Abstract:

Lignicolous fungi, including dozens of butt-rot pathogenic fungi, are abundant in Northeast China. In the past decades, many investigations have been carried out on fungal species diversity, and thus plentiful species distribution data has been obtained. However, it is not clear whether there remains a region that has yet to be investigated for the presence of fungal species. In this study, four representative butt-rot pathogenic fungi, Fomitopsis pinicola, Porodaedalea laricis, Piptoporus betulinus and Trametes suaveolens, of Northeast China were selected. Their geographical distribution data and the correlating environmental factors were used to model their potential distribution using the maximum entropy model (MaxEnt). The area under the receiver operating characteristic curve (AUC) was examined to evaluate the model performance. Thus, the ecological niches of these species were analyzed. The results showed that all the species prediction models obtained high AUC values (0.990, 0.990, 0.989 and 0.967), which suggests that the prediction models were effective for the four species. The most effective environmental variables, which were the precipitation of warmest quarter (Bio18), the temperature annual range (Bio7) and the mean temperature of driest quarter (Bio9), were shown to contribute more to the species distribution models than other factors. The results delineate possible distribution ranges for the four pathogenic fungi in Northeast China, thereby offering forest managers a guide for where to focus prevention and treatment efforts for these pathogenic fungi.

Key words: MaxEnt, AUC, butt-rot pathogenic fungi, ecological niches