Landscape and Habitat Characteristics Associated with Fish Occurrence and Richness in Southern Brazil Palustrine Wetland Systems
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Environ Biol Fish DOI 10.1007/s10641-013-0152-4 Landscape and habitat characteristics associated with fish occurrence and richness in southern Brazil palustrine wetland systems Leonardo Maltchik & Luis Esteban Krause Lanés & Friedrich Wolfgang Keppeler & Ana Silvia Rolon & Cristina Stenert Received: 18 July 2012 /Accepted: 12 June 2013 # Springer Science+Business Media Dordrecht 2013 Abstract We investigated the influence of environ- The predictors of fish richness were not similarly appli- mental factors in fish communities of 146 palustrine cable to different ecoregions. Our results showed that wetlands, covering a wide range of altitude and wetland the habitat diversity, macroinvertebrate richness, altitude surface area in Neotropical region. Two questions were and hydroperiod were the environmental predictors that analyzed: (1) Are wetland altitude, area, habitat diversi- potentially structure and maintain the fish occurrence ty, hydroperiod (permanent and intermittent), ecoregion, and richness in southern Brazil palustrine wetlands. and macroinvertebrate richness good predictors of oc- Such information is essential to develop wetland con- currence, richness, abundance and composition of fish servation and management programs in this region, species? and (2) Are the predictors of fish richness where more than 90 % of wetland systems have already similarly applicable to different ecoregions in Southern been lost and the remaining ones are still at high risk due Brazil? Our data showed that fish richness was to the anthropogenic activities. related to habitat diversity and macroinvertebrate richness, and fish occurrence was influenced by Keywords South American fishes . Ecoregions . wetland area and macroinvertebrate richness. Fish Ichthyofauna . Biodiversity conservation abundance was influenced by altitude, hydroperiod and macroinvertebrate richness, and the fish composition was jointly associated with ecoregion, and hydroperiod. Introduction Understanding patterns and factors that influence spe- cies occurrence, richness and distribution are among the * : : : L. Maltchik ( ) L. E. K. Lanés F. W. Keppeler main goals of community ecology and conservation A. S. Rolon : C. Stenert Laboratory of Ecology and Conservation of Aquatic biology (Ricklefs 1987; Zimmerman and Simberloff Ecosystems, University of Vale do Rio dos Sinos 1996). Area is a core component of modern explana- (UNISINOS), tions for the presence and absence of species across a Av. Unisinos, 950, landscape. The relationship between area and species CEP: 93022-000 São Leopoldo, RS, Brazil e-mail: [email protected] richness predicts that larger areas harbor more species than smaller ones (Arrhenius 1921;Rosenzweig1995). L. E. K. Lanés The positive relationship between area and species rich- Laboratory of Ichthyology, Instituto Pró-Pampa ness can be considered a valid generalization to fresh- (IPPAMPA), Rua Uruguai, 1242, Bairro Centro, water fishes (Ricklefs and Lovette 1999;Zhaoetal. CEP 96010-630 Pelotas, RS, Brazil 2006; Latta et al. 2008;Lubinskietal.2008;Kruket Environ Biol Fish al. 2009), which includes the coastal freshwater wet- et al. 2009, 2010) and it is concentrated in Brazil lands of southern Brazil (Maltchik et al. 2010a). (Buckup et al. 2007). In this sense, understanding fish Several hypotheses have been proposed to explain species composition and richness patterns in fragmented the positive relationship between area and species rich- and natural wetlands is a priority for developing biodi- ness (Neigel 2003). The habitat heterogeneity hypothe- versity conservation strategies in this region. sis suggests that as the sampled area increases, the The biodiversity patterns in fragmented wetlands richness of microhabitats rises, incorporating more spe- were analyzed in several communities in Southern cies to the assemblages (Andren 1996). In addition to Brazil, e.g. macrophytes (Rolon and Maltchik 2006; area and habitat diversity, other factors such as altitude, Rolon et al. 2008), macroinvertebrates (Stenert and hydroperiod, and availability of food resources also are Maltchik 2007; Stenert et al. 2008) and waterbirds recognized as determinants of fish assemblage structure (Guadagnin et al. 2005, 2009; Guadagnin and (Angermeier and Schlosser 1989; Abell et al. 2008; Maltchik 2007). However, the effects of the landscape Lévêque et al. 2008; Pinto et al. 2009). Ruetz et al. fragmentation on fish communities in Southern Brazil (2005) indicated that seasonal drought shapes spatio- wetlands are still little known (Fernandes et al. 2009; temporal patterns of wetland fish populations, since Maltchik et al. 2010a). In this study, we investigated 146 many aquatic species do not have adaptations for toler- palustrine wetlands over an extensive area of the ating long dry periods (Williams 2006). Neotropical region (~280,000 km2, Southern Brazil), In a broad spatial scale, freshwater ecoregions are covering a wide gradient of altitude and wetland surface defined as large areas encompassing one or more areas. Two questions were analyzed: (1) Are wetland freshwater systems with a distinct assemblage of nat- altitude, area, habitat diversity, hydroperiod (permanent ural freshwater communities and species (primarily and intermittent), ecoregion, and macroinvertebrate fishes) (Abell et al. 2008). In this sense, freshwater richness good predictors of occurrence, richness, abun- ecoregions capture the broad patterns of fish species dance and composition of fish species? and (2) Are the associated to ecological and evolutionary processes predictors of fish richness similarly applicable to differ- generated primarily by continental (mountain build- ent ecoregions in Southern Brazil? ing, speciation and glaciation) and regional scale fil- ters (broad climatic and physiographic patterns, and regional catchments). Understanding the effects of Materials and methods landscape and habitat on fish species richness and distribution have important conservation implications Study area since ecological patterns observed within a local com- munity might be considerably different from those The state of Rio Grande do Sul is located in Southern found over broader areas such as landscapes or regions Brazil and has an area of 282,184 km2 (Fig. 1). The Moist (Angermeier and Schlosser 1989). Subtropical Mid-Latitude Climateprevailsinthisregion; Wetlands are vanishing from many landscapes and the altitude ranges from sea level to 1,200 m (NE). The becoming smaller in area due to the human occupation annual precipitation varies between 1,200 and 1,800 mm, (Gibbs 2000). Almost half of the wetlands of the world being relatively well distributed without the existence of disappeared in the last century due to agricultural and a dry period (Köppen 1931). The mean temperature urban development (Shine and Klemm 1999). In varies between 12 °C, in winter, and 26 °C, in summer Southern Brazil, many of the wetlands have been (Radambrasil 1986). The vegetation is characterized by drained, leaving behind fewer, more isolated wetland small fragments of forest, and temperate and tropical fragments in an agricultural landscape (Maltchik 2003). grassland areas. The forest is represented by three major This can be expected to affect Neotropical freshwater types: temperate summer-green and mixed ever-green fishes – the most diversified freshwater fish fauna of the deciduous forests, and temperate mountainous conifer- world (Reis et al. 2003) – especially fish species which ous forest. The grasslands are represented by savanna, are more sensitive to environmental variations due to steppe, and pioneering formations (Radambrasil 1986; relatively short life spans. An important fraction of this Rambo 2000). diversity (including endemic and threatened species) is Rio Grande do Sul has approximately 3,441 wetlands, exclusive to wetland systems (Costa 2002, 2008; Volcan with a total inundation area of approximately 30,332 km2 Environ Biol Fish Fig. 1 Wetlands sampled in southern Brazil, distributed in freshwater ecoregions according Abell et al. (2008). Occurrence of fishes (black square); No records of fish (white circle). 1-Laguna dos Patos; 2-Lower Uruguay; 3-Tramandaí-Mampituba; 4-Upper Uruguay (10.7 % of the total area of the state) (Maltchik 2003). surface water runoff, groundwater discharge, and in- Approximately 72 % of the wetlands have an area small- undation from small streams and lakes. Terrestrial er than 1 km2 (Maltchik 2003). The study area is com- ecosystems have a great influence on the studied posed by four ecoregions: Laguna dos Patos, Lower palustrine wetlands. Sampling was performed initially Uruguay, Upper Uruguay and Tramandaí-Mampituba in the eastern portion of the state of Rio Grande do (Abell et al. 2008). Delineating ecoregions required com- Sul, and then moved towards the western portion. piling and synthesizing information on the distribution of Each wetland was sampled once from March to fish species. The freshwater species, dynamics, and en- October 2002 always during the period with surface vironmental conditions within a given ecoregion are water. Since each wetland was sampled once from more similar to each other than to those of surrounding March to October (8 months), the influence of the ecoregions. The criteria applied to the ecoregion delin- sampling period (seasonal variations) on fish occur- eation in the study area was based on the major habitat rence and richness was analysed to identify if our types (temperate, tropical and subtropical coastal rivers, results reflect