Developing pilot ecological indicator framework for detecting climate refugia, instability, and extinction debt using orchids.

Mountain forest biodiversity is highly vulnerable to climate-driven shifts in temperature and microclimate, yet conventional metrics often fail to capture long-term ecological risk. Using epiphytic orchids as climate-sensitive indicators, we modeled current and future distributions of 10 species in the Northern Western Ghats, India, under RCP2.6 and RCP8.5 scenarios for 2050 and 2070 using ensemble species distribution models (SDMs; receiver operating curve [ROC] = 0.80). We developed a spatially explicit conservation framework integrating four ecological indicators: priority index (PI), ecological sensitivity zoning (ESZ), habitat stability index (HSI), and extinction debt (ED). Precipitation of the warmest quarter and climatic seasonality were dominant drivers of distribution. Suitable habitats remained relatively stable under low emissions but contracted and shifted under high emissions. PI and ESZ identified climate refugia, HSI revealed limited long-term hotspot persistence, and ED highlighted hidden future biodiversity losses. Integrating these indicators provides a robust framework for climate-resilient conservation planning.