A Network Perspective for Community Assembly

Species interactions are responsible for many key mechanisms that govern the dynamics of ecological communities. Variation in the way interactions are organized among species results in different network structures, which translates into a community's ability to resist collapse and change. To better understand the factors involved in dictating ongoing dynamics in a community at a given time, we must unravel how interactions affect the assembly process. Here, we build a novel, integrative conceptual model for understanding how ecological communities assemble that combines ecological networks and island biogeography theory, as well as the principles of niche theory. Through our conceptual model, we show how the rate of species turnover and gene flow within communities will influence the structure of ecological networks. We conduct a preliminary test of our predictions using plant-herbivore networks from differently-aged sites in the Hawaiian archipelago. Our approach will allow future modeling and empirical studies to develop a better understanding of the role of the assembly process in shaping patterns of biodiversity

Vulnerabilidade das microrregiões da Região Sul do Brasil à pandemia do novo coronavírus (SARS-CoV-2)

This is the first report of the ‘Observatório COVID191 - Grupo: Redes de Contágio – Laboratório de Estudos de Defesa’ for the South region of Brazil. We have combined data of confirmed cases of the new coronavirus (SARS-CoV-2) for the South available up to 17/04/2020, with structural analyses of road networks, from within and between states, to estimate the vulnerability and potential influence of the South micro-regions to propagate the disease.Este é o primeiro relatório do Observatório COVID19 - Grupo: Redes de Contágio – Laboratório de Estudos de Defesa para a região Sul do Brasil. Combinamos dados de casos confirmados do novo coronavírus (SARS-CoV-2) para o Sul, disponíveis até o dia 17/04/2020, com análises estruturais da rede de rotas rodoviárias intra e interestaduais para estimarmos a vulnerabilidade e potencial influência das microrregiões sulinas na propagação da doença

Morphological adaptations to arboreal habitats and heart position in species of the neotropical whipsnakes genus Chironius

The evolution of arboreality in snakes is accompanied by modifications that are remarkably similar across species. Gravity is one of the most important selective agents, and arboreal snakes present adaptations to circumvent the gradient of pressure, including modifications on heart position (HP) and body slenderness (BS). However, the degree to which different life-history traits influence the cardiovascular system of snakes remains unclear. Here, we used an ecological and a phylogenetic approach to explore the relationship between habitat, HP, BS, and heart size (HS) in five species of the neotropical whipsnakes genus Chironius that occupy terrestrial, semiarboreal, and arboreal habits. Our ecological comparison indicated that the arboreal species have the most posterior-positioned heart, the most slender body, and the smallest HS, whereas the terrestrial representative of the group exhibited the most anterior heart, the less flattened body, and the largest HS. After removing the phylogenetic effect, we found no difference in HP and BS between terrestrial and arboreal species. Habitat only differed when contrasting with HS. Body slenderness and HS were correlated with HP. Our results suggest that different restrictions, such as anatomical constraints, behavior, and phylogenetic inertia, may be important for the studied species. © 2013 The Royal Swedish Academy of Sciences

Seasonal decomposition of frog abundance, temperature and precipitation.

<p>Seasonal decomposition of the time series data of: (A) the mean number of individuals found in four stream transects, and (B) monthly minimum temperature (°C) and precipitation (mm) at Parque Estadual da Serra do Mar, Brazil.</p

Intensity of <i>Bd</i> infection.

<p><i>Batrachochytrium dendrobatidis</i> infection intensity of <i>Cycloramphus boraceiensis</i> (Cb), <i>Hylodes asper</i> (Ha) and <i>Hylodes phyllodes</i> (Hp) during winter and summer stream surveys at Parque Estadual da Serra do Mar, Brazil. The total number of individuals swabbed is shown in the bottom of each bar. We measured genomic equivalents (GEs) using qPCR, and report the proportion of individuals infected by each zoospore category: 0, 1–10, 11–100, 101–1000, and >1001 GEs.</p

Frog abundance, temperature and precipitation.

<p>Trends of the time series data of: (A) the mean number of individuals found in four stream transects, and (B) monthly minimum temperature (°C) and precipitation (mm) at Parque Estadual da Serra do Mar, Brazil.</p