Anuran Species Richness Research Articles

Species richness and endemism of anurans in lake Duminagat, Mt. Malindang range natural park, Mindanao, Philippines

Species richness and endemism of anurans in lake Duminagat, Mt. Malindang range natural park, Mindanao, Philippines

Relationships of primary productivity with anuran abundance, richness, and community composition in tropical streams.

The relationship between primary productivity and diversity has been demonstrated across taxa and spatial scales, but for organisms with biphasic life cycles, little research has examined whether productivity of larval and adult environments influence each life stage independently, or whether productivity of one life stage's environment outweighs the influence of the other. Experimental work demonstrates that tadpoles of stream-breeding anurans can exhibit a top-down influence on aquatic primary productivity (APP), but few studies have sought evidence of a bottom-up influence of primary productivity on anuran abundance, species richness and community composition, as seen in other organisms. We examined aquatic and terrestrial primary productivity in two forest types in Borneo, along with amphibian abundance, species richness, and community composition at larval and adult stages, to determine whether there is evidence for a bottom-up influence of APP on tadpole abundance and species richness across streams, and the relative importance of aquatic and terrestrial primary productivity on larval and adult phases of anurans. We predicted that adult richness, abundance, and community composition would be influenced by terrestrial primary productivity, but that tadpole richness, abundance, and community composition would be influenced by APP. Contrary to expectations, we did not find evidence that primary productivity, or variation thereof, predicts anuran richness at larval or adult stages. Further, no measure of primary productivity or its variation was a significant predictor of adult abundance, or of adult or tadpole community composition. For tadpoles, we found that in areas with low terrestrial primary productivity, abundance was positively related to APP, but in areas with high terrestrial primary productivity, abundance was negatively related to APP, suggesting a bottom-up influence of primary productivity on abundance in secondary forest, and a top-down influence of tadpoles on primary productivity in primary forest. Additional data are needed to better understand the ecological interactions between terrestrial primary productivity, aquatic primary productivity, and tadpole abundance.

Species-richness, abundance, and body size of stream-breeding anurans across land-use types in Sabah, Malaysia (Borneo)

Approximately 70% of Earth’s surface is impacted by human land-use. While numerous studies have demonstrated that species richness is higher in primary (undisturbed) forest than in secondary forest or agriculture sites, some studies fail to detect differences in species richness across land-use type. Recent work suggests that individual-level changes such as body size or body condition can occur more rapidly than population- or community-level processes, such as abundance and species richness, respectively. Thus, body size and condition may be more sensitive measures of environmental changes. We examined body size, body condition, abundance, and species richness of anurans in primary forest, secondary forest, and agriculture in Sabah, Malaysian Borneo, to determine whether individual-, population-, and community-level measures show similar sensitivities to land-use type. We found that observed anuran species richness and estimated population size are lower in agriculture than in primary or secondary forest, as were body size (SVL), mass, and body condition of female Meristogenys orphnocnemis. Further, anuran body condition (all species pooled) was higher in primary forest than agriculture or secondary forest, and size (SVL), mass, and body condition of male M. orphnocnemis were higher in primary forest than in agriculture or secondary forest areas. Collectively, our data demonstrate that primary forests are the best habitat for anurans in Sabah, and that individual-level processes such as size, mass, and body condition, show larger differences across land-use type than population- (abundance) or community-level processes (species richness). These data highlight the importance of primary forest for preserving anuran biodiversity in Borneo.

Conserving nature's chorus: Local and landscape features promoting frog species richness in farm dams

Habitat loss is a key factor in the ongoing freshwater biodiversity crisis. A promising way to help tackle the rapid decline in freshwater biodiversity is to improve the potential for artificial wetlands to provide habitat for aquatic wildlife. Farm dams (also known as agricultural ponds) are among the most abundant waterbodies in agricultural landscapes and can act as “oases” against droughts for many species. Despite their prominent role in agriculture, predictive models to evaluate their ecological potential are yet to emerge. Here we use a continental-scale data set of 104,013 audio recordings from citizen scientists to identify and locate 107 species of frogs near 8800 Australian farm dams. Frog species are among the most threatened taxa on earth and we asked: What characteristics promote higher frog species richness at farm dams? We found that the highest values of frog species richness were at old (>20 years) farm dams of intermediate size (0.1 ha in surface area), with small or medium rainfall catchments (<10 ha), and situated near other freshwater systems or conservation sites. The relationships shown here are highly generalisable and applicable on a continental scale. By identifying quantifiable features improving the ecological value of farm dams, we help identify “win-win” outcomes for agricultural productivity and conservation. In the future, “biodiversity credit” policies could incentivise large-scale ecological restoration by rewarding individuals who invest in enhancing their farm dams to support and promote local biodiversity.

Fighting the flames: site-specific effects determine species richness of Australian frogs after fire

Context Fire has played an integral role in regulating patterns of biodiversity for millions of years. However, anthropogenic disturbance and climate change has altered fire activity – driving increases in both fire severity and scale. The effect fire now has on the persistence of biodiversity is poorly known, especially for frogs. Studies examining frog responses to fire usually have small sample sizes, focus upon small geographic areas and are based on low-severity fires, which can mean results are not applicable to high-severity fires, such as those expected under future climate change. Aims Our aims were to examine (1) persistence of frog species, measured by species richness, up to 18 months post-fire, and (2) the effects of varying fire severity on frog species richness and recovery, where we expected higher fire severity to lead to lower species richness after fire. Methods Using large-scale citizen science data from the Australian Museum’s FrogID project, coupled with remotely sensed fire data, we present a spatially and taxonomically broad analysis examining post-fire recovery responses for Australian frog species after the 2019/2020 ‘Black Summer’ bushfires. Key results We reveal no overall decrease in the species richness of Australian frogs both in the short- and long-term post-fire. Furthermore, species richness did not decline with increasing fire severity. Instead, species richness and its response to fire was highly site-specific. Conclusions We provide evidence that widespread and common Australian frog species have persisted post-fire in most sites and concluded that this is potentially due to their ability to shelter from fire adequately and/or La Niña-driven high rainfall offering conditions conducive to breeding activity and persistence. Implications We show how citizen science provides critical data for conservation, especially in response to unprecedented disturbance events, such as the 2019/2020 megafires. Our research also highlights the need for ongoing and targeted scientific monitoring, especially for less common or threatened species.

The effect of inundation on frog communities and chorusing behaviour

Globally, river regulation has degraded wetlands, including parts of the Murray-Darling Basin (MDB), an ecologically significant basin in Australia. Frogs in a floodplain environment largely depend on habitats created by river flows, but little is known about how frogs in the northern MDB are impacted by river regulation. We tested how wetland inundation affected frogs in a catchment of the northern MDB. We surveyed frogs between 2015 and 2019 to determine long-term changes in the community composition associated with wetland inundation from river flows. Additionally, we recorded nightly soundscapes for four days before and after the arrival of river flows between 2019 and 2020. The abundance and richness of frog species increased during larger inundation events leading to altered community composition (beta diversity). Warmer temperatures increased frog species richness, and frog community dominance decreased with decreasing vegetation cover (i.e., the relative abundance became more even across species). The abundance of five frog species (Limnodynastes tasmaniensis, Limnodynastes fletcheri, Crinia parinsignifera, Litoria peronii, and Litoria latopalmata) was higher in response to increased inundation extent. The total species richness of chorusing frogs increased after the arrival of river flows; six species chorused over the four nights preceding flow, whereas eight species chorused following the flow arrival, but the responses varied among species and sites. Frog species richness increased at three sites after flows, but not at others. After inundation, the choruses of Limnodynastes tasmaniensis increased whereas Limnodynastes fletcheri decreased. Our findings indicate that wetland inundation is beneficial for frog communities and suggest that chorusing behaviour varied in response to river flows inundating floodplain wetlands.

Population divergence associated with spatial asynchrony in precipitation in Neotropical frogs

AbstractAimThe role that geography plays in promoting speciation by spatially isolating populations has been studied extensively, but less attention has been devoted to assessing the role of isolation by time mediated by spatial variation in climate as a mechanism promoting population divergence. Gene flow between populations differing in their reproductive schedules might be reduced relative to that between populations with overlapping breeding seasons, potentially leading to genetic divergence. Assuming that precipitation influences reproductive schedules, we explored the effect of asynchronous precipitation regimes on intraspecific genetic divergence. In addition, we examined whether microevolutionary processes are reflected in macroevolutionary patterns by assessing whether regions with more asynchronous precipitation across space have higher frog species richness and have experienced greater speciation rates than regions with more spatially synchronous precipitation regimes.LocationCentral and South America.TaxonAnurans: across 38 species of Neotropical frogs.MethodsFor microevolutionary analyses, we assessed the relationship between spatial asynchrony in precipitation and mitochondrial DNA genetic divergence accounting for ecological connectivity using multiple regression and phylogenetic meta‐analyses. For macroevolutionary analyses, we assessed the relationship between species richness, speciation rates estimated from a comprehensive molecular phylogeny, and the degree of spatial asynchrony in precipitation using generalized linear models.ResultsWe found that spatial asynchrony in precipitation is positively associated with genetic differentiation in 39% of the species tested, resulting in a weak cross‐species effect. However, the effect of asynchrony in precipitation on population divergence seems not to scale to macroevolutionary patterns because spatial asynchrony in precipitation was not associated with geographical patterns of species richness nor speciation rates.Main ConclusionsOur results indicate that asynchronous breeding may promote genetic divergence even in the absence of geographical barriers in species where breeding is associated with water availability, but such effects may not be stable enough through time to influence macroevolutionary patterns.

Anurans (Amphibia: Anura) of the Brazilian state of Amapá, eastern Amazonia: species diversity and knowledge gaps

We herein present the first annotated anuran checklist for the Brazilian state of Amapá, eastern Amazonia, based on a thorough literature review. We recorded the occurrence of 111 species belonging to 13 anuran families distributed across 48 localities throughout Amapá, within two biomes. Among these species, 62.5% occur exclusively in the Tropical Moist Broadleaf Forest biome, ~8% occur exclusively in the Tropical Savanna biome, and ~29% occur in both. Two species were considered endemic to Amapá and were registered only in the central portion of the state. Regarding the conservation status, only one species (Dendropsophus amicorum) is classified as threatened, assigned to the “critically endangered” category. The other species are categorized as either “least concern” or “data deficient” (85 and 8, respectively), whereas 21 are not evaluated. The current annotated list contributes to the incipient knowledge on anuran species richness in Amapá and, despite the research regarding anuran taxonomy has considerably progressed over the past 20 years, there is still much to do. Our data highlight the need for trained taxonomists to develop research in the state.

Human density and sampling time explain richness of anurans in the brazilian biomes

Anuran richness patterns are strongly influenced by environmental factors. However, investigations on this issue have focused on the influence of abiotic factors without considering the joint effect of many existing variables, including the data sampling methodology and human demography. In this study we investigated the relationship between 21 environmental variables and anuran richness in brazilian biomes. Environmental variables represent a combination of human demographics, topographic, climatic and vegetation characteristics, and data sampling methodologies. We used principal component factorization and regressive and autoregressive models to select the most relevant variables for explaining anuran richness. Richness was correlated with demographic density, vegetation, accumulated rainfall, accumulated rainfall in the third and fourth quarter of the year, and accumulated rainfall in the first and second half of the year. However, the regressive and autoregressive models showed that human demographic density, sampling time, and sampling methodology were the best predictors of anuran richness. Our results highlight the importance of considering the effects of the human footprint and the methodology used for data collection on anuran species richness.

Altitude and temperature drive anuran community assembly in a Neotropical mountain region

AbstractUnderstanding the spatial variation in species richness and the mechanisms that limit species range sizes along geographical gradients belong to the central research issues in macroecology. Here, we aim to test the topographic and climatic effects on anuran species richness and community composition in mountainous regions in the Brazilian Atlantic Forest biome. We used Individual‐Based Rarefaction Curve (interpolation and extrapolation), Generalized Additive Model (GAM), Midpoint method and Principal Coordinates Analysis (PCoA) to analyze the topographic and climatic effects on anuran community composition, richness, and range sizes in a global biodiversity hotspot. Our results showed that altitude and annual mean temperature and temperature seasonality were the main drivers of species altitudinal range sizes and community assembly in mountainous regions. In conclusion, Anuran community richness peaked at intermediate altitudes following thus a hump‐shaped pattern and corroborated the Rapoport's altitudinal rule as range sizes increased with altitude in mountainous regions from the Atlantic Forest biome. This study revealed new insights into the patterns and drivers of Neotropical anuran communities.Abstract in Portuguese is available with online material.

High species turnover shapes anuran community composition in ponds along an urban-rural gradient

The rapid expansion of urban areas in which natural and semi-natural areas are replaced by human infrastructure, is a major threat to biodiversity worldwide. However, little is known about how the structure of biotic communities is affected by urbanization in the tropics. Here, we tested the effect of land use types and pond size in urban and rural areas on frog species richness and community composition in central Brazil. We selected 20 ponds differing in size and surrounding levels of urbanization and native vegetation cover. We quantified relationships between environmental variables and species richness and community composition using a Poisson GLM and a distance-based Redundancy Analysis (db-RDA), respectively. Variation in species richness was positively related to pond size and negatively related to the amount of urbanization in a 500 m buffer around ponds. Community composition was mainly driven by species turnover than by nestedness, with turnover being explained primarily by urbanization and native vegetation cover. Our results indicate that urbanization negatively influences species richness. Moreover, as the amount of urbanization increased, several species were replaced by other taxa better adapted to urban environments. Our results indicate that understanding the effects of urbanization on amphibians in tropical cities might improve conservation strategies, such as preserving large ponds in urban environments.

Biodiversity hotspot revisited: reptile and amphibian assemblages of the Uluguru Mountain Forest Reserves, south-eastern Tanzania

ABSTRACT Although the knowledge about the Tanzanian reptiles and amphibians has drastically increased in recent years, the knowledge on the amphibian and reptile fauna of the remaining forest reserves of the Uluguru Mountains (UMs) is only partially known. Amphibians and reptiles were studied in 17 forest reserves and sampled using diurnal and nocturnal time-constrained visual encounter surveys, acoustic surveys and opportunistic searches. A total of 51 quadrats of 25 × 25 m were randomly established on the forest floor, totalling 459 person-hours of sampling effort. Overall, 54 herpetofauna species (27 amphibian and 27 reptile species) were recorded from the area, including two anurans and seven reptile species, which are new records for the region. The estimated Chao1 species richness for the study region was 51 for amphibians and 76 for reptiles. Amphibian and reptile species composition did not differ significantly across the forest reserves, but similarities in species composition of different levels were evident across the reserves. For both communities, α-diversity and relative abundance did not vary significantly across the reserves. Based on multiple regression analyses, leaf-litter anuran species richness was positively influenced by percentage canopy cover, whereas abundance was negatively influenced by total fragment size. Partial correlations showed that variation in leaf-litter anuran abundance was explained by relative humidity, percentage canopy cover and soil moisture, while controlling for altitude. Percentage canopy cover was also the best predictor of species richness of leaf-litter anurans. Overall, these findings highlight the importance of protecting the UMs forest reserves for herpetofauna conservation.

Increasing number of point counts influences estimates of bird and anuran species richness at the wetland scale

Increasing number of point counts influences estimates of bird and anuran species richness at the wetland scale

The Role of Urbanness, Vegetation Structure, and Scale in Shaping Puerto Rico's Acoustically Active Mangrove Fauna Communities.

The mangroves of Puerto Rico occupy a gradient of urbanization that offers a chance to test hypotheses on urban faunal communities. These hypotheses state that urban avifaunal communities have greater representation by generalists and that certain mangrove specialists can utilize urban landscapes. Much of this is said to be driven by food resources, with frugivores and nectarivores benefiting from abundant residential flowers and fruits, while insectivores are driven away by low food resources. This study used passive acoustic monitoring to identify the audible anuran and avifaunal species in mangroves across an urban gradient of Puerto Rico. Five anurans and thirty-one avian species were detected across all sites, with twenty-three species found at the most species rich site, and eight at the least rich site. Analyses on urban effects were conducted at an island-wide scale as well as a local scale with different results between the two. Island wide, the most urban faunal communities were more similar to each other in species composition relative to the least urban communities, and there was a significant difference in the community composition between the two. However, there were no differences in avian or anuran species richness between the least and most urban sites. Minimum canopy height was the strongest predictor of overall avian richness and avian invertivore richness, while the extent of mixed forest cover was the strongest predictor for increasing anuran richness. Some urban metrics, such as street density and the percent of surrounding urban and developed open space were strong predictors of certain avian feeding guilds and distribution groups. At the local scale, sites of maximum urbanness held 2-3 more bird species on average than corresponding sites of minimum urbanness at the same location, although there was no difference in anuran species and no differences in avian or anuran community composition between the two. Further, avian richness did increase significantly from the minimum to maximum urbanness site at six of the nine locations. These findings highlight that higher mangrove canopies are the strongest predictor of higher avian richness, but depending on the scale of observations, urbanness also plays a limited role in shaping mangrove faunal communities.

Urbanization negatively impacts frog diversity at continental, regional, and local scales

Urban environments are novel ecosystems, with increased chemical, sound, and light pollution differentially impacting many animals. Understanding the impacts of urban environments on biodiversity is the first step to understanding how to best mitigate biodiversity losses in an increasingly urbanizing world. Analyses with broad geographic and taxonomic coverage can offer critical context for informing urban biodiversity conservation. But such studies are currently lacking, especially for under-studied, but likely highly impacted, taxa such as frogs. Our objective was to document frog diversity in relation to urban environments at continental, regional, and local scales. We used FrogID data, ⁠an opportunistic citizen science dataset generated by volunteers recording calling frogs using a smartphone and validated by experts ⁠throughout continental Australia, to calculate species richness, Shannon diversity, and phylogenetic diversity of frogs in urban and non-urban areas, as well as along a continuous urbanization gradient. The overall species richness of frogs was, on average, 57% less in urban than non-urban areas across six ecoregions. Further, we found significantly lower frog diversity in urban environments compared with non-urban environments across the country, with an average reduction of 59% species richness, 86% Shannon diversity, and 72% phylogenetic diversity. We also found evidence for a steady decrease in frog diversity along an urbanization gradient, with no obvious thresholds. Our results highlight the negative impacts of urbanization, ⁠at a continental scale, ⁠on frog diversity, and clearly highlight the necessity to consider frog diversity in future urban land development decisions.

Battling habitat loss: suitability of anthropogenic waterbodies for amphibians associated with naturally acidic, oligotrophic environments

Habitat destruction is a key threatening process for amphibians. Modified or anthropogenic waterbodies can be used to compensate for habitat loss, with several amphibian species utilising created or modified waterbodies. We measured usage of anthropogenic/modified waterbodies by adult and tadpole frog species, including threatened species, in coastal wallum habitat in eastern Australia. Nine road trenches/ditches, 8 artificial ‘lakes’, 6 golf course waterbodies and 13 natural waterbodies were surveyed for frog adults and tadpoles during the summer/spring period 2011–2012. Additionally, we examined the relationship between frog assemblages and environmental factors (water chemistry, aquatic predators, vegetation types), focusing on Litoria olongburensis and Litoria fallax. Frog species richness differed between waterbody types, with two of three threatened frog species present in both natural and anthropogenic/modified waterbodies. The frog assemblage was influenced by pH, turbidity, salinity and percentage cover of certain vegetation types. Measured abundance of L. olongburensis adults and tadpoles were highest in natural waterbodies with high sedge density and low pH. The measured abundance of adult L. fallax was highest within artificial lakes. We conclude that differences in water chemistry and vegetation density can affect the amphibian assemblage within these environments. Therefore, effective conservation of all frog species would be enhanced by conserving a variety of waterbody types. However, natural waterbodies are more likely to be used by threatened species and the conservation of these waterbodies provides the best conservation outcomes. Where habitat offsets may be required, environmental managers should critically assess the quality of constructed habitat for specialist frog species including those associated with acidic, oligotrophic environments.

Habitat amount and ambient temperature dictate patterns of anuran diversity along a subtropical elevational gradient

AbstractAimPatterns of diversity along elevational gradients are driven by species characteristics but remain poorly understood. Filling this gap is imperative given the deteriorating conservation status of anurans worldwide. Here, we examine frog diversity and species composition along a sharp subtropical elevational gradient and assess the degree to which these are determined by environmental and spatial predictors.LocationAn extensive southern Brazilian Atlantic Forest elevational gradient ranging from 300 to 1,800 m above sea level.MethodsWe sampled 38 ponds and used structural equation modelling to examine the direct and indirect effects of area, climate, habitat amount, habitat complexity and productivity on frog species richness and abundance. We also applied joint species distribution models to investigate the importance of these predictors on frog species composition using species distribution and co‐occurrence along the elevational gradient.ResultsWe recorded 12,636 individuals of 41 frog species. Frog species richness was highest at intermediate elevations, showing a hump‐shaped pattern. Frog abundance was highest at lowlands and decreased towards higher elevations. We found support for only the habitat amount hypothesis in explaining overall species richness. Although temperature had a positive influence on productivity and frog abundance, neither predictors were related to species richness. Species composition diverged markedly between lowland and highland frog assemblages, which was mainly attributed to differences in ambient temperature.Main conclusionElevations containing more extensive natural habitat areas retained the most species‐rich frog assemblages. The mid‐elevational peak is likely attributed to lowland habitat (&lt;800 masl) heterogeneity and extreme climatic conditions in highland areas (&gt;1,400 masl). The entire elevational gradient is, however, critical in maintaining anuran species diversity as lowland assemblages are distinct from those at mid‐ to high elevations. Our study also shows that anthropogenic habitat loss has a decisive effect on montane frog diversity, reinforcing the need to effectively protect these areas.

Structure of the leaf litter frog community in an area of Atlantic Forest in southeastern Brazil

Different spatial and temporal factors can influence the species richness and abundance of leaf anurans that are fundamental for the ecosystem functioning, as they act as predators and integrate the trophic chain as prey of other animals. There are relatively few studies that aimed to understand the spatio-temporal variation and the influence of environmental factors on leaf litter communities. We studied parameters of the anuran community living in the forest leaf litter in the Duas Bocas Biological Reserve (DBBR), Espírito Santo, Brazil. We sought to understand the extent to which richness, abundance, biomass and density varied between two locations with different stages of preservation (primary and secondary forest). In addition, we tested the effect of temperature and local humidity on abundance. We conducted the samplings monthly from October 2017 to September 2018, establishing 98 4 x 4 m plots (16 m2 each) demarcated on the DBBR forest leaf litter. We measured temperature (°C) and relative air humidity (%), and each plot was carefully surveyed by four observers. We tested for differences in anuran density between the two sampled locations and estimated the effects of environmental variables in the community. We recorded 102 individuals of anurans from 11 species belonging to eight families. The DBBR anuran community parameters significantly differed between the two studied locations, with the highest values of anuran richness and abundance occurring in the area covered by primary forest, probably due to differences in the preservation of each area. However, temperature and humidity did not affect the abundance of anurans in the sampled areas. Our results provide the first information about spatial variation and influence of environmental factors, directed to the community of leaf litter anurans in DBBR, and represents the second study on this group of anurans in the state of Espírito Santo.

Cumulative effects of high intensity hurricanes on herpetofaunal assemblages along a tropical dry forest chronosequence

If combined with anthropogenic disturbances and global climatic change, hurricanes may lead to major effects on animal populations and assemblages. The combined effects of cumulative natural and human disturbances on vertebrates have been little studied. There is evidence that herpetofaunal assemblages are sensitive in species richness, abundance, and diversity to anthropogenic and natural disturbances, or to their interaction. In the Pacific coast of Jalisco, Mexico, we aimed to evaluate the cumulative effects of hurricanes Jova (2011) and Patricia (2015) on herpetofaunal assemblages along tropical dry forest successional stages by comparing before and after the hurricanes. We conducted a long-term survey (2009 to 2018) on anuran, lizard and snake populations within five dry forest successional stages (from 0 to > 50 years after forest clearance), including the following: active pastures, early forests, young forests, intermediate forests, and old-growth forests as experimental controls. We hypothesized that cumulative effects of hurricanes will result in a general pattern of a decrease in abundance, richness and diversity, and an increase in evenness of anurans, lizards and snakes. We also expected that herpetofaunal diversity will decrease and evenness will increase in those stages with higher vegetation complexity, such as old-growth forest (OGF), and an increase in similarity and evenness in herpetofaunal assemblages in all successional stages. Overall, the abundance of anurans, lizards and snakes significantly decreased after hurricanes, but only for lizards and anurans the interaction of successional stage-hurricane was significant. Furthermore, species richness and diversity increased for lizards and decreased for snakes after hurricanes landed. Although, the pattern of anuran species richness among successional stages was similar after hurricanes, the richness in OGF markedly diminished after hurricanes.Interestingly our results showed that tropical dry secondary forests, under the impact of low intensity hurricanes, might function as buffers that promote herpetofauna resilience. However, cumulative effects of hurricanes resulted in a homogenization tendency among successional stages, suggesting a negative effect for ecosystem functioning. The changes in the buffering role of secondary forests highlights the importance of these ecosystems for conserving biodiversity in times when hurricane disturbances are increasing in frequency and intensity. Overall, we discuss how the complex interactions between human and natural disturbances such as hurricanes might be a factor that contributes to maintain biotic diversity in anthropic landscapes of tropical dry forests.

Soil moisture & roads influence the occurrence of frogs in Kathmandu Valley, Nepal

Urbanization and linear infrastructure are reported to influence amphibian assemblages and populations. In areas undergoing rapid infrastructure development and urbanization, the mounting threats to biodiversity are evident. Although protected area coverage and focus on charismatic species conservation are well recognized, non-charismatic species such as amphibians are far from mainstream conservation actions and policies in Nepal. Studies on pattern and distribution of amphibians are limited, as are the roles of environmental variables in amphibian diversity in the urban landscape. This study was designed to assess the frog species richness and correlates of amphibian occurrence in Kathmandu valley. Visual encounter survey of 161 belt transects was carried out in August 2018. Data analysis used two part or Hurdle regression methods where the richness of frogs was considered a response variable. A total of 10 frog species belonging to six families were recorded. The occurrence of frogs was negatively associated with the dry soil conditions and positively associated with increased distance from roads. Occurrence of frogs along road distance gradient depicts the influence of urban infrastructure in amphibian distribution. This entails consideration of systematic conservation planning for rapidly urbanizing areas.