Phylobetadiversity among forest types in the Brazilian Atlantic Forest complex.

Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao's H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like Myrtaceae, are also very representative of this forest type. We point out to the need of more attention to Mixed forests as a conservation target within the Brazilian Atlantic Forest given their high phylogenetic uniqueness.

Plant population structure and insect herbivory on Solanum mauritianum Scopoli (Solanaceae) in southern Brazil: a support to biological control

Solanum mauritianum Scopoli (Solanaceae), a native Brazilian shrub, has become naturalized and invasive in several countries. In South Africa, where invasions are severe, herbivorous insects that attack S. mauritianum in its native area have been considered for introduction as biological control agents. To assess the action of such herbivores on the plant, studies were carried out on a population of S. mauritianum in an area undergoing regeneration in southern Brazil. An analysis of the structure of that population was performed, as well as of herbivory by insects, in particular of Anthonomus (Curculionidae). The population structure showed an "inverted J" pattern in diameter classes, but not in height classes. Individual plants showed an aggregate distribution. The damage caused by Anthonomus did not amount to the loss of a large leaf area, but since it was inflicted on young leaves and in a large proportion, could lead to the survival decrease.

Solanum mauritianum Scopoli (Solanaceae), um arbusto endêmico do sul do Brasil, naturalizou-se e tornou-se invasor em vários países do mundo. Na África do Sul, onde as invasões são severas, insetos fitófagos associados à planta no país de origem têm sido considerados para introdução como agentes de controle biológico. Para avaliar a ação de tais insetos no ambiente natural, foram conduzidos estudos em uma população de S. mauritianum em uma área em regeneração no sul do Brasil. Foi realizada análise da estrutura populacional, bem como da herbivoria causada por insetos, em particular para uma espécie do gênero Anthonomus (Curculionidae), para subsidiar o trabalho sobre controle biológico. A estrutura da população mostrou um padrão "J invertido" nas classes de diâmetro, mas não nas classes de altura; a distribuição espacial dos indivíduos era agregada. O dano causado por Anthonomus sp. não refletiu na perda real de grande área foliar. No entanto, uma vez que foi detectada uma grande freqüência de danos sobre indivíduos jovens, a herbivoria poderia levar à diminuição da sobrevivência da planta.