Sentinel 2 images enable reliable prediction of fine-scale habitat dynamics of narrow endemic plant species in serpentine soils

Abstract

Aims: Serpentine soils are rare globally, covering <1% of the land surface, but frequently harbouring large numbers of narrow endemic species. Many serpentine areas are endangered and would benefit from actions informed by species distribution models (SDMs). Here, we assessed, for the first time, the potential use of remotely sensed descriptors of water and carbon cycles derived from Copernicus Sentinel 2 images for fine-scale habitat characterization and mapping of narrow endemic serpentine-tolerant species.Location: We focused on three endemic species with a very limited distribution in the Serra de Careón ultramafic outcrop, a regional plant biodiversity hotspot in Spain. Methods: We developed SDMs based solely on remotely sensed descriptors of plant water content and habitat dynamics estimated from multitemporal Sentinel 2 images.Results: The predictive capacity of the models was very high (area under the receiver operating characteristic curve (AUC) > 0.9, sensitivity> 90 and specificity> 84), even for projections beyond the range of data used for calibration (AUC > 0.8, sensitivity> 77 and specificity> 81). Overall, the suitable habitat areas predicted by the modelswere similar for all three species (Schoener’s D metric > 0.7). The annual mean and coefficient of variation of the Normalized Difference of Water Index provided a good representation of the hydromorphic soils with serpentine clay minerals and characterized by the formation of temporary pools during winter months. The annual mean and coefficient of variation of the Modified Soil Adjusted Vegetation Index were also important predictors owing to their capacity to capture the serpentine habitat conditions, characterized by open vegetation and highly exposed soil.Conclusions: These findings confirm the potential of ecosystem functioning descrip-tors derived from spectral Sentinel 2 indices as a cost- effective means of characterizing the ecological niche of endemic plant species in serpentine habitats and as a promising tool to support their conservation and monitoring