A comparison of bird communities in natural and revegetated grasslands in south Brazil

Abstract

Natural grasslands are declining due to loss, fragmentation and degradation, resulting in the decline of grassland-associated bird species. The Pampas Biome in south Brazil is not exception to this worldwide trend, facing the expansion of croplands and afforestation with exotic tree plantations for cellulose production. To cope with the continuous degradation and loss of grasslands, restoration is an important conservation strategy, but basic information regarding the response of the fauna to restoration practices in southeastern South America grasslands is lacking. Here we compared the structure of bird communities in natural grasslands and revegetated grasslands after mining by planting native and exotic grasses. We sampled birds using 5-min point counts with unlimited radius in three replicates of each habitat (natural and revegetated grasslands; average size 22.2 ± 2.3 ha). We also compared the vegetation density between the two habitat types. The structure of bird communities at natural and revegetated grasslands differed, with natural grasslands presenting higher species richness (42 vs. 35 species) and abundance (1459 vs. 839 records) than revegetated areas, and also a distinct species composition. Ten of the 11 grassland species that were associated to one of the two habitat types occurred more frequently in natural grasslands, which had higher vegetation density than revegetated areas. Even a decade after the beginning of the restoration process, revegetated areas did not resemble natural grasslands in bird species richness, abundance, and composition. These results differed from another study conducted in the Brazilian Pampas in which native plant species were used to actively restore a grassland. Therefore, until we have additional studies addressing the use of exotic grasses for the recovery of bird communities in South America grasslands, we encourage greater representation of native plant species in restoration projects.

Temperate forest bird communities associated with a historic mining impact area: do tailing remnant effects modify their structure?

“…As suggested, food resources, perching structures, and breeding sites can be some of the primary limiting factors in the species distributions and preferences within a given habitat (Cody 1985, Hutto 1985, Jones 2001. Studies on the effects of secondary succession in forests have shown that in general, early successional bird communities include more generalist granivorous, omnivorous and insectivorous species, considered as pioneer species indicative of disturbance (Rangel-Salazar et al 2009, Becker et al 2013. As succession progresses, structural diversity of vegetation increases and, depending on the community composition, specialized frugivorous, nectarivorous, and specialized insectivorous species (soil, bark, understory and foliage gleaning) colonize the habitat and increase in numbers (May 1982, Winkler 2005, Rangel-Salazar et al 2009.…”

“…As succession progresses, structural diversity of vegetation increases and, depending on the community composition, specialized frugivorous, nectarivorous, and specialized insectivorous species (soil, bark, understory and foliage gleaning) colonize the habitat and increase in numbers (May 1982, Winkler 2005, Rangel-Salazar et al 2009. Becker et al (2013) found that bird communities in restored mining areas in southern Brazil had similar species richness between sites after 10-20 years of abandonment, although differences in the abundance of species according to feeding guild were evident: granivorous species decreased, whereas carnivorous, frugivorous, and nectarivorous increased (especially those forests dependent species); omnivorous species remained stable. Their findings suggest that effects could be reflected through changes in functional groups, or can be species specific.…”