Response of South American Terrestrial Ecosystems to Future Patterns of Sea Surface Temperature

Global warming in the first half of the 21st century is likely to have profound influences on South American vegetation and climate. Although coupled atmosphere-biosphere models have been widely used to forecast future vegetation patterns under various scenarios of global warming, they have not been used to assess the potentially critical role of variations in sea surface temperature (SST) in modifying the climate-vegetation interactions. Here, we use monthly output of a 100-year coupled model run to investigate the relationship between SST, precipitation, and productivity of vegetation. Specifically, we assess statistical correlations between SST variability and vegetation in six different South America regions: Northern South America, Western Amazonia, Eastern Amazonia, Northeast Brazil, Central Brazil, and Patagonia. Our model robustly simulates changes in mean precipitation, net primary production (NPP), upper canopy leaf area index (LAI), and lower canopy LAI under warming and nonwarming scenarios. Most significantly, we demonstrate that spatial-temporal variability in SST exerts a strong influence over the vegetation dynamics in all six South American regions

Environmental factors driving plant trait distributions in coastal zones of Atlantic Forest

Publisher Copyright: © 2021 Instituto de Pesquisas Jardim Botanico do Rio de Janeiro. All rights reserved.Environmental filtering has been defined as the effect of environmental gradients on species in a plant community and can be the dominant driver of community assembly. Here, we evaluate the relationship between plant communities and the environment in the Restinga vegetation. For this, we measured 11 functional traits of plant species present along transects covering a marked edaphic environmental gradient. This gradient was characterized through Principal Component Analysis of soil characteristics. The relationships between the edaphic gradient and functional traits were evaluated using linear models. Finally, we compared the contributions of species turnover and intraspecific variation to among-site variation in functional traits. The gradients associated with soil nutrients (PCA axis 1) and soil acidity and organic matter (PCA axis 2) were then used to test the observed changes in community composition and were significant predictors of the distribution of water potential, leaf dry matter content and K content, height and chlorophyll index. Decomposing the total variation in the distribution of functional traits between species turnover and intraspecific variation revealed that species turnover explains a greater proportion of the observed variation. We conclude that community assembly is strongly limited by environmental filters and mediated by functional traits at the species level.Peer reviewe

Vegetation patterns in South America associated with rising CO2: Uncertainties related to sea surface temperatures

Spatially precise forecasts of the impacts of climate change on the distribution of major vegetation types are essential for the implementation of effective conservation and land use policy. However, existing studies frequently omit major sources of climate variability that can significantly increase the uncertainty of projections. In this study we demonstrate how different predictions for sea surface temperature (SST) for the first half of the twenty-first century increase the uncertainty associated with forecasts of the future distribution of major ecosystems in South America. This is demonstrated through a numerical experiment using a coupled climate-vegetation model (CCM3-IBIS) for IPCC emission scenario A2 that incorporates the SST data from ten different models. The study reveals an increasing uncertainty in the ability to forecast future vegetation patterns, such that by 2050 the simulation is unable to robustly forecast the vegetation cover in an area equivalent to 28 % in South America (5 × 106 km2). The future of the central and northeastern regions of Brazil is especially uncertain, with outcomes, ranging from savanna, and open shrubland to grassland. Recognizing and managing such uncertainty should be a priority for decision makers. © 2012 Springer-Verlag

Predicting land cover changes in the Amazon rainforest: An ocean-atmosphere-biosphere problem

Accurate studies of the impacts of climate change on the distribution of major vegetation types are essential for developing effective conservation and land use policy. Such studies require the development of models that accurately represent the complex and interacting biophysical factors that influence regional patterns of vegetation. Here we investigate the impacts of Sea Surface Temperature (SST) on the vegetation of the Amazon, testing the hypothesis that changes in Amazonian vegetation structure are a consequence of an ocean-atmosphere-biosphere interaction. We design a numerical experiment in which we force a coupled climate-biosphere model by 10 SST patterns produced by different IPCC AR4 models, for the A2 scenario for the period 2000-2050. Simulations for 2011-2050 show that certain patterns of SST are likely to decrease the ensemble for tropical evergreen rainforest and savanna, and that these areas will be occupied mainly by tropical deciduous rainforest, emitting an average of 0.53 Pg-C.yr-1 during the transition. © Copyright 2012 by the American Geophysical Union

Assets em Áreas Protegidas: Estudo de Caso em Áreas Úmidas

As áreas protegidas (APs) são as principais ferramentas capazes de assegurar a preservaçãodos sistemas naturais e sua respectiva biodiversidade, principalmente no caso de áreas com prioridade para conservação, como ocorre com as áreas úmidas. A implementação de APs tem potencial para gerar benefícios fundamentais para proteger paisagens icônicas, espécies ameaçadas e serviços ecossistêmicos; entretanto, essas áreas têm custos sociais e econômicos que, muitas vezes, se tornam difíceis de justificar em períodos de crescente insegurança alimentar e crise financeira. Recentemente, sugeriu-se um modelo conceitual para apoiar a gestão das APs (PA Asset Framework) que (re)define as APs como um sistema de assets biofísicos, humanos, de infraestrutura, institucionais e culturais. De acordo com esse marco, as APs podem ser geridas e planejadas para gerar diferentes formas de valores, desse modo contribuindo para aumentar sua resiliência política/social e identificar investimentos financeiros que possam auxiliar o reconhecimento e a captura de valores por distintos públicos. Neste artigo, aplicamos o PA asset framework para levantar a presença de assets em parques nacionais localizados em áreas úmidas, a partir da revisão sistemática dos planos de manejo. Nestes, identificamos os assets presentes e mais recorrentes em tais áreas. Nossos resultados mostram que o número de assets representados e reconhecidos nos planos de manejo é limitado, concentrando-se, principalmente, em algumas classes biofísicas relacionadas à conservação da biodiversidade (ex: espécies de importância para a conservação e espécies de importância econômica), de infraestrutura necessária paramanutenção das atividades de gestão (ex: funcionário permanente, infraestrutura para gestão, eletricidade e veículos) e institucionais (estratégias de planejamento e zoneamento). Por outro lado, dada a importância sociocultural das áreas úmidas em nível nacional e global, o baixo reconhecimento de assets humanos e culturais nessas áreas sugere que a inclusão desses valores nos planos de manejo pode ser benéfica para potencializar os valores associados a essas tipologias de asset. Argumentamos que o levantamento dos assets em APs, além de revelar os bens/recursos/atributos/dimensões-chave que podem estar sendo negligenciados nos planos de manejo, oferece uma abordagem inovadora para que os gestores possam elaborar estratégias de investimento a partir do reconhecimento de valores tangíveis e intangíveis das APs e dos seus assets, para além dos biofísicos

Merging the adaptive random walks planner with the randomized potential field planner

Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing from southwest to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (gt;20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the northwest of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density