Late Quaternary vegetation, biodiversity and fire dynamics on the southern Brazilian highland and their implication for conservation and management of modern Araucaria forest and grassland ecosystems (pdf)

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Late Quaternary vegetation, biodiversity and fire dynamics on the southern Brazilian highland and their implication for conservation and management of modern Araucaria forest and grassland ecosystems

Downloaded from rstb.royalsocietypublishing.org on October 30, 2014 Late Quaternary vegetation, biodiversity and fire dynamics on the southern Brazilian highland and their implication for conservation and management of modern Araucaria forest and grassland ecosystems Hermann Behling and Valério DePatta Pillar Phil. Trans. R. Soc. B 2007 362, doi: 10.1098/rstb.2006.1984, published 28 February 2007 References This article cites 27 articles http://rstb.royalsocietypublishing.org/content/362/1478/243.full.html#ref-list-1 Article cited in: http://rstb.royalsocietypublishing.org/content/362/1478/243.full.html#related-urls Email alerting service Receive free email alerts when new articles cite this article - sign up in the box at the top right-hand corner of the article or click here To subscribe to Phil. Trans. R. Soc. B go to: http://rstb.royalsocietypublishing.org/subscriptions Downloaded from rstb.royalsocietypublishing.org on October 30, 2014 Phil. Trans. R. Soc. B (2007) 362, 243–251 doi:10.1098/rstb.2006.1984 Published online 19 December 2006 Late Quaternary vegetation, biodiversity and fire dynamics on the southern Brazilian highland and their implication for conservation and management of modern Araucaria forest and grassland ecosystems Hermann Behling1,* and Valério DePatta Pillar2 1 Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Georg-August-Universität Göttingen, Abteilung für Palynologie und Klimadynamik, Untere Karspüle 2, 37073 Göttingen, Germany 2 Departamento de Ecologia, Universidade Federal do Rio Grande do Sul, CEP 91540-000 Porto Alegre, Brazil Palaeoecological background information is needed for management and conservation of the highly diverse mosaic of Araucaria forest and Campos (grassland) in southern Brazil. Questions on the origin of Araucaria forest and grasslands; its development, dynamic and stability; its response to environmental change such as climate; and the role of human impact are essential. Further questions on its natural stage of vegetation or its alteration by pre- and post-Columbian anthropogenic activity are also important. To answer these questions, palaeoecological and palaeoenvironmental data based on pollen, charcoal and multivariate data analysis of radiocarbon dated sedimentary archives from southern Brazil are used to provide an insight into past vegetation changes, which allows us to improve our understanding of the modern vegetation and to develop conservation and management strategies for the strongly affected ecosystems in southern Brazil. Keywords: Late Quaternary; Araucaria forest; Campos (grassland); palaeoecology; conservation; management Abbreviations: AD, Anno Domini; cal yr BP, calibrated radiocarbon years before present; uncal yr BP, uncalibrated radiocarbon years before present 1. INTRODUCTION Several Neotropical regions harbour the most biodiverse ecosystems on Earth, yet we know only little about why they are so biodiverse. We are especially ignorant of the role that history has played in the development of these hotspots of species richness including endemism (Churchill et al. 1995, Broecker 1997). This problem is particularly acute in the extraAndean ranges of eastern Brazil, the so-called ‘Mata Atlantica biodiversity hotspot’, where rigorous palaeoecological work has only begun during the last few years. In this paper, we present data from the southern Brazilian highland region, where a mosaic of Campos (grassland) and Araucaria forests is found. The presence of these mosaics under modern wet climatic conditions favourable for forest development has puzzled naturalists and ecologists for a long time. Lindman, travelling across southern Brazil in the late nineteenth century, observed that forests should be able to expand over these grasslands, and attributed their presence to the transitional situation between * Author for goettingen.de). correspondence tropical forests to the north and temperate grasslands to the south (Lindman 1906). In addition, Rambo (1956a,b) and Klein (1975, 1984), hypothesized based primarily on plant geographical evidence, that the grasslands were the older vegetation type, with forest expansion being a more recent process after changes to the more humid climate conditions. Also Hueck (1966) raised the question of how the southern Brazilian grassland can exist under the present humid forest climatic conditions. Understanding the origin of the grasslands is of prime importance to their conservation. If the grasslands are as a consequence of human-induced deforestation, vegetation management would probably be focused on re-establishment of forest vegetation. If, however, the grasslands have prevailed in the past due to different climatic regimes, it could be reasonable to conserve these ‘natural’ relicts and their high biodiversity. Sustainable management and conservation of the modern mosaics of Campos and Araucaria forest depends, in part, therefore on the determination of historical reference conditions for the past human impact, e.g. fire magnitude and frequency, and the applied use of this information in developing long-term management and monitoring plans. In this study, we present the results from a palaeoecological study (fossil pollen and microfossil charcoal) of a sediment core (- One contribution of 14 to a Theme Issue ‘Biodiversity hotspots through time: using the past to manage the future’. 243 q 2006 The Royal Society Downloaded from rstb.royalsocietypublishing.org on October 30, 2014 244 H. Behling & V. D. P. Pillar Biodiversity on southern Brazilian highland 20˚ Rio de Janeiro 6 25˚ 5 3 7 2 4 Atlantic Ocean X 1 Porto Alegre 30˚ 100 km 55˚ 50˚ 45˚ Figure 1. Map showing the distribution of Araucaria forest and Campos in southern Brazil (adapted after Hueck 1953, 1966) and the location of Cambará do Sul (X) and other sites mentioned in the text: (1) Aparados da Serra, (2) São Francisco de Paula, (3) Serra do Rio Rastro, (4) Morro da Igreja, (5) Serra da Boa Vista, (6) Serra Campos Gerais and (7) São Francisco de Assis. sampled at Cambará do Sul on the southern Brazilian highland (Behling et al. 2004) to analyse past vegetation and fire dynamics. Special emphasis is placed on past plant diversity dynamics, in order to provide essential information for management and conservation of this biodiverse region. Important questions to be addressed include the following. How natural is the diverse mosaic of forest and grassland vegetation in southern Brazil? Was its development caused by pre-Columbian slash and burn activity, and deforestation of the postColumbian settlers or rather a natural process of climate-driven forest expansion constrained by grassland fires? Are fires natural or of anthropogenic origin? What is the effect of climate change, fire and human impact on the overall biodiversity of the region through the time? How should we manage and conserve the modern species-rich forest and grassland ecosystems? 2. (...truncated)