Old climatically-buffered infertile landscapes(OCBILs):more than harsh habitats,Atlantic Forest inselbergs can be drivers of evolutionary diversity

Granite-gneiss rock outcrop inselbergs are ancient stable ecosystems with old,climaticallybuffered infertile landscapes(OCBILs).Although inselbergs provide key ecosystem services,little is done for their conservation and,so far,a lot of their unknown evolutionary history has already been lost by human activities.Using a fine-scale approach,here we tested if habitat and environmental filtering(the inselberg’s harshness)affect the evolutionary diversity of an Atlantic Forest inselberg in Brazil.We recorded all trees with a diameter at breast height≥5cm in 20 plots in four habitat types(total sampled area of 0.8 hectares),from highest to lowest:island,hillside,foothill,and semideciduous forest(matrix).We also collected soil samples for chemical,textural and physical soil characterization.We fitted linear models to test the effects of soil and habitat on plotlevel metrics of phylogenetic diversity and structure,lineage diversity,phylogeneticβ-diversity,and evolutionary distinctiveness.We found that the upper inselberg habitats contain a distinct set of ancient,closely related,harsh-tolerant lineages,as well as a subset of lineages that persist under harsh conditions with a certain degree of water availability.The inferior inselberg habitats harbor higher lineage diversity than expected by chance.Soil strongly predicted evolutionary diversity.We concluded that soil depth,slope,nutrients and texture(environmental filtering)and habitat types and topography(habitat filtering)shape the evolutionary history contained in fine-scale inselberg habitats,which should encourage the conservation of these ancient ecosystems.

Tree succession across a seasonally dry tropical forest and forest-savanna ecotone in northern Minas Gerais,Brazil

Aims Understanding succession in tropical forest is an important aspect of vegetation science,but to date,successional processes in sea-sonally dry tropical forests(SDtFs)have received much less atten-tion than evergreen humid tropical forests.We aim to fill this knowledge gap.Methods We investigated vegetation succession in SDtF areas consisting of three different successional stages(early,intermediate,late),and a SDtF-savanna ecotone in the municipal district of Juramento,north of Minas Gerais State,Brazil.Using twelve 400 m2 plots in each area,we compared vegetation parameters and structural variables(absolute density and basal area)and examined the floristic composition of the tree component to find gradients of change.Important Findings We found evidence of species turnover along a successional gradi-ent,with the intermediate stage showing the highest species rich-ness and diversity.this was accompanied with a significant increase in the number of tree individuals and basal area from the early to intermediate successional stage.However,the intermediate and late SDtF successional stages were more similar in structure and floristics.the ecotone was the most species rich and was similar to the intermediate SDtF and early successional stage in species richness and floristic composition respectively.these results will have implications for guiding SDtF management and recovery programs.