Guilherme Dubal dos Santos Seger

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.

Land Use Explains the Distribution of Threatened New World Amphibians Better than Climate

Background We evaluated the direct and indirect influence of climate, land use, phylogenetic structure, species richness and endemism on the distribution of New World threatened amphibians. Methodology/Principal Findings We used the WWF’s New World ecoregions, the WWFs amphibian distributional data and the IUCN Red List Categories to obtain the number of threatened species per ecoregion. We analyzed three different scenarios urgent, moderate, and the most inclusive scenario. Using path analysis we evaluated the direct and indirect effects of climate, type of land use, phylogenetic structure, richness and endemism on the number of threatened amphibians in New World ecoregions. In all scenarios we found strong support for direct influences of endemism, the cover of villages and species richness on the number of threatened species in each ecoregion. The proportion of wild area had indirect effects in the moderate and the most inclusive scenario. Phylogenetic composition was important in determining the species richness and endemism in each ecoregion. Climate variables had complex and indirect effects on the number of threatened species. Conclusion/Significance Land use has a more direct influence than climate in determining the distribution of New World threatened amphibians. Independently of the scenario analyzed, the main variables influencing the distribution of threatened amphibians were consistent, with endemism having the largest magnitude path coefficient. The importance of phylogenetic composition could indicate that some clades may be more threatened than others, and their presence increases the number of threatened species. Our results highlight the importance of man-made land transformation, which is a local variable, as a critical factor underlying the distribution of threatened amphibians at a biogeographic scale.

Discriminating the effects of phylogenetic hypothesis, tree resolution and clade age estimates on phylogenetic signal measurements

Understanding how species traits evolved over time is the central question to comprehend assembly rules that govern the phylogenetic structure of communities. The measurement of phylogenetic signal (PS) in ecologically relevant traits is a first step to understand phylogenetically structured community patterns. The different methods available to estimate PS make it difficult to choose which is most appropriate. Furthermore, alternative phylogenetic tree hypotheses, node resolution and clade age estimates might influence PS measurements. In this study, we evaluated to what extent these parameters affect different methods of PS analysis, and discuss advantages and disadvantages when selecting which method to use. We measured fruit/seed traits and flowering/fruiting phenology of endozoochoric species occurring in Southern Brazilian Araucaria forests and evaluated their PS using Mantel regressions, phylogenetic eigenvector regressions (PVR) and K statistic. Mantel regressions always gave less significant results compared to PVR and K statistic in all combinations of phylogenetic trees constructed. Moreover, a better phylogenetic resolution affected PS, independently of the method used to estimate it. Morphological seed traits tended to show higher PS than diaspores traits, while PS in flowering/fruiting phenology depended mostly on the method used to estimate it. This study demonstrates that different PS estimates are obtained depending on the chosen method and the phylogenetic tree resolution. This finding has implications for inferences on phylogenetic niche conservatism or ecological processes determining phylogenetic community structure.

Phylogenetic composition and structure of tree communities shed light on historical processes influencing tropical rainforest diversity

The Neotropics, Afrotropics and Madagascar have different histories which have influenced their respective patterns of diversity. Based on current knowledge of these histories, we developed the following predictions about the phylogenetic structure and composition of rainforest tree communities: (Hypothesis 1) isolation of Gondwanan biotas generated differences in phylogenetic composition among biogeographical regions; (H2) major Cenozoic extinction events led to lack of phylogenetic structure in Afrotropical and Malagasy communities; (H3) greater angiosperm diversification in the Neotropics led to greater phylogenetic clustering there than elsewhere; (H4) phylogenetic overdispersion is expected near the Andes due to the co-occurrence of magnoliids tracking conserved habitat preferences and recently diversified eudicot lineages. Using abundance data of tropical rainforest tree species from 94 communities in the Neotropics, Afrotropics and Madagascar, we computed net relatedness index (NRI) to assess local phylogenetic structure, i.e. phylogenetic clustering vs. overdispersion relative to regional species pools, and principal coordinates of phylogenetic structure (PCPS) to assess variation in phylogenetic composition across communities. We observed significant differences in phylogenetic composition among biogeographical regions (agreement with H1). Overall phylogenetic structure did not differ among biogeographical regions, but results indicated variation from Andes to Amazon. We found widespread phylogenetic randomness in most Afrotropical and all Malagasy communities (agreement with H2). Most of central Amazonian communities were phylogenetically random, although some communities presented phylogenetic clustering (partial agreement with H3). We observed phylogenetic overdispersion near the Andes (agreement with H4). We were able to identify how differences in lineage composition are related to local phylogenetic co-occurrences across biogeographical regions that have been undergoing different climatic and orographic histories during the past 100 Myr. We observed imprints of the history following Gondwana breakup on phylobetadiversity and local phylogenetic structure of rainforest tree communities in the Neotropics, Afrotropics and Madagascar.

Checklist of climbing plants in an Araucaria forest of Rio Grande do Sul State, Brazil

Trepadeiras sao importantes componentes florestais, contribuindo na diversidade e dinâmica de comunidades vegetais. Estudos focados em trepadeiras sao escassos e para muitos tipos vegetacionais pouco se sabe sobre a composicao de especies de trepadeiras e seus atributos relevantes para dispersao e estabelecimento. O foco deste estudo e fornecer o primeiro inventario floristico de plantas trepadeiras em uma floresta de Araucaria no Brasil, descrevendo as sindromes de dispersao e mecanismos de escalada das especies e comparando esses atributos e a composicao de especies com outros sitios no Sul do Brasil. Foram encontrados 104 taxa pertencentes a 33 familias, sendo Asteraceae (22 spp.) e Apocynaceae (14 spp.) as familias mais ricas. Dentre os mecanismos de escalada, o tipo voluvel (50 spp.) e o mais comum, seguido por gavinhas (20 spp.) e apoiantes (12 spp.), enquanto em relacao es sindromes de dispersao as especies anemocoricas (65 spp.) sao as mais relevantes seguidas por endozoocoricas (28 spp.). Tres novos registros de especies foram encontrados para o Estado do Rio Grande do Sul, expandindo suas extensoes de ocorrencia para o Sul do Brasil. A comparacao entre sitios evidenciou dois grupos nitidos em relacao e composicao de especies e proporcao de atributos, sitios em florestas sazonais e nas florestas com Araucaria e Atlântica, porem nao ha diferenca na frequencia dos atributos entre os sitios. Ha uma predominância de especies voluveis em todos os sitios, entretanto a diferenca relativa para especies com gavinhas aumenta nos sitios de floresta com Araucaria e Atlântica. As familias Asteraceae e Apocynaceae foram as mais relevantes, contrastando com florestas sazonais no Sudeste do Brasil. Padroes interessantes podem ser encontrados com uma classificacao mais detalhada dos mecanismos de escalada e os resultados encontrados neste estudo contribuem para aumentar o conhecimento sobre os atributos e a diversidade de trepadeiras no Sul do Brasil.

Phylogenetic and functional structure of climbing plant assemblages in woody patches advancing over Campos grassland

Seger, G.D.S. (corresponding author, guiseger@yahoo.com.br), Cappelatti, L. (lauracappelatti@gmail.com), Gonc alves, L.O. (larissa.oligon@gmail.com), Becker, F.G. (fgbecker@ufrgs.br), Melo, A.S. (asm.adrimelo@gmail.com), Duarte, L.D.S. (duarte.ldas@gmail.com) Programa de P os-Graduac ~ao em Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil; Current address: Programa de P os-Graduac ~ao em Ecologia e Conservac ~ao, Universidade Federal do Paran a, Curitiba, PR, zip Code 19031, 81531-990, Brazil; Departamento de Ecologia, Universidade Federal de Goi as, Goiânia, GO 74001-970, Brazil Abstract

Taxonomic and ecological aspects of Myrceugenia mesomischa (Myrtaceae), an endemic tree from southern Brazil

Myrceugenia mesomischa (Burret) D. Legrand & Kausel (Myrtaceae), a tree species poorly cited in floristic and phytosociological surveys in its area of known occurrence, was recorded as one of the species with the highest importance value in a fragment of Araucaria forest in Sao Francisco de Paula municipality, Rio Grande do Sul state, Brazil. The species was abundant in the understory strata of the forest, showing the highest frequency and density of the survey. Considering the paucity of data on the species, its degree of rarity and endemism (occurring only in the states of Rio Grande do Sul and Santa Catarina, Brazil), more studies are needed to evaluate the true current state of conservation of populations of this species.