Hydrological sensitivity of mountainous wetlands to precipitation and potential evapotranspiration using elasticity curves

Abstract

Wetlands are recognized as one of the most productive ecosystems and provide important ecosystem services. Climate change is reported to be a major threat to mountainous wetlands, and understanding how the hydrological functioning of wetlands responds to climate variability is important for the conservation and restoration of wetland ecosystems. The hydrological sensitivity of wetlands to climate variability is best analyzed using long-term observations, but observations of wetlands are rare, and long-term observations are not always easy to obtain due to cost. To address the lack of hydrological observations in these wetlands, this study devised a simple wetland-specific hydrological model, calibrated the model parameters using limited observations, and input long-term meteorological data into the model to produce long-term hydrological component data for wetlands. Using the long-term meteorological time series (i.e. precipitation and potential evapotranspiration), the produced time series of the hydrological components of the wetland (such as wetland water level and/or groundwater exchange between upland and wetland), and the concept of elasticity curves, the hydrological sensitivity of the wetland to precipitation and/or potential evapotranspiration was analyzed. The climate resilience of a wetland is defined as the rate of change of the wetland hydrological components for a 1 % change in climate variables, and from the percentile-based elasticity curve approach, the response of the wetland hydrological components to different percentiles of annual and/or seasonal climate variability was examined. The climate elasticity curves of the wetlands showed that different percentiles of hydrological components have different climate elasticities. In addition, the sensitivity of the climate elasticity to the physical characteristics of the wetland and/or wetland drainage area was assessed to see which hydrological components are affected by which physical characteristics at which percentile level. The sensitivity assessment showed that the climate elasticity of the two applied wetlands was most affected by changes in wetland area. This study provides an avenue for analyzing how the hydrological function of wetlands can be affected by changes in climate variables at annual or seasonal scales, and how much physical characteristics can influence the hydrological sensitivity of wetlands to climate variability, and the insights gained from these analyses can provide valuable information for the conservation and/or restoration of wetlands.