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Monitoring Herbivore Impact

The experts are predicting a long term dry cycle, less than average rainfall and a level of unpredictability.  A vegetation monitoring programme around some of our water holes has been initiated.

Elephant Pan, Bird Hide, Hyena Dam, Deadwood Dam, Goedehoop Dam, Sibon Dam and Jackalberry Dam are included.

Our conservation Intern, Paige Ezzey, is measuring herbivore impact on a 50 metre radius around these water points. A disc pasture meter is used to determine plant utilization over time. 

It is hope that this project will be extended to include water holes in the east and west of the Umbabat, for comparison to the centrally located Ingwelala properties. Ndlopfu in the west, and the Buchner family in the east have demonstrated interest in participating in the project. Dr Mike Peel from ARC (Agricultural Research Council) is assisting as project mentor and drafting the monitoring protocol. 

The objective of this veld monitoring exercise is to complement the annual veld data that ARC technicians already collect from established monitoring sites throughout the Umbabat.

If the dry prediction is correct, more and more pressure will be placed on the artificial water points as time goes by, particularly by water dependant species such as elephant, impala, buffalo, zebra and white rhino. Herbivore congregations/concentrations will occur around the water points with increased impact on the surrounding vegetation.

Healthy veld is any protected area’s most important asset. Healthy veld means healthy basal cover (grasses and forbs) which protect the soil. Exposed soil is vulnerable to soil erosion through surface run off. Soil loss leads to natural erosion and loss of plant biodiversity. This in turn leads to loss of suitable habitat for herbivores and ultimately these animals will migrate in search of “greener” pastures. Predators will move off too in search of better prey densities.

So the challenge at hand is to accurately monitor the changes to vegetation biomass and understand the thresholds of potential concern before the velddeterioratesbeyond a point of reasonable return. The term “thresholds of potential concern” was formally referred to as “acceptable limits of change”. Very simply, certain limits of change are identified, and when these limits near their identified thresholds, man intervention may be necessary to protect the veld from further deterioration and negative utilization impact.  

Examples of man intervention are temporary closure of artificial water holes, judicious burning to attract herbivores to other areas and even more extreme measures such as live capture and/or culling. Fortunately Ingwelala is part of a massive “open system” where animal movement and migration is easily achievable, so temporary water closure is likely to be the preferred management option.

 

by John Llewellyn