integrity using a small group of wetlands by comparing anuran calling and subsequent tadpole development with an established index employing vegetation composition and structure. We then verified that the results could be expanded to a variety of sites throughout the region. Finally, we focused on urbanized wetlands to determine whether urbanization could interfere with the use of anurans to assess wetland integrity. 4. We used PRESENCE to estimate occupancy and detection probabilities and to examine the relationship between occupancy and five covariates expected to influence individual species occurrence. We used FRAGSTATS to calculate the mean proximity index for urbanized wetlands, which assesses the size and distribution of land use types within a specified area. 5. Our results showed that the group of species including oak toad Anaxyrus quercicus, southern cricket frog Acris gryllus, pinewoods treefrog Hyla femoralis, barking treefrog Hyla gratiosa ,a nd little grass frog Pseudacris ocularis is a reliable indicator of wetland integrity. However, this same group of species, which is sensitive to wetland health, is selectively excluded from urbanized wetlands. 6. Synthesis and applications. Although anurans are effective indicators of wetland health and complement vegetation surveys, the usefulness of this group for monitoring the ecological integrity of wetlands can be substantially reduced, or eliminated, as a consequence of urbanization. We urge for careful consideration of confounding factors in any studies examining the utility of indicator species.

Context Both manual call surveys (MCS) and visual encounter surveys (VES) are popular methods used to monitor anuran populations. Recent statistical developments, specifically the development of occupancy models that permit the use of data from various survey methods to assess method-specific detection probabilities, provide a rigorous framework for evaluating the effectiveness of field methods. Aim To compare species-specific detection probabilities generated by MCS and VES and to evaluate the effectiveness of these methods throughout the activity season of several riparian-zone anuran species. Methods During 2010 and 2011, we sampled 21 sites along the Broad and Pacolet Rivers, in South Carolina, USA, using MCS and VES. Anuran species were surveyed across three seasons (fall, spring and summer) each year. Key results For six species, MCS resulted in a higher mean probability of detection, whereas VES resulted in a higher mean probability of detection for four species. In addition, survey date was an important influence on detection probability of most anurans when using MCS, but largely unimportant when employing VES. Conclusions Our findings indicated that VES are as effective as MCS for detecting some species of anurans, and for others, VES represent a more effective method. Furthermore, when using VES outside the breeding window, some anurans can be reliably detected, and in some cases, detected more easily than by using MCS. Implications We suggest that VES is a complimentary technique to MCS and a potentially important tool for population monitoring of anurans. VES can provide more flexibility for anuran researchers, as robust estimates of detection and occupancy can be obtained outside a narrow breeding window.