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1. Behavior and detection method influence detection probability of a translocated, endangered amphibian

   https://doi.org/10.1111/acv.12645  

   Hammond, Talisin T. ; Curtis, Michelle J. ; Jacobs, Leah E. ; Tobler, Mathias W. ; Swaisgood, Ronald R. ; Shier, Debra M. ( October 2020 , Animal Conservation)

   Accurate estimates of survival are crucial for many management decisions in translocation programs. Maximizing detection probabilities and reducing sampling biases for released animals can aid in estimates of survival. One important source of sampling bias is an animal’s behavior. For example, individuals that are consistently more exploratory or active may be more likely to be detected visually. Behavioral traits can be related to survival after reintroduction, and because many pre‐release treatments aim to manipulate animal behavior, it is critical to tease apart relationships between behavior and detection probability. Here, we assessed the repeatability (intra‐individual consistency and inter‐individual variation) of behavioral traits for an endangered amphibian, the mountain yellow‐legged frog (Rana muscosa). Because new technological tools offer one potential solution for reducing sampling biases while increasing detection, we also tested whether a long‐range passive integrated transponder (PIT) tag reader could enhance surveys for these individuals after translocation into the wild. After confirming thatex situbredR. muscosaexhibit repeatable behavioral traits (repeatability = 0.25–0.41) and releasing these frogs (N = 196) into the wild, we conducted post‐release surveys visually and with the long‐range PIT tag reader. Integrating the long‐range reader into surveys improved detection probability four‐fold in comparison to visual surveys alone (~0.09 to ~0.36). Moreover, mark–recapture modeling revealed that tag reader detection probability was not biased toward detecting individuals of specific behavioral types, while visual detection was significantly related to behavioral traits. These results will enable a more accurate understanding of individual differences in post‐release success in translocations. This may be particularly important for amphibian species, which can be difficult to detect and are expected to increasingly be involved in human‐managed breeding and translocation programs due to their vulnerable conservation status.

    

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2. Avian use of avocado farms and intact forest in the northern Sierra de Bahoruco, Dominican Republic

   https://doi.org/10.55431/jco.2023.36.147-161  

   Young, Avery ; Aborn, David ; Latta, Steven C. ; Boyd, Jennifer Nagel ( February 2023 , Journal of Caribbean Ornithology)

   Abstract The Dominican Republic is experiencing increased forest loss due to the expansion of avocado farming. While agricultural lands can provide viable habitat for birds, knowledge of avian use of avocado farms relative to native forest is limited. We conducted surveys in fall 2021 to compare the bird communities and vegetation complexity of two avocado farm sites and two native dry forest sites in the northern Sierra de Bahoruco region of the Dominican Republic to assess avian habitat use. Overall, we found that habitat associations differed for bird species distinguished by contrasting geographic ranges. In particular, the abundance, richness, and diversity of bird species endemic to Hispaniola were significantly greater in forests than in farms, while non-endemic resident bird species had the opposite habitat associations. The abundance, richness, and diversity of Neotropical migrants exhibited fewer distinct differences between farm and forest sites. Vegetation structural complexity was reduced in avocado farms relative to forests and was positively associated with the abundance, richness, and diversity of endemic bird species but negatively associated with these community measures of non-endemic resident species. Collectively, our findings suggest that avocado farms could provide viable habitat for non-endemic resident and migrant bird species, but that endemic species could be negatively impacted by an increase in avocado farming in the region. We offer recommendations for forest preservation, farming practices, and future research that could help to inform the conservation of endemic species in the region. Keywords agriculture, avian conservation, Dominican Republic, endemic species, habitat use, land-use change, Neotropical migrants Resumen Uso de granjas de cultivo de aguacate y bosques nativos por parte de las aves en el norte de la Sierra de Bahoruco, República Dominica • La República Dominicana está experimentando una mayor pérdida de bosques nativos como consecuencia de la expansión de los cultivos de aguacate. Aunque las tierras agrícolas pueden proporcionar un hábitat propicio para algunas aves, el conocimiento sobre el uso que hacen de los cultivos de aguacate en comparación con las áreas forestales nativas es limitado. En otoño de 2021, realizamos muestreos en dos granjas de aguacate y dos bosques secos nativos en la región norte de la Sierra de Bahoruco (República Dominicana), y comparamos las comunidades de aves y la complejidad de la vegetación para evaluar el uso del hábitat que hacen las aves. En general, observamos diferencias entre las asociaciones de hábitats de las especies de aves con distribuciones geográficas distintas. En particular, la abundancia, riqueza y diversidad de especies de aves endémicas de La Española fueron significativamente mayores en los bosques que en las granjas; mientras que las especies de aves residentes no endémicas mostraron asociaciones de hábitat opuestas. La abundancia, riqueza y diversidad de las aves migratorias neotropicales exhibieron menos diferencias entre las granjas y los bosques. La complejidad estructural de la vegetación se redujo en las granjas de aguacate en relación con los bosques y tuvo una correlación positiva con la abundancia, riqueza y diversidad de aves endémicas, pero negativa con las mismas medidas comunitarias de especies residentes no endémicas. En conjunto, nuestros resultados sugieren que los cultivos de aguacate podrían proporcionar un hábitat adecuado para aves residentes no endémicas y migratorias; mientras que las especies endémicas podrían verse afectadas negativamente por un aumento de estos cultivos en la región. Por último, proporcionamos recomendaciones para la conservación de los bosques, prácticas agrícolas y futuras investigaciones que podrían contribuir a la conservación de las aves endémicas de esta región. Palabras clave agricultura, aves migratorias neotropicales, cambio de uso de suelo, conservación de aves, especies endémicas, República Dominicana, uso de hábitat Résumé Utilisation par les oiseaux des plantations d’avocatiers et des forêts non exploitées dans le nord de la Sierra de Bahoruco, en République dominicaine • En République dominicaine, la forêt indigène est en régression en raison de l’augmentation de la culture des avocatiers. Bien que les terres agricoles puissent fournir un habitat approprié à certains oiseaux, les connaissances sur l’utilisation des plantations d’avocatiers par rapport à celle des forêts indigènes sont limitées. Nous avons échantillonné deux plantations d’avocatiers et deux forêts sèches indigènes dans la Sierra de Bahoruco (République dominicaine) au cours de l’automne 2021, et nous avons comparé leurs communautés d’oiseaux et la complexité de leur végétation afin d’évaluer l’utilisation de ces deux habitats par les oiseaux. Dans l’ensemble, nous avons observé que les associations entre espèces d’oiseaux et habitats différaient en fonction de la répartition géographique des oiseaux. En particulier, l’abondance, la richesse et la diversité de l’avifaune endémique à Hispaniola étaient significativement plus fortes dans les forêts que dans les plantations, tandis que les espèces d’oiseaux sédentaires non endémiques étaient inversement associées à ces habitats. L’abondance, la richesse et la diversité des migrateurs néotropicaux présentaient moins de différences distinctes entre les milieux agricoles et forestiers. La complexité de la structure de la végétation était plus faible dans les plantations d’avocatiers que dans les forêts, et était positivement corrélée à l’abondance, à la richesse et à la diversité des espèces d’oiseaux endémiques, mais négativement corrélée à ces mesures pour les communautés d’espèces sédentaires non endémiques. Dans l’ensemble, nos résultats semblent indiquer que les plantations d’avocatiers pourraient constituer un habitat viable pour les espèces d’oiseaux sédentaires et migrateurs non endémiques, mais que les espèces endémiques pourraient être affectées négativement par une augmentation de ces cultures dans la région. Nous formulons des recommandations pour la préservation des forêts, les pratiques agricoles et les recherches futures qui pourraient contribuer à la conservation des espèces endémiques dans la région. Mots clés agriculture, changement d’affectation des terres, conservation de l’avifaune, espèces endémiques, migrateurs néotropicaux, République dominicaine, utilisation des habitats

    

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3. Salted roads lead to oedema and reduced locomotor function in amphibian populations

   https://doi.org/10.1111/fwb.13907  

   Brady, Steven P. ; Goedert, Debora ; Frymus, Lauren E. ; Zamora‐Camacho, Francisco Javier ; Smith, Peter C. ; Zeiss, Caroline J. ; Comas, Mar ; Abbott, Timothy A. ; Basu, Silvia P. ; DeAndressi, Jason C. ; et al ( March 2022 , Freshwater Biology)

   Human activities have caused massive losses of natural populations across the globe. Like many groups, amphibians have experienced substantial declines worldwide, driven by environmental changes such as habitat conversion, pollution, and disease emergence. Each of these drivers is often found in close association with the presence of roads.

   Here we report a novel consequence of roads affecting an amphibian native to much of North America, the wood frog (Rana sylvatica). Across 38 populations distributed from southern to central New England, we found that adult wood frogs living adjacent to roads had higher incidence and severity of oedema (indicated by obvious bloating caused by subcutaneous fluid accumulation) during the breeding season than frogs living away from the influence of roads. This effect was best explained by increased conductivity of breeding ponds, probably caused by runoff pollution from road salt used for de‐icing. Oedema severity was negatively correlated with locomotor performance in more northerly populations.

   Interestingly, northern populations experience more intense winters, which tends to result in more de‐icing salt runoff and increased energetic demands associated with overwintering cryoprotection needs. Thus, this emerging consequence of roads appears to impose potential fitness costs associated with locomotion, and these effects might be most impactful on populations living in regions where de‐icing is most intense.

   Together, our findings reveal a novel set of impacts of roads and runoff pollution on wood frog physiology and performance, which seem likely to contribute to population decline. Given the global prevalence of roads and increasing salinisation of freshwater habitats, oedema and related impacts could be widespread consequences faced by amphibian populations across much of the planet's temperate zones.

    

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4. Experimental confirmation of effects of leaf litter type and light on tadpole performance for two priority amphibians

   https://doi.org/10.1002/ecs2.3729  

   Burrow, Angela K. ; Maerz, John C. ( September 2021 , Ecosphere)

   Isolated wetlands embedded within longleaf pine savannas support a high proportion of regional biodiversity including many amphibian species. Today, remnant isolated wetlands are often overgrown and hydrologically altered due to fire exclusion or incompatible, cool season fire regimes. In the absence of warm season fires when wetlands are dry, shrubs and trees succeed herbaceous plants, which alters wetland productivity via effects on light and detritus quality. We used a factorial aquatic mesocosm study to test the effects of altered detritus and shade on the growth, development, and survival of tadpoles of two priority amphibian species: gopher frogs (Rana capito) and ornate chorus frogs (Pseudacris ornata). Gopher frog survival was higher among maidencane, sedge, and pine treatments compared to oak and sweetgum treatments. While gopher frog larval periods were lowest in the sedge treatment, there was a nominal general effect of litter type on gopher frog larval periods, growth rates, and mass at metamorphosis. Shading had a nominal and inconsistent effect on gopher frog growth rates, but did extend larval periods in all litter treatments, decreased survival in all litter treatments except oak, and decreased mass at metamorphosis in all litter treatments except pine and sweetgum. Ornate chorus frog survival was minimally affected by shading and litter treatments, but growth rates and mass at metamorphosis were highest in maidencane and sedge treatments, and larval periods were extended with shading in all litter treatments. Shading also decreased growth rates in maidencane and sedge litters and decreased mass at metamorphosis in pine and sweetgum litters. Our results demonstrate that succession of isolated wetlands can reduce tadpole performance for two priority species both through changes in leaf litter and shading, though the effect on survival, larval growth, larval period, and size at metamorphosis can differ between species. These results support management recommendations to restore and maintain open canopy, grassy conditions in isolated wetlands for conservation of priority amphibian species.

    

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5. Can artificial retreat sites help frogs recover after severe habitat devastation? Insights on the use of “coqui houses” after Hurricane Maria in Puerto Rico

   Burrowes, Patricia A ; Hernandez-Figueroa, Abner D ; Acevedo, Gustavo D ; Aleman-Rios, Junangel ; Longo, Ana V. ( June 2021 , Amphibian reptile conservation)

   Hassapakis, Craig ; Grieneisen, M. (Ed.)

   On September 2017, Hurricane Maria swept over Puerto Rico as a Category 4 storm. Severe canopy loss, augmentation of forest floor debris, and a significant increase in temperature and light reaching the understory were among the most evident changes at El Yunque National Forest, where a population of Eleutherodactylus coqui frogs has been monitored over the past 30 years. When sampling was re-established, the frogs could be heard calling, but it was very difficult to find them among the complexity of vegetation in the forest floor. We inferred that canopy disturbance had left frogs without optimal arboreal habitats for retreat, nocturnal perching, feeding, and reproductive activities, and wondered whether they would use artificial habitats placed in the forest understory. To test this, two types of artificial habitats (i.e., “coqui houses”) were introduced in the forest understory, consisting of either open PVC pipes or single-entrance natural bamboo shoots. Surveys were conducted twice a month for 15 months in an experimental transect with coqui houses, and a control transect without them. Data were collected on the occupancy rate of the artificial sites, type of usage, time of day occupied, and the number of E. coqui observed. The effects of time since the hurricane, microhabitat temperature, type of coqui house, and seasonality on the occupancy rate were also evaluated. Results showed that coquis used bamboo houses mostly during daytime as retreat and nesting sites, whereas the PVC houses were used mostly at night as calling sites. Daytime occupancy of coqui houses showed a significant bell-shaped pattern over time since the hurricane. This may be explained by a steady increase in usage after severe forest damage, a peak during the stressful cool-dry season, and a decline afterwards as the forest began to recover. No differences were found in frog counts between experimental and control transects, probably because the coquis could also hide among the fallen vegetation, but either disparities in forest conditions or inappropriateness of the methods for estimating population numbers may have overshadowed this effect. Coquis used artificial houses more often during the most stressful environmental conditions, suggesting that these shelters may serve to enhance habitat quality for amphibians after extreme weather events. 

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