Does the edge effect influence plant community structure in a tropical dry forest?

Abstract

-Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m) were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.

Analyzing the edge effects in a Brazilian seasonally dry tropical forest

“…However, a number of other authors have noted the absence of edge effects in tropical dry vegetation formations: Sampaio and Scariot (2011) did not find any differences between the forest edge and interior in relation to the composition and abundance of seedling and adult individuals in a fragment of dry forests subjected to the same type of climate as the present study; Oliveira et al (2013) did not find difference in tree height, stem diameter, basal area, species richness, abundance and LAI index; and Santos and Santos (2008) did not observe any significant edge and internal differences in a shrub caatinga site. In these cases, the absence of edge effects could be explained by the fact that these vegetations do not have continuous canopies (temporally and spatially, in the case of shrub caatinga) that could protect them from climatic adversities.…”

“…Noteworthy are Oliveira-Filho et al (1997, 2007 in semideciduous forest, Lima-Ribeiro (2008) and Dodonov et al (2013) in differents physiognomy of cerrado (tropical savanna), which found some effect, and Santos and Santos (2008) (in caatinga -tropical shrubland), Sampaio and Scariot (2011) and Oliveira et al (2013) in dry forest, who did not find.…”

The role of temporal scale in linear edge effects on a submontane Atlantic forest arboreal community

“…Nevertheless, other research suggests that edge effects may actually not have serious negative outcomes, exerting positive influences on some variables, or even no influence at all (Oliveira et al 2013).…”

Banco de sementes do solo de sítios de Caatinga sob influência do Projeto de Integração do Rio São Francisco

“…Essa comprovação refutaria os resultados de outros estudos que concluíram que esse efeito (se existir) não altera o componente biológico da Caatinga [26,33].…”