Passive restoration contributes to bird conservation in Brazilian Pampa grasslands

Abstract

The global decline of biodiversity makes it important to find affordable ways to conserve and restore habitats. Restoration is useful for conserving native grasslands, with passive restoration defined as either natural colonization or unassisted recovery. Grasslands in southeastern South America have been transformed into croplands and impacted by other human activities. We describe the first assessment of passive restoration as a management tool to conserve birds in the Pampa grasslands of Brazil. We compared bird species richness using coverage-based rarefaction and extrapolation, applying PERMANOVA for composition, and the abundance of bird communities between sites undergoing passive restoration (PR) and sites with native grasslands (NG). We employed fitted generalized linear mixed models (GLMM) to quantify relationships between bird occurrence and vegetation structure and cover. We recorded 61 species of birds during our study (45 in PR and 46 in NG) and 762 individuals (333 in PR and 429 in NG). Of these species, 15 were restricted to PR and 16 to NG. Grassland specialists and threatened species were found in both PR and NG, and only vegetation height differed between PR and NG. We detected eight species of conservation concern, including three recorded only in PR, three only in NG, and two in both PR and NG. The absence of marked differences in species richness and composition of bird communities between passiverestoration and native grasslands in our study suggests that grasslands in the process of passive restoration can provide habitat for many species of grassland birds and that passive restoration is an appropriate management tool for biodiversity conservation in Brazilian grasslands.

Remnants of Native Vegetation Surrounding Do Not Affect the Diversity and Density of Birds in Brazilian Grassland-Restoration Sites

“…In view of this, and considering the high proportion of degraded grasslands in the Brazilian Pampa biome in southeastern South America (SESA Grasslands; Azpiroz et al, 2012), we have compared the structure of bird communities of restoration sites with those of native grasslands. We found similarity in the species richness and composition between sites under passive restoration and sites in native grassland (Silva et al, 2019), but these variables differed between sites under active restoration and sites in native grassland (Silva and Fontana, 2020). These findings suggested that the similarities might be due to effects from fragments of native grassland in the surroundings of grassland under restoration.…”

“…We carried out the study at five restoration sites located in the Brazilian Pampa grasslands, state of Rio Grande do Sul, southern Brazil, which have been used in previous studies (Silva et al, 2019;Silva and Fontana, 2020; Supplementary Figure 1). This was the maximum number of restoration sites found after more than 6 months of search during previous study design.…”

“…All five sites had similar relief, soil types, and climates, besides a low cattle stocking rate (≤1 animal unit per ha). They were at least 2.5 km apart, and had a restoration time ranging from 5 to 35 years (the location map and details of each study site are in Silva et al, 2019 andFontana, 2020).…”

Success of active restoration in grasslands: a case study of birds in southern Brazil

“…Thus, each case should be analyzed individually and depends on the eventual goal, since studies evaluating passive restoration in grassland habitats have demonstrated positive results for recovery of the flora and fauna (e.g. Torchelsen et al ; Reiley et al ; Silva et al ).…”

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“…In view of this, and considering the high proportion of degraded grasslands in the Brazilian Pampa biome in southeastern South America (SESA Grasslands; Azpiroz et al, 2012), we have compared the structure of bird communities of restoration sites with those of native grasslands. We found similarity in the species richness and composition between sites under passive restoration and sites in native grassland (Silva et al, 2019), but these variables differed between sites under active restoration and sites in native grassland (Silva and Fontana, 2020). These findings suggested that the similarities might be due to effects from fragments of native grassland in the surroundings of grassland under restoration.…”