Drought drives the pine caterpillars (Dendrolimus spp.) outbreaks and their prediction under different RCPs scenarios: A case study of Shandong Province, China

Abstract

Drought is an important driver of forest pests, and reports of climate change are becoming more conspicuous as a result of enhanced drought. These projected changes have a positive impact on forest insect pests that result in substantial forest damage, adverse economic impacts, and losses of ecosystem resources. Therefore, we explored the impact of drought on the outbreak of pine caterpillars and predicted the future trend of pine caterpillar outbreaks under different emission scenarios by constructing a drought-pine caterpillar model (using a greenhouse gas emission scenario: Representative Concentration Pathways, RCP4.5 and RCP8.5 from 2016 to 2099). The results showed that: (1) Long-term or prolonged drought had a greater positive impact on pine caterpillar outbreaks than short-term drought; (2) The drought was more severe in the RCP 8.5 scenario than that in RCP 4.5; (3) The outbreaks of pine caterpillars in Shandong Province will gradually decrease approaching 2100 under the RCP4.5 and RCP8.5 scenarios. There is a trend of cyclical changes of approximately 30 years under the RCP4.5 scenario, while these changes primarily occurred before the 2050s and then decreased significantly and even became almost zero in the 2090s. (4) Under the two scenarios, light infestations comprised the largest area, followed by moderate and severe. Our study is important to promote the understanding of climate change and provide references and direction for forest managers.