Agricultural expansion over fragments of atlantic rainforest in northeast brazil and its impacts on lichens

Abstract

Agricultural and urban expansion has been compressing and eradicating areas of native forests, leading to biodiversity loss and species extinction. In the Atlantic Forest of Northeastern Brazil, sugar cane farming dominates the landscape, where fragments of the biome remain. Although there have been many studies on the organisms component of the Atlantic Forest, and the effects of human action being the subject of much research, little is known about edge effects on the occurrence and habitat preference of lichens. This study aimed to correlate the preference of lichens for the edge, center, or broad distribution in three forest fragments (São Braz, Café, and Xangô) of the Gurjaú Biological Reserve, Cabo de Santo Agostinho, Pernambuco (Brazil). Lichens were collected and then identified by morphological and chemical characters. Specimens were georeferenced, and their preference was determined. It was observed that most species and families preferred the edge of the fragment, followed by a broad distribution, which can be explained by the penetration of sunlight caused by deforestation. On the other hand, it was possible to determine that some fragments were more conserved than others. Correlation dendrograms between habitat preferences showed that the fragments have few species in common. However, it was still possible to point out the similarity between the centers and between the edges of Xangô and São Braz and the similarity of lichen diversity with broad distribution. The fragments’ lichen diversity is more distinct. In contrast, the diversity in each sector of these fragments combined is more similar, showing that the average lichen richness is more determined by the sector than by the fragment. It was possible to conclude that the survey of lichen occurrence preferences within the fragments allows us to verify the advanced stage of degradation in the area. The increase in planted areas and the misinformation of the local population have increased the degradation, making it extremely difficult to reverse the situation.

Keywords

• bioindicadores
• cana-de-açúcar
• impacto ambiental
• efeito de borda
• biodiversidade