Vegetation and soil controls on water redistribution on recently constructed ecosystems in water-limited environments

[Truncated abstract] Vegetated engineered covers are arti cially constructed ecosystems designed to minimize the environmental risks posed by hazardous wastes. Covers serve multiple objectives, which include supporting a stable vegetation community resembling natural ecosystems, and minimizing deep drainage into buried wastes by enhancing soil moisture storage in the top layers, and subsequent water loss through evapotranspiration. Vegetation directly contributes to cover hydrology through transpiration, and conversely, hydrology in uences transpiration and vegetation growth, forming a feedback loop. These vegetation-soil feedbacks may drive early ecosystem development, and control hydrology and vegetation patterns in water-limited ecosystems. Until now, information on the ecohydrology of recently constructed ecosystems such as covers has been lacking. Available literature has a disciplinary bias towards eld evaluation and predictive modelling of cover hydrology (Chapter 1), while a systems perspective integrating material hydraulic properties, vegetation characteristics and their interaction is still lacking. In particular, little was known about the spatial patterns of hydraulic properties and ne roots on covers, and their impacts on transpiration and plant water relations. Moreover, earlier studies lumped together bare soil evaporation and transpiration as evapotranspiration, thereby confounding our mechanistic understanding of the individual processes.