PARENTS, AND NETWORKS ORDINANCES: DETECTION OF STRUCTURE IN THE INTERACTIVE

Neste artigo apresentamos três abordagens usuais para a detecção de padrões em comunidades de plantas e animais que interagem entre si por meio de processos ecológicos como a polinização, a frugivoria ou a herbivoria. Modelos estruturais simples revelam padrões de interação em gradientes, compartimentados ou aninhados; padrões intermediários entre um gradiente e compartimentos também são possíveis. De forma semelhante, o aninhamento no interior de compartimentos gera ainda um modelo estrutural combinado. Os padrões de interação podem ser visualizados e analisados sob a forma de matrizes, redes bipartidas ou gráficos de ordenação obtidos através de uma Análise de Correspondência. Neste trabalho, propomos que as diferenças entre os padrões de interação observados em comunidades representam resultados de diferentes processos ecológicos e evolutivos que atuam sobre tais comunidades. De maneira geral, a compartimentação deveria refletir o histórico da coevolução e os limites impostos às espécies presentes na comunidade, ao passo que diferenças na abundância e na capacidade de dispersão dessas espécies podem gerar uma estrutura aninhada. Portanto, ao invés de ser testada para um modelo estrutural a priori, a estrutura de comunidades ecológicas deve ser confrontada com uma gama inteira de padrões possíveis. Esperamos que as abordagens para a detecção de estruturas em comunidades interativas aqui apresentadas facilitem a elaboração de hipóteses ecológicas mais abrangentes e melhor formuladas.In this paper we present a comprehensive approach to detect structural patterns in interactive communities of plant and animal species, linked by ecological processes such as pollination, frugivory or herbivory. Simple structural models can reveal gradient, compartmented or nested patterns of interaction; intermediate patterns between a gradient and compartments are also possible. Of special potential interest is a combined model, in which nested structures are embedded within compartments. Interaction patterns can be visualized and analyzed in different ways, either as matrices, as bipartite networks or as multivariate sets through correspondence analysis or other ordination procedures. We also propose that differences among patterns represent outcomes of distinct evolutionary and ecological processes that will be especially relevant in highly diversified communities. In general, compartmentation should reflect coevolutionary histories and constraints, whereas differences in species abundances or dispersal rates may generate nestedness. Hence, instead of choosing one model a priori, to be empirically verified, community structure should be probed for a suite of patterns. The comprehensive approach for detecting community structure that we advocate should help to improve ecological hypotheses on compositional patterns in interactive communities, as well as their attendant empirical tests in actual communities.

ASPECTOS DA SILVIGÊNESE DE UMA MATA PLUVIAL ATLÂNTICA EM UNHARES, ES

O trabalho estudou alguns aspectos do ciclo silvigenético e arquitetura de uma floresta atlântica primária em Unhares, ES. As árvores dominantes que interceptavam linhas de inventário de uma parcela de cerca de 0,5 ha foram mapeadas e categorizadas de acordo com características arquiteturais e grau de de­senvolvimento em: árvores do futuro, passado e presen­te. Foi possível estabelecer com base neste inventário um mosaico de ecounidades em reorganização, desen­volvimento, maturidade e em degradação. Os resulta­ dos indicam que, apesar de mostrar características de floresta madura e estável, esta área pode ter sofrido no passado explorações seletivas de madeira

Climate drivers of malaria at its southern fringe in the Americas

In this work we analyze potential environmental drivers of malaria cases in Northwestern Argentina. We inspect causal links between malaria and climatic variables by means of the convergent cross mapping technique, which provides a causality criterion from the theory of dynamic systems. Analysis is based on 12 years of weekly malaria P. vivax cases in Tartagal, Salta, Argentina—at the southern fringe of malaria incidence in the Americas—together with humidity and temperature time-series spanning the same period. Our results show that there are causal links between malaria cases and both maximum temperature, with a delay of five weeks, and minimum temperature, with delays of zero and twenty two weeks. Humidity is also a driver of malaria cases, with thirteen weeks delay between cause and effect. Furthermore we also determined the sign and strength of the effects. Temperature has always a positive non-linear effect on cases, with maximum temperature effects more pronounced above 25C and minimum above 17C, while effects of humidity are more intricate: maximum humidity above 85% has a negative effect, whereas minimum humidity has a positive effect on cases. These results might be signaling processes operating at short (below 5 weeks) and long (over 12 weeks) time delays, corresponding to effects related to parasite cycle and mosquito population dynamics respectively. The non-linearities found for the strength of the effect of temperature on malaria cases make warmer areas more prone to higher increases in the disease incidence. Moreover, our results indicate that an increase of extreme weather events could enhance the risks of malaria spreading and re-emergence beyond the current distribution. Both situations, warmer climate and increase of extreme events, will be remarkably increased by the end of the century in this hot spot of climate change.Fil: Laneri, Karina Fabiana. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones No Nucleares. Gerencia de Física (cab). División Física Estadística; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Cabella, Brenno. Universidade Estadual Paulista Julio de Mesquita Filho. Faculdade de Engenharia; BrasilFil: Prado, Paulo Inácio. Universidade de Sao Paulo; BrasilFil: Coutinho, Renato Mendes. Universidad Federal Do Abc; BrasilFil: Kraenkel, Roberto André. Universidade Estadual Paulista Julio de Mesquita Filho. Faculdade de Engenharia; Brasi

Beyond the Fragmentation Threshold Hypothesis: Regime Shifts in Biodiversity Across Fragmented Landscapes

Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andrén proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions - that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework, providing a powerful tool for analysing the potential effectiveness of management interventions

Estrutura da comunidade de plantas vasculares em clareiras naturais e em área perturbada por fogo em uma floresta pluvial tropical Atlântica no Sul da Bahia, Brasil

The effects of disturbances on plant community structure in tropical forests have been widely investigated. However, a majority of these studies examined only woody species, principally trees, whereas the effects of disturbances on the whole assemblage of vascular plants remain largely unexplored. At the present study, all vascular plants < 5m tall were surveyed in four habitats: natural treefall gaps, burned forest, and their adjacent understorey. The burned area differed from the other habitats in terms of species composition. However, species richness and plant density did not differ between burned area and the adjacent understorey, which is in accordance to the succession model that predict a rapid recovery of species richness, but with a different species composition in areas under moderate disturbance. The treefall gaps and the two areas of understorey did not differ among themselves in terms of the number of individuals, number of species, nor in species composition. The absence of differences between the vegetation in treefall gaps and in understorey areas seems to be in agreement with the current idea that the species present in treefall gaps are directly related to the vegetation composition before gap formation. Only minimal differences were observed between the analyses that considered only tree species and those that considered all growth habits. This suggests that the same processes acting on tree species (the best studied group of plants in tropical forests) are also acting on the whole assemblage of vascular plants in these communities.Os efeitos das perturbações sobre parâmetros da estrutura de comunidade de plantas em florestas tropicais têm sido freqüentemente analisados. Porém, a maioria dos estudos realizados até o momento tem considerado somente plantas lenhosas, principalmente árvores, e o efeito de perturbações sobre toda a comunidade de plantas vasculares ainda não havia sido avaliado. No presente estudo, todas as plantas vasculares menores que 5 metros de altura foram amostradas em clareiras naturais, em uma área de floresta queimada em um incêndio acidental e em áreas de sub-bosque adjacentes. A área queimada diferiu das outras áreas em relação à composição de espécies, porém a riqueza de espécies e a densidade de indivíduos não foi diferente entre a área queimada e as áreas de sub-bosque. Estes resultados estão de acordo com os modelos sucessionais que prevêem que em locais sujeitos a perturbações de intensidade moderada ocorre uma rápida recuperação da riqueza de espécies, porém com uma composição de espécies diferenciada. As clareiras naturais e as áreas de sub-bosque não diferiram quanto ao número de indivíduos e de espécies, nem em relação à composição de espécies. A ausência de diferenças entre a vegetação em clareiras e no sub-bosque sugere que as espécies encontradas em clareiras estão diretamente relacionadas às espécies presentes antes da formação das clareiras. Foram observadas apenas pequenas diferenças entre os resultados das análises que consideraram somente as espécies arbóreas e as análises considerando todos os hábitos de crescimento, sugerindo que os mesmos processos que atuam sobre as espécies arbóreas estão também atuando sobre toda a comunidade de plantas vasculares nestas florestas.303313Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Percolation across households in mechanistic models of non-pharmaceutical interventions in SARS-CoV-2 disease dynamics

We thank all members of Observatório COVID-19 BR and the CoMo Consortium for the collaborative work. The authors also thank the research funding agencies: São Paulo Research Foundation (FAPESP) – Brazil (grant number: 2019/26310-2 and 2017/26770-8 to CF, 2018/24037-4 to SP, 2018/23984-0 to VS and contract number: 2016/01343-7 to RAK), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – Brazil (Finance Code 001 to LSF) and the Brazilian National Council for Scientific and Technological Development (CNPq) (grant number: 315854/2020-0 to MEB, 313055/2020-3 to PIP and 311832/2017-2 to RAK). RA is funded by the Bill and Melinda Gates Foundation (OPP1193472). LW is funded by the Li Ka Shing Foundation, Hong Kong. The CoMo Consortium has support from the Oxford University COVID-19 Research Response Fund (ref: 0009280).Peer reviewedPublisher PD

Modeling the impact of school reopening and contact tracing strategies on COVID-19 dynamics in different epidemiologic settings in Brazil

This study was funded by the Brazilian National Council for Scientific and Technological Development (CNPq) - Process # 402834/2020-8 (request for proposals MCTIC/CNPq/FNDCT/MS/SCTIE/Decit Number 07/2020). The funding sources played no role in the study design; collection, analysis, or interpretation of the data; writing the report, or decision to submit the paper for publication. MEB received a technological and industrial scholarship from CNPq (grant number 315854/2020-0). LSF received a masters scholarship from Coordination of Superior Level Staff Improvement (CAPES) (finance code 001). SP was supported by Sao Paulo State Research Support Foundation (FAPESP) (grant number: 2018/24037-4). CF was supported by FAPESP (grant number: 2019/26310-2 and 2017/26770-8). RAK has been supported by CNPq (grant number: 311832/2017-2) and FAPESP (contract number: 2016/01343-7). PIP has been supported by CNPq (grant number: 313055/2020-3). RSK has been supported by CNPq (proc. 312378/2019-0). MQMR received a postdoctoral scholarship from CAPES (grant number 305269/2020-8). CMT has been supported by CNPq productivity fellowship and the National Institute of Science and Technology for Health Technology Assessment (IATS) (proc: 465518/2014-1). AMB received a technological and industrial scholarship from CNPq (grant number 402834/2020-8). LMS received a technological and industrial scholarship from CNPq (grant number 315866/2020-9). JAFD-F has been supported by CNPq productivity fellowship and the National Institutes for Science and Technology in Ecology, Evolution and Biodiversity Conservation (INCT-EEC), supported by MCTIC/CNPq (proc. 465610/2014-5) and FAPEG (proc. 201810267000023).Preprin

Modelling the impact of school reopening and contact tracing strategies on Covid-19 dynamics in different epidemiologic settings in Brazil

We simulate the impact of school reopening during the COVID-19 pandemic in three major urban centers in Brazil to identify the epidemiological indicators and the best timing for the return of in-school activities and the effect of contact tracing as a mitigation measure. Our goal is to offer guidelines for evidence-based policymaking. We implement an extended SEIR model stratified by age and considering contact networks in different settings – school, home, work, and community, in which the infection transmission rate is affected by various intervention measures. After fitting epidemiological and demographic data, we simulate scenarios with increasing school transmission due to school reopening, and also estimate the number of hospitalization and deaths averted by the implementation of contact tracing. Reopening schools results in a non-linear increase in reported COVID-19 cases and deaths, which is highly dependent on infection and disease incidence at the time of reopening. When contact tracing and quarantining are restricted to school and home settings, a large number of daily tests is required to produce significant effects in reducing the total number of hospitalizations and deaths. Policymakers should carefully consider the epidemiological context and timing regarding the implementation of school closure and return of in-person school activities. While contact tracing strategies prevent new infections within school en- vironments, they alone are not sufficient to avoid significant impacts on community transmission