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Alien & invasive animals: a South African perspective
Nicola van Wilgen
African Zoology , 2012,
Abstract:
Evidence, Perceptions, and Trade-offs Associated with Invasive Alien Plant Control in the Table Mountain National Park, South Africa
Brian W. van Wilgen
Ecology and Society , 2012, DOI: 10.5751/es-04590-170223
Abstract: The Table Mountain National Park is a 265 km2 protected area embedded within a city of 3.5 million people. The park contains an extremely diverse flora with many endemic species, and has been granted World Heritage Site status in recognition of this unique biodiversity. Invasive alien plants are arguably the most significant threat to the conservation of this biodiversity, and the past decade has seen the implementation of aggressive programs aimed at the removal of invasions by these plants. These invasive alien plants include several species of trees, notably pines (Pinus species) and eucalypts (Eucalyptus species), which historically have been grown in plantations, and which are utilized for recreation by the city's residents. In addition, many citizens regard the trees as attractive and ecologically beneficial, and for these reasons the alien plant control programs have been controversial. I briefly outline the legal obligations to deal with invasive alien plants, the history of control operations and the scientific rationale for their implementation, and the concerns that have been raised about the operations. Evidence in support of control includes the aggressive invasive nature of many species, and the fact that they displace native biodiversity (often irreversibly) and have negative impacts on hydrology, fire intensity, and soil stability. Those against control cite aesthetic concerns, the value of pine plantations for recreation, the (perceived) unattractive nature of the treeless natural vegetation, and the (incorrect) belief that trees bring additional rainfall. The debate has been conducted through the press, and examples of perceptions and official responses are given. Despite opposition, the policy promoting alien plant removal has remained in place, and considerable progress has been made towards clearing pine plantations and invasive populations. This conservation success story owes much to political support, arising largely from job creation, and a strong body of scientific evidence that could be cited in support of the program.
Fires, science and society
Brian W. van Wilgen
South African Journal of Science , 2010, DOI: 10.4102/sajs.v106i5/6.279
Abstract:
Convergence and divergence in fire-prone ecosystems
Brian W. van Wilgen
South African Journal of Science , 2012,
Abstract:
The evolution of fire and invasive alien plant management practices in fynbos
B.W. van Wilgen
South African Journal of Science , 2010, DOI: 10.4102/sajs.v105i9/10.106
Abstract: The history and development of fire and invasive alien plant management policies in fynbos during the 20th century are reviewed. Fire was initially condemned outright as a destructive force, but as its vital role became better understood, management policies switched from protection to active burning in 1968. During the 1970s, large, coordinated research programmes were established, resulting in a solid basis of knowledge on which to develop fire management policies. Despite policies of prescribed burning, wild fires remain the dominant feature of the region, fortunately driving a variable fire regime that remains broadly aligned with conservation objectives. The problem of conserving fire-adapted fynbos is complicated by invading alien trees that are also fire-adapted. Research results were used to demonstrate the impacts of these invasions on water yields, leading to the creation of one of the largest alien plant control programmes globally. Despite improvements in control methods, alien trees, notably pines, continue to spread almost unchecked. Biological control offered some hope for controlling pines, but was ruled out as too high a risk for these commercially-important trees. Failure to address this problem adequately will almost certainly result in the severe degradation of remaining fynbos ecosystems.
The evolution of fire management practices in savanna protected areas in South Africa
B.W. van Wilgen
South African Journal of Science , 2010, DOI: 10.4102/sajs.v105i9/10.107
Abstract: The history and development of ecologically-based fire management policies in savanna protected areas during the 20th century are reviewed. Research on fire in savannas began in the 1950s, and from the 1980s onwards, managers of savanna protected areas experimented on large scales with different management approaches. New ecological paradigms that embraced variability in space and time, and management goals that broadened from single-species to biodiversity conservation, precipitated significant changes to management approaches in the 1990s. Many lessons have been learnt in the process, allowing for the derivation of general principles regarding both the effects of fire and managerial ability to influence fire regimes on a large scale. Significant challenges remain; these include dealing with increasing CO2 concentrations in the atmosphere, and with interactions between fire and increasing elephant numbers in protected areas. The ability of savanna managers to deal with these challenges in the context of an imperfect understanding will be determined by how well, and how fast, they can learn from experience.
The recent fire history of the Table Mountain National Park and implications for fire management
Greg G. Forsyth,Brian W. van Wilgen
Koedoe : African Protected Area Conservation and Science , 2008, DOI: 10.4102/koedoe.v50i1.134
Abstract: This paper provides an assessment of fire regimes in the Table Mountain National Park over the past four decades. We compiled a GIS database of all fires between 1970 and 2007 and analysed the fire regime in terms of the frequency, season and size of fires and the relationship between fire occurrence and fire weather. Most fires (90.5% of area burnt) occurred in summer and autumn, the ecologically acceptable season for fires. However, mean fire return intervals declined by 18.1 years, from 31.6 to 13.5 years, between the first and last decades of the record respectively. The area subjected to short (≤ six years) intervals between fires covered > 16% of the park in the last two decades of the record, compared to ~ 4% in the first two decades. A relatively small number of large fires dominated in terms of area burnt. Of the 373 fires recorded, 40 fires > 300 ha burnt 75% of the area, while 216 fires < 25 ha burnt 3.4% of the area. Fires occurred under a wide range of weather conditions, but large fires were restricted to periods of high fire danger. Prescribed burning was a relatively unimportant cause of fires, and most (> 85%) of the area burnt in wildfires. Areas subjected to short fire return intervals should be considered for management interventions. These could include the re-establishment of extirpated fire-sensitive species, the clearing of invasive alien plants and increased precautions for the prevention or rapid suppression of future accidental fires.
Research projects and capacity building
CM Breen, JJ Jaganyi, BW Van Wilgen, E Van Wyk
Water SA , 2004,
Abstract: A World Bank long-term perspective study on Sub-Saharan Africa highlighted the need to build human and institutional capacity in virtually all sectors and countries. In South Africa, establishment of a democratic government in 1994 saw increased emphasis placed on capacity building. This led to the revision of policies and legislation directing human resources development. This emphasis on capacity development is reflected in procurement policies to the extent that it is increasingly difficult to successfully bid for funding from government and parastatal organisations unless there is both a plan and a commitment to capacity building in the previously marginalised sectors. There are currently no guidelines to support researchers in their attempts to support the intentions of legislation and policy. It has been assumed that researchers have the understanding and expertise to effectively promote capacity building. Under such conditions the expectations of research administrators are neither clearly structured nor are they understood by researchers. Not surprisingly, researchers often fail to meet the expectations of administrators. In an attempt to contribute towards developing a structured approach, this paper interprets what is meant by capacity building in the context of research projects. Based on this interpretation, reasonable and unreasonable expectations with respect to the extent to which capacity building can be achieved within a given project duration are discussed. A model is suggested, which would improve understanding and delivery and in doing so, achieve better congruence between expectations and outcomes. Key Words: Capacity building, Research, Change, Performance, Innovation WaterSA Vol.30(4) 2004: 429-434
The Management of Fire-Adapted Ecosystems in an Urban Setting: the Case of Table Mountain National Park, South Africa
Brian W. van Wilgen,Greg G. Forsyth,Philip Prins
Ecology and Society , 2012, DOI: 10.5751/es-04526-170108
Abstract: The Table Mountain National Park is a 265-km2 conservation area embedded within a city of 3.5 million people. The highly diverse and unique vegetation of the park is both fire prone and fire adapted, and the use of fire forms an integral part of the ecological management of the park. Because fires are both necessary and dangerous, fire management is characterized by uncertainty and conflict. The response of vegetation to fire is reasonably well understood, but the use of fire for conservation purposes remains controversial because of key gaps in understanding. These gaps include whether or not the vegetation is resilient to increases in fire frequency, how to deal with fire-sensitive forests embedded in fire-prone shrublands, and how to integrate fire and invasive alien plant control. National legislation emphasizes the need to protect communities from dangerous wildfires, and this compels fire managers to adopt a cautious approach to the application of fire. Ecological outcomes are optimized under a fire regime of relatively high-intensity, dry-season fires. Obtaining permission to burn under such conditions is not possible, and so the practice of prescribed burning is constrained, and this results in a fire regime dominated by wildfires. Ecological uncertainties, and the divergent requirements for maintaining healthy ecosystems on the one hand, and ensuring human safety on the other, result in a complex fire management environment. These complexities could be, and in some cases are being, alleviated by raising awareness, increasing fire management capacity, improving ecological monitoring of the effects of fire, and prioritizing areas for integrated fire and invasive alien plant management.
Past approaches and future challenges to the management of fire and invasive alien plants in the new Garden Route National Park
Tineke Kraaij,Richard M. Cowling,Brian W. van Wilgen
South African Journal of Science , 2011, DOI: 10.4102/sajs.v107i9/10.633
Abstract: The recently established Garden Route National Park (GRNP) along the Cape south coast of South Africa occurs in a landscape where indigenous forests, fire-prone fynbos shrublands and fire-sensitive plantations of alien invasive trees are interspersed. We used the area as a case study in the challenges facing conservation managers in the achievement of biodiversity goals in a fire-prone environment. We explored the context within which fire management was practised during the past century by interviewing former catchment managers and reviewing forestry and catchment management policies. Mountain fynbos adjacent to plantations was subjected to burning regimes aimed at the protection of commercial timber resources rather than the preservation of fynbos biodiversity. Prescribed burning of fynbos adjacent to the plantations was typically done in multiple belt systems at rotations of about 4–8 years during spring, summer and autumn, to avoid the winter berg wind season. Such short-rotation and low-intensity fires favour resprouting graminoids over slow-maturing reseeders, and likely account for the compositional impoverishment observed in fynbos near plantations. Current and future challenges faced by the GRNP include (1) balancing conflicting fire management requirements for plantation safety against fynbos conservation; (2) the continual invasion of fynbos by fire-propagated alien pines sourced from plantations; (3) inadequate resources to redress the ‘invasion debt’ caused by the socio-economic legacy and past management neglect; and (4) fragmentation of land use between conservation and forestry threatening the sustainability of the region at large. We provide recommendations for management actions and research priorities to address these challenges.
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