Abstract:Monitoring wildlife responses is essential to assess restoration projects. Birds are widely used as bioindicators of ecosystem restoration, but most studies use only taxonomic descriptors to compare categories of reference and restoring sites. Here, we used forest structure as a continuous predictor variable to evaluate avifaunal taxonomic and functional indicators in riparian forest reference and restoration sites on southeastern Brazil. Reference sites were riparian forest remnants, and restoration sites were pasture before seedling reintroduction. Forest structure variables (mean tree height, canopy depth, mean diameter at breast height, basal area, tree layering, tree density, and grass cover) were reduced into two axes using a Principal Component Analysis (PCA), Forest Axis 1 (tree biomass vs. grass cover) and Forest Axis 2 (canopy depth vs. tree density). Bird species were classified in relation to five functional categories (i.e., diet, foraging stratum, nest height, cavity dependence for nesting, and forest dependence). Forest Axis 1 influenced the functional diversity of bird assemblages and the relative abundance within levels of each functional category (except for nest height). The relative abundance of all functional categories combined was also affected by Forest Axis 2. Therefore, forest structure affected the predominant functional traits of bird species in riparian sites under restoration. Sites with higher tree biomass were the richest, with canopy birds that were insectivores and frugivores of high forest dependence, whereas more open sites were associated with birds of low forest dependence and ground-foraging insectivores. Forest structures of similar-aged sites were strongly variable, due to natural and anthropic disturbances, so restoration age was a poor indicator of forest development. These unpredictable disturbances can change the development of sites under restoration, so that forest structure can be a better descriptor of the trajectory of these ecosystems.
Mortality from collision with vehicles is the most visible impact of road traffic on wildlife. Mortality due to roads (hereafter road-kill) can affect the dynamic of populations of many species and can, therefore, increase the risk of local decline or extinction. This is especially true in Brazil, where plans for road network upgrading and expansion overlaps biodiversity hotspot areas, which are of high importance for global conservation. Researchers, conservationists and road planners face the challenge to define a national strategy for road mitigation and wildlife conservation. The main goal of this dataset is a compilation of geo-referenced road-kill data from published and unpublished road surveys. This is the first Data Paper in the BRAZIL series (see ATLANTIC, NEOTROPICAL, and BRAZIL collections of Data Papers published in Ecology), which aims make public road-kill data for species in the Brazilian Regions. The dataset encompasses road-kill records from 45 personal communications and 26 studies published in peer-reviewed journals, theses and reports. The road-kill dataset comprises 21,512 records, 83% of which are identified to the species level (n = 450 species). The dataset includes records of 31 amphibian species, 90 reptile species, 229 bird species, and 99 mammal species. One species is classified as Endangered, eight as Vulnerable and twelve as Near Threatened. The species with the highest number of records are: Didelphis albiventris (n = 1,549), Volatinia jacarina (n = 1,238), Cerdocyon thous (n = 1,135), Helicops infrataeniatus (n = 802), and Rhinella icterica (n = 692). Most of the records came from southern Brazil. However, observations of the road-kill incidence for non-Least Concern species are more spread across the country. This dataset can be used to identify which taxa seems to be vulnerable to traffic, analyze temporal and spatial patterns of road-kill at local, regional and national scales and also used to understand the effects of road-kill on population persistence. It may also contribute to studies that aims to understand the influence of landscape and environmental influences on road-kills, improve our knowledge on road-related strategies on biodiversity conservation and be used as complementary information on large-scale and macroecological studies. No copyright or proprietary restrictions are associated with the use of this data set other than citation of this Data Paper.
Incubation is an energetically costly parental task of breeding birds. Incubating parents respond to environmental variation and nest‐site features to adjust the balance between the time spent incubating (i.e. nest attentiveness) and foraging to supply their own needs. Non‐natural nesting substrates such as human buildings impose new environmental contexts that may affect time allocation of incubating birds but this topic remains little studied. Here, we tested whether nesting substrate type (buildings vs. trees) affects the temperature inside the incubation chamber (hereafter ‘nest temperature’) in the Pale‐breasted Thrush Turdus leucomelas, either during ‘day’ (with incubation recesses) or ‘night’ periods (representing uninterrupted female presence at the nest). We also tested whether nesting substrate type affects the incubation time budget using air temperature and the day of the incubation cycle as covariates. Nest temperature, when controlled for microhabitat temperature, was higher at night and in nests in buildings but did not differ between daytime and night for nests in buildings, indicating that buildings partially compensate for incubation recesses by females with regard to nest temperature stability. Females from nests placed in buildings exhibited lower nest attentiveness (the overall percentage of time spent incubating) and had longer bouts off the nest. Higher air temperatures were significantly correlated with shorter bouts on the nest and longer bouts off the nest, but without affecting nest attentiveness. We suggest that the longer bouts off the nest taken by females of nests in buildings is a consequence of higher nest temperatures promoted by man‐made structures around these nests. Use of buildings as nesting substrate may therefore increase parental fitness due to a relaxed incubation budget, and potentially drive the evolution of incubation behaviour in certain urban bird populations.
Invasive species are among the major threats to global biodiversity. Plant invasions are often driven by great propagule pressure that overcomes barriers to early colonisation and establishment, such as the biotic resistance from pathogens and seed predators. However, the way in which biotic resistance interacts with propagule pressure and affects seed survival remains poorly understood. Here, we experimentally assessed the effect of seed abundance on seed removal in the Brazilian Cerrado (savanna). We tested whether the invasive Leucaena leucocephala and the native Anadenanthera macrocarpa (both Fabaceae) differ in post-dispersal seed removalan indicator of granivore pressureby different guilds of seed predators, varying seed abundance (2, 5 or 10 seeds of each species per treatment) and distance from a disturbance (5, 20 and 50 m from a firebreak) in two fragments of Cerrado. Treatment encounter, that is the chance of at least one seed being removed, increased 72% from 2 to 10 seeds per treatment, but seed removal increased only by 32%, suggesting a threshold in granivore response to seed availability. Native seeds suffered higher removal than exotic seeds, but removal rates did not vary with distance to disturbance or interact with vertebrate and invertebrate exclusions. Our results suggest a patchy pattern of seed predation influenced by resource abundance and emphasise the efficiency of high propagule pressure in overcoming the density-dependent biotic resistance during early stages of exotic plant invasions in Cerrado. Seeds of fast-germinating species, such as L. leucocephala, that reach appropriate spots for regeneration may still overcome the biotic resistance due to the patchy nature of seed predation.
Selection of safe nest sites is a first step toward improving the chances of breeding successfully. Reusing old nests can save time and energy for breeding birds, but nest reuse is rare among open‐cup nesting songbirds and the factors contributing to this behavior and its consequences for reproductive output remain little known. We studied an urban population of Pale‐breasted Thrushes (Turdus leucomelas) in southeastern Brazil to determine whether nest reuse (1) was more likely after a successful nesting attempt both within and between breeding seasons, (2) affected the number of fledglings in the next nesting attempt, (3) reduced the chances of nest parasitism by Shiny Cowbirds (Molothrus bonariensis), and (4) was associated with earlier initiation of nests at the beginning of breeding seasons and shorter re‐nesting intervals within breeding seasons. We monitored 266 nests from 2010 to 2019 and obtained data on 130 re‐nesting events by individually marked birds. Nest reuse was more frequent after successful nesting attempts within breeding seasons. New nests were more likely to be parasitized by cowbirds, which had a negative effect on the number of fledglings per clutch. Reusing nests allowed earlier initiation of breeding at the start of breeding seasons, but did not shorten re‐nesting intervals within seasons. Nest reuse by Pale‐breasted Thrushes followed the win‐stay lose‐switch strategy and corroborated the time‐saving hypothesis. Our results suggest that nest reuse may increase the fitness of Pale‐breasted Thrushes by reducing the likelihood of cowbird parasitism.
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