Forest fire severity estimation in 2023 in UNESCO Global Geopark Imbabura with the impact review at the archaeological heritage in the geosite “Yachay Archaeological Sites”

Wildfires are phenomena that affect large areas of land worldwide, causing substantial economic and human losses every year. Ecuador is a country with important geology and archaeological heritage, recognized by several authors historically and awarded by UNESCO in 2019. On the other hand, agriculture widely distributed all along the country constitutes one of the major economic activities that supports the gross domestic product. Both resources are susceptible to the manifestation of forest fires, becoming a major problem in the country.  

In 2023, the months of August and September showed the highest recurrence of fires at national level. One of the most damaged regions was Imbabura UNESCO Global Geopark that covers the total surface of Imbabura province (4712,37 Km2) here the fires burned about 1600 hectares of land. Fires in Ecuador are usually caused by a combination of factors including inadequate human practices, highly flammable dry vegetation, and meteorological conditions. Thus, this research focuses on the estimation of the severity of damage during forest fires, also considering the forest-urban interface it was possible to estimate the impact to settlements in the geopark. The processing of satellite data was performed by applying the algorithm in Google Earth Engine (GEE), from the ImageCollection package that contains information on burned surface to Sentinel-2 satellite images based on key indices, such as Normalized Difference Vegetation Index (NDVI), Normalized Burned Area Ratio (NBR) and shortwave infrared (SWIR) (UN-SPIDER).   

The geopark embraces 12 geosites, including the “Yachay Archaeological Sites” located on the grounds of the City of Knowledge Yachay, in Urcuquí, being one of the most important cultural heritage, which importance stems from its inclusion of bone remains, malacological, ceramic, lithic, and monumental structures. It holds particular significance for the descendants of the Caranqui population that inhabits the entire area of influence; therefore, preserving it for future generations is crucial. The monuments (Tolas, Pucarás, and Pirámides), distributed aleatory in the geosite, were highly affected. Sentinel 2 has a resolution of 30 m, and some monuments are less than 5m, for this reason it was necessary to use high-resolution images captured with unmanned aerial equipment to evaluate the impact. The final analysis reveals that, for the geosite "Yachay Archaeological Sites," 127 hectares were affected, with a considerable harm in several levels that 29 out of the 37 monumental structures, this represents the 78% of the total structures were potentially damaged.  

Key words: Severity, Forest Fires, GEE, Geosites, Imbabura Geopark, Archaeological Sites Yachay, Tolas  

Reference:  

UN-SPIDER Knowledge Portal. Paso a paso: Mapeo de la severidad de incendios forestales en Google Earth Engine https://www.un-spider.org/es/asesoria/practicas-recomendadas/practica- recomendada-mapeo-gravedad-quemaduras/paso-a-paso/google-earth-engine