Browsing by Author "Baard, Johan A."

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    Assessing the effectiveness of invasive alien plant management in a large fynbos protected area
    (AOSIS Publishing, 2017) Kraaij, Tineke; Baard, Johan A.; Rikhotso, Diba R.; Cole, Nicholas S.; Van Wilgen, Brian W.
    Background: Concern has been expressed about the effectiveness of invasive alien plant (IAP) control operations carried out by Working for Water (WfW). South African legislation now also requires reporting on the effectiveness of IAP management interventions. Objectives: We assessed the effectiveness of IAP management practices in a large fynbos protected area, the Garden Route National Park, South Africa. Methods: We undertook field surveys of pre-clearing IAP composition and the quality of treatments applied by WfW during 2012–2015 in 103 management units, covering 4280 ha. We furthermore assessed WfW data for evidence of change in IAP cover after successive treatments, and adherence to industry norms. Results: Despite the development of detailed management plans, implementation was poorly aligned with plans. The quality of many treatments was inadequate, with work done to standard in only 23% of the assessed area. Problems encountered included (1) a complete absence of treatment application despite the payment of contractors (33% of assessed area); (2) treatments not being comprehensive in that select areas (38%), IAP species (11%) or age classes (8%) were untreated; (3) wrong choice of treatment method (9%); and (4) treatments not applied to standard (7%). Accordingly, successive follow-up treatments largely did not reduce the cover of IAPs. Inaccurate (or lack of) infield estimation of IAP cover prior to contract generation resulted in erroneous estimation of effort required and expenditure disparate with WfW norms. Conclusions: We advocate rigorous, compulsory, infield assessment of IAP cover prior to contract allocation and assessment of the quality of treatments applied prior to contractors’ payment. This should improve the efficiency of control operations and enable tracking of both the state of invasions and effectiveness of management.
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    An assessment of climate, weather, and fuel factors influencing a large, destructive wildfire in the Knysna region, South Africa
    (SpringerOpen, 2018-08-30) Kraaij, Tineke; Baard, Johan A.; Arndt, Jacob; Vhengani, Lufuno; Van Wilgen, Brian W.
    Background: In June 2017, wildfires burned 15 000 ha around the town of Knysna in the Western Cape, destroying > 800 buildings, > 5000 ha of forest plantations, and claiming the lives of seven people. We examined the factors that contributed to making this one of the worst fires on record in the region. Results: One third of the area that burned was in natural vegetation (mainly fynbos shrublands), and more than half was in plantations of invasive alien (non-native) pine trees, or in natural vegetation invaded by alien trees. We used satellite imagery to assess burn severity in different land cover types by comparing pre- and post-fire images to estimate biomass consumed. We used daily weather data from two weather stations to calculate fire danger and drought indices over 70 years, and compared the fire weather conditions during the 2017 Knysna fires to the long-term weather record. The amount of biomass consumed was significantly higher in plantations of invasive alien trees, and in fynbos invaded by alien trees, than in uninvaded fynbos, providing support for the contention that invasion by alien trees increases the impact and difficulty of control of wildfires. Fire danger indices on the days of the fires were in the top 0.1 to 0.2% of days in the historic record, indicating that fire weather conditions were extreme but not unprecedented. The fires were preceded by a prolonged drought, and 18-month running means for two drought indices were the highest on record. Conclusion: The severity of the fires was exacerbated by very high fire danger conditions, preceded by an unprecedented drought, and further worsened by the conversion of natural fynbos vegetation to plantations, and invasion of vegetation by alien trees. Historical fire suppression also resulted in fuel buildups, further aggravating the problem of fire control, while residential development within and adjacent to fire-prone areas increased the risks faced by residents. Our results support calls to control invasive alien plants, reduce commercial planting of invasive alien trees, strictly regulate development in areas of high fire risk, and maintain awareness of the need for fire-wise practic.
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    Biological invasions in South African National Parks
    (AOSIS Publishing, 2017) Foxcroft, Llewellyn C.; Van Wilgen, Nicola J.; Baard, Johan A.; Cole, Nicolas S.
    Objectives: A core objective in South African National Parks (SANParks) is biodiversity conservation and the maintenance of functional ecosystems, which is compromised by alien species invasions. The 2016 Alien and Invasive Species Regulations of the National Environmental Management: Biodiversity Act (NEM:BA) requires landowners to develop management plans for alien and invasive species, as well as report on the status and efficacy of control. Method: To compile the species list, we started with the 2011 SANParks alien species list. Name changes were updated and SANParks ecologists and park managers contacted to verify the species lists and add new records. Species reported by external experts were added in the same manner. The management programme costs and species controlled per park per year were extracted from SANParks’ Working for Water programme database. Results: SANParks has listed 869 alien and extra-limital species, including 752 plants and 117 animals, increasing from 781 alien species in 2011. About R 590 million has been spent by the Working for Water/Biodiversity Social Programmes since 2000/2001. Of the species recorded, 263 are listed by NEM:BA, including 12 Category 1a species, 184 Category 1b species, 28 Category 2 species and 39 Category 3 species. Conclusion: While large clearing programmes have been maintained since at least 1998, improving prioritisation is necessary. We provide a short synopsis of (1) what alien species are present in SANParks, (2) the species and parks that management has focused on, (3) the implications of the NEM:BA Invasive Alien Species Regulations and (4) future developments in monitoring.