Rationale
(Changed due to Same category but change in criteria)
This species has an extent of occurrence (EOO) 10,585 km2 and an area of occupancy (AOO) of 92 km2 and continuing decline in habitat extent, habitat quality and number of mature individuals due to upstream activities, combined with spread of invasive alien species. There are approximately 20 locations and some of these locations may be fragmented and experiencing fluctuations in habitable extent due to land use and drought-related dewatering, negatively impacting individual subpopulation viability, however these fluctuations can not be classified as extreme at present. The species thus qualifies as Near Threatened B1b(i,iii,iv)+2b(i,iii,iv).
Distribution
The main subpopulations exist in the headwaters of the Lepalala, Mokolo and Mogalakwena Rivers, being sub-catchments of the Limpopo River Catchment, Limpopo Province. These tributaries all drain the Waterberg Mountain Range (Skelton 2001). Some of these tributaries are protected by Marakele National Park, while numerous others flow through private game reserves. There is one isolated subpopulation in the Pienaar River, Crocodile (West) catchment, to the south of the Waterberg.
Threatened by varied impacts in upland catchments such as sedimentation caused by agricultural activities, predation by alien fish such as Largemouth Bass (Micropterus salmoides), effects of small dams and water abstraction for irrigation and deteriorating water quality. A severe drought (2015-2016) has acted synergistically with these land-use effects to limit the actual extent of occupied habitat in several locations, with many reaches within these locations completely dewatered at the time of this assessment (for example Witklip stream in the Sandrivier Catchment, north of Modimolle). This has probably resulted in recent fluctuations in the number of locations and their habitable extent, with long-term stability dependent on future climatic trends.
Conservation
Eradication of Bass species (Micropterus species) from certain key conservation catchments may improve the conservation of this species. Discussions with riparian land owners to attempt to reduce sedimentation impacts may also help for example increasing riparian buffer zones. Environmental flow releases from key headwater impoundments would mitigate against low-flow habitat loss in vulnerable downstream locations.
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