Theme 5-2: Drought Management and Climate Change--Poster Sessions
Description
Namibia is one of the global dryland regions facing desertification threats due to overgrazing and recurrent drought. This has disastrous effects on forage provision and consequently on local livelihoods. Unfortunately, the mechanisms underlying sudden shifts of rangeland ecosystems towards a desertified state are still poorly understood. The ability to predict desertification tipping points with the aid of suitable ecological indicators is critical to ensure sustainable management of rangeland resources, which are a backbone of rural livelihood in drylands worldwide. Accordingly, we aimed to identify key perennial grass species that can be used as early-warning indicators for desertification tipping points; and to assess their dynamics and response to grazing pressure. The study was conducted in the eastern region (Otjozondjupa) of Namibia where 4 communal areas and 4 freehold farms (commercial) were selected in order to compare perennial grass population responses within differently management land-use systems. A space-for-time approach was used for this purpose, where plots were laid out along local grazing gradients. Data on species occurrence, size structure and recruitment were collected. Preliminary findings show that a sudden decrease or disappearance of some sensitive native perennial grass species along grazing gradients and lack of seedling recruitment could be a useful hint to an approaching desertification tipping point.
Citation
Munyebvu-Chambara, F.; Nesongano, W. C.; Bilton, M. C.; and Linstädter, A., "Utilizing Perennial Grass Species’ Population Patterns to Detect Looming Desertification Tipping Points in Semi-Arid Regions" (2022). IGC Proceedings (1993-2023). 21.
https://uknowledge.uky.edu/igc/24/5-2/21
Included in
Utilizing Perennial Grass Species’ Population Patterns to Detect Looming Desertification Tipping Points in Semi-Arid Regions
Namibia is one of the global dryland regions facing desertification threats due to overgrazing and recurrent drought. This has disastrous effects on forage provision and consequently on local livelihoods. Unfortunately, the mechanisms underlying sudden shifts of rangeland ecosystems towards a desertified state are still poorly understood. The ability to predict desertification tipping points with the aid of suitable ecological indicators is critical to ensure sustainable management of rangeland resources, which are a backbone of rural livelihood in drylands worldwide. Accordingly, we aimed to identify key perennial grass species that can be used as early-warning indicators for desertification tipping points; and to assess their dynamics and response to grazing pressure. The study was conducted in the eastern region (Otjozondjupa) of Namibia where 4 communal areas and 4 freehold farms (commercial) were selected in order to compare perennial grass population responses within differently management land-use systems. A space-for-time approach was used for this purpose, where plots were laid out along local grazing gradients. Data on species occurrence, size structure and recruitment were collected. Preliminary findings show that a sudden decrease or disappearance of some sensitive native perennial grass species along grazing gradients and lack of seedling recruitment could be a useful hint to an approaching desertification tipping point.
