Assembly structures of coastal woody species of eastern South America:Patterns and drivers

Tropical regions have provided new insights into how ecological communities are assembled.In dry coastal communities,water stress has been hypothesized to determine plant assembly structure by favoring preadapted lineages from neighboring ecosystems,consistent with functional clustering.However,it is unclear whether this hypothesis is sufficient to explain how coastal communities in tropical ecosystems are assembled.Here,we test whether water stress or other factors drive community assembly in woody plant communities across the coastal zone of Brazil,a tropical ecosystem.We characterized functional and phylogenetic structures of these communities and determined the underlying environmental factors(e.g.,water stress,historical climate stability,edaphic constraints,and habitat heterogeneity)that drive their community assembly.Assemblages of coastal woody species show geographically varied patterns,including stochastic arrangements,clustering,and overdispersion of species relative to their traits and phylogenetic relatedness.Topographic complexity,water vapor pressure,and soil nutrient availability best explained the gradient in the functional structure.Water deficit,water vapor pressure,and soil organic carbon were the best predictors of variation in phylogenetic structure.Our results support the water-stress conservatism hypothesis on functional and phylogenetic structure,as well as the effect of habitat heterogeneity on functional structure and edaphic constraints on functional and phylogenetic structure.These effects are associated with increased phenotypic and phylogenetic divergence of woody plant assemblages,which is likely mediated by abiotic filtering and niche opportunities,suggesting a complex pattern of ecological assembly.

The Bird Community in a Threatened Coastal Lagoon in Southeastern Brazil

We provide a list of bird species for Ribeira lagoon, a protected area in Rio de Janeiro, southeastern Brazil. Data were obtained in monthly surveys in points along a continuous transect, between August 2008 and July 2009, and 21 ad libitum observations. In total, 174 species were listed, including 121 land birds and 53 waterbirds. Of these, 11 are considered threatened at regional level. Waterbird richness was significantly higher in the dry season (April to September) than in the rainy season (October to March), whereas land bird richness remained constant. However, land bird richness varied throughout the year, with the highest value in February 2009 (77 species) and the lowest in May 2009 (41 species). The species listed account for 23% of the total of 745 bird species listed for Rio de Janeiro, and for 49% of 108 waterbirds recorded for the state.

Traits uncover quasi-neutral community assembly in a coastal heath vegetation

Aims Trait-based approaches are increasingly being used in ecology due to their potential to explain and predict community structure and dynamic regardless of species identities.Here,we asked whether coastal heath vegetation established in stressful habitats could be assembled by quasi-neutral mechanisms based on functional trait distribution.Communities are organized through quasi-neutral dynamics if abiotic gradients and/or species interactions impose sorting on functional traits and species performances,but not on species phylogenetic relatedness and occurrence.Methods The study was conducted in a coastal area containing tall dunes near the sea,and relatively flat areas punctuated by short palaeodunes further inland,Northeastern South America.We evaluated 10 traits of the 21 most abundant species,as well as eight abiotic variables in 70 plots(25 m^(2))established in dune tops,valleys,flat and steep microenvironments.The effect of environmental filter was tested by linear mixed models(LMM)between each community-weighted mean(CWM)trait and the abiotic variables,and by two indices of environmental filtering based on intra-and interspecific-trait vari-ability relative to null models.To evaluate the effect of species inter-actions,we used an index of niche overlap relative to null models,and LMMs between this index and the species richness of plots.Important Findings The environmental filtering index did not deviate from null expect-ations for any trait.Models that included individual variability per-formed similarly to models that used species mean traits.However,the explicit consideration of environmental gradients by CWM ana-lyses revealed functional patterns that would remain undetected if trait distribution was analyzed only.In addition,intraspecific vari-ation in the stem length was an important driver of species diversity as suggested by the relationship between species richness and the niche overlap index.Based on the occurrence and phylogenetic re-latedness of species,previous work in the same system found neu-tral community assembly.We concluded that to ignore functional traits may lead to underestimations of niche-based processes,and that analyses of species occurrence and phylogenetic relatedness should be complemented with functional traits to reinforce our in-terpretation of processes underpinning community assembly.In this regard,the study heath vegetation is influenced by quasi-neutral effects on functional trait distribution.