Department of Conservation Ecology and Entomology
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Browsing Department of Conservation Ecology and Entomology by browse.metadata.type "Review"
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- ItemGrasses as invasive alien plants in South Africa(Academy of Science for South Africa, 2004) Milton, S. J.Grasses are important, but often overlooked, elements of the South African alien flora. Current information shows that 15% of the grass genera and 12% of grass species in southern Africa are naturalized aliens. Many of these species are invasive in other parts of the world, where they are reducing the biodiversity of indigenous communities, changing ecosystem processes, retarding ecosystem restoration and reducing profits from ranching and arable agriculture. Their spread has been facilitated by domestic livestock, disturbance, long-distance transport and nitrogen addition to soils. Control is complicated by abundant seed production, persistent seed banks, positive response to disturbance, a dearth of biocontrol research and, in some cases, by herbicide resistance. This review of the impacts of alien grasses in other parts of the world suggests that alien grasses will become increasingly prevalent in South Africa, and that more research, aimed at identifying appropriate management responses, would be justified.
- ItemMonitoring effects of anthropogenic climate change on ecosystems : a role for systematic ecological observation?(Academy of Science for South Africa, 2007) Midgley, G. F.; Chown, S. L.; Kgope, B. S.WE CONSIDER HERE THE OPPORTUNITIES and challenges for South Africa in long-term ecological research (LTER) to detect the impacts of anthropogenic climate change on biota (as one of several competing objectives of long-term monitoring). The LTER approach has high potential for this purpose in South Africa because of a wealth of historical climate data relative to much of the African continent, and good representation of many African ecosystem types. However, there are substantial challenges to the identification and attribution of climate change impacts on African ecosystems. These are posed by climate variability at a range of time scales, the importance of rainfall rather than temperature as an ecological driver, and the significance of fire as a stochastic disturbance. An awareness of environmental and climate history will be crucial to interpreting data on trends, and sites with established historical data should be preferred for this reason. The placement of LTER sites to provide representivity of ecosystem types may unintentionally limit the detectability of climate change impacts, because change might best be detected in ecotonal or azonal environments. This could be overcome by additional experimental manipulations at LTER sites to 'force' anticipated changes and characterize species and ecosystem responses. A focus on the detection of climate change would sharpen an LTER programme's emphasis over time and provide policy advice, and science training rationales for the long term. It should especially interpret key information to decision-makers as a priority.
- ItemNorth-south cooperation through BIOTA : an interdisciplinary monitoring programme in arid and semi-arid southern Africa(Academy of Science for South Africa, 2006) Krug, C. B.; Esler, K. J.; Hoffman, M. T.; Henschel, J.; Schmiedel, U.; Jurgens, N.CONNECTING DISCIPLINES IN A NORTH-South collaboration has many advantages: mutualisms evolve, synergies are created and spin-offs emerge. The BIOTA South (Biodiversity Monitoring Transect Analysis in southern Africa) programme, with its long-term vision to generate knowledge of biodiversity along a north-south transect in southern Africa, is providing opportunities for research, technology transfer and capacity building while focusing on potential solutions for critical challenges that face this environmentally vulnerable part of the subcontinent.
- ItemScaling up from site-based research to a national research and monitoring network : lessons from Tierberg Karoo Research Centre and other design considerations(Academy of Science for South Africa, 2007) Milton, S. J.; Dean, W. R. J.; O'Connor, T. G.; Mills, A. J.South Africa is in the process of setting up a national environmental observatory system (SAEON) to monitor and gain a predictive understanding of the effects of climate change and land use on biodiversity, carbon and nutrient fluxes, soils and sediments, primary and secondary productivity, hydrology and disturbance regimes. It is intended that the data should be archived, analysed and translated into information accessible to decision-makers. We present a case that illustrates the infrastructural needs and challenges for long-term research and then discuss optimal designs and collaborations required to detect change in many variables, land-use types and geographical areas of South Africa.