Vulnerability of Global Afforestation Projects to a Polyphagous Invasive Fall Webworm

Global plantations, crucial for restoring degraded landscapes, face rising invasive pest threats, in recent decades. This study highlights that the invasion and proliferation of the fall webworm have been facilitated by the global afforestation boom in the last 80 years and could pose a threat to all global ecological projects until 2050. Since 1940, this polyphagous pest has spread to 40 countries, following an S- curve pattern. The distribution of the fall webworm is positively correlated with the expansion rates of afforestation and host tree plantation areas. China is now the most affected country by the fall webworm, with the highest comprehensive threat index (CTI). The number of host species has risen from 121 in the U.S. to 400 in China, and the host range has expanded from hardwoods to include coniferous trees. Notably, two-thirds of the total 600 host plants are tree species utilized for afforestation purposes. The preferred host species, Acer , Quercus , and Populus , are predominant in eight major global ecological projects. Additionally, hydroclimate extremes are projected to increase threats to 65.8% of afforestation zones by 2070, highlighting the need for strategic tree species selection to achieve sustainable ecological goals of global ecological projects, and protect against pests.