Time-series-based habitat model development for surface water management on endangered aquatic plant Isoetes taiwanensis conservation in mountain wetlands

Abstract

Wetland scientists and ecological engineers are encouraged to comprehend hydrological driving forces for enhancing environmental conservation, ecological restoration, and integrated management. The spatiotemporal distribution and dynamics of aquatic plants are critical for improving their functional niche in mountain wetlands. This study evaluates the hydrological variation of a mountain wetland to determine the adverse and advantageous situations of an endemic and endangered aquatic plant by establishing a time-variant habitat index model considering the inundation frequency and duration of a specific water level. The model was developed and verified by integrating with a field survey of biotic and abiotic data to build the corresponding habitat suitability indices through conducting polynomial regression analysis. The results indicate its capability to effectively quantify the intricate relationship between water level and plant coverage in different places and seasons. The habitat quality can be derived as the combined functions of total scattered and maximum continuous periods of dominant and nondominant water depths. Although the coverage area fluctuated in different seasons, the model reveals significant capabilities to bridge the gaps for reaching the extreme hydrological conditions which might cause the extinction of the endangered aquatic plant Isoetes taiwanensis. The plant is found to be more competitive in the region, implemented by excavation and consolidation, with deeper water depth and higher water conservation. We suggest adaptative water level management at the planning and design phases and rehabilitating these essential habitat patterns to enrich the survival of I. taiwanensis in the dry season. Strengthening the water retention capacity of the bottom soil to reduce water leakage and groundwater seepage velocity may also help achieve integrated management for surface water conservation in the wetland.