Amphibian Community Structure Research Articles

Phenological mismatches mitigate the ecological impact of a biological invader on amphibian communities.

Horizon scans have emerged as a valuable tool to anticipate the incoming invasive alien species (IAS) by judging species on their potential impacts. However, little research has been conducted on quantifying actual impacts and assessing causes of species-specific vulnerabilities to particular IAS due to persistent methodological challenges. The underlying interspecific mechanisms driving species-specific vulnerabilities therefore remain poorly understood, even though they can substantially improve the accuracy of risk assessments. Given that interspecific interactions underlying ecological impacts of IAS are often shaped by phenological synchrony, we tested the hypothesis that temporal mismatches in breeding phenology between native species and IAS can mitigate their ecological impacts. Focusing on the invasive American bullfrog (Lithobates catesbeianus), we combined an environmental DNA (eDNA) quantitative barcoding and metabarcoding survey in Belgium with a global meta-analysis, and integrated citizen-science data on breeding phenology. We examined whether the presence of native amphibian species was negatively related to the presence or abundance of invasive bullfrogs and whether this relationship was affected by their phenological mismatches. The field study revealed a significant negative effect of increasing bullfrog eDNA concentrations on native amphibian species richness and community structure. These observations were shaped by species-specific vulnerabilities to invasive bullfrogs, with late spring- and summer-breeding species being strongly affected, while winter-breeding species remained unaffected. This trend was confirmed by the global meta-analysis. A significant negative relationship was observed between phenological mismatch and the impact of bullfrogs. Specifically, native amphibian species with breeding phenology differing by 6 weeks or less from invasive bullfrogs were more likely to be absent in the presence of bullfrogs than species whose phenology differed by more than 6 weeks with that of bullfrogs. Taken together, we present a novel method based on the combination of aqueous eDNA quantitative barcoding and metabarcoding to quantify the ecological impacts of biological invaders at the community level. We show that phenological mismatches between native and invasive species can be a strong predictor of invasion impact regardless of ecological or methodological context. Therefore, we advocate for the integration of temporal alignment between native and IAS's phenologies into invasion impact frameworks.

Amphibian community structure in Isau-Isau Wildlife Reserve, South Sumatra, Indonesia

Abstract. Tanjung RD, Kusrini MD, Mardiastuti A, Yustian I, Setiawan A, Iqbal M. 2023. Amphibian community structure in Isau-Isau Wildlife Reserve, South Sumatra, Indonesia. Biodiversitas 24: 6836-6843. Amphibian community structures in Isau-Isau Wildlife Reserve, South Sumatra, were investigated from Mei until July 2023. The data were obtained by Visual Encounter Survey combination with line transect. The data analyzed were Species Richness (Margalef Index), Diversity Index (H', Shannon-Wiener), Dominance (D, Simpson Index), and Evenness Index (J', Pielou) calculated using PAST 4.0 software. In addition, we also analyzed abiotic factors such as air temperature, humidity, water temperature, pH, total dissolved solids (TDS), and dissolved oxygen (DO). The abiotic data were included as explanatory variables in Canonical Correspondence Analysis (CCA). A total of 12 amphibian species consisting of 11 genera and 4 families were recorded. Of them, 11 species are classified as least concern, while one species, Theloderma licin, is classified as data deficient by the IUCN Red List of Threatened Species.

Community structure, species–habitat relationships, and conservation of amphibians in forested vernal pools in the Georgian Bay region of Ontario

Forested vernal pools serve an integral role in the recruitment of amphibians in glaciated northeastern North America. In south-central Ontario, vernal pools exist in relatively unimpacted forest networks, but the amphibian communities face uncertain challenges from anthropogenic-induced climate change. We surveyed amphibian larvae and collected measurements of habitat characteristics from vernal pools to collect baseline information on amphibian community structure and species–habitat relationships. Amphibian communities were influenced by hydroperiod length and canopy openness, and the relative abundances of early breeding amphibians were affected by changes in the structure of vegetation communities within pools. Our study suggests that, even across moderate ranges of breeding habitat characteristics, the structure of amphibian communities is dynamic. With anthropogenic-induced climate change leading to more drought-prone summers, the conservation of intact forests that support diverse wetland assemblages will be a necessary component of future legislation.

Multidimensional amphibian diversity and community structure along a 2 600 m elevational gradient on the eastern margin of the Qinghai-Tibetan Plateau.

Mountain systems harbor an evolutionarily unique and exceptionally rich biodiversity, especially for amphibians. However, the associated elevational gradients and underlying mechanisms of amphibian diversity in most mountain systems remain poorly understood. Here, we explored amphibian phylogenetic and functional diversity along a 2 600 m elevational gradient on Mount Emei on the eastern margin of the Qinghai-Tibetan Plateau in southwestern China. We also assessed the relative importance of spatial (area) and environmental factors (temperature, precipitation, solar radiation, normalized difference vegetation index, and potential evapotranspiration) in shaping amphibian distribution and community structure. Results showed that the phylogenetic and functional diversities were unimodal with elevation, while the standardized effect size of phylogenetic and functional diversity increased linearly with elevation. Phylogenetic net relatedness, nearest taxon index, and functional net relatedness index all showed a positive to negative trend with elevation, indicating a shift from clustering to overdispersion and suggesting a potential change in key processes from environmental filtering to competitive exclusion. Overall, our results illustrate the importance of deterministic processes in structuring amphibian communities in subtropical mountains, with the dominant role potentially switching with elevation. This study provides insights into the underlying assembly mechanisms of mountain amphibians, integrating multidimensional diversity.

Genetic variation of Batrachochytrium dendrobatidis is linked to skin bacterial diversity in the Pacific treefrog Hyliola regilla (hypochondriaca).

Symbiotic bacterial communities are crucial to combating infections and contribute to host health. The amphibian skin microbiome plays an important role in protecting their hosts against pathogens such as Batrachochytrium dendrobatidis (Bd), one of the causative agents of chytridiomycosis, which is responsible for dramatic amphibian population declines worldwide. Although symbiotic skin bacteria are known to inhibit Bd growth, an understanding of the relationship between Bd genetic variability, environmental conditions, and skin bacterial communities is limited. Therefore, we examined the associations between Bd infection load, Bd genetic diversity and skin bacterial communities in five populations of Hyliola regilla (hypochondriaca) from environmentally contrasting sites in Baja California, Mexico. We observed differences in Bd genetics and infection load among sites and environments. Genetic analysis of Bd isolates revealed patterns of spatial structure corresponding to the five sites sampled. Amphibian skin bacterial diversity and community structure differed among environments and sites. Bacterial community composition was correlated with Bd genetic differences and infection load, with specific bacterial taxa enriched on infected and un-infected frogs. Our results indicate that skin-associated bacteria and Bd strains likely interact on the host skin, with consequences for microbial community structure and Bd infection intensity.

Low-Intensity Agriculture Shapes Amphibian and Reptile Communities: Insights from a 10-Year Monitoring Study

Intensification and expansion of agriculture is one of the most pressing concerns for biodiversity conservation. Amphibian and reptile communities can be particularly sensitive to land-use change; therefore, understanding how land use and agricultural practices influence these communities in areas under increasing agricultural pressure is prudent. Over 10 yr, we sampled amphibian and reptile communities in and around 18 man-made ponds set within an agricultural/forest matrix on a military installation in western Tennessee. Ponds had either cattle access or were cattle restricted and had different surrounding land uses (forest, pasture, row crops, and industrial development). We used Akaike information criterion, corrected (AICc), model selection and nonmetric multidimensional scaling (NMDS) to assess how land-cover and pond characteristics influence amphibian and reptile richness, diversity, and community structure. Our results indicate that, despite reduced water quality, amphibian diversity was higher in ponds with cattle access, though this is likely influenced by surrounding forest, pasture, and row-crop cover. Pond permanence was important in shaping amphibian community structure and is a key factor in determining amphibian richness. We did not find any link between land cover and cattle access on reptile richness or diversity, though reptile community structure was influenced by cattle access, pasture, and row-crop cover.

Multi‐Species Occupancy Modeling Provides Novel Insights into Amphibian Metacommunity Structure and Wetland Restoration

A fundamental goal of community ecology is to understand species-habitat relationships and how they shape metacommunity structure. Recent advances in occupancy modeling enable habitat relationships to be assessed for both common and rare species within metacommunities using multi-species occupancy models (MSOM). These models account for imperfect species detection and offer considerable advantages over other analytical tools commonly used for community analyses under the elements of metacommunity structure (EMS) framework. Here, we demonstrate that MSOM can be used to infer habitat relationships and test metacommunity theory, using amphibians. Repeated frog surveys were undertaken at 55 wetland sites in southeastern Australia. We detected 11 frog species from three families (Limnodynastidae, Myobatrachidae, and Pelodryadidae). The rarest species was detected at only one site whereas the most common species was detected at 42 sites (naive occupancy rate 0.02-0.76). Two models were assessed representing two competing hypotheses; the best-supported model included the covariates distance to the nearest site (connectivity), wetland area, presence of the non-native eastern mosquitofish (Gambusia holbrooki), proportion cover of emergent vegetation, an interaction term between Gambusia and emergent vegetation cover, and the proportion canopy cover over a site. Hydroperiod played no detectable role in metacommunity structure. We found species-habitat relationships that fit with current metacommunity theory: occupancy increased with wetland area and connectivity. There was a strong negative relationship between occupancy and the presence of predatory Gambusia, and a positive interaction between Gambusia and emergent vegetation. The presence of canopy cover strongly increased occupancy for several tree frog species, highlighting the importance of terrestrial habitat for amphibian community structure. We demonstrated how responses by amphibians to environmental covariates at the species level can be linked to occupancy patterns at the metacommunity scale. Our results have clear management implications: wetland restoration projects for amphibians and likely other taxa should maximize wetland area and connectivity, establish partial canopy cover, and eradicate Gambusia or provide aquatic vegetation to mitigate the impact of this non-native fish. We strongly advocate the use of MSOM to elucidate the habitat drivers behind animal occupancy patterns and to derive unbiased occupancy estimates for monitoring programs.

Multi-species occupancy modeling provides novel insights into amphibian metacommunity structure and wetland restoration.

A fundamental goal of community ecology is to understand species-habitat relationships and how they shape metacommunity structure. Recent advances in occupancy modeling enable habitat relationships to be assessed for both common and rare species within metacommunities using multi-species occupancy models (MSOM). These models account for imperfect species detection and offer considerable advantages over other analytical tools commonly used for community analyses under the elements of metacommunity structure (EMS) framework. Here, we demonstrate that MSOM can be used to infer habitat relationships and test metacommunity theory, using amphibians. Repeated frog surveys were undertaken at 55 wetland sites in southeastern Australia. We detected 11 frog species from three families (Limnodynastidae, Myobatrachidae, and Pelodryadidae). The rarest species was detected at only one site whereas the most common species was detected at 42 sites (naive occupancy rate 0.02-0.76). Two models were assessed representing two competing hypotheses; the best-supported model included the covariates distance to the nearest site (connectivity), wetland area, presence of the non-native eastern mosquitofish (Gambusia holbrooki), proportion cover of emergent vegetation, an interaction term between Gambusia and emergent vegetation cover, and the proportion canopy cover over a site. Hydroperiod played no detectable role in metacommunity structure. We found species-habitat relationships that fit with current metacommunity theory: occupancy increased with wetland area and connectivity. There was a strong negative relationship between occupancy and the presence of predatory Gambusia, and a positive interaction between Gambusia and emergent vegetation. The presence of canopy cover strongly increased occupancy for several tree frog species, highlighting the importance of terrestrial habitat for amphibian community structure. We demonstrated how responses by amphibians to environmental covariates at the species level can be linked to occupancy patterns at the metacommunity scale. Our results have clear management implications: wetland restoration projects for amphibians and likely other taxa should maximize wetland area and connectivity, establish partial canopy cover, and eradicate Gambusia or provide aquatic vegetation to mitigate the impact of this non-native fish. We strongly advocate the use of MSOM to elucidate the habitat drivers behind animal occupancy patterns and to derive unbiased occupancy estimates for monitoring programs.

The Amphibian Skin Microbiome and Its Protective Role Against Chytridiomycosis

Here we review the knowledge about skin microbiomes in amphibians accumulated over the last two decades and the evidence regarding the protective role of skin bacteria. Amphibians all over the world are declining because of several factors, including chytridiomycosis disease caused by the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans. In this context, the antifungal capacities of many bacteria living symbiotically on amphibian skin, which have been described both in vitro and in vivo, are important in disease prevention. We discuss the major factors influencing amphibian skin bacterial communities, the fungal component of the amphibian skin microbiome, and the potential use of antifungal bacteria as probiotics. The structure of amphibian skin microbial communities is influenced by host-specific microhabitat, biogeographic, and climatic factors, but the functional aspects of these microbiomes and how these nested factors modulate skin microbial functions remains largely unexplored. However, the field has grown considerably, and recent technologies have prompted the exploration of exciting new questions aimed at providing more detailed knowledge about the ecology of amphibian–microbial symbioses and the precise role of the skin microbiome in protecting host amphibians against emerging diseases.

Invasive Species and Amphibian Conservation

The recognition that invasive alien species (IAS) are among the greatest threats to biodiversity has stimulated a growing interest in their impacts on native amphibians. Here we describe the multifaceted consequences of biological invasions on native amphibians and identify potential mechanisms and strategies that could better enable the long-term persistence of native species. IAS can influence amphibian fitness, population size, and community structure via multiple pathways and can exert major, direct impacts through predation, competition, and hybridization. The consequences of indirect impacts, too, such as habitat alteration and the spread of emerging diseases, can be particularly severe in native populations. Native amphibians may respond to IAS by modulating aspects of their behavior, morphology, or life history. Nevertheless, it is still unclear the extent to which phenotypic plasticity and rapid evolution may help native species withstand the impacts of IAS in invaded communities. Practical management strategies focused on prevention, monitoring, and early control are the most effective approaches to allay the impacts of IAS and should be prioritized in proactive conservation plans. Eradications of IAS and mitigation approaches, should IAS become established, are feasible and can greatly improve the status of native populations.

Functional Responses of Larval Marbled Salamanders (Ambystoma opacum) and Adult Lesser Sirens (Siren intermedia) on Anuran Tadpole Prey

Predation can have strong effects on the structure of pond-breeding amphibian communities. Many factors can influence the outcome of predator–prey interactions, including differences in densities, identities, and body sizes of both predator and prey. These different mediating factors can impart synergistic impacts on predation rates, though distinguishing such interactions among multiple factors are underexplored. We examined whether different body sizes of two predators, larval Marbled Salamanders (Ambystoma opacum) and adult Lesser Sirens (Siren intermedia), varied in their ability to forage on larval anurans across a range of prey densities. We specifically tested whether attack rates and handling times, the two main parameters of functional response models, varied across three size classes in both predator species. We found that larval Marbled Salamanders exhibited a Type II (saturating) functional response and that larger individuals had higher attack rates and shorter handling times, resulting in greater prey mortality at higher prey densities with larger predators. In contrast, Lesser Sirens were largely ineffective predators despite being an order of magnitude larger in body size than Marbled Salamanders; tadpole mortality was largely unrelated to their own density. Predator body size was a significant predictor of prey mortality for both predator species. Overall, our study shows that species identity could be as important as predator body size when predicting the outcomes of predator–prey interactions.

Land cover drives amphibian diversity across steep elevational gradients in an isolated neotropical mountain range: Implications for community conservation

Over 70% of land in the tropics is in some form of agricultural matrix which poses a threat to biodiversity. In Colombia, montane regions are dominated by varying intensities of agriculture and high levels of biodiversity and endemism. Globally, Colombia has the second largest number of amphibian species and is also the third largest coffee producer. Our study region, the Sierra Nevada de Santa Marta (SNSM), has high levels of amphibian endemism (38% and 10 threatened endemics) and is the fourth largest coffee growing region in Colombia. The SNSM rises from the sea to 5,775 m in just 42 km, with a direct overlap between coffee and amphibian habitat occurring across 600–1,800 m. We examined how land cover and elevation (from 800 to 3,700 m asl) influenced amphibian community structure, species richness, and abundance. We conducted surveys from September 2017 to July 2018 at 35 transects across five major land cover types: forest, ecotone, páramo, pasture, and shade coffee. In total, we recorded 19 species (366 individuals; 16 endemic species). Land cover was the main determinant of amphibian community structure, while the interaction between elevation and land cover was the main determinant of species richness and abundance. Forest and ecotone contained 73% of overall richness (14 species) with one species found exclusively in ecotone and three exclusively in forest. Pasture and coffee supported 42% (8 species) of species with only two species found exclusively at these land cover types. Shade coffee had low species richness and abundance and we detected just one endemic species in this land cover. The preservation of ecotone, transitional degraded habitat that occurs between two or more types of contiguous land cover types, represents an opportunity to safeguard microhabitats and microclimates. Conservation in the region should be collaborative and include private landowners, NGO’s, government agencies, and academics. Conservation actions should prioritize protecting extant natural habitat, restoring degraded habitats, increasing the heterogeneity of production systems, and improving landscape connectivity and watershed health. To achieve those actions, local communities will require economic incentives to maintain forest cover and reduce the contamination of streams through agricultural runoff.

A Preliminary Study on the Amphibian Community Structure in South Sudan (East Africa)

The structure of amphibian communities in South Sudan (East Africa) has never been studied so far. In this paper, the community composition and the diversity patterns of amphibians in nine study sites and in four different habitat types in Jubek area of South Sudan, are analyzed. In addition, the effects of habitat types on the abundance patterns of each species are also explored by Generalized Linear Models. Both pitfall traps with drift fences and Active Search Visual encounter survey were used for the sampling of the amphibians. A total of 551 individuals from 14 species, and belonging to 9 different families, were recorded during the present study, with two ranid and one Ptychadenidae species dominating the sample (i.e., Phrynobatrachus natalensis , Hoplobatrachus occipitalis , Ptychadena nilotica ). The arthroleptid Leptopelis bocagii was reported for the first time in South Sudan. Despite an identical field effort among habitats, there was a statistically uneven number of individuals by habitat, with significantly higher-than-expected individuals found in wetlands/swamps and in farmlands. Farmlands had higher values for Shannon – Wiener and Evenness was much higher in stream and in farmlands than in any other habitats. Our study revealed a relatively low diversity of amphibian species across sites and habitats. For instance, whereas in our study we found a range of 2 – 13 species per locality and 4 – 11 species per habitat type, whereas there were up to 24 – 29 species per site in Uganda.

Amphibian community structure along elevation gradients in eastern Nepal Himalaya

BackgroundSpecies richness and composition pattern of amphibians along elevation gradients in eastern Nepal Himalaya are rarely investigated. This is a first ever study in the Himalayan elevation gradient, the world’s highest mountain range and are highly sensitive to the effects of recent global changes. The aim of the present study was to assess amphibian community structure along elevation gradients and identify the potential drivers that regulate community structures. Amphibian assemblages were sampled within 3 months in both 2014 and 2015 (from May to July) using nocturnal time constrained and acoustic aids visual encounter surveys. In total, 79 transects between 78 and 4200 m asl were sampled within 2 years field work. A combination of polynomial regression, generalized linear models, hierarchical partitioning and canonical correspondence analysis were used to determine the effects of elevation and environmental variables on species richness, abundance, and composition of amphibian communities.ResultsSpecies richness and abundance declined linearly with increasing elevation, which did not support the Mid-Domain Model. Among all the environmental variables, elevation, surface area and humidity were the best predictors of species richness, abundance and composition of amphibians. The majority of amphibian species had narrow elevation ranges. There was no significant correlation between species range size and elevation gradients. However, body size significantly increased along elevation gradients, indicating that Bergmann’s rule is valid for amphibians in eastern Nepal Himalaya.ConclusionsThis study indicates that eastern Nepal Himalaya is a hotspot in amphibian diversity, and it should be served as a baseline for management and conservation activities.

Response of reptile and amphibian communities to the reintroduction of fire in an oak/hickory forest

Fire can have diverse effects on ecosystems, including direct effects through injury and mortality and indirect effects through changes to available resources within the environment. Changes in vegetation structure such as a decrease in canopy cover or an increase in herbaceous cover from prescribed fire can increase availability of preferred microhabitats for some species while simultaneously reducing preferred conditions for others. We examined the responses of herpetofaunal communities to prescribed fires in an oak/hickory forest in western Kentucky. Prescribed fires were applied twice to a 1000-ha area one and four years prior to sampling, causing changes in vegetation structure. Herpetofaunal communities were sampled using drift fences, and vegetation attributes were sampled via transects in four burned and four unburned plots. Differences in reptile community structure correlated with variation in vegetation structure largely created by fires. Amphibian community structure differed on a yearly basis, indicating that sampled communities were likely influenced by environmental factors other than the burning. We found taxa-specific differences in abundances for Coluber constrictor, Diadophis punctatus, Sceloporus undulatus, Lithobates clamitans and snakes as a group, being more abundant in burned areas while Anaxyrus sp., Notophthalmus viridescens and Plethodon glutinosus were more abundant in unburned areas. Differences in amphibian taxa abundances may have been influenced by availability of aquatic breeding habitat and yearly weather variation. Our results suggest that the vegetation structure changes caused by prescribed fire can have indirect impacts on reptile abundances and community structure, while not significantly impacting amphibian communities.

Effects of agriculture and topography on tropical amphibian species and communities.

Habitat loss is the greatest threat to the persistence of forest-dependent amphibians, but it is not the only factor influencing species occurrences. The composition of the surrounding matrix, structure of stream networks, and topography are also important landscape characteristics influencing amphibian distributions. Tropical forests have high diversity and endemism of amphibians, but little is known about the specific responses of many of these species to landscape features. In this paper, we quantify the response of amphibian species and communities to landscape-scale characteristics in streams within the fragmented Brazilian Atlantic Forest. We surveyed amphibian communities during a rainy season in 50 independent stream segments using Standardized Acoustic and Visual Transect Sampling (active) and Automated Acoustic Recorders (passive) methods. We developed a hierarchical multi-species occupancy model to quantify the influence of landscape-scale characteristics (forest cover, agriculture, catchment area, stream density, and slope) on amphibian occurrence probabilities while accounting for imperfect detection of species using the two survey methods. At the community level, we estimated an overall mean positive relationship between amphibian occurrence probabilities and forest cover, and a negative relationship with agriculture. Catchment area and slope were negatively related with amphibian community structure (95% credible interval [CI] did not overlap zero). The species-level relationships with landscape covariates were highly variable but showed similar patterns to those at the community level. Species detection probabilities varied widely and were influenced by the sampling method. For most species, the active method resulted in higher detection probabilities than the passive approach. Our findings suggest that small streams and flat topography lead to higher amphibian occurrence probabilities for many species in Brazil's Atlantic Forest. Our results combined with land use and topographic maps can be used to make predictions of amphibian occurrences and distributions beyond our study area. Such projections can be useful to determine where to conduct future research and prioritize conservation efforts in human-modified landscapes.

Трансформация структуры нерестовых сообществ бесхвостых амфибий пойменных озёр долины р. Медведица (Саратовская область) в условиях многолетнего снижения водности

The structure of spawning taxocenoses of anuran amphibians in five floodplain lakes of the Medveditsa river valley in 2009–2018 is analysed. Two near-terrace lakes (Lebyazhye and Koblovo) and three lakes of the central floodplain (Sadok, Kruglen’koye, and Cherepashie) were used as model ones. The degradation of the populations of the three most numerous species, a decrease in the dominance degree of the common spadefoot toad were established. Degradation is more characteristic of species with a longerer distance of spawning migrations – the severity of changes consistently decreases in the row of species: Pelophylax ridibundus → Pelobates fuscus → Bombina bombina . Indices of the structure of amphibian communities in the near-terrace lakes Lebyazhye and Koblovo were stable. Against the background of low water content and unstable hydrological regime of the central floodplain lakes with a survey duration of five or more years, three periods were established to characterize the structure of spawning amphibian taxocenoses, namely: a stable structure, a sharp decrease in dominance and an increase in evenness, and an increase in the variability of the main attributes of the structure. At the end of the third period, which characterizes the structure of taxocenoses, some stabilization of the main parameters was noted with an extremely low number of mature individuals of all amphibian species. The high level of spring flood of the Medveditsa river in 2018 determined the beginning of the exit from the abnormally long period of low water content of the spawning lakes in the floodplain (from 2009 till 2017) and their functioning in the hydrological regime as temporary water bodies. The sudden increase in water content of the floodplain lakes and the extension of their hydroperiod allow the beginning of the recovery process of the population size and community structure of anuran amphibians to be noted.

In the Shadow of Trees: Does Eucalyptus Afforestation Reduce Herpetofaunal Diversity in Southern Brazil?

Abstract. Tree cultivation is widely stimulated due to the provision of environmental services by sequestering atmospheric carbon, but forestry is a potential danger to biodiversity, mainly when cultivation replaces originally non-forested landscapes. Due to the rapid expansion of afforestation in grassland ecosystems, we used environmental descriptors and structure of amphibian and reptile communities as a tool to assess the possible effects of forestry on wildlife. We used pitfall traps with drift fences in Eucalyptus afforestation and native grasslands of the Pampa biome from southern Brazil. Amphibians and reptile species richness was lower in afforestation than in native grasslands. Furthermore, the reptile community found in afforestation was a poor subset of the community recorded in native grasslands. Indeed, the structure of communities for both amphibians and reptiles in afforestation was highly dissimilar from the native grasslands, with major environmental descriptors that influenced this diff...

A metabolic view of amphibian local community structure: the role of activation energy

In the context of the metabolic theory of ecology (MTE), the activation energy (E) reflects the temperature dependence of metabolism and organism performance in different activities, such as calling behavior. In this contribution we test the role of temperature in affecting local amphibian community structure, particularly the number of species engaged in calling behavior across a temperature gradient. Toward this aim, we compiled phenological calling activity for 52 Neotropical anuran communities. For each community we estimated the activation energy of calling behavior (E), finding values significantly higher than previous reports. A wide range of methodological issues with the potential to produce overestimated E‐values were shown to have no significant effect on reported E‐values, supporting a biological interpretation of their high values and of geographic trends. Further, a path analysis related variation in E among communities with communities’ phylogenetic structure, local environmental conditions, richness, and seasonality. The decrease of activation energy at higher latitudes and less productive environments suggests that amphibians’ activity could become more dependent of internal individuals’ resources once external sources are reduced. The increase in phylogenetic attraction with latitude points to a rise in the role of niche conservatism and community filtering operating over conserved traits. Finally, flexibility in activation energy related to amphibians’ calling could be an important and poorly recognized determinant of their thermal dependence. The temporal structuring of amphians’ communities was related here with the interplay between ecological and evolutionary processes operating at different scales. Our results support the view of activation energy as an important parameter of biodiversity organization, which unravels the effects of ecological and evolutionary processes on biodiversity structure and function.

An inter-dependence of flood and drought: disentangling amphibian beta diversity in seasonal floodplains

Species composition in floodplains is often affected by different structuring factors. Although floods play a key ecological role, habitat selection in the dry periods may blur patterns of biodiversity distribution. Here, we employed a partitioning framework to investigate the contribution of turnover and nestedness to β-diversity patterns in non-arboreal amphibians from southern Pantanal ecoregion. We investigated whether components of β-diversity change by spatial and environmental factors. We sampled grasslands and dense arboreal savannas distributed in 12 sampling sites across rainy and dry seasons, and analysed species dissimilarities using quantitative data. In the savannas, both turnover and nestedness contributed similarly to β diversity. However, we found that β diversity is driven essentially by turnover, in the grasslands. In the rainy season, balanced variation in abundance was more related to altitude and factors that induce spatial patterns, whereas dissimilarities were not related to any explanatory variable during dry season. In the Pantanal ecoregion, amphibian assemblages are influenced by a variety of seasonal constraints on terrestrial movements and biotic interactions. Our findings highlighted the role of guild-specific patterns and indicated that mass effects are important mechanisms creating amphibian community structure in the Pantanal.