Impact of deforestation on ecosystem functions of Ecuador's tropical dry forest under different protection status

Abstract

The highly diverse equatorial dry forests are among the most threatened ecosystems on Earth due to the alarming rates of deforestation, and are currently classified as "critically endangered" according to IUCN criteria. Understanding the causes of its deforestation and its impacts on local communities is essential for its management and conservation. In this study, we used public information in geographic information systems (GISs) from 1990–2020 together with remote sensing data and local expert knowledge to assess the drivers of deforestation and the provision of regulatory ecosystem services (ESs) through the Nature’s Contributions to People (NCP) framework in the Arenillas and Zarumilla watersheds (Province of El Oro, Ecuador). Our results clearly identify the expansion of agricultural and rangelands as the main driver of deforestation, especially starting in 2000. The reduction in area of equatorial dry forest by more than 42,224.45 ha implies a broad reduction of carbon storage and water regulation, and increased erosion. As a consequence, the ESs associated with air quality regulation (NCP3), control of harmful organisms (NCP10), climate regulation (NCP4), pollination (NCP2) and habitat maintenance (NCP1) all declined over the study period. The protected areas in the study region were insufficient to stop this trend and preserve ESs. More precisely, one of the two protected areas in the region, BP-Tahuín, presented levels of provision of services similar to non-protected areas. Our study highlights the urgency to identify alternative conservation measures, which respond to social needs and valorize regulatory services to stop deforestation due to agricultural and rangeland expansion.