# Human Activities and Climate Change Accelerate the Spread Risk of Hyphantria cunea in China

## TL;DR

Human activities and climate change are increasing the spread of fall webworms in China, especially in urban and densely populated areas.

## Contribution

A novel predictive framework combining human settlement data, climate, and forest distribution to assess fall webworm spread risk.

## Key findings

- Densely populated regions are more conducive to fall webworm habitation than sparsely populated areas.
- Human settlement density is the dominant factor driving fall webworm spread, contributing over 50% to the model.
- Future climate projections suggest a continued expansion of suitable habitats, especially under high-emission scenarios.

## Abstract

Invasive pests are spreading more rapidly worldwide as a result of a warming climate and increasing human activities, with particularly severe impacts on forest ecosystems. The fall webworm is an important quarantine pest in China, as this leaf-feeding moth can cause serious damage to forests, orchards, and urban trees. This study aims to identify the areas where fall webworms are most likely to occur at present, and to examine potential future changes in these risk ranges. By combining historical outbreak records with regional information on climate conditions, forest distribution, and human settlements, we developed a predictive framework to map areas at risk across China. The results demonstrate that densely populated regions—such as cities and their surrounding areas—are far more conducive to the habitation of fall webworms than sparsely populated areas. At present, areas at highest risk are primarily concentrated in the Beijing–Tianjin–Hebei region and the North China Plain. In the future, strong climate-warming scenarios are projected to induce further expansion of the habitable areas for fall webworms. These findings highlight the pivotal role of human activities in driving pest dispersal and provide practical guidance for early warning, targeted monitoring, and effective forest protection.

Anthropogenic activities and climate change have accelerated biological invasions, leading to profound ecological, economic, social, and health impacts. The invasive species fall webworm (Hyphantria cunea) has been reported to have outbreaks in areas with climate anomalies and human settlements in recent years, highlighting the necessity to explore the species’ suitable habitat and associated future changes. We built an ensemble species distribution model using Random Forest, MaxEnt, and Support Vector Machine, achieving excellent predictive performance (AUC = 0.996). Our results identify human settlement density as the dominant driving factor, with a contribution > 50%, far exceeding climatic and forest structure variables. Therefore, densely urbanized regions such as Beijing–Tianjin–Hebei, the Liaodong Peninsula, and the North China Plain comprise the current highly suitable areas. Future climate projections suggest a continued expansion of the suitable habitat for H. cunea, with the most pronounced growth expected under the high-emission pathway (SSP5-8.5), where human activity is greatest. Such a correlation indicates that highly urbanized regions should be given priority for corresponding monitoring and control measures. As climate warming continues, northeastern China will face escalating invasion risks. Conversely, some regions within the Yangtze River Delta may become less suitable for the habitation of H. cunea. These findings provide insightful guidance for region-specific surveillance, quarantine measures, and the precision management of H. cunea in China.