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opencc-zeroJun 2023View details →

Data for: Meta analysis reveals impacts of disturbance on reptile and amphibian body condition

Ecosystem disturbance is increasing in extent, severity, and frequency across the globe. To date, research has largely focused on the impacts of disturbance on animal population size, extinction risk, and species richness. However, individual responses, such as changes in body condition, can act as more sensitive metrics and may provide early warning signs of reduced fitness and population declines. We conducted the first global systematic review and meta-analysis investigating the impacts of ecosystem disturbance on reptile and amphibian body condition. We collated 384 effect sizes representing 137 species from 133 studies. We tested how disturbance type, species traits, biome, and taxon moderate the impacts of disturbance on body condition. We found an overall negative effect of disturbance on herpetofauna body condition (Hedges' g = -0.37, 95%CI: -0.57, -0.18). Disturbance type was an influential predictor of body condition response and all disturbance types had a negative mean effect. Drought, invasive species, and agriculture had the largest effects. The impact of disturbance varied in strength and direction across biomes, with the largest negative effects found within Mediterranean and temperate biomes. In contrast, taxon, body size, habitat specialisation, and conservation status were not influential predictors of disturbance effects. Our findings reveal the widespread effects of disturbance on herpetofauna body condition and highlight the potential role of individual-level response metrics in enhancing wildlife monitoring. The use of individual response metrics alongside population and community metrics would deepen our understanding of disturbance impacts by revealing both early impacts and chronic effects within affected populations. This could enable early and more informed conservation management.

Data from: Decadienal afforestation and risks to montane grassland amphibians in the Udzungwa Plateau, Tanzania

Human modification of the environment has drastically changed ecosystems around the globe. While forest-loss (deforestation) has been well studied for its effects on ecosystems, afforestation also has major impacts on ecosystems. The Udzungwa Plateau in Tanzania is naturally a mix of forests and grasslands. However, non-native pine plantations have recently increased in the area displacing the native grasslands of the montane plateau. In this study, we explored the effects of land use change on amphibian communities by comparing amphibian surveys before non-native plantations were introduced (~ 2000) and after (2017-2019). To put these amphibian surveys into wider context across the plateau, to distinguish local population loss compared to plateau-wide extinctions, we compared new sampling locations and broader surveys and assessed landscape change through remotely sensed data. Amphibian encounter surveys found approximately the same species diversity across all sampling locations, but local extinctions appear likely. Remaining amphibians appear to be limited to small refugia in non-pine wetlands. Approximately half (45%) of the species found have limited distributional ranges (<72,000 km2) and are described as habitat specialists by the IUCN Red List. Monitoring pine plantation growth using remote sensing techniques suggested only limited extensions of plantations between 2000 through to 2013-2016, but ground-surveys found small pines (<3 years old) throughout almost all areas identified as grasslands on satellite imagery. Our study highlights the plight of this narrowing biome on the African continent and calls for more intensive research on the impact of non-native plantations on natural communities.

Data from: The costs of living on the coast: reduction in body size and size-specific reproductive output in coastal populations of a widespread amphibian

<ol> <li>Body size is a critical component of organismal biology. Body size is known to be influenced by a plethora of environmental conditions, among which exposure to large-scale variations of salinity has been comparatively overlooked. Yet, exposure to salinity is known to affect energetic allocation toward growth and reproduction.</li> <li>In this study, we investigated the morphological differences between inland and coastal individuals of spined toads (Bufo spinosus) in Western France. </li> <li>We measured adult morphology both outside and during the reproductive season on 190 individuals, and assessed reproduction in pairs originating from inland (N=20) and coastal (N=30) environments.</li> <li>Overall, we found that adult coastal toads were smaller and lighter than inland individuals. Reproductive correlates of these differences included lower fecundity and smaller egg size (but higher egg density) in coastal females. Interestingly, these differences were not allometric correlates of body size, as coastal females invested proportionally less in all components of reproduction (fecundity, egg size and egg protection).</li> <li>These results suggest altered resource allocation to growth and reproduction in coastal amphibians, which may be related to the marked spatial gradient of salinity (measured in reproductive ponds) and the associated costs of osmoregulation (higher osmolality in coastal individuals), for which local adaptation and higher tolerance to salinity remains to be tested.</li> </ol>

Data for: Responses to saltwater exposure vary across species, populations, and life-stages in anuran amphibians

To predict the impacts of environmental change on species, we must first understand the factors that limit the present-day ranges of species. Most anuran amphibians cannot survive at elevated salinities, which may drive their distribution in coastal locations. Previous research showed that coastal Hyla cinerea are locally adapted to brackish habitats in North Carolina (USA). Although Hyla squirella and Hyla chrysoscelis both inhabit coastal wetlands nearby, they have not been observed in saline habitats. We take advantage of naturally occurring microgeographic variation in coastal wetland occupancy exhibited by these congeneric treefrog species to explore how salt exposure affects oviposition site choice, hatching success, early tadpole survival, plasma osmolality, and tadpole body condition across coastal and inland locations. We observed higher survival among coastal H. cinerea tadpoles than inland H. cinerea, which corroborates previous findings. But contrary to expectations, coastal H. cinerea had lower survival than H. squirella and H. chrysoscelis, indicating that all three species may be able to persist in saline wetlands. We also observed differences in tadpole plasma osmolality across species, locations, and salinities, but these differences were not associated with survival rates in saltwater. Instead, coastal occupancy may be affected by stage-specific processes like higher probability of total clutch loss as shown by inland H. chrysoscelis or maladaptive egg deposition patterns as shown by inland H. squirella. Although we expected saltwater to be the primary filter driving species distributions along a coastal salinity gradient, it is likely that the factors dictating anuran ranges along the coast involve stage-, species-, and location specific processes that are mediated by ecological processes and life history traits.

Data for: Photoperiod effects in a freshwater community: amphibian larvae develop faster and zooplankton abundance increases under an early-season photoperiod

Organisms that shift their phenologies in response to global warming will experience novel photic environments, as photoperiod (daylength) continues to follow the same annual cycle. How different organisms respond to novel photoperiods could result in phenological mismatches and altered interspecific interactions. We conducted an outdoor mesocosm experiment exposing green frog (Rana clamitans) larvae, gray treefrog (Hyla versicolor) larvae, phytoplankton, periphyton, and zooplankton to a three-month shift in photoperiod: an early-season photoperiod (simulating April) and a late-season photoperiod (simulating July). We manipulated photoperiod by covering and uncovering tanks with clear or light-blocking lids to mimic realistic changes in daylength. We assessed amphibian life history traits and measured phytoplankton, periphyton, and zooplankton abundances. Green frog larvae and gray treefrog metamorphs were more developed under the early-season photoperiod. Gray treefrog total length was also reduced, but photoperiod did not affect green frog total length. Although phytoplankton and periphyton abundances were not affected by photoperiod, copepod nauplii were in greater abundance under the early-season photoperiod. Overall, this simplified aquatic community did not exhibit significant changes to structure when exposed to a three-month shift in photoperiod. Temperate amphibians that breed earlier in the year may develop faster, which may have long-term costs to post-metamorphic growth and performance. Asynchronous shifts in zooplankton abundances in response to altered photoperiods could subsequently affect freshwater community structure. While photoperiod has been shown to individually affect freshwater organisms, our study using replicated outdoor wetland communities shows that the comprehensive effects of photoperiod may be less important than other cues such as temperature and precipitation.

openother-openAug 2023View details →

Data and code for "Dietary carotenoid supplementation has long-term and community-wide effects on the amphibian skin microbiome"

Data, R code and R markdown report for the manuscript "Dietary carotenoid supplementation has long-term and community-wide effects on the amphibian skin microbiome" by Risely, A., Phillip G. Byrne, Bethany J. Hoye, and Aimee J. Silla Data frog_final.RDS = Processed phyloseq dataset of frog skin microbiome Code Frog_diet_analysis_V1.Rmd = Rmarkdown code Frog_diet_analysis_V1.html = Rmarkdown report (html version - need to download to view) Frog_diet_analysis_V1.pdf = Rmarkdown report (PDF version)

opencc-by-4.0Dec 2022View details →

Ecological barriers for an amphibian pathogen: a narrow ecological niche for Batrachochytrium salamandrivorans in an Asian Chytrid hotspot

We used GLM and Maxent models to predict the potential distribution of Batrachochytrium salamandrivorans (Bsal) based on the climate, non-climate, and biotic variables.

opencc-by-4.0Aug 2023View details →

Supplementary material to "Partnerships between private landowners and conservationists to protect one of the most evolutionarily distinct amphibians"

Table S1 (PDF file): Habitat quality scores for two high-gradient streams present in the private protected area Refugio de Ranitas Aldea del Viento, Los Pellines, Valdivia, Chile. Scores for 10 habitat parameters were determined using the visual-based habitat assessment protocol described by Barbour et al. (1999) for high-gradient streams. Parameters were measured at four points per stream, distributed evenly across a 250-m section. Habitat quality scores defined by Barbour et al. (1999) are coloured according to four condition categories (green = optimal, yellow = suboptimal, orange = marginal, red = poor). Insuetophrynus acarpicus individuals were only found in stream B. Literature search Barrio's frogs (xls file): Research publications about Barrio’s frogs published since the description of the species in 1970. Publications were searched using Web of Science and Google Scholar with the terms “Insuetophrynus” OR “Barrio’s frog”. We excluded species checklists or reviews that mentioned the species without providing novel information or analyses. In this file we provide the full list of articles, including bibliographic information. The search was performed on 7th August 2023.

opencc-by-4.0Aug 2023View details →

Supplementary material to "Partnerships between private landowners and conservationists to protect one of the most evolutionarily distinct amphibians"

Table S1 (PDF file): Habitat quality scores for two high-gradient streams present in the private protected area Refugio de Ranitas Aldea del Viento, Los Pellines, Valdivia, Chile. Scores for 10 habitat parameters were determined using the visual-based habitat assessment protocol described by Barbour et al. (1999) for high-gradient streams. Parameters were measured at four points per stream, distributed evenly across a 250-m section. Habitat quality scores defined by Barbour et al. (1999) are coloured according to four condition categories (green = optimal, yellow = suboptimal, orange = marginal, red = poor). Insuetophrynus acarpicus individuals were only found in stream B. Literature search Barrio's frogs (xls file): Research publications about Barrio’s frogs published since the description of the species in 1970. Publications were searched using Web of Science and Google Scholar with the terms “Insuetophrynus” OR “Barrio’s frog”. We excluded species checklists or reviews that mentioned the species without providing novel information or analyses. In this file we provide the full list of articles, including bibliographic information. The search was performed on 7th August 2023.