Potential distribution of borers, defoliators, barking beetles and mistletoes in coniferous forests of Mexico

Abstract

The distribution of forest pests in Mexico is uncertain. Information on forest areas potentially affected by a type of pest and their climatic and ecological preferences is scarce. The objective of this study was to model the potential distribution of insect borers (B), defoliators (d), bark beetles (D) and mistletoes (M), using climate and mensuration variables and the software Maximum Entropy (MaxEnt). Records of forest pests were obtained during the National Forest and Soil Inventory (2009-2014) provided by the National Forestry Commission. The training and validation of the models was performed with k-fold partitioning through the dismo package of R. The analyses of results indicate that the generated models had acceptable fit (AUC > 0.85). The potential area estimated by the model, in accord with the lower threshold of known presence (> 0.1), was around 270 (B), 307 (D), 315 (d) and 308 mil km² (M). The largest potential area is predicted for the states of Chihuahua, Durango and Oaxaca, as well as the highest probability of occurrence (> 0.90). Climate variables had the highest percentage of contribution for D and d (75.1 and 71.9 %), whereas the mensuration variables were the highest for B and M (73.6 and 59.8 %). Analysis of the mensuration parameters indicate that, for the records of presence used, the four types of pest tend to prefer forests with small diameter trees and sites with fewer host species. The forests with the greatest susceptibility are found in Chihuahua (M) and Michoacán, Estado de México, Chihuahua, Nuevo León, Jalisco and Chihuahua (D).