PREDICTING THE DISTRIBUTION OF SUITABLE HABITAT OF ARMILLARIA MELLEA (AGARICALES, PHYSALACRIACEAE) USING ECOLOGICAL NICHE MODELING

Abstract

Armillaria mellea is an economically and ecologically significant fungal pathogen; however, the distribution of this fungus in eastern North America is not well understood. This study aims to use ecological niche modeling to predict the extent of suitable habitat of the species and identify the environmental predictors that affect its ecogeographic distribution. In this study, herbarium vouchers and mycelia obtained from cultures were selected to document occurrences, which were identified and annotated using a combination of morphological and molecular analyses. The records of all specimens that were confidently identified were georeferenced. Environmental variables were compiled from relevant databases, values of variable importance were estimated given prior constraints, and a smaller subset of abiotic variables were identified that were important for predicting habitat suitability of A. mellea in eastern North America. Annual mean temperature had the greatest importance on the predicted suitable habitat of A. mellea. Five other variables (annual mean moisture index, mean temperature of the driest quarter, mean diurnal temperature range, annual precipitation, and precipitation seasonality) were identified as significant in contributing to the model. This study assembled a collection of annotated herbarium vouchers that represent the occurrence of A. mellea in eastern North America. The results of the present study indicate that niche modeling may be used to understand the suitable habitat of an important pathogenic fungus.