Assessing riparian habitat : an approach for planning rehabilitation.
Challen, Duncan Nicholas Rance.
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Riparian systems perform many critical ecological functions and services. Riparian areas are in urgent need of rehabilitation to restore their natural functioning. In order to successfully implement rehabilitation efforts in riparian areas, a management plan for rehabilitation is required. An important facet of a management plan would be the assessment of riparian habitat quality. The aim of this study is to produce a riparian habitat assessment approach that would be helpful in developing a rehabilitation management plan. The approach needs to assess habitat from a landscape scale through to a site scale, be concise, user friendly, effective and be able to be used by all land managers. It must also allow for the identification of areas of high asset value that will be prioritised for rehabilitation efforts. Existing local and international habitat assessment methodologies reviewed did not satisfactorily meet all the above objectives. Accordingly, a new methodology for riparian habitat assessment was developed, consisting of a 3-leve1 approach which assesses habitat from a landscape scale (macroscale assessment), a reach scale (intermediate-scale assessment) and at a site scale (microscale assessment). The approach was tested in a case study of the Rivers Bend farm in the Nkwaleni Valley, KwaZulu-Natal, South Africa. The developed methodology allows for an assessment technique of riparian areas that now explicitly includes landscape attributes, local characteristics of the river system (reach scale) and site scale level of assessment. Both the macroscale and the microscale assessments produced spatial representations of asset values within the study area. These areas were prioritised for rehabilitation efforts. Although these assessments produced results for identifying asset sites, the scoring· systems did not reflect the changes in habitat quality with enough detail. It is recommended that the characteristics determining the quality ratings and the scoring systems of these assessments be reassessed. The intermediate-scale assessment produced relevant stream profiles and gradient classes, but the application of the assessment did not successful1y delineate the river into homogenous segments. Further study is required to better integrate the 3-levels of the developed methodology.