Padrões espaciais da vegetação lenhosa associados ao processo de expansão da floresta com araucaria sobre campos excluídos de manejo

O processo de expansão florestal tem sido observado em regiões de mosaicos de campo-floresta no Sul do Brasil, especialmente em campos excluídos de fogo e pastejo. Outros fatores influenciam esse processo, porém a magnitude ainda permanece pouco compreendida. Neste estudo, avaliamos os padrões da vegetação lenhosa estabelecida num campo excluído de manejo por 34 anos, relacionando-os com variáveis de solo e espaço. Estabelecemos 110 parcelas (113 m2 cada) de forma sistemática sobre áreas mapeadas como campos em 1985, na Estação Ecológica de Aracuri, Rio Grande do Sul, Brasil. Foram amostrados todos os indivíduos lenhosos e variáveis de solo. Análises de ordenação e de partição da variância da composição de espécies nos componentes solo, espaço, e solo estruturado no espaço foram empregadas. Os padrões da vegetação foram melhor explicados pelo espaço, principalmente a distância da área fonte florestal. Comunidades mais próximas da antiga borda florestal são caracterizadas por mais espécies e indivíduos com dispersão zoocórica. Áreas mais distantes têm predomínio de arbustos campestres (Baccharis uncinella) e poucas arbóreas se estabeleceram. O solo apresentou baixa explicação (5%), porém as condições modificam-se conforme o desenvolvimento florestal avança. Concluímos que a expansão florestal em área excluída de distúrbios tem forte associação com o espaço – a distância de áreas fonte, e que os fatores edáficos pouco contribuem com a magnitude do avanço sobre o campo.The forest expansion process has been observed in forest-grassland mosaics regions in the south of Brazil, mainly over grasslands excluded from cattle grazing and fire. Other factors influence this process, but the magnitude remains almost unknown. Here, we evaluated woody species community patterns on a grassland area, excluded from management for 34 years, relating them to soil and space variables. We established 110 plots (113 m2 each) over areas that were mapped in 1985 as grasslands, in the Estação Ecológica de Aracuri, Rio Grande do Sul, Brazil. All woody individuals and soil variables were sampled in the plots. Ordination analyses and partial redundancy analysis were applied on these data to meet our aims. Vegetation patterns were better explained by spatial variables, especially concerning the distance from the forest source. Communities closer to the old forest border were characterised by forest species – higher richness and density of zoocoric species. In the most distant border areas, grassland shrubs (Baccharis uncinella) still prevail with few established trees. Although soil had a low proportion of vegetation variance explanation (5%), this situation, however, changes as forest development advances. We conclude that forest expansion in excluded grassland areas is strongly associated with space – the forest source distance and that the effect of soil factors in this process is negligible

Answers to grazing or exclusion can be characterized by functional types?

O trabalho foi desenvolvido no Centro de Pesquisa de Forrageiras, da FEPAGRO, em São Gabriel, RS, numa área de pastagem natural, de janeiro de 1998 a dezembro de 2000, com o objetivo de defi nir tipos funcionais para os fatores avaliados. O delineamento experimental utilizado foi um fatorial completamente casualizado em parcela subdividida, com três repetições. Os tratamentos pastejo e exclusão foram alocados nas parcelas principais e os níveis de adubação (com ou sem NPK) nas subparcelas. O pastejo foi realizado por bovinos, equinos e ovinos a partir de janeiro de 1998 e a adubação, anualmente, de fevereiro de 1994 a fevereiro de 1996. A exclusão iniciou em dezembro de 1996. Altura da planta, consistência e superfície ventral da lâmina foliar são atributos que melhor caracterizam os ambientes pastejados e excluídos.The study was conducted at the Forage Research Center of FEPAGRO, São Gabriel, RS, using an area of native pasture, from January 1998 to December 2000. The objective of this research was to defi ne the plant functional types to the particular assessed environment. The experiment design was splitplot arranged in randomized blocks, with three replications. The treatments, grazed and not grazed areas, were allocated to the main plots and different fertilization levels (with and without NPK) were allocated to the subplots. Plots were grazed by cattle, horse and sheep from January 1998 and the fertilizer was applied annually from February 1994 to February 1996. The ungrazed plots were excluded from grazing in December 1996. Plant height, consistency and adaxial surface of the leaf lamina are characteristics that represent the grazed and ungrazed environments

Valores, Estratégias de Pesquisa e Aplicação do Conhecimento: Os Campos Sulinos em Questão

A ciência não é livre de valores. O filósofo Hugh Lacey desenvolveu um modelo das interações entre valores e atividade científica. O objetivo principal do presente trabalho é apresentar o modelo de Lacey e aplicá-lo ao contexto das possibilidades de uso produtivo dos Campos Sulinos, ecossistemas campestres da região sudeste da América do Sul. A conversão dos Campos Sulinos em grandes áreas de monoculturas agrícolas e silviculturais está baseada num entendimento científico guiado por estratégias descontextualizadoras (ED). A conservação dos Campos Sulinos também é informada pelo entendimento científico, mas guiado principalmente por estratégias sensíveis ao contexto (EC). Na medida em que a escolha da estratégia de pesquisa molda as aplicações possíveis, a adoção quase exclusiva de ED na ciência atual contraria o ideal de neutralidade da ciência. Para a atividade científica ser efetivamente regulada pelos ideais de abrangência e neutralidade é necessário que seja estruturada por uma pluralidade de estratégias

sPlotOpen : an environmentally balanced, open-access, global dataset of vegetation plots

Motivation: Assessing biodiversity status and trends in plant communities is critical for understanding, quantifying and predicting the effects of global change on ecosystems. Vegetation plots record the occurrence or abundance of all plant species co-occurring within delimited local areas. This allows species absences to be inferred, information seldom provided by existing global plant datasets. Although many vegetation plots have been recorded, most are not available to the global research community. A recent initiative, called ‘sPlot’, compiled the first global vegetation plot database, and continues to grow and curate it. The sPlot database, however, is extremely unbalanced spatially and environmentally, and is not open-access. Here, we address both these issues by (a) resampling the vegetation plots using several environmental variables as sampling strata and (b) securing permission from data holders of 105 local-to-regional datasets to openly release data. We thus present sPlotOpen, the largest open-access dataset of vegetation plots ever released. sPlotOpen can be used to explore global diversity at the plant community level, as ground truth data in remote sensing applications, or as a baseline for biodiversity monitoring. Main types of variable contained: Vegetation plots (n = 95,104) recording cover or abundance of naturally co-occurring vascular plant species within delimited areas. sPlotOpen contains three partially overlapping resampled datasets (c. 50,000 plots each), to be used as replicates in global analyses. Besides geographical location, date, plot size, biome, elevation, slope, aspect, vegetation type, naturalness, coverage of various vegetation layers, and source dataset, plot-level data also include community-weighted means and variances of 18 plant functional traits from the TRY Plant Trait Database. Spatial location and grain: Global, 0.01–40,000 m². Time period and grain: 1888–2015, recording dates. Major taxa and level of measurement: 42,677 vascular plant taxa, plot-level records. Software format: Three main matrices (.csv), relationally linked

Composição do banco de sementes do solo (BSS) em vegetação campestre da depressão central do Rio Grande do Sul

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The Program for Biodiversity Research in Brazil: The role of regional networks for biodiversity knowledge, dissemination, and conservation

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes

Long-term ecological research in southern Brazil grasslands: effects of grazing exclusion and deferred grazing on plant and arthropod communities

Grazing exclusion may lead to biodiversity loss and homogenization of naturally heterogeneous and species-rich grassland ecosystems, and these effects may cascade to higher trophic levels and ecosystem properties. Although grazing exclusion has been studied elsewhere, the consequences of alleviating the disturbance regime in grassland ecosystems remain unclear. In this paper, we present results of the first five years of an experiment in native grasslands of southern Brazil. Using a randomized block experimental design, we examined the effects of three grazing treatments on plant and arthropod communities: (i) deferred grazing (i.e., intermittent grazing), (ii) grazing exclusion and (iii) a control under traditional continuous grazing, which were applied to 70 x 70 m experimental plots, in six regionally distributed blocks. We evaluated plant community responses regarding taxonomic and functional diversity (life-forms) in separate spatial components: alpha (1 x 1 m subplots), beta, and gamma (70 x 70 m plots), as well as the cascading effects on arthropod high-taxa. By estimating effect sizes (treatments vs. control) by bootstrap resampling, both deferred grazing and grazing exclusion mostly increased vegetation height, plant biomass and standing dead biomass. The effect of grazing exclusion on plant taxonomic diversity was negative. Conversely, deferred grazing increased plant taxonomic diversity, but both treatments reduced plant functional diversity. Reduced grazing pressure in both treatments promoted the break of dominance by prostrate species, followed by fast homogenization of vegetation structure towards dominance of ligneous and erect species. These changes in the plant community led to increases in high-taxa richness and abundance of vegetation-dwelling arthropod groups under both treatments, but had no detectable effects on epigeic arthropods. Our results indicate that decision-making regarding the conservation of southern Brazil grasslands should include both intensive and alleviated levels of grazing management, but not complete grazing exclusion, to maximize conservation results when considering plant and arthropod communities

Effects of Brazil's political crisis on the science needed for biodiversity conservation

The effects of Brazil’s political crisis on science funding necessary for biodiversity conservation are likely to be global. Brazil is not only the world’s most biodiverse nation, it is responsible for the greater part of the Amazon forest, which regulates the climate and provides rain to much of southern South America. Brazil was a world leader in satellite monitoring of land-use change, in-situ biodiversity monitoring, reduction in tropical-forest deforestation, protection of indigenous lands, and a model for other developing nations. Coordinated public responses will be necessary to prevent special-interest groups from using the political crisis to weaken science funding, environmental legislation and law enforcement. Keywords: Brazil, biodiversity, climate change, governance, fundin

Padrões espaciais e suas relações com fatores de ambiente de um campo pastejado

Padrões de distribuição espacial e suas relações com fatores ambientais, em diferentes escalas, são identificados em uma área de vegetação campestre de aproximadamente 100 ha sob pastejo ovino e bovino em Eldorado do Sul, RS, Brasil (30o05’S, 51o40’W). O levantamento no campo foi efetuado em 138 unidades amostrais de 0,5 x 0,5 m localizadas sistematicamente ao longo de gradientes de relevo. As unidades amostrais foram dispostas em conjuntos de 3 quadros contíguos, que foram agrupados para análise, formando 46 quadros de 1,5 x 0,5 m, definindo, desta forma, duas escalas de observação. A descrição da vegetação envolveu o registro da presença e a estimativa visual da abundânciacobertura das espécies em cada quadro. Foram registradas 148 espécies pertinentes a 30 famílias. As condições ambientais em cada local foram descritas por 30 variáveis relacionadas a propriedades químicas e físicas do solo, inclinação, exposição e posição no relevo. A análise dos dados empregou análise de agrupamentos, avaliação de nitidez de grupos, ordenação, avaliação da significância de eixos de ordenação, medidas de congruência e testes de aleatorização. Os resultados obtidos na análise estatística na escala de 46 quadros confirmaram aqueles encontrados para a escala de 138 quadros. Os padrões da vegetação na área de estudo estão relacionados à posição no relevo e a outros fatores associados, tais como umidade do solo. Dois grupos nítidos de comunidades campestres foram detectados, um ocorrendo nas encostas e outro ocorrendo nas baixadas úmidas.Spatial distribution patterns and their relations with environmental factors at different scales were identified in ca. 100-ha grassland under cattle and sheep grazing, in Eldorado do Sul, RS, Brazil (30o05’S, 51o40’W). The field survey used 138 0.5 x 0.5 m quadrats located systematically on transects along relief gradients. The quadrats were arranged in groups of 3 contiguous quadrats, which were pooled for the analysis, thus forming 46 quadrats 1.5 x 0.5 m, in this way defining two observation scales. Vegetation description involved recording the presence and the visual estimation of coverabundance of species in each quadrat. A total of 148 species belonging to 30 families was detected. The environmental conditions at each site were described by 30 variables related to soil chemical and physical properties, slope, exposure and relief position. Data analysis used cluster analysis, evaluation of group partition sharpness, ordination, significance of ordination axes, evaluation of environmental congruence and randomization testing. The results of the analysis with 46 quadrats supported those found with 138 quadrats. The vegetation patterns in the study area are associated to relief position and other related factors such as soil moisture. Two clearly defined grassland community types were detected, one occurring on the slopes and another on the wet lowlands

Análise das macroalgas na Reserva Biológica Marinha do Arvoredo

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