Chronic anthropogenic disturbance on Caatinga dry forest fragments

1. Understanding how chronic anthropogenic disturbances are distributed in
space leads to more effective conservation and management practices. This
study provides a large-scale overview of how the Caatinga dry forest is
potentially altered by chronic anthropogenic disturbance. In particular,
we investigate how the intensity of the potential disturbance varies (i)
among geographic regions, (ii) among fragment sizes, and (iii) as a
function of distance to the fragment edge. 2. A Chronic Anthropogenic
Disturbance Index (CDI) was derived to represent five anthropogenic
disturbance vectors: human population, infrastructure, grazing, logging,
and fire. CDI was spatialized for the whole Caatinga landscape (826 411
km2) and posteriorly averaged for ca. 47 100 remaining fragments. 3.
Chronic anthropogenic disturbance was unevenly distributed across the
Caatinga landscape, with more conserved sites on the western and southern
regions. Larger fragments were, on average, as disturbed as smaller ones.
However, smaller fragments varied from highly disturbed to very well
preserved depending on the regional context. Strong edge effects were
recognized for the chronic anthropogenic disturbance index and its five
vectors. 4. Policy implications. Although half of the original Caatinga
vegetation remains, most remnant fragments potentially suffer from chronic
anthropogenic disturbances. This suggests that a large portion of the
Caatinga can be currently threatened, and its biodiversity and natural
resources eroded by processes that are less evident than habitat loss.
Proper management practices and expansion of the existing conservation
area network are needed to halt the Caatinga biodiversity decline.