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RESEARCH PRODUCT
Using hydrological connectivity to detect transitions and degradation thresholds: Applications to dryland systems
Samira AzadiMaría Julieta RossiSaskia KeesstraSaskia KeesstraSteven G. SandiJantiene BaartmanMariano Moreno-de Las HerasPatricia M. SacoJosé F. RodríguezJesús Rodrigo-cominoJesús Rodrigo-cominosubject
010504 meteorology & atmospheric sciencesWater en Landgebruikmedia_common.quotation_subjectWetlandSemi-arid environments01 natural sciencesSoilBodemSoil Water and Land UseTemporal scales0105 earth and related environmental sciencesEarth-Surface Processesmedia_commongeographygeography.geographical_feature_categoryWIMEKbusiness.industryWater and Land UseEnvironmental resource management04 agricultural and veterinary sciencesVegetation15. Life on landBodemfysica en LandbeheerPE&RCHydrological connectivityAridLandscape evolutionGeoecologyBodem Water en LandgebruikSoil Physics and Land ManagementDesertification040103 agronomy & agricultureLand degradationErosion0401 agriculture forestry and fisheriesEnvironmental scienceLand degradationbusinessSurface runoffdescription
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.
year | journal | country | edition | language |
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2020-03-01 |