van Wilgen B.W.,South African Council for Scientific and Industrial Research |
Biggs H.C.,Scientific Services
Biological Conservation | Year: 2011
This paper uses five inter-related topics (the management of rivers, fire regimes, invasive alien species, rare antelope and elephants) to assess 15. years of adaptive management in the Kruger National Park (KNP), South Africa. The importance of adaptive planning (a process for developing achievable objectives, which is adaptive because objectives are revised as understanding grows), has been highlighted by this assessment, and the KNP's track record of adaptive planning is better than that of adaptive management. Adaptive management has identified important issues with regard to biodiversity conservation, and resulted in a shift in management focus to these issues. Because the conservation outcomes of management shifts will only manifest themselves in the longer term, the relative success of adaptive management should be measured by the degree to which management has been refocused onto priority issues, and by the rate at which new understanding is generated. Some issues previously seen as important (fire, rare antelope), are now regarded as less so, while others remain important and difficult to solve, although there has been some progress (rivers, alien plants and elephants). It has also proved difficult to implement active adaptive management (large-scale, replicated trials using different approaches), because of local variation and logistical problems. Adaptive management will remain the approach of choice because there is some progress, and no known alternative to managing this complex ecosystem. It is simply not an option to return to the easily-understood " implementable" solutions (such as culling, regular prescribed burning, or artificial water provision) that demonstrably did not work. © 2010 Elsevier Ltd.
Carbutt C.,Scientific Services
Bothalia | Year: 2012
An 'early detection'-based desktop study has identified 23 taxa as 'current' emerging invasive alien plants in the Drakensberg Alpine Centre (DAC) and suggests a further 27 taxa as probable emerging invaders in the future. These 50 species are predicted to become problematic invasive plants in the DAC because they possess the necessary invasive attributes and have access to potentially suitable habitat that could result in them becoming major invaders. Most of the 'current' emerging invasive alien plant species of the DAC are of a northern-temperate affinity and belong to the families Fabaceae and Rosaceae (four taxa each), followed by Boraginaceae and Onagraceae (two taxa each). In terms of functional type (growth form), most taxa are shrubs (9), followed by herbs (8), tall trees (5), and a single climber. The need to undertake a fieldwork component is highlighted and a list of potential study sites to sample disturbed habitats is provided. A global change driver such as increased temperature is predicted to not only result in extirpation of native alpine species, but to also possibly render the environment more susceptible to alien plant invasions due to enhanced competitive ability and pre-adapted traits. A list of emerging invasive alien plants is essential to bring about swift management interventions to reduce the threat of such biological invasions.
Kraaij T.,Scientific Services
South African Journal of Botany | Year: 2011
Six-hundred-and-fifty plant species from 280 genera and 85 families have been recorded as indigenous to the Bontebok National Park (BNP), which lies 5km south of Swellendam, in the Western Cape. Twenty-nine of these plant species are globally threatened with extinction and another 23 are species of conservation concern. Three species (Aspalathus burchelliana, Diosma fallax, Erica filamentosa) are endemic to the park. The Asteraceae, Iridaceae and Fabaceae ranked high as speciose families, in line with the Cape Floristic Region (CFR) as a whole, while the Asphodelaceae, Crassulaceae, Poaceae and Cyperaceae were overrepresented, and the Rutaceae, Proteaceae and Ericaceae underrepresented at BNP. The largest genera were Aspalathus (19 species), Crassula (17), Pelargonium (16), Erica (15), Oxalis (12), Moraea (11), Helichrysum (10) and Hermannia (10). Geophytes were the dominant growth form (23% of species recorded), followed by dwarf shrubs (20%), herbs (16%), graminoids (15%), shrubs (13%), succulents (8%), trees (3%) and climbers (2%). Forty alien plant species were recorded (likely an underestimate of true numbers) with the Poaceae most speciose and arguably the biggest invasive threat at the park. With 20 plant species/km2, the flora of BNP is richer than expected based on its location within the south-eastern CFR. Similarity with floras of other lowland and montane protected areas in the region is low (<33% and <20% respectively), demonstrating that a large component of BNP's flora is not conserved elsewhere. Within a landscape context, BNP forms part of a cluster of connected core sites for Renosterveld conservation. This work confirms the high importance of BNP for flora conservation nationally and even globally. © 2010 Elsevier B.V.
Kingsford R.T.,University of New South Wales |
Biggs H.C.,Scientific Services |
Pollard S.R.,Association for Water and Rural Development AWARD
Biological Conservation | Year: 2011
Aquatic ecosystems are connected over large spatial scales, have varied drivers, strong and often conflicting societal interests and interacting management processes. Many of the world's protected areas (100,000, ~12% of land) include freshwater ecosystems, some specifically declared for freshwater protection, but often supplied by rivers outside their protected boundaries. Such complex socio-ecological systems have considerable challenges. We report on Strategic Adaptive Management (SAM), a management framework that should be implemented, irrespective of resourcing, in protected areas of any river system, ranging from heavily managed or regulated through to pristine rivers. We briefly outline the four stages of the SAM process for aquatic protected areas and present three case studies from South Africa and Australia in different stages of SAM implementation. Progress is incremental, reflecting gaps, problems, and socio-ecological dynamism. Real-world implementation usually means such management is passive although experimentation with environmental flows remains possible. While maturity in SAM is incremental over years or decades, it can and should be applied even if environmental problems are urgent and contentious. The stages of SAM should produce an agreed vision and/or mission among stakeholders, with an appropriate hierarchy of objectives that determines indicators to be measured, allowing ongoing reflection, learning and adaptation. There is no panacea for achieving aquatic conservation, but Strategic Adaptive Management offers hope with its interlinked processes for navigating complexity and learning. SAM in freshwater conservation is progressing because of the imperative for sustainability, history of interaction between scientists and managers and the need for transdisciplinary governance of rivers. © 2010.
Kraaij T.,Scientific Services
South African Journal of Botany | Year: 2010
This paper evaluates the history of fire management in the Bontebok National Park (3435 ha) over a period of almost four decades. A GIS database was compiled of all fires between 1972 and 2009 and the fire regime was analysed in terms of the frequency, season, size and cause of fires. Since the early 1970s, short interval burning was implemented to promote grazing for bontebok, but from 2004 the fire interval was lengthened to favour plant species diversity, an increasingly urgent conservation priority for the park. In total, 43 fires were recorded, ranging in size from 9 to 1007 ha, collectively spanning 14. 013 ha. The majority of fires were large (100-500 ha), with fires of >100 ha accounting for 96% of the area burnt. The overall mean fire return period (FRP) for the park was 7.2 years, which is short judged by fynbos standards. FRPs under the old and new management regimes were 6.7 and 10.9 years respectively. Under the old regime, FRPs in renosterveld and fynbos were 5.8 and 8.0 years respectively. Large parts of the park repeatedly experienced fires at immature vegetation ages resulting in the elimination of slow-maturing seed-regenerating plant species such as Protea repens. Post-fire age distribution was highly skewed towards young vegetation, with 75% of fire-prone vegetation burning at post-fire ages of ≤7 years, and <10% of fire-prone vegetation surviving beyond 10 years of age. Prescribed and accidental fires respectively accounted for 70% and 30% of the total area burnt. Prescribed burning was mostly done in March-April, and only 8% of the total area burnt, burnt outside of the ecologically acceptable fire season. This study identified areas which have been subject to ecologically appropriate and inappropriate fire return intervals, providing a basis for informed future management and research. © 2010 Elsevier B.V.