Biological corridor analysis and potential for conservation in Brazil’s northern Atlantic Forest
Modeling habitat connectivity is integral to conservation planning as habitat corridors may act as conduits for organism movement and gene flow. Brazil’s Atlantic Forest supports one of the highest levels of endemism and species richness on the planet, but has undergone huge territory losses with a high degree of fragmentation. We used photo interpretation and field verification of remotely-sensed images to map the Atlantic rainforest in a previously unmapped area at its farthest northern extent. Fragment size, shape, inter-fragment distance, fragment density, degree of connectivity, and distribution across the landscape were measured using Fragstats. Field surveys were conducted to map bird and primate populations within existing forest fragments. Circuitscape software was used to model landscape connectivity and movement pathways for species between forest fragments surrounded by other land uses. Ownership and existing protection levels were additional factors used to evaluate areas for prioritization for conservation.
Brazilian Atlantic rainforest fragments in its northern-most region are embedded in a matrix of sugar cane, coconut plantation, pasture land, urban and rural housing, and restinga and mangrove forests. Their size and shape vary widely, with the largest fragment measured at 2780 acres (1126 hectares) and most fragments less than 125 acres (50 hectares) in size. Several functional corridors and ways of establishing networks of forest fragments were demonstrated using Circuitscape. Simulations showed that reforestation of sugar cane fields between forest fragments would considerably increase the area of interior forest habitat and connectivity between fragments. The ability to do this within the local economic and socio-political context of northeastern Brazil is discussed.