Ecological Niches and Suitability Areas of Three Host Pine Species of Bark Beetle Dendroctonus mexicanus Hopkins

Abstract

Bark beetles are a natural part of coniferous forests. Dendroctonus mexicanus Hopkins is the most widely distributed and most destructive bark beetle in Mexico, colonizing more than 21 pine species. The objectives of this study were to generate ecological niche models for D. mexicanus and three of its most important host species, to evaluate the overlap of climate suitability of the association Dendroctonus–Pinus, and to determine the possible expansion of the bark beetle. We used meticulously cleaned species occurrence records, 15 bioclimatic variables and ‘kuenm’, an R package that uses Maxent as a modeling algorithm. The Dendroctonus–Pinus ecological niches were compared using ordination methods and the kernel density function. We generated 1392 candidate models; not all were statistically significant (α = 0.05). The response type was quadratic; there is a positive correlation between suitability and precipitation, and negative with temperature, the latter determining climatic suitability of the studied species. Indeed, a single variable (Bio 1) contributed 93.9% to the model (Pinus leiophylla Schl. & Cham). The overlap of suitable areas for Dendroctonus–Pinus is 74.95% (P. leiophylla) and on average of 46.66% in ecological niches. It is observed that D. mexicanus begins to expand towards climates not currently occupied by the studied pine species.

Climatic Suitability and Distribution Overlap of Sawflies (Hymenoptera: Diprionidae) and Threatened Populations of Pinaceae

“…Although there is no consensus on the optimal number of variables that define an ecological niche, those calculated here meet the condition of parsimony: less complex models can give the most logical explanation of the environmental suitability of the species of interest, and can estimate its potential distribution (but not the distribution per se) [60]. However, the low number of variables in the definition of the models (three for N. abietis: precipitation of wettest month, precipitation seasonality, and mean temperature of the coldest quarter; three for N. omosus: isothermality, precipitation seasonality, minimum temperature of coldest month, and temperature annual range; and four for Z. rohweri: mean temperature of wettest quarter, temperature seasonality, and precipitation of driest month) can be considered as a sign of climate vulnerability, since dependence on one or two variables could make the species vulnerable to sudden changes over time [61].…”

Distribución actual y potencial de Pinus engelmannii Carriére bajo escenarios de cambio climático

“…La selección de variables predictivas, se basó en los siguientes criterios: 1) las de mayor contribución acorde a la prueba de jackknife, haciendo una modelación preliminar (Ávila, Villavicencio y Ruiz, 2014; García-Aranda, Méndez-González y Hernández-Arizmendi, 2018; Aceves-Rangel, Méndez, García y Nájera et al, 2018), 2) las de mayor contribución relativa obtenida de un ACP realizado según lo propuesto por Méndez et al (2021), 3) de acuerdo con la biología de la especie, 4) no correlacionadas (r ≤ 0.8) (Elith et al, 2006;Cruz-Cárdenas, Villaseñor, López-Mata, Martínez-Meyer y Ortiz, 2014; Martínez-Méndez Aguirre-Planter, Eguiarte y Jaramillo-Correa, 2016), 5) que tuvieran una distribución normal o sesgada (Méndez et al, 2021) y 6) por el tipo de respuesta de la variable bioclimática. De esta selección preliminar, se organizaron tres grupos (sets) con diferentes variables bioclimáticas, utilizados para calibrar el modelo para predecir la distribución de P. engelmannii (Cobos et al, 2019).…”

“…Bio 1 muestra un sesgo a la derecha (Fig. 7a), Beaumont, Hughes y Poulsen, (2005) determinaron que, una distribución normal o sesgada de la variable, es relevante para definir el perfil bioclimático de la especie, mientras que otros autores (Méndez et al, 2021), indican que es indicio de una adecuada elección del predictor.…”

“…Esquema general de pasos y procedimientos para la generación, validación, transferencia de modelos de nicho ecológico. (modificado deMéndez et al, 2021).…”