Potential distribution of pine wilt disease under future climate change scenarios.

Akiko Hirata,Kohei Takenaka Takano,Haruka Ohashi,Tetsuya Matsui,Katsunori Nakamura,Katsuhiro Nakao,Yuji Kominami,Wataru Takeuchi,Nobuyuki Tanaka,William Oki Wong

doi:10.1371/journal.pone.0182837

Abstract

Pine wilt disease (PWD) constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22). For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5) and two time periods (2050s and 2070s). We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area). Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

Highlights

Pine wilt disease (PWD) poses a serious threat to pine forests [1]
In Europe, native Pinus species that are widely cultivated such as P. sylvestris and P. pinaster are known to be susceptible to PWD [32,33], and the European and Mediterranean Plant Protection Organization (EPPO) recommends the prohibition of imported softwood products unless they properly treated to exterminate PWN [6,34]
The area ratio of vulnerable regions was high in East Asia, while in the future, the ratio increased in several countries in Europe, North Asia, and North America

Summary

Introduction

The pine wood nematode (PWN, Bursaphelenchus xylophilus) is the causal agent, while pine sawyer beetles (Monochamus spp.) act as a vector. In Asia and Europe, PWN is an invasive pathogen introduced artificially from PWD-affected countries and subsequently causing damage to native Pinus trees [5,6,7]. PWD causes significant damage to forestry, local economies, and the ecologies of affected countries, degrading the quality and decreasing the quantity of pine wood products. The loss of pine trees reduces ecosystem functions and services, decreasing habitats for wild animals [10] and affecting soil erosion [5,11]. Once introduced into a region, PWN spreads rapidly to neighboring areas through vector beetles or accompanying human activity [11,12]. Control is labor-intensive and costly [13], highlighting the importance of identifying vulnerable areas and prioritizing control measures

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Conclusion