New insights into vegetation, climate and fire history of southern Brazil revealed by a 40,000 year environmental record from the State Park Serra do Tabuleiro

Vivian Jeske-Pieruschka 0 1 2 Valerio D. Pillar 0 1 2 Marcelo A. T. De Oliveira 0 1 2 Hermann Behling 0 1 2 0 M. A. T. De Oliveira Departamento de Geociencias, Universidade Federal de Santa Catarina , Florianopolis, SC, Brazil 1 V. D. Pillar Departamento de Ecologia, Universidade Federal do Rio Grande do Sul , Porto Alegre, RS 91540-000, Brazil 2 V. Jeske-Pieruschka (&) H. Behling Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Gottingen , Untere Karspule 2, 37073 Gottingen, Germany The present study reveals palaeoenvironmental changes in the coastal southern Brazilian highlands during the last 39720 B.P., by the means of pollen, charcoal and multivariate data analyses. The isolated mountain range of Serra do Tabuleiro corresponds to the southern distribution limit of many tropical plant species and is therefore sensitive to climate change. Palaeoenvironmental reconstructions from the Ciama 2 core at 860 m a.s.l. indicate that Campos (subtropical grassland) covered extensive areas on the highlands throughout the recorded glacial period, thus suggesting cold and dry climatic conditions. The initial development of the Atlantic rainforest occurred after the glacial period, whereas plant diversity began to increase at the beginning of the Holocene due to climate change towards warmer and wetter conditions. At about 10400 cal. B.P., the Atlantic rainforest started to move over the slopes and Campos retracted. Multivariate data analysis showed a change of vegetation dynamics after 11200 cal. B.P. with the initial development of the Atlantic rainforest continuing until the mid-Holocene. Major vegetation changes, including the further expansion of the Atlantic rainforest and the initial development of the Araucaria forest in the higher regions of the Serra do Tabuleiro, occurred during the late Holocene after about 3600 cal. B.P. These changes reflect higher precipitation levels without an annual dry season. Multivariate data analysis reveals a clearly directional change of vegetation dynamics corresponding to the progressive expansion of the Atlantic rainforest from 3850 to 1600 cal. B.P. A second directional change of vegetation dynamics occurred from 320 to 160 cal. B.P. (A.D. 1630 to 1790) with a further development of the Atlantic rainforest and the partial replacement of Campos by Araucaria forest and Atlantic rainforest. Thereafter, an ecosystem disturbance, which resulted in forest opening, took place. Palaeofires probably did not occur during glacial times, whereas fire events, which were probably caused by Amerindians, were common in the Serra do Tabuleiro region from ca. 10400 until 3600 cal. B.P. - Previous palaeoenvironmental studies conducted in southern Brazil have been considerably improving the understanding of vegetation dynamics in relation to climate changes during the late Quaternary. For the southern Brazilian highlands, Campos seems to be the predominant vegetation type during glacial times when colder and drier climate conditions prevailed (Behling 1998, 2002; Roth and Lorscheitter 1993; Ledru et al. 1998; Behling et al. 2004; Leonhardt and Lorscheitter 2010). The initial Araucaria forest expansion occurred about 2850 B.P. in Serra dos Campos Gerais (Behling 1997) and after 2000 B.P. in Serra do Aracatuba (Behling 2007), both in Parana state (Fig. 1c). For the highlands of Santa Catarina state, Behling (1995) proposed a first Araucaria forest expansion at about 3460 B.P. in Serra da Boa Vista and at about 2390 B.P. in Serra do Rio do Rastro. In Rio Grande do Sul, located further south than Santa Catarina, the initial Araucaria forest expansion is documented for about 3950 B.P. in Cambara do Sul (Behling et al. 2004) and after 4000 B.P. in the Sao Francisco de Paula region (Leonhardt and Lorscheitter 2010; Jeske-Pieruschka and Behling 2012). A marked Araucaria forest expansion is reported since about 1400 cal. B.P. in the state of Parana (Behling 1997, 2007) and for the last 1,000 years for the highlands of the state of Santa Catarina and Rio Grande do Sul (Behling 1995; Behling et al. 2001, 2004). Although the early expansion of Araucaria forests occurred at different times, all interpretations suggest that Araucaria forest initially expanded by migrating out of gallery forests along rivers and wet areas after the mid-Holocene, when climate changed to more humid conditions. The vegetation history of the Atlantic rainforest in Volta Velha, southern Brazil is reported by Behling and Negrelle (2001). The authors documented an initial Atlantic rainforest development after 12300 B.P. as part of a successional sequence and the appearance of a dense forest after the marine regression at about 6100 B.P. for the Santa Catarina lowlands. Furthermore, Lorscheitter (2003) indicates fossil evidence of Atlantic rainforest taxa at the beginning of the Holocene at about 100008000 B.P. along the coastal plain and valleys of Rio Grande do Sul. More recently, Leal and Lorscheitter (2007) propose the occurrence of some Atlantic rainforest species in Serra Velha on the lower slopes of the Serra Geral, Rio Grande do Sul since 8800 B.P. However, with the exception of Behling et al. (2004), who reported environmental changes over a time frame of 42840 B.P. for the Cambara do Sul site in the southeastern highlands of Rio Grande do Sul state, no other record which reaches back as far as to the pre-last glacial maximum (LGM) period is available for the entire region of southern Brazil. Thus, our study, covering the last 39720 B.P. of vegetation, climate and fire history in Santa Catarina state, located about 175 km to the north from Cambara do Sul site, contributes to a better understanding of palaeoenvironmental changes and human activities in a very sensitive climatic region of South America. Here we present new palaeoecological data from a peat core of the Serra do Tabuleiro costal mountain range. This region is covered by Campos (subtropical grassland) with some patches of Araucaria forest on the highlands and Atlantic rainforest growing in the lowlands and on the slopes. The Atlantic rainforest ecosystem is described as a hotspot of biological diversity (e.g. Myers et al. 2000; Tabarelli et al. 2005) and is known to be highly vulnerable Fig. 1 a Map of the study area, showing the vegetation types of the State Park Serra do Tabuleiro. b View of the Ciama area with the peat bog surrounded by Campos with Araucaria forest and Atlantic rainforest in the background. c Map of southern Brazil with sites mentioned in the text. Palaeoecological records: (star) study site Serra do Tabuleiro 1 Aparados da Serra 2 Lagoa dos Patos 3 Serra do Rio do Rastro 4 Serra da Boa Vista 5 Morro da Igreja 6 Serra dos Campos Gerais 7 Volta Velha 8 Cambara do Sul 9 Serra do Aracatuba 10 Serra Velha 11 Campo Alegre 12 Sao Francisco de Paula 13 Caverna Botuvera. Sources: Vegetacao Original [map]. 1:100,000. [Parque Estadual da Serra do T (...truncated)