scholarly journals Climatic changes and distribution of plant formations in the state of Paraíba, Brazil

2021 ◽  
Author(s):  
Rafael Cámara Artigas ◽  
Bartolomeu Israel de Souza ◽  
Raquel Porto de Lima
Keyword(s):  
Climate Change ◽  
Last Glacial Maximum ◽  
The State ◽  
Glacial Maximum ◽  
Mata Atlântica ◽  
Last Glacial ◽  
Bioclimatic Conditions ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Anthropic Pressure

The state of Paraíba in northeast Brazil contains four of the seven biomes present in the country: Mata Atlântica, Cerrado, Caatinga and Matas Serranas. On the other hand, Amazônia, Pantanal and Pampa were not found in this area. This special situation allows us to analyse changes in the distribution of these four large Brazilian biomes according to bioclimatic conditions, using the methodology of bioclimatic regime types. Based on the analysis of variables from periods of hydric and thermal vegetation stagnation, obtained from hydric and bioclimatic balances, average monthly temperature and rainfall, that methodology enables us to establish a typology of 27 types of bioclimatic regimes and 243 bioclimatic regime subtypes with the 9 Thornthwaite ombrothermal levels. In Paraíba 4 types of bioclimatic regimes are currently identified (mesophyllo, tropophyllo, xerophyllo and eurythermophilous) and 9 subtypes according to ombrothermal levels. In order to analyse the changes, extreme change situations were chosen: a past scenario with the Last Glacial Maximum (40 ky); and an RCP 8.5 climate change scenario for the CMSS 4.0 model for the year 2070. This enabled 3 bioclimatic regime maps of each of the 3 aforementioned situations to be obtained, providing a map of potential distribution of the plant formations of Paraíba state according to the specific field knowledge and bioclimatic mapping obtained for the present. This paper concludes that a retrocession of the Mata Atlântica can be seen from the Last Glacial Maximum up to the present, losing its optimal bioclimatic conditions and therefore remaining in a highly fragile relict situation in the face of anthropic pressure (sugarcane cultivation and urban expansion); an advance toward 2070 of the Caatinga in its shrub form as a predominant formation is indicated by the projection of climate change in 2070 for the analysed situation, specifically resulting from anthropic pressure, in this case due to livestock activities which have affected this biome in Paraíba since the mid-19th century.

scholarly journals Climate impacts on deglaciation and vegetation dynamics since the Last Glacial Maximum at Moossee (Switzerland)

2019 ◽  
Author(s):  
Fabian Rey ◽  
Erika Gobet ◽  
Christoph Schwörer ◽  
Albert Hafner ◽  
Willy Tinner
Keyword(s):  
Climate Change ◽  
Last Glacial Maximum ◽  
Fagus Sylvatica ◽  
Glacial Maximum ◽  
Future Climate ◽  
Central European ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Since the Last Glacial Maximum (LGM, end ca. 19 000 cal BP) Central European plant communities were shaped by changing climatic and anthropogenic disturbances. Understanding long-term ecosystem reorganizations in response to past environmental changes is crucial to draw conclusions about the impact of future climate change. So far, it has been difficult to address the post-deglaciation timing and ecosystem dynamics due to a lack of well-dated and continuous sediment sequences covering the entire period after the LGM. Here, we present a new palaeoecological study with exceptional chronological time control using pollen, spores and microscopic charcoal from Moossee (Swiss Plateau, 521 m a.s.l.) to reconstruct the vegetation and fire history over the last ca. 19 000 years. After lake formation in response to deglaciation, five major pollen-inferred ecosystem rearrangements occurred at ca. 18 800 cal BP (establishment of steppe tundra), 16 000 cal BP (spread of shrub tundra), 14 600 cal BP (expansion of boreal forests), 11 600 cal BP (establishment of first temperate deciduous tree stands composed of e.g. Quercus, Ulmus, Alnus) and 8200 cal BP (first occurence of mesophilous Fagus sylvatica trees). These vegetation shifts were released by climate changes at 19 000, 16 000, 14 700, 11 700 and 8200 cal BP. Vegetation responses occurred with no apparent time lag to climate change, if the mutual chronological uncertainties are considered. This finding is in agreement with further evidence from Southern and Central Europe and might be explained with proximity to the refugia of boreal and temperate trees (< 400 km) and rapid species spreads. Our palynological record sets the beginning of millennial-scale land use with periodically increased fire and agricultural activities of the Neolithic period at ca. 7000 cal BP (5050 cal BC). Subsequently, humans rather than climate triggered changes in vegetation composition and structure. We conclude that Fagus sylvatica forests were resilient to long-term anthropogenic and climatic impacts of the mid and the late Holocene. However, future climate warming and in particular declining moisture availability may cause unprecedented reorganizations of Central European beech-dominated forest ecosystems.

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