scholarly journals Plant invasions in South Africa: Insights from the 2017 National Status Report on Biological Invasions

2018 ◽  
Vol 115 ◽  
pp. 314-315
Author(s):  
J.R. Wilson ◽  
K. Faulkner ◽  
L. Henderson ◽  
T. Munyai ◽  
S. Rahlao ◽  
...  
Author(s):  
Tendamudzimu Munyai

In November 2018, South Africa published the first National Status Report on Biological Invasions and Their Management (SANBI and CIB 2018). This report represents a milestone for the Republic of South Africa and the world since it is believed to be the first comprehensive national-scale assessment for biological invasions. Moreover, the report is a formal mechanism to increase the connectivity between research, policy, and implementation, and it will be followed by assessments every three years. Data used in the report originated from a range of data sources, including formal and grey data repositories, atlas data, published scientific papers, theses, inputs from experts and practitioners, and management records from government agencies and Non-Governmental Organizations (NGOs). Several important data gaps were identified during data collection and analysis. These data gaps are largely due to a lack of a central data repository, inconsistent species checklists, data transparency, and data interoperability (due in part to a lack of consistent definitions, taxonomic classification, and use of varying data standards). To address these data gaps, the team identified several forms of databases and requested access to the data. The data received required that the team perform a preliminary validation for metadata and data completeness. Parallel to the process of sourcing and validating the data, the team compiled three comprehensive national alien and invasive species checklists, which were then verified and validated by taxonomists. These processes were followed by adopting and developing metrics to prepare data for analyses. The team identified, notwithstanding the numerous data classification schemes available, A Proposed Unified Framework for Biological Invasions (Blackburn et al. 2011), and the Environmental Impact Classification for Alien Taxa (EICAT) Scheme (Hawkins et al. 2015). These two classifications were used to assess the status of species introduction and impact, respectively. Other metrics that were developed include the confidence level metrics to assign the validated data to the indicators and criteria for reviewing area-based invasive species management plans. Finally, the data were used to assess four aspects of the report: pathways of introduction; status of alien species; status of invaded areas; and effectiveness of control measures and regulations. A total of 21 indicators were developed to assess the status of these aspects. In addition, four high-level indicators (one for each aspect) were developed for use in the national suite of environmental indicators on which the Department of Environmental Affairs reports on a regular basis. The next steps include communicating and interpreting the indicators as part of the final report; developing monitoring and reporting systems in an attempt to fill the data gaps; testing and refining the indicators with stakeholders; continuously validating and verifying the alien and invasive species checklists with a wider network of country experts; and building simulation models to assess the inter-relationship and value of indicators.


Bothalia ◽  
2017 ◽  
Vol 47 (2) ◽  
Author(s):  
John R.U. Wilson ◽  
Mirijam Gaertner ◽  
David M. Richardson ◽  
Brian W. Van Wilgen

South Africa has committed to producing a National Status Report on Biological Invasions by October 2017 and thereafter every three years. This will be the first status report at a national level specifically on biological invasions. As part of soliciting input, a workshop was held in May 2016 that led to this special issue of 19 papers in the journal Bothalia: African Biodiversity and Conservation. This editorial introduces the symposium, discusses the special issue and summarises how each contribution provides an estimate of ‘status’. Papers focus on key pathways, taxa, areas, and evaluations of interventions, specifically the movement of taxa between South Africa and neighbouring countries; the dispersal pathways of amphibians; a review of alien animals; a report on changes in the number and abundance of alien plants; in-depth reviews of the status of invasions for cacti, fishes, fungi and grasses; an assessment of the impact of widespread invasive plants on animals; reviews on invasions in municipalities, protected areas and subAntarctic Islands; assessments of the efficacy of biological control and other control programmes; and recommendations for how to deal with conflict species, to conduct scientific assessments and to improve risk assessments. The papers in this special issue confirm that South Africa is an excellent place to study invasions that can provide insights for understanding and managing invasions in other countries. Negative impacts seem to be largely precipitated by certain taxa (especially plants), whereas invasions by a number of other groups do not, yet, seem to have caused the widespread negative impacts felt in other countries. Although South Africa has effectively managed a few biological invasions (e.g. highly successful biological control of some invasive plants), the key challenge seems to be to establish and maintain a strong link between implementation, monitoring, reporting and planning.


2016 ◽  
Vol 62 (1-2) ◽  
pp. 32-43 ◽  
Author(s):  
Nicole L. Kinlocka ◽  
Bracha Y. Schindler ◽  
Jessica Gurevitch

Green roofs can mitigate a number of urban environmental problems when green roof plant communities provide ecosystem services. However, this perspective may fail to address ecological aspects of the plant community. In particular, it does not account for the potential for green roofs to facilitate biological invasions. We consider current research in green roof ecology in light of the literature on biological invasions, focusing on plant invasion. We evaluate the role of species composition and novel communities, species interactions, succession, and dispersal on the trajectory of green roof plant communities. Green roofs have the potential to introduce invasive species through initial plantings, to become dominated by invasive species, and to spread invasive species, and we provide recommendations for plant selection and maintenance to reduce the risks of facilitating plant invasions to surrounding communities.


Bothalia ◽  
2017 ◽  
Vol 47 (2) ◽  
Author(s):  
Ndifelani Mararakanye ◽  
Modau N. Magoro ◽  
Nomakhazi N. Matshaya ◽  
Matome C. Rabothata ◽  
Sthembele R. Ncobeni

Background: Alien plant invasions are among the major threats to natural and semi-natural ecosystems in South Africa on approximately 18 million hectares of land. Much of the available data are not suitable for planning of local scale management because it is presented at a quarter degree grid square scale, which makes accurate location and estimates of invaded areas difficult.Objectives: The aim was to identify the dominant alien plant species and quantify their areal extent along a 479 km railway corridor in the Mpumalanga province.Method: The extent of the invaded area was obtained by manual digitising of alien plant distribution and density from Satellite Pour l’Observation de la Terre 5 imagery and by further applying an Iterative Self-Organising Data Analysis technique of the unsupervised classification method. Species’ occurrences were located and identified in the field using a Global Positioning System.Results: The most dominant invaders in terms of the number of individual polygons and the infested area were Eucalyptus spp., Acacia spp., Populus alba L., Pinus patula Schltdl Cham., Salix babylonica L. and Caesalpinia decapetala (Roth) Alston. These species have also been previously classified as major invaders, although the Conservation of Agricultural Resources Act regulations permit their planting provided spreading to adjacent areas is avoided except for C. decapetala, which must be cleared under all circumstances.Conclusion: Knowledge of the species’ occurrence and their extent will assist landowners and relevant authorities to control the spread of alien plants, which impact rail safety, agricultural production, water availability and biodiversity.


Author(s):  
John R. Wilson ◽  
John Measey ◽  
David M. Richardson ◽  
Brian W. van Wilgen ◽  
Tsungai A. Zengeya

2017 ◽  
Vol 19 (12) ◽  
pp. 3541-3555 ◽  
Author(s):  
Phil McLean ◽  
Laure Gallien ◽  
John R. U. Wilson ◽  
Mirijam Gaertner ◽  
David M. Richardson

Author(s):  
Brian W. van Wilgen ◽  
Tsungai A. Zengeya ◽  
David M. Richardson

Author(s):  
Thabiso M. Mokotjomela ◽  
Tshamaano Nemurangoni ◽  
Tsedzuluso Mundalamo ◽  
Thulisile P. Jaca ◽  
Anesu G. Kuhudzai

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