Microclimate persistence in island montane cloud forests

Montane cloud forests (MCFs), ecosystems critically dependent on persistent cloud immersion and high moisture availability, have been presumed vulnerable to regional warming and atmospheric drying. Yet their microclimatic resilience under regional climate variability remains poorly understood. Here we show that MCFs maintain remarkably stable near-surface relative humidity (RH), despite sustained regional warming, using a 42-year (1980–2021) high-resolution (2-km, hourly) climate dataset from Taiwan. These forests also exhibit substantially lower interannual RH variability than adjacent non-cloud-forested regions. This persistence arises from an interplay of mechanisms, including local and nonlocal water vapor supply under variable rainfall regimes, cloud-mediated temperature moderation, and nonlinear thermodynamic regulation. Together, these processes buffer MCFs against atmospheric drying. Our results complement prevailing assessments of MCF vulnerability to changing climate, by revealing their retention of a stable microclimate amid regional climate fluctuations. This study advances understanding of how mountain ecosystems regulate their microclimate and provides a mechanistic framework for evaluating microclimate persistence in cloud forests worldwide.