Watershed Ecology and Its Applications

Global climate change and intense human activities greatly alter natural eco-hydrological processes in multiscale watersheds, resulting in a series of threats to human society and ecosystems that include the increase of extreme climatic events, water quality degradation, and decreases in biodiversity and ecosystem stability.Many theories and approaches on ecological restoration for different types of water environments (e.g., rivers, lakes, marshes, and estuaries) have been proposed in the existing research.However, hydrological connections, mass and energy transports are usually considerable among the different types of water environments in a watershed, and restoration measures for one component typically affect other components in the same watershed.In addition, the interactions that occur among social activities, economic activities, and natural eco-hydrological processes are complex.Therefore, it is essential to explore sustainable watershed management from a systems perspective.Watershed ecology treats natural hydrological units (i.e., watersheds) as systems and analyzes the interacting biotic and abiotic components in a watershed.By exploring knowledge on system structures and interactions among the human and natural processes in a watershed, it offers useful tools for managers to assess the effects of environmental changes on ecosystem health and to create strategies for ecological restoration from a systems perspective.Motivated by the critical significance of watershed ecology in directing sustainable management, this special issue of Engineering was proposed in order to establish a forum for the discussion of recent progress in watershed ecology.Seven papers exploring new theories and approaches are collected in this special issue and contribute to the discussion on the following two hot topics:(1) Environmental changes and eco-hydrological response.Environmental data are essential for revealing environmental changes and their effects.In this issue, Lega et al. conduct a data analysis of their abundant collected data in order to assess the effects of environmental changes on the risks of natural hazards (e.g., rock falls and debris flows) in a mountain region.They demonstrate that appropriate policies can be planned, based on