TY - JOUR
T1 - Using hydrological connectivity to detect transitions and degradation thresholds: Applications to dryland systems
AU - Saco, Patricia M.
AU - Rodríguez, José F.
AU - Moreno-de las Heras, Mariano
AU - Keesstra, Saskia
AU - Azadi, Samira
AU - Sandi, Steven
AU - Baartman, Jantiene
AU - Rodrigo-Comino, Jesús
AU - Rossi, María Julieta
PY - 2020/3
Y1 - 2020/3
N2 - In arid and semi-arid ecosystems, shortage of water can trigger changes in landscapes’ structures and function leading to degradation and desertification. Hydrological connectivity is a useful framework for understanding water redistribution and scaling issues associated with runoff and sediment production, since human and/or natural disturbances alter surface water availability and pathways increasing/decreasing connectivity. In this paper, we illustrate the use of the connectivity framework for several examples of dryland systems that are analysed at a variety of spatial and temporal scales. In doing so, we draw particular attention to the analysis of coevolution of system structures and function, and how they may drive threshold behaviour leading to desertification and degradation. We first analyse the case of semi-arid rangelands, where feedbacks between the decline in vegetation density and landscape erosion reinforces degradation processes driven by changes in connectivity until a threshold is crossed above which the return to a functional system is unlikely. We then focus on semi-arid wetlands, where decreases in water volumes promote terrestrial vegetation encroachment that changes drainage conditions and connectivity, potentially reinforcing redistribution of flow paths to other wetland areas. The analysis of dryland wetlands is based on a novel hydrologic connectivity index derived using inundation requirements for wetland vegetation associations. The examples presented highlight the need to incorporate a coevolutionary framework for the analysis of changing connectivity patterns and the emergence of thresholds in arid and semi-arid systems.
AB - In arid and semi-arid ecosystems, shortage of water can trigger changes in landscapes’ structures and function leading to degradation and desertification. Hydrological connectivity is a useful framework for understanding water redistribution and scaling issues associated with runoff and sediment production, since human and/or natural disturbances alter surface water availability and pathways increasing/decreasing connectivity. In this paper, we illustrate the use of the connectivity framework for several examples of dryland systems that are analysed at a variety of spatial and temporal scales. In doing so, we draw particular attention to the analysis of coevolution of system structures and function, and how they may drive threshold behaviour leading to desertification and degradation. We first analyse the case of semi-arid rangelands, where feedbacks between the decline in vegetation density and landscape erosion reinforces degradation processes driven by changes in connectivity until a threshold is crossed above which the return to a functional system is unlikely. We then focus on semi-arid wetlands, where decreases in water volumes promote terrestrial vegetation encroachment that changes drainage conditions and connectivity, potentially reinforcing redistribution of flow paths to other wetland areas. The analysis of dryland wetlands is based on a novel hydrologic connectivity index derived using inundation requirements for wetland vegetation associations. The examples presented highlight the need to incorporate a coevolutionary framework for the analysis of changing connectivity patterns and the emergence of thresholds in arid and semi-arid systems.
KW - Geoecology
KW - Hydrological connectivity
KW - Land degradation
KW - Landscape evolution
KW - Semi-arid environments
U2 - 10.1016/j.catena.2019.104354
DO - 10.1016/j.catena.2019.104354
M3 - Article
AN - SCOPUS:85076570326
VL - 186
JO - Catena
JF - Catena
SN - 0341-8162
M1 - 104354
ER -