Biotic Homogenization of the South American Cerrado

Abstract

The South American Cerrado is a world biodiversity hotspot and at the same time is one of the fastest degrading biomes on Earth. About half of the original vegetation cover of the Cerrado has been converted to agriculture, pasture, urban area, and infrastructure. There are 223 non-native plant species known to be naturalized in the Cerrado, which is equivalent to almost 2% of the flora of the biome. Among those plants, at least 56 species are considered invasive. There are also 13 species of flies, pertaining to the family Drosophilidae, that have been introduced from other biogeographical regions. These insects are equivalent to approximately 10% of the total drosophilid insects in the biome. In this chapter, we review the primary literature on species invasions in the Cerrado and discuss how invasions might be contributing to biotic homogenization with a focus on grasses and flies. Existing research suggests that current high levels of habitat conversion and degradation, associated with low levels of conservation efforts, imply that the Cerrado is becoming dominated by non-native species, either in the form of cultivated crops and pasture, naturalized, or invasive species. It also suggests that more native species are increasingly threatened by extinction due to habitat losses. Furthermore, there are numerous abandoned and unrestored pastures inside national parks and other reserves. Through invasions and extinctions, biotic homogenization increases the similarity of biotas. Hence, there is an urgent need to increase both awareness and management efforts to reduce the threat posed by invasive species and habitat losses.