LB 13-163 - Impacts of climate change on the potential distribution of Bursaphelenchus xylophilus and vectors of genus Monochamus

Background/Question/Methods:

Pine wilt disease (PWD) is one of the most serious and devastating invasive diseases affecting pine forests worldwide, resulting in huge economic loss in many countries. Pine wood nematode (PWN), Bursaphelenchus xylophilus Nickle, is a causal agent of PWD, which is transmitted by pine sawyer beetles, Monochamus spp. It’s important to predict the potential distribution of PWN to control the spread of PWD. However, previous studies haven’t considered the impacts of 13 vectors on the potential distribution of PWN. We aimed to predict the current and future potential distribution of PWN and 13 vectors worldwide by using an ensemble ecological niche modeling approach. We obtained species occurrence records from references and GBIF (https://www.gbif.org/), historical (1981-2010) and future climate data (2011-2040, 2071-2100) based on two alternate climate change scenarios (ssp126, ssp585) from CHELSA database. We used the omission rate for assessing model performance. Then, we developed ensemble SDMs for PWN and 13 vectors by using eight different model algorithms in the “Biomod2” package. We maximized the distribution of 13 vectors to represent the distribution of a pseudo-vector species in the worst-case scenario. Finally, we overlaid the distribution of PWN and the pseudo-vector species to obtain a biologically realistic distribution of PWN.

Results/Conclusions:

The potential distribution of each vector species will have a relative constraint range, which will be mainly distributed in the northern hemisphere, especially in Northern America, Europe, and Asia under future climate conditions. The potential distribution of the pseudo-vector species will have a wider potential distribution range than any individual vectors because we get the maximum predicted values among 13 vectors in each grid cell, which will cover a large area in the northern hemisphere. PWN will be also mainly distributed in Northern America, Europe, and Asia under future climate conditions. The potential distribution area of PWN and pseudo-vector species will be different, especially for the most suitable area. Combining the vectors will make a difference in the PWN suitable climate projections. Our study can guide for controlling PWD and also highlights the importance of considering the biotic interactions (host-vector) when predicting species’ potential distributions.