Data from: Cross-scale interactions among bark beetles, climate change and wind disturbances a landscape modeling approach

Bark beetles are a key forest disturbance agent worldwide, with their impact shaped by climate, forest susceptibility, and interactions with other disturbances such as windthrow and fire. There is ample evidence on the interactions among these factors at small spatial and temporal scales, but projecting their long-term and landscape-scale impacts remains a challenge. We developed a spatially explicit model of European spruce bark beetle (Ips typographus) dynamics that incorporates beetle phenology and forest susceptibility, and integrated it in a climate-sensitive landscape model (LandClim). We first corroborated model outputs at various spatial and temporal scales and then applied the model in three case studies (in the Black Forest, Germany, and Davos, Switzerland) that cover an extended climatic gradient. We used this model and case study framework to examine the mechanisms and feedbacks that are driving short-term and long-term interactions among beetle disturbance, climate change and windthrow, and how they may shift in the future. At the current cold-wet end of the Norway spruce (Picea abies) distribution, climate change is projected to increase temperature and drought, such that beetles become a more dominant disturbance agent. At the warm-dry end of the spruce distribution, where under current climate beetle outbreaks were confined to the simultaneous occurrence of drought and windthrow, the simulated level of drought alone sufficed for triggering beetle outbreaks, such that elevated drought- and beetle-induced spruce mortality would negatively feed back on beetle disturbance in the long term leading to receding beetle populations due to the local extinction of Norway spruce. These results suggest that depending on initial environmental conditions climate change may shift the importance of direct and indirect drivers of disturbances. These shifts may affect the sign and strength of cross-scale disturbance interactions and may impact the cost-benefit trade-off between beetle suppression and preventive management strategies.

树皮甲虫（Bark beetles）是全球范围内关键的森林干扰营力，其影响受气候、森林易感性，以及与风倒、火灾等其他干扰的相互作用共同塑造。现有大量证据揭示了这些因子在小空间与时间尺度上的相互作用，但对其长期及景观尺度影响的预测仍是一项挑战。我们开发了一款整合了甲虫物候与森林易感性的欧洲云杉树皮甲虫（Ips typographus）空间显式动力学模型，并将其集成至气候敏感型景观模型（LandClim）中。我们首先在多空间与时间尺度上验证了模型输出结果，随后将该模型应用于涵盖广泛气候梯度的三个案例研究——分别位于德国黑森林与瑞士达沃斯。我们借助该模型与案例研究框架，探究驱动甲虫干扰、气候变化与风倒之间短期与长期相互作用的机制与反馈，以及这些相互作用未来可能发生的变化。在挪威云杉（Picea abies）分布区的当前冷湿端，气候变化预计将升高温度并加剧干旱，使得甲虫成为更具主导性的干扰营力。而在云杉分布区的暖干端，当前气候条件下甲虫暴发仅局限于干旱与风倒同时发生的场景；模拟结果显示，仅干旱程度提升便足以触发甲虫暴发，长期来看，干旱与甲虫诱导的云杉死亡率升高会对甲虫干扰产生负反馈，最终因挪威云杉的局地灭绝导致甲虫种群衰退。这些研究结果表明，气候变化或会根据初始环境条件改变干扰直接与间接驱动因子的重要性。此类变化可能会影响跨尺度干扰相互作用的方向与强度，并可能影响甲虫防控与预防性管理策略之间的成本收益权衡。