Conserving water resources is a current challenge that will become increasingly urgent in
future due to climate change. The arid and semi-arid areas of the globe are expected to be particularly
affected by changes in water availability. Consequently, advances in ecohydrology sciences, i.e., the
interplay between ecological and hydrological processes, are necessary to enhance the understanding
of the critical zone, optimize water resources’ usage in arid and semi-arid areas, and mitigate climate
change. This Special Issue (SI) collected 10 original contributions on sustainable land management
and the optimization of water resources in fragile environments that are at elevated risk due to climate
change. In this context, the topics mainly concern transpiration, evapotranspiration, groundwater
recharge, deep percolation, and related issues. The collection of manuscripts presented in this
SI represents knowledge of ecohydrology. It is expected that ecohydrology will have increasing
applications in the future. Therefore, it is realistic to assume that efforts to increase environmental
sustainability and socio-economic development, with water as a central theme, will have a greater
chance of success.