Temporal changes in species composition, diversity, and woody vegetation structure of savannas in the Cerrado-Amazon transition zone

Leonardo Maracahipes-Santos,Eddie Lenza,Simone Matias Reis,Josias Oliveira Dos Santos

doi:10.1590/0102-33062017abb0316

Leonardo Maracahipes-Santos, Eddie Lenza + Show 2 more

Open Access

https://doi.org/10.1590/0102-33062017abb0316

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Abstract

ABSTRACT Vegetation in the transition between tropical forest and savanna is hyperdynamic and there is evidence that in the absence of fire, forest advances over savanna. Between 2008 and 2013 we evaluated changes in species composition and diversity and in the structure of the woody vegetation of savanna physiognomies in the transition between the Cerrado and Amazon biomes that were fire free for 11 years. The physiognomies form a gradient from savanna woodland (Typical Cerrado - TC), to low woodland (Dense Cerrado - DC), to woodland (locally called Cerradao - CO). We hypothesise that: 1) the more open physiognomies (TC and DC) are more dynamic compared to the closed physiognomy (CO); and 2) in the absence of fire vegetation tends to become more forested. We found that: 1) TC was more dynamic (e.g. greater increases in richness, diversity, and abundance of plants and basal area) than CO and DC; 2) The three physiognomies experienced an increase in basal area and abundance of individuals, but only certain key species contributed to these increases. These results indicate that the open physiognomies were more dynamic than the closed physiognomies, and in the absence of fire the savanna physiognomies became more forested and accumulated biomass.

Highlights

Transition zones between biomes tend to be temporally dynamic, with distinct plant communities expanding and retracting over time (Staver et al 2011 a; b; Gowda et al 2012; Joly et al 2012)
We found that: 1) TC was more dynamic than CO and Dense Cerrado (DC); 2) The three physiognomies experienced an increase in basal area and abundance of individuals, but only certain key species contributed to these increases
In 2008, we recorded 945 individuals distributed in 63 species, 45 genera, and 27 families at the three sites, while in 2013, we registered 1,061 individuals belonging to 69 species, 51 genera, and 30 families, with a clear tendency for increasing densities and species richness in all three physiognomies, except for low woodland (DC) (Tab. 1)

Summary

Introduction

Transition zones between biomes tend to be temporally dynamic, with distinct plant communities expanding and retracting over time (Staver et al 2011 a; b; Gowda et al 2012; Joly et al 2012). The last process, which occurs especially in the absence of fire (Staver et al 2011 a; b; Stevens et al 2017), has been observed primarily in the vast area of the forest–savanna transition in central and northern Mato Grosso, Brazil (Marimon et al 2006; 2014; Mews et al 2011 a; b) This region is characterised by an intricate and complex interaction between the two ecosystems (Askew et al 1970), which provides an excellent opportunity to monitor temporal and spatial patterns and understand

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