Abstract Phylogenetic niche conservatism can be investigated at multiple scales on an explicit geographical context. Haplotype-based comparative analyses of lineages occupying the same region, and thus subjected to similar environmental factors, allow decoupling shared evolutionary and ecological patterns, as well as multiple dimensions of adaptive diversification. Here we aimed to assess the role of environmental drivers on diversification of subtropical grassland, based on haplotypic diversity of two plant genera. We sampled two closely related and co-distributed grassland plant genera, Petunia and Calibrachoa, across their entire distribution area. Eigenvectors extracted from pairwise distances based on chloroplast DNA haplotypes were used to fit Phylogenetic Signal-Representation (PSR) curves to estimate evolutionary patterns in 19 bioclimatic variables and altitude. The PSR curves showed that altitude, precipitation, and temperature variables changed at different rates with haplotype differentiation. Altitude and temperature traits evolved under conditions closer to a neutral dynamics, whereas precipitation traits differentiated following more complex models. Our results indicated that the diversification in the two genera was more limited by precipitation conditions. Based on these novel findings, we suggest that future studies should test the possible impact of precipitation variables on the process of ecological differentiation in these genera.

Abstract The Tropical Niche Conservatism hypothesis is one of the most relevant theories to explain why tropical diversity is high, although the mechanisms underlying this hypothesis require further clarification. A possible research avenue to address the underlying mechanisms includes determining population-level processes associated with such a hypothesis, in particular by trying to identify how adaptation may occur in extreme niche conditions at the edges of species ranges. However, the determinants of molecular diversity at the edges of geographical distributions of tropical taxa are still poorly known. Here we assessed which environmental variables determine diversity in nuclear and plastid genetic markers for populations of four Passiflora species in the southern limit of their geographical distributions. Climatic factors can drive genetic diversity, and their importance varies according to the marker. The primary predictors are variables representing higher temperatures during cold periods of the year and higher precipitation during dry periods. We concluded that, although these species are present in colder areas at the edge of their range, Tropical Niche Conservatism acts as a restraining force on genetic diversity in southern populations of Passiflora.

The comparison of genetic divergence or genetic distances, estimated by pairwise F ST and related statistics, with geographical distances by Mantel test is one of the most popular approaches to evaluate spatial processes driving population structure. There have been, however, recent criticisms and discussions on the statistical performance of the Mantel test. Simultaneously, alternative frameworks for data analyses are being proposed. Here, we review the Mantel test and its variations, including Mantel correlograms and partial correlations and regressions. For illustrative purposes, we studied spatial genetic divergence among 25 populations of Dipteryx alata ("Baru"), a tree species endemic to the Cerrado, the Brazilian savannas, based on 8 microsatellite loci. We also applied alternative methods to analyze spatial patterns in this dataset, especially a multivariate generalization of Spatial Eigenfunction Analysis based on redundancy analysis. The different approaches resulted in similar estimates of the magnitude of spatial structure in the genetic data. Furthermore, the results were expected based on previous knowledge of the ecological and evolutionary processes underlying genetic variation in this species. Our review shows that a careful application and interpretation of Mantel tests, especially Mantel correlograms, can overcome some potential statistical problems and provide a simple and useful tool for multivariate analysis of spatial patterns of genetic divergence.

Several metrics have been developed for estimating phylogenetic signal in comparative data. These may be important both in guiding future studies on correlated evolution and for inferring broad-scale evolutionary and ecological processes (e.g., phylogenetic niche conservatism). Notwithstanding, the validity of some of these metrics is under debate, especially after the development of more sophisticated model-based approaches that estimate departure from particular evolutionary models (i.e., Brownian motion). Here, two of these model-based metrics (Blomberg's K-statistics and Pagel's λ) are compared with three statistical approaches [Moran's I autocorrelation coefficient, coefficients of determination from the autoregressive method (ARM), and phylogenetic eigenvector regression (PVR)]. Based on simulations of a trait evolving under Brownian motion for a phylogeny with 209 species, we showed that all metrics are strongly, although non-linearly, correlated to each other. Our analyses revealed that statistical approaches provide valid results and may be still particularly useful when detailed phylogenies are unavailable or when trait variation among species is difficult to describe by more standard Brownian or O-U evolutionary models.

Caranguejos do gênero Uca Leach, 1814 (caranguejo "violinista") são um grupo bem conhecido e caracterizado por um acentuado dimorfismo sexual e assimetria da quela do macho. Atualmente, estão descritas 97 espécies no mundo. Objetivou-se estimar a distribuição geográfica potencial de 4 espécies do gênero Uca que ocorrem na costa do continente Americano: Uca maracoani Latreille, 1802-1803, U. uruguayensis Nobili, 1901, U. panacea Novak & Salmon, 1974 e U. monilifera Rathbun, 1914. Para modelar a distribuição dessas espécies nas Américas foram utilizados pontos de ocorrência compilados da literatura. Para a modelagem foram utilizados os programas Maxent e GARP a partir de 10 variáveis climáticas e três variáveis topográficas. Todas as variáveis foram convertidas para uma malha com resolução de 0,0417 graus. Nos dois modelos (Maxent e GARP) as espécies apresentaram distribuição geográfica maior do que sugerido por outros trabalhos de registro de ocorrência, com exceção de U. monilifera. Segundo o critério de área sob a curva (AUC), os modelos gerados pelo GARP apresentaram melhores resultados do que os modelos do Maxent. Entretanto, avaliando em conjunto os resultados dos dois modelos é possível melhor estabelecer planos de conservação para espécies com habitat restrito (U. panaceae e U. monilifera), além de recomendar um aumento na amostragem de U. maracoani no nordeste brasileiro e U. uruguyaensis no sudeste brasileiro, a fim de detectar possíveis aumentos na sua distribuição geográfica com base nas predições dos modelos de nicho.

The genus Uca Leach, 1814 (fiddler-crabs) is a well-know group characterized by a marked sexual dimorphism. Worldwide, there are 97 species of fiddler crabs described. Here, we predicted the potential geographical distribution of four species of this genus (Uca maracoani Latreille, 1802-1803, U. uruguayensis Nobili, 1901, U. panacea Novak & Salmon, 1974 e U. monilifera Rathbun, 1914), which occur in the American continent coast. Data used in the modeling were compiled from occurrence records available in the literature. We used Maxent and GARP programs for modelling, 10 climatic variables and three topographical variables. All variables were converted to a grid resolution of 0.0417 degrees. In both Maxent and GARP models the predicted geographical distribution of the species was larger than suggested by other observed data works, except for U. monilifera. According to the AUC criterion, the models generated by GARP were better than those obtained from Maxent. Evaluating the two models together, it is recommended conservation plans for species with restricted habitat (U. panaceae and U. monilifera) besides suggesting sampling of U. maracoani in the Brazilian northeast and U. uruguyaensis in the Brazilian southeast.

Visando conhecer a estrutura genética e a diversidade fenotípica da espécie Eupemphix nattereri Steindachner, 1863, análises morfométricas e moleculares foram realizadas em nove populações do Estado de Goiás. Onze caracteres morfométricos foram avaliados e a diversidade genética foi estimada com o uso de marcadores RAPD. As matrizes de distâncias genéticas e fenotípicas foram correlacionadas com as distâncias geográficas e dados macro e microambientais, utilizando o teste de Mantel. Em relação aos caracteres genéticos, foram encontrados altos níveis de diversidade (Φst= 0,3) entre as nove populações. Não houve, entretanto, uma correlação positiva significativa entre as distâncias genéticas e geográficas, indicando que populações geograficamente próximas não seriam geneticamente similares, mesmo estando situadas entre distâncias menores do que 50 km. Uma análise discriminante dos onze caracteres morfométricos evidenciou também uma elevada divergência entre as nove populações. Entretanto, foi encontrada uma correlação quase significativa (P=0,008) entre as distâncias genéticas e morfométricas. A correlação observada não foi casual entre fenótipo e genótipo, mas indicou estruturas espaciais comuns. Desta forma, nossos resultados sugerem que processos de isolamento por distância poderiam explicar a divergência populacional na espécie Eupemphix nattereri.

To assess genetic structure and phenotypic diversity of Eupemphix nattereri Steindachner, 1863, morphometric and molecular analyses were carried out for nine populations from the State of Goiás. A total of 11 morphometric traits were evaluated and genetic information was estimated using RAPD markers. Genetic and phenotypic distances were determined as a function of geographical origin. Correlation among genetic, morphometric, micro, and macroenviromental were analyzed by the Mantel test. Genetic data indicated high levels of genetic diversity (Φst= 0.3) among the nine populations. Mantel tests did not reveal a significant positive correlation between genetic and geographical distances, indicating that locally geographical populations were not genetically similar, even in distances smaller than 50 km. Discriminant analysis on 11 morphometric measurements showed a high divergence among the nine populations. However, a marginally significant correlation (P=0.08) between genetic and morphometric distances was found. The observed correlation was not causal in terms of the relationship between phenotype and genotype, but indicated common spatial structures. Thus, our results suggest that isolation-by-distance processes may explain population divergence in Eupemphix nattereri.

Zeyheria montana, planta arbustiva da família Bignoniaceae, é uma espécie endêmica do Cerrado e possui atividade anti-câncer, sendo utilizada como estimulante na medicina popular. O objetivo deste estudo foi avaliar a variabilidade genética de oito populações localizadas no estado de São Paulo, utilizando marcadores moleculares de Polimorfismo de DNA Amplificado ao Acaso (RAPD). Após a otimização da reação de amplificação, nove iniciadores selecionados geraram 105 fragmentos RAPD reprodutíveis, sendo que a maioria (60,0%) foi polimórfica. A análise molecular de variância (AMOVA) mostrou que a variabilidade dentro de populações (84,03%) foi maior que entre populações (15,97%). As estimativas de variação fiST (0,1597) indicam estruturação populacional moderadamente alta. O agrupamento por meio de UPGMA, a ordenação pelo NMDS e o teste de Mantel entre as matrizes de distâncias genéticas e geográficas demonstraram que a estruturação encontrada segue um modelo de "ilhas", onde uma única população de tamanho infinito pode ter dado origem às populações atuais de Zeyheria, sem relação com sua posição espacial. Com base nos resultados obtidos foi estruturado um banco de germoplasma de indivíduos, representando a variabilidade da espécie. Adicionalmente, as informações deste estudo são importantes para dar suporte a estratégias de conservação de Z. montana.

Zeyheria montana, an endemic species of the Bignoniaceae family from the Brazilian Cerrado's known for its anti-cancer properties, is widely used as imuno stimulant in the popular medicine and its therapeutic activity must be validated by scientific data. The objective of this work was to evaluate the genetic variability of eight plant populations collected within the state of São Paulo, Brazil, via Random Amplification of Polymorphic DNA (RAPD) used as molecular markers. After an optimized protocol for the amplification reaction, nine selected primers generated 105 reproducible bands, indicating up to 60% polymorphism. Analysis of molecular variance (AMOVA) revealed higher genetic variation within populations (84.03%) than among populations (15.97%). The variation values estimated by phiST (0.160) indicated moderate to high inter population structuration. Levels of similarity inter plants with genetic and geographical distances, estimated by the unweighted pair-group method analysis (UPGMA) clustering and non-metric multidimensional scaling (NMDS) ordination methods and by the Mantel test (-0.2345 p = 0.118) denoted that the structure found follows the island model, which assumes that a single population of infinite size may have initiated the existing populations of Zeyheria montana, with no spatial position correlation. Based on the obtained data, a germplasm bank from individuals representing the species variability was established. Furthermore the information here reported can be of importance to develop strategies for the conservation of Z. montana.

The relationship between body size and geographic range was analyzed for 70 species of terrestrial Carnivora ("fissipeds") of the New World, after the control of phylogenetic patterns in the data using phylogenetic eigenvector regression. The analysis from EcoSim software showed that the variables are related as a triangular envelope. Phylogenetic patterns in data were detected by means of phylogenetic correlograms, and 200 simulations of the phenotypic evolution were also performed over the phylogeny. For body size, the simulations suggested a non-linear relationship for the evolution of this character along the phylogeny. For geographic range size, the correlogram showed no phylogenetic patterns. A phylogenetic eigenvector regression was performed on original data and on data simulated under Ornstein-Uhlenbeck process. Since both characters did not evolve under a simple Brownian motion process, the Type I errors should be around 10%, compatible with other methods to analyze correlated evolution. The significant correlation of the original data (r = 0.38; P < 0.05), as well as the triangular envelope, then indicate ecological and adaptive processes connecting the two variables, such as those proposed in minimum viable population models.

Dentre as diversas árvores frutíferas nativas dos cerrados, a cagaiteira (Eugenia dysenterica DC.) merece destaque pelo seu amplo potencial econômico. A fim de fornecer algumas informações relativas ao padrão espacial da variabilidade genética desta espécie, foram realizadas análises de autocorrelação espacial das freqüências alélicas em dez subpopulações locais da região sudeste do Estado de Goiás. Foram utilizados marcadores isoenzimáticos, em um total de seis sistemas enzimáticos (SKDH, 6-PGD, alfa-EST, MDH, PGI e PGM), com oito locos polimórficos. Foi realizada uma análise de autocorrelação espacial, utilizando índices I de Moran estimados em quatro classes de distância geográfica. Os correlogramas mostraram que, de fato, a divergência genética está estruturada no espaço em um padrão clinal de variação. Simulações de evolução neutra da variação nas freqüências alélicas entre as subpopulações, geradas a partir de um processo Ornstein-Uhlenbeck (O-U), foram utilizadas para avaliar os padrões espaciais sob essa hipótese e compará-los com os correlogramas obtidos com as freqüências alélicas. As análises indicaram que um processo estocástico (evolução neutra) deve ser o responsável pela diferenciação genética dessas populações, havendo assim um balanço entre fluxo gênico em pequenas distâncias geográficas e deriva genética dentro das populações locais, como o esperado para modelos de isolamento-por-distância ou "stepping-stone".

Among the many fruit trees from "cerrado" region that show large economic potential in traditional agricultural systems, the "cagaiteira" (Eugenia dysenterica DC.) deserves a special place. In this work, spatial autocorrelation analyses were used to evaluate spatial patterns of genetic variation among ten local populations from southeastern Goiás State, Brazil. Six isoenzymatic markers (SKDH, 6-PGD, alpha-EST, MDH, PGI e PGM) were used to evaluate genetic variability, in a total of eight polymorphic loci. Moran’s I coefficients were estimated for four geographic distance classes, and correlograms thus obtained showed clinal patterns of variation for most alleles. Simulations of neutral evolution among local populations were performed using the Ornstein-Uhlenbeck process, both to establish null patterns to test this hypothesis and to define the limits of similarity among correlograms. These analyses showed that population differentiation in this species probably occurred under a neutral process in which local drift is counteracted by low geographic distance gene flow, as in isolation-by-distance or stepping-stone models.