Diversity of amphibians in rice fields from northeastern Argentina (original) (raw)
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Northwestern Buenos Aires province is located within the Pampas region of Argentina. Agricultural practices have extensively modified native grasslands in a relatively short period, leaving no intact pristine areas. Based on data collected between 2006 and 2015 at 153 ponds in agricultural landscapes, we compiled an annotated list of the amphibians of northwestern Buenos Aires province. We report 13 extant species of amphibians , which represent 43% of the known amphibian diversity in Buenos Aires province, and extend the ranges of three species. Three species found only in her-petological collections extend the list to 16 species. Our study is the first long-term survey of amphibians conducted in this part of Argentina and provides valuable information for future conservation actions across agricultural landscapes.
Composition of amphibian assemblages in agroecosystems from the central region of Argentina
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Rice fields are important substitute wetlands for frogs. Traditionally, rice fields in Japan were supplied with water and drained via shallow earth ditches (old-style). In the last 30 years, however, more than 80% of rice fields have been converted to a new irrigation system in which water is typically supplied through underground pipes via taps and is drained into deep, concrete-sided ditches (new-style). We compared the occurrence of frogs in paired areas of old-and new-style rice fields at six locations in Ibaraki Pref., central Japan, from May to August 1995. The Japanese tree frog (Hyla japonica) did not differ in abundance between the two types of rice fields, but the Japanese brown frog (Rana japonica) and the Tokyo daruma pond frog (Rana porosa porosa) preferred the old-style rice fields. These findings suggest that the status of Rana species has been adversely affected by the conversion of rice fields to the new irrigation system. Modification of the deep, U-shaped concrete ditches and the water management regime during the spawning season is needed to safeguard these species.
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The biodiversity values of temporary pools in tropical ecosystems are poorly understood. Such wetlands are often threatened by agriculture. Constructed pools provide a means to mitigate for loss of natural pools but design features associated with restoration successful are not known. In this paper, we evaluated the effects of environmental variables at local (breeding pools) and regional spatial scales (landscape configuration) on species richness and abundance of anurans in heavily altered landscapes of southeastern Brazil. Frog and toad communities of 18 constructed temporary breeding pools were sampled every 2 weeks from October 2008 to March 2009. Two variables-hydroperiod and percentage of vegetation in the interior of the pools-explained 62% of species richness variation. Three other variables-pool area, distance of pools to forest fragments, and distance of pools to road-explained between 22 and 46% of the variation in frog and toad abundance. Our results indicate that localand regional-scale variables, and their interaction, are important drivers of the structure of frog and toad communities in these agricultural landscapes. To facilitate amphibian conservation we suggest that cattle ranchers create and maintain heavily vegetated temporary pools near protected forest reserves as both a water source for livestock and breeding habitat for amphibians.
Landscape use and habitat configuration effects on amphibian diversity in southern Brazil wetlands
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In this study, we evaluated the effect of changes in natural wetlands on the amphibian diversity at differing spatial and temporal scales. We sampled 10 wetland sites along floodplains in southern Brazil. We classified the sites as reference or altered ponds according to the preservation degree and presence of human impact. The amphibian monitoring was conducted through calling surveys performed between 2015/2016 using an automated recording system that identified the calling male species. We identified 23 species, mainly distributed in the families Hylidae (43%) and Leptodactylidae (34.8%). The altered ponds had lower diversity and higher species dominance. Even ponds with the greatest landscape change revealed a high degree of resilience concerning the amphibian species composition. However, only Boana pulchella was dominant in altered ponds and B. pulchella and Pseudopaludicola falcipes were dominant in reference ponds. A reduction of amphibian richness was driven by the expansion of the urban area and loss of flooding areas. From 1999 to 2016 all sampled sites had their wetland area reduced as the surrounding urban area increased, contributing to the combined loss of habitat and reproductive sites of anurans in subtropical wetlands.
Agusan Marsh is the 1009th RAMSAR site, a wildlife sanctuary which harbour unique and pristine faunal species. It is considered one of the most ecologically significant wetland ecosystems in the Philippines. The study assessed species distribution and abundance using Geographic Information System Map in Agusan Marsh between Sago Palm and Terminalia Forest. Results showed a total of 322 individuals, 11 species and 6 families of amphibians documented. Of the 11 species of amphibians documented in Sago Palm and Terminalia Forest, 6 were Philippine endemics, 3 were invasive species in the area. Terminalia forest had the highest number of individuals documented during the conduct of the study. Sago Palm and Terminalia Forest have almost the same type of vegetation where amphibian species thrive most. Furthermore, ecological and environmental threats (conversion of Terminalia Forest to agricultural land, runoff of environmental pollutants, pesticides run-off and Kaingin or Slash and Burns) being identified in the two habitat types should be given urgent attention. This shows that Agusan Marsh particularly Sago Palm and Terminalia Forest still harbour unique features of endemic amphibian species despite of the on-going anthropogenic activities in the said areas.
Effects of agriculture and topography on tropical amphibian species and communities
Ecological applications : a publication of the Ecological Society of America, 2018
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