scholarly journals Railway side mapping of alien plant distributions in Mpumalanga, South Africa

Bothalia ◽  
2017 ◽  
Vol 47 (2) ◽  
Author(s):  
Ndifelani Mararakanye ◽  
Modau N. Magoro ◽  
Nomakhazi N. Matshaya ◽  
Matome C. Rabothata ◽  
Sthembele R. Ncobeni
Keyword(s):  
South Africa ◽  
Plant Invasions ◽  
Unsupervised Classification ◽  
Plant Distribution ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
Production Water ◽  
Analysis Technique ◽  
Salix Babylonica ◽  
Species Occurrences

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.

scholarly journals Economic analysis of the eradication and management of invasive alien vegetation in the Mhlatuze river catchment (KwaZulu-Natal, South Africa)

2002 ◽  
Vol 5 (2) ◽  
pp. 452-472
Author(s):  
Jennifer Cooper ◽  
Jessica Schroenn ◽  
Nevil Quinn
Keyword(s):  
South Africa ◽  
Land Use ◽  
Economic Viability ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
River Catchment ◽  
Adverse Impacts ◽  
Kwazulu Natal ◽  
Alien Vegetation ◽  
The Stability

Alien invasive vegetation threatens the functioning and existence of natural ecosystems in South Africa because many of these plants have no predators or competitors, allowing them to dominate the ecosystem which they inhabit. The rapid proliferation of this alien vegetation, ascribed to the increase in afforestation and changes in land use, has had significant adverse impacts on water resources, biodiversity and the stability as well as integrity of these ecosystems. Although eradicating alien invasive vegetation gives rise to a number of different benefits, this process entails enormous costs. Consequently, in order to establish the economic viability of alien plant eradication it is essential to analyse these costs as well as the benefits associated with eradication.

The economic consequences of the environmental impacts of alien plant invasions in South Africa

2011 ◽  
pp. 295-323 ◽  
Author(s):  
D Le Maitre ◽  
W de Lange ◽  
D Richardson ◽  
R Wise ◽  
B van Wilgen
Keyword(s):  
South Africa ◽  
Environmental Impacts ◽  
Plant Invasions ◽  
Economic Consequences ◽  
Alien Plant

scholarly journals Use of a rapid roadside survey to detect potentially invasive plant species along the Garden Route, South Africa

Koedoe ◽  
2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Johan A. Baard ◽  
Tineke Kraaij
Keyword(s):  
South Africa ◽  
South African ◽  
National Park ◽  
Invasive Plant ◽  
Alien Plants ◽  
Plant Distribution ◽  
Plant Management ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Roadside Survey

Early detection of emerging or sleeper weeds and monitoring of alien plant invasions forms the foundation of effective invasive alien plant management. Using a rapid roadside survey technique, we aimed to (1) establish a baseline of alien plant distribution and abundance along roads in the Garden Route, South Africa, and (2) identify priority species (particularly sleeper weeds) and priority areas to inform appropriate management action. We surveyed along 530 km of roads and recorded 109 alien and/or extralimital species across 1942 point locations. Of these, 35 species were considered to be sleeper weeds on account of displaying estimated dispersal distances distinctive of invasive plants and not being listed by the South African Plant Invaders Atlas (SAPIA) or regulated by South African legislation. Roads along natural forest and fynbos vegetation (often within the Garden Route National Park) displayed lower incidences of alien plants than those associated with degraded or transformed land, with roads along farmland associated with the highest incidences of alien plants. Roads in the Southern Cape region had more species and higher densities of alien plants than roads in the Tsitsikamma region, and a few species were exclusive to either.Conservation implications: Our inventory contributed significant new records and range extensions to SAPIA, while the identified sleeper weeds offered suggestions for species that may be considered for regulation under the National Environmental Management: Biodiversity Act of South Africa. We furthermore provided information to facilitate (1) timely management of emerging invasive alien plants, (2) prioritisation of species and areas for management action, and (3) future monitoring of alien plants in the Garden Route National Park and surrounds.

scholarly journals Evaluating the environmental and social net-worth of controlling alien plant invasions in the Inkomati catchment, South Africa

Water SA ◽  
2020 ◽  
Vol 46 (1 January) ◽  
Author(s):  
Rashid Hassan ◽  
Siphokuhle Mahlathi
Keyword(s):  
South Africa ◽  
Plant Invasions ◽  
Social Benefit ◽  
Eradication Programme ◽  
Alien Plant ◽  
Net Worth ◽  
Invasive Alien Plant ◽  
Benefit Cost Analysis ◽  
The Social ◽  
The Impact

The present study attempted to bridge some gaps in the existing literature evaluating the net economic worth of South Africa’s Working for Water (WfW) programme for eradicating invasive alien plant species (IAPS). Specifically, the study employed the social benefit-cost analysis (BCA) methodology to assess the impact of accounting for the opportunity cost of invested capital funds and treating labour as a social benefit on the social worthiness of the WfW programme in the Inkomati catchment. The study also used improved measures of the value of other ecosystem services, particularly the carbon sequestration values. Results of the social BCA provided strong empirical evidence in support of the continuation of IAPS eradication activities, as economically and socially worthwhile investment of the country’s resources. The programme generates higher net worth under lower rates of discounting future values. This confirms the importance of the water-saving benefits, which continue theoretically for ever, at zero cost to the society, as all direct and indirect financial costs cease upon completion of the eradication operations. The social net worth of the IAPS eradication programme obviously increases when expenditure on labour wages was considered a social benefit rather than a direct financial cost, even under strict project funding scenarios that require funding through private capital markets, i.e., paying commercial rates of interest. However, more strategic planning for the control of IAPS is critically important given their high cost. Challenges facing the sustainability of IAPS eradication programmes in the study area and South Africa include: raising sufficient funding from private and public sources, and introducing incentive systems to encourage higher collaboration and participation of private landowners in the currently primarily publicly driven IAPS eradication efforts. The study also suggests a number of policy and technological reforms to address the said challenges.

The Biology of Invasive Alien Plants in Canada. 4. Heracleum mantegazzianum Sommier & Levier

2006 ◽  
Vol 86 (2) ◽  
pp. 569-589 ◽  
Author(s):  
Nicholas A. Page ◽  
Ronald E. Wall ◽  
Stephen J. Darbyshire ◽  
Gerald A. Mulligan
Keyword(s):  
British Columbia ◽  
Urban Areas ◽  
Native Species ◽  
Invasive Plant ◽  
Leaf Shape ◽  
Herbarium Specimens ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Heracleum Mantegazzianum

Heracleum mantegazzianum (giant hogweed) is an invasive alien plant of management concern in southern Canada where it has escaped from horticulture and established and spread in natural, ruderal, and agricultural ecosystems. It poses a threat to natural ecosystems and human health, and is also a weed in agricultural and urban areas. It is a member of the Carrot family (Apiaceae) and is closely related to the native species Heracleum maximum Bartram (cow-parsnip). It is a monocarpic perennial, which generally flowers in its 3rd or 4th year. Large size, leaf shape, dark reddish pigments in patches on stems and petioles, and fruit characteristics readily distinguish H. mantegazzianum from other plants in Canada. It is increasingly common in riparian areas, floodplains, and forest edges in or near urban areas in southwestern British Columbia and southern Ontario. Based on herbarium specimens, H. mantegazzianum was first recorded in Ontario in 1949, British Columbia in 1964, Nova Scotia in 1980, Quebec in 1990, and New Brunswick in 2000. The development of dense stands of H. mantegazzianum can also reduce the richness of native plants. Contact with H. mantegazzianum can cause phytophotodermatitis, a serious skin inflammation caused by UV photo-activation of furanocoumarins present in the sap. Control methods include herbicide application, mechanical cutting, and animal grazing, but strategies to address seed dispersal and re-establishment from dormant seed must also be adopted. Widespread establishment in southern Canada suggests that eradication is unlikely. However, range expansion and rapid population growth can be prevented through strategic management including public education. Key words: Giant hogweed, Heracleum mantegazzianum, Apiaceae, HERMZ, invasive plant, weed biology, furanocoumarins

Bird species richness and abundance in riparian vegetation invaded by exotic Reynoutria spp.

Biologia ◽  
2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Lenka Hajzlerová ◽  
Jiří Reif
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Riparian Vegetation ◽  
Bird Species ◽  
Plant Invasions ◽  
Alien Plant ◽  
Bird Species Richness ◽  
River Bank ◽  
Management Actions ◽  
Acrocephalus Palustris

AbstractImpacts of invasive alien plant species are threatening biodiversity worldwide and thus it is important to assess their effects on particular groups of organisms. However, such impacts were studied mostly in case of plant or invertebrate communities and our understanding the response of vertebrate species to plant invasions remains incomplete. To improve our knowledge in this respect, we studied bird communities in riparian vegetation along the rivers with different levels of Reynoutria spp. invasion in the Czech Republic. These findings will be interesting for basic ecology enhancing our knowledge of consequences of plant invasions, as well as for conservation practice. We surveyed understory bird species in 26 vegetation blocks along parts of three rivers running from the Beskydy Mountains in spring 2011. We used principal component analysis to assess vegetation structure of particular blocks and the first axis ordinated the blocks according to the degree of invasion by Reynoutria spp. Using generalized linear mixed-effects models we found that counts of Motacilla cinerea, Cinclus cinclus and Sylvia borin, as well as the total bird species richness, significantly decreased with increasing degree of Reynoutria spp. invasion, while Acrocephalus palustris showed the opposite pattern. These results suggest that Reynoutria spp. impacts negatively on the species strictly bond with river banks and habitats specialists, whereas habitat generalist species like Sylvia atricapilla were not affected. Preference of Acrocephalus palustris for Reynoutria spp. corroborates affinity of this species to large invasive herbs observed also in other studies. Our study showed that Reynoutria spp. invasion can reduce species richness of understory birds in riparian communities. Although the distribution of this plant species is still quite limited in central Europe, our results suggest that its more widespread occurrence could potentially threat some river bank bird species. Therefore, we urge for development of management actions that will act counter the Reynoutria spp. invasion.

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