Nest site selection and reproductive parameters of the threatened Atlantic Royal Flycatcher(Onychorhynchus swainsoni)and their significance for conservation

Background:Patterns of rarity can be explained by reproductive rates,levels of endemism,and habitat specificity,and knowledge on these parameters is important to understand the levels of vulnerability of each species and to formulate conservation strategies.Here,we studied nest-site selection and breeding biology of the Atlantic Royal Flycatcher(Onychorhynchus swainsoni),a poorly known vulnerable bird endemic to the Brazilian Atlantic Forest.Methods:We addressed nest site selection in three different levels:first,we searched for nests near and far from water to investigate whether birds could select water proximities to construct nests;second,we examined if they could select certain streams in detriment of others,and we analyzed the characteristics of used and non-used streams,and third,in streams in which nests were found,we addressed nest site selectivity by comparing a number of parameters between nest sites and random sites.Further,we provide information on breeding biology parameters related to annual fecundity.Results:During five breeding seasons,we found 23 nests in a well-preserved forest continuum.All of the nests were constructed above water,and they were found in streams that were about 4 m in width,instead of smaller streams with about 1.5 m in width.Modeling analyses revealed that within the used streams,nests were constructed in sites with lower vegetation density in relation to random points,while stream width,water speed,and canopy cover presented no significant correlation.Atlantic Royal Flycatchers in our study had a 22-day incubation period and 24 to 27-day nestling period.Overall nest survival was comparatively high(62%),but clutch size was small(N=2 eggs)and Along the nesting streams,we found an average of 1.62±0.07 breeding pairs/km.Conclusions:These data suggest that nesting habitat specificity and low annual fecundity are among the factors contributing to the rarity of the Atlantic Royal Flycatcher in large forest continuums and to its absence in fragmented environments.It reinforces the importance of large well-preserved forest continuums for the conservation of habitat specialist Atlantic Forest bird species.

10-Years Land Use Changes Decrease Landscape Integrity in a Brazilian Hydrographic Basin

Changes in land use associated with the suppression of native vegetation can greatly alter the landscape configuration, affecting biodiversity and environmental services availability. This study analyzes how changes in land use affect landscape patterns of vegetation remnant over a 10 year period. We quantified spatial landscape patterns throughout a hydrographic basin for the years 2002, 2008, 2010 and 2012, using nine landscape metrics. An indicator of integrity was used to details the transformation processes occurring in the basin that could be used to monitor the impact of landscape changes and its spatial patterning. Results showed that over this decade, extension of farming activities reduced the cover of native vegetation by 4.4%, with grassy-woody savanna, wooded savanna and forested savanna impacted especially strongly. Suppression of vegetation across this period reduced the size of fragments and their connectivity. The landscape fragmentation indicator indicated that the fragmentation pattern varied spatially, with the upland areas along river headwaters, being most fragmented. Areas of floodplains vegetation, belonged to the Pantanal Wetland, although in better integrity states, are the most threatened by current pressures of land use change. An intense recovery program for headwaters and aquifer recharge areas, as well as riparian forests, is recommended to avoid the future depletion of water production. Besides, we also recommend the maintenance and recovering of the connectivity of the current remaining patches of natural vegetation corridors and elaboration of specific laws that incoporate the consolidated scientific knowladge about wetland ecosystem functioning, like the Pantanal.

Species richness and density evaluation for plants with aggregated distributions:fixed vs.variable area methods

Aims Knowledge of species richness is of prime importance to both basic and applied aspects of ecological studies.However,quantifying plant species richness in the tropics is potentially time-consuming because of high species diversity.Plant species richness estimates are also frequently biased,because many rare species are not detected.to address these problems,the use of a variable area method has been proposed as an alternative to fixed area methods,but its appli-cability to plants with aggregated distributions has been questioned based on simulation studies.We use empirical data to compare the efficiency and accuracy of a variable area method and a fixed area method for estimating species richness,density and basal area for plants with aggregated distributions,using palms as a model taxon.Methods Adult palms were sampled in twenty 10×30 m transects in an Atlantic Forest in Rio de Janeiro state,Brazil.All individuals were considered in the fixed area method,while in the variable area method only the first six adults in each transect were sampled;in this case,transect length was defined according to the distance of the sixth adult from the beginning of the transect.When fewer than six individuals were observed in a given transect,transect length was extended up to 50 m to search for additional individuals.the efficiency of both methods was compared based on species rarefaction curves,using the chao 1 statistic(for abundance data).For each species we calculated mean density per transect and basal area,according to each sampling method.Sampling effort in terms of the number of individual plants and the area necessary to characterize maximum species richness in each sampling method,as well as mean time taken to sample a single transect,were compared as measures of efficiency.Important findings An accurate estimate of species richness was achieved using both methods,but in the variable area method,a quarter of the number of individuals and half the area was sufficient to characterize maximum species richness.Density and basal area did not differ between meth-ods for any of the species studied.In the fixed area method sampling effort was 90 min per transect,whereas in the variable area method it was 30 min per transect.the variable area method,with its faster assessment of palm species richness,should facilitate greater spatial representativeness by making it easier to sample a larger number of plots at different spatial scales.We thus find sufficient evidence to recommend the variable area method for rapid and robust evaluations of species richness for palms with aggregate distributions,as well as for other plants with similar spatial patterns,in tropical forests.