Cintia Cornelius

What is the avifauna of Amazonian white-sand vegetation?

White-sand vegetation (WSV) is a rare vegetation type in the Amazon basin that grows in nutrient impoverished sandy soils that occur as patches of variable size. Associated with this vegetation is bird assemblage that has not yet been fully characterized. Based on published species inventories and our own field data we compile a checklist of bird species recorded in WSV. In addition, we compared the avifauna of WSV with that found in savanna patches, another type of Amazonian open vegetation. WSV hosted a distinctive avifauna including endemic and threatened species. The number of bird species was lower in WSV compared to nearby terra firme forests, seasonally flooded forests and Amazonian savannas. Despite its low diversity, the avifauna of WSV has a distinctive species composition and makes a significant contribution to Amazonian beta diversity. At least 35 bird species can be considered as indicator species for this environment. Previously identified areas of endemism within the Amazon basin house at least one WSV indicator bird including cases of congeneric species with allopatric distributions. Seven of the WSV indicator species (20% of this avifauna) are in an IUCN threatened category, with one species Polioptila clementsi considered Critically Endangered. Their isolated distribution, small area occupied, and fragility to human-driven disturbances makes WSV one of the most threatened vegetation types in the Amazon basin. The study of WSV avifauna contributes to a better understanding of mechanisms that generate and maintain species diversity as well as of the environmental history of the most biologically diverse biome of the planet.

High Emigration Propensity and Low Mortality on Transfer Drives Female-Biased Dispersal of Pyriglena leucoptera in Fragmented Landscapes

Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An important limitation of most empirical studies is that inferences about sex-biased dispersal are based only on emigration proneness or immigration success data. Thus, we still do not know whether sex-biased immigration in fragmented landscapes occurs during emigration, transfer or in both stages. We conducted translocation and radiotracking experiments to assess i) whether inter-patch dispersal movements of a rainforest bird (Pyriglena leucoptera) is sex-biased and ii) how dispersal stages and the perceptual range of the individuals are integrated to generate dispersal patterns. Our results showed that inter-patch dispersal is sex-biased at all stages for P. leucoptera, as females not only exhibit a higher emigration propensity but are subjected to a lower risk of predation when moving through the matrix. Moreover, our data support a perceptual range of 80 m and our results showed that dispersal success decreases considerably when inter-patch distances exceeds this perceptual range. In this case, birds have a higher probability of travelling over longer routes and, as a consequence, the risk of predation increases, specially for males. Overall, results supported that assuming dispersal as a single-stage process to describe dispersal behavior may be misleading. In this way, our study advanced our understanding of processes and patterns related to inter-patch dispersal of neotropical forest birds, shedding light on potential implications for population dynamics and for the management of fragmented landscapes.

Isolation and characterization of polymorphic microsatellite DNA Markers from an Amazonian white-sand vegetation specialist bird, Xenopipo atronitens (Aves: Pipridae)

ABSTRACT Thirteen novel polymorphic microsatellite loci were isolated and characterized from the Amazonian Black Manakin, Xenopipo atronitens. The loci were screened using 30 samples from Brazil. A total of 13 loci were variable with number of alleles per locus ranging from 2 to 17, whilst the observed and expected heterozygosities varied from 0.067–0.900 and 0.310–0.910, respectively. Five loci deviated significantly from the Hardy–Weinberg equilibrium, whereas one pair of loci deviated significantly from linkage disequilibrium. The set of markers will be a useful tool for future population genetic and kinship studies of X. atronitens, an Amazonian white-sand vegetation specialist.

Isolation and characterization of seventeen polymorphic microsatellite DNA markers from Elaenia ruficeps (Aves: Tyrannidae)

Seventeen new polymorphic microsatellites were isolated and characterized for the South American Rufous-crowned Elaenia, (Elaenia ruficeps). E. ruficeps is a bird commonly found in white sand vegetation, a naturally fragmented and threatened Amazonian habitat. The number of alleles per locus ranged from 2 to 20, whilst the observed and expected heterozygosities varied from 0.074 to 0.967 and from 0.173 to 0.919, respectively. Seven loci significantly deviated from Hardy–Weinberg equilibrium. Eleven microsatellite loci were cross-amplified in at least one additional Tyrannidae species. These microsatellite markers will be useful tools for further studies of avian population structure and genetic variability in this unique habitat.