Effects of grazing on functional diversity along secondary succession in a tropical dry forest (Caatinga, Brazil)

Abstract

Aim

Livestock production is among the main anthropogenic disturbances in seasonally dry tropical forests. However, its effects on plant functional composition in dry forests is poorly understood. Our goal was to analyze the variation in both functional composition and functional diversity of plant communities under goat grazing and at different ages of fallow in a tropical dry forest.

Location

Brazilian dry forest (Caatinga) in Rio Grande do Norte State, northeastern Brazil.

Methods

We measured the height, leaf area, and specific leaf area of all shrub-tree and herbaceous species along a gradient of stocking rate, years of grazing, and age of fallow. Additionally, we quantified the foliar contents of nitrogen, phosphorus, and tannins in the tree shrub layer. We tested the effects of grazing and deforestation using linear mixed models.

Results

Our findings suggest that the functional diversity of plant communities in the Caatinga is not altered when goat grazing and secondary succession are examined independently. However, the interaction of both factors has affected the functional diversity, particularly in the herbaceous layer. Although grazing influenced specific traits in the shrub-tree layer, the overall functional diversity remained unaltered by grazing, succession, or their interaction.

Conclusions

Grazing does not interfere with the natural succession process nor diminish the functional diversity of plant communities in the Caatinga. Therefore, with appropriate management, grazing can coexist with the conservation goals of the Caatinga.