Projected Changes in Climate Suitability for the Brown Planthopper (Nilaparvata lugens) in West Java under Future Climate Scenarios

Abstract

One of the impacts of climate change in the agricultural sector in Indonesia is the shift in the distribution of the brown planthopper (Nilaparvata lugens), a significant threat to rice cultivation in Indonesia, which is very sensitive to changes in temperature and rainfall patterns. This study examines how future climate scenarios may affect the climatic suitability and spatial distribution of this pest across West Java Province, Indonesia. We employed the CLIMEX 4.0 modelling platform, supported by ArcMap and RStudio, to simulate both current and projected climate conditions (2040–2060) under the SSP2-4.5 and SSP5-8.5 emission scenarios derived from four CMIP6 models (ACCESS-CM2, EC-Earth3-Veg, GISS-E2-1-G, and HadGEM3-GC31-LL). Climatic suitability was assessed using the Ecoclimatic Index (EI), and spatial clustering among districts was evaluated using Moran's statistics. Our results indicate that, at present, high-suitability zones (EI 51–75) are concentrated in northern coastal regions, specifically in Indramayu, Karawang, and Subang. The results of projections of ecoclimatic conditions from future climate change scenarios indicate that the suitable area is expanding increasingly to the south and to middle altitudes. The suitable area increases from around 40% currently to almost 80% under the SSP5-8.5 scenario. The results of spatial analysis show that adjacent districts have similar climate suitability profiles. These findings suggest that increasing temperatures can lead to ecoclimatic conditions that increasingly support the development of brown planthoppers, thereby increasing the risk of pests in rice production centres in the West Java region.