4) Dr. Micha Silver

Connectivity is recognized as a key concept in ecology, used to measure and evaluate species biodiversity and the resilience of an ecosystem to changes. In wetlands, an equivalent measure, termed hydrological connectivity (HC), can assess the ability to support and sustain the unique groups of species in those environments. Many wetlands experience seasonal cycles of flooding and drying. During dry seasons, the water surface (WS) is reduced, leaving large areas of vegetation or exposed soil with varying soil moisture (SM) levels. Typically, the area of wetlands has been regarded as a measure of the health or degradation of the wetlands. A wetland that shrinks in size over an extended period has been considered degraded. However, a comprehensive review of global wetland area loss by Hu et al. (2017) compared wetland areas compiled by different methods, leading to uncertainty, and raising doubts (Murray (2023), Zedler and Kercher (2005)) as to the efficacy of these area measurements. The current work suggests that HC, rather than size, can represent the health of wetlands. Sentinel-2 images were analyzed from four study areas in arid and semi- arid regions worldwide to extract both WS and SM. The WS areas were identified using the Modified Normalized Difference Water Index (MNDWI)(Xu (2006)), and those of SM were by the OPtical TRApezoid Model (OPTRAM). Thus, using the high spatial and temporal resolution of this satellite imagery, the dynamics of wetland connectivity were monitored. By measuring and comparing the connectivity of WS areas to the SM patches, lag times of several months was revealed. This analysis illustrates that the dynamics of HCin wetlands can track wetland health.