A LOW-COST ENVIRONMENTAL ACOUSTIC PLATFORM FOR EVALUATING HUMAN EXPLOITATION OF TROPICAL FORESTS

The tropical forests of Central America are increasingly under environmental pressure from unchartered threats. In these areas it is typical to monitor disturbances such as clear-cutting and forest fires with satellite imaging techniques. However, concealed by the forests canopy other threats such as illegal poaching and selective logging can proceed undiscovered. Recent developments in micro-controller and surface mount microphone technology means that continuous acoustic sensing at low-cost is now a possible solution. Consequently, we propose an acoustic data acquisition system to effectively monitor anthropogenic activities that aerial photography cannot. Two preliminary case studies are discussed emphasizing the feasibility of the systems hardware. The first study compares two types of surface-mount microphone, looking at their sensitivity to gunshot and chainsaw noise over varying distances. The second considers the advantages and limitations of low-cost microprocessor based hardware. Here, we trial a custom designed acoustic logger over a three month deployment to detect and record a local rare species of insect. Our findings show the hardware to be an efficient real time detection tool with power consumption suitable for long duration recordings. The microphones sensitivity also proves sufficient for detecting gunshots at distances of at least half a kilometer.