Amphibia-Reptilia 33 (2012): 227-237 Effects of pine invasion on anurans assemblage in southern Brazil coastal ponds Iberê F. Machado 1 , Leonardo F.B. Moreira 1 , Leonardo Maltchik 1,∗ Abstract. The destruction of wetlands due to afforestation areas is a common activity in temperate and subtropical regions in Southern America. The expansion of pine in the Coastal Plain of Southern Brazil is out of control and its impacts on aquatic biodiversity are little known. We tested the following hypotheses: the pine occurrence diminishes the anuran richness and abundance in ponds and it changes the anuran composition; the beta-diversity between pine and native grassland matrix ponds (natural ponds) is determined mainly by nestedness. Sampling was carried out from 2007 to 2009 in five ponds in pine invasion matrix and five ponds in native grassland matrix. The natural ponds showed a greater richness of tadpoles (10 species) than pine ponds (5 species). The mean richness of adults was higher in natural ponds than pine ponds throughout the entire study. The species composition was different between natural and pine ponds, for both adults and tadpoles. Comparing natural ponds with each other and the pine ponds with each other, our results showed that neither nestedness nor turnover was determinant for beta-diversity. However, when natural ponds were compared with pine ones, we found that the contribution of nestedness was higher for the anurans beta-diversity than turnover. Increases in the nestedness mechanism indicated that the pine occurrence results in species loss in Southern Brazil ponds. Since 90% of its wetland has been already affected, the removal of Pinus in the conservation areas in southern Brazil is important to minimize their impacts on aquatic biodiversity. Keywords: anuran conservation, exotic species, hydroperiod, pine silviculture, wetlands. Introduction Scientific studies have shown in recent decades an accentuated decline in amphibian popula- tion, including the extinctions of species (Al- ford, Dixon and Pechmann, 2001; Collins and Storfer, 2003; Stuart et al., 2004). Habitat loss, fragmentation and alterations were the major cause of these disappearances (Blaustein and Wake, 1995; Global Amphibian Assessment, 2004). The indiscriminate use of pesticides and fertilizers in agro-ecosystems also has affected the living areas of amphibians (Relyea, 2005; Rohr et al., 2006). Many species of anurans have a highly permeable skin and their tadpoles are susceptible to changes in water chemistry (Vitt, Wilbur and Smith, 1990; Boone et al., 2007). The interspecific differences in life histo- ries of amphibians, such as larval development time and the ability of locomotion, limit the dis- 1 - Laboratory of Ecology and Conservation of Aquatic Ecosystems, University of Vale do Rio dos Sinos, UNISINOS, Av. Unisinos, 950, CEP 93.022-000, São Leopoldo, RS, Brazil ∗ Corresponding author; e-mail: maltchik@unisinos.br placement among aquatic habitats and their re- productive success (Babitt and Tanner, 2000). Anurans are especially dependent on aquatic habitats for successful reproduction (Gerlanc and Kaufman, 2005). The loss of 50% of world- wide wetlands in the last 100 years (Shine and Klemm, 1999) has contributed to the disappear- ance of many amphibians species. Agriculture is one of the main human activities responsible for this decline (Czech and Parsons, 2002). In recent years, Pinus spp. monoculture had been introduced in many parts of the world as ex- otic species for commercial purposes. The de- struction of wetlands due to afforestation areas (establishment of forests in areas where they did not occur previously) is a common activ- ity in South America (Richardson, Williams and Hobbs, 1994; Nosetto, Jobbágy and Paruelo, 2005). Pine silviculture has several effects on South American natural ecosystems – mainly in grass- lands and dune areas due to strong invasiveness potential (Richardson, Williams and Hobbs, 1994; Bustamante and Simonetti, 2005). Such potential concerns the wetland biodiversity con- © Koninklijke Brill NV, Leiden, 2012. DOI:10.1163/156853812X638518