Detection and Measurement of Natural and Anthropogenic Disturbances in a Protected Area Using the Rasch Model

This study aimed to assess the extent of major threats in the 244.13-hectare Tugbo Natural Biotic Area (TNBA) on Masbate Island, Philippines. Threat-focused patrolling has covered the entire continuum, with a specified recording interval along the protected area (PA), divided into numerous patrol routes. Categorized into human-induced and natural calamities, a total of 27 individual threats were geo-tagged and recorded, with mixed perennial farming as the most frequent threat. Using geo-spatial technologies, the risks were reduced to 10, largely represented by broad expanses of rangelands and invasive monocrop plantations. This paper presents a new methodology for measuring and visualizing threats to protected areas based on the Rasch model. This probabilistic analysis is based on the presence or absence of the threat in each location, disturbance estimates, and the calculation of misfits. The visualization map illustrates that the protected area had an unequal distribution of threats. Most locations have less disturbed areas; hence, the data indicate that the protected area is nearly pristine. This approach is a useful methodology for assessing in-depth environmental disturbance.