Conservation of Terrestrial Invertebrates and Their Habitats in Brazil

Abstract:  As one of the world's prime megadiverse countries, Brazil holds an immense number of terrestrial invertebrates. Current knowledge of this biota is very heterogeneous. Several taxa are sufficiently well known to be used as indicators of ecological integrity or of endemism. The current Brazilian national and regional red lists include 130 terrestrial invertebrate species, of which 42% are butterflies. These lists are contingent on available knowledge, and many taxa that are omitted certainly include species at risk. Knowledge of various biomes and habitats is also quite irregular, with the Caatinga and Pantanal in need of more study, compared with the Atlantic Forest, the Amazon, and Cerrado. Canopy, host-associated, and soil faunas also need further intensive study. Invertebrate conservation will be promoted more effectively by habitat preservation and management rather than single-species initiatives. To this end, better geographic surveys of entire taxonomic or functional assemblages are needed. An improved understanding of the invertebrate role in ecosystem processes will strengthen enormously the case for their conservation.     

Effects of Urbanization on the Distribution and Abundance of Amphibians and Invasive Species in Southern California Streams

Abstract:  Urbanization negatively affects natural ecosystems in many ways, and aquatic systems in particular. Urbanization is also cited as one of the potential contributors to recent dramatic declines in amphibian populations. From 2000 to 2002 we determined the distribution and abundance of native amphibians and exotic predators and characterized stream habitat and invertebrate communities in 35 streams in an urbanized landscape north of Los Angeles (U.S.A.). We measured watershed development as the percentage of area within each watershed occupied by urban land uses. Streams in more developed watersheds often had exotic crayfish ( Procambarus clarkii ) and fish, and had fewer native species such as California newts ( Taricha torosa ) and California treefrogs ( Hyla cadaverina ). These effects seemed particularly evident above 8% development, a result coincident with other urban stream studies that show negative impacts beginning at 10–15% urbanization. For Pacific treefrogs ( H. regilla ), the most widespread native amphibian, abundance was lower in the presence of exotic crayfish, although direct urbanization effects were not found. Benthic macroinvertebrate communities were also less diverse in urban streams, especially for sensitive species. Faunal community changes in urban streams may be related to changes in physical stream habitat, such as fewer pool and more run habitats and increased water depth and flow, leading to more permanent streams. Variation in stream permanence was particularly evident in 2002, a dry year when many natural streams were dry but urban streams were relatively unchanged. Urbanization has significantly altered stream habitat in this region and may enhance invasion by exotic species and negatively affect diversity and abundance of native amphibians.