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
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.


Water SA ◽  
2020 ◽  
Vol 46 (1 January) ◽  
Author(s):  
Rashid Hassan ◽  
Siphokuhle Mahlathi

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.


Author(s):  
Mutambuli J. Hadji

This article aims to evaluate government's communication strategy and citizens' awareness of the 16 Days of Activism for No Violence against Women and Children campaign in Soshanguve, South Africa. The study applied the diffusion of innovation theory because of its ability to assess how communities receive communication about the campaign from various media. Survey method was used to collect data, which was analysed using descriptive statistics. It was found out that mass media and other communication channels were main sources of campaign messages, which help the community to know how to address gender-based violence issues. Notably, this study found that females were more likely to know about the campaign than males. This article recommends that this campaign should be visible throughout the year and there should be more campaigns targeting men, and school curriculum, which educate pupils about the social and economic consequences of GBV.


Biologia ◽  
2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Lenka Hajzlerová ◽  
Jiří Reif

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.


2018 ◽  
Vol 21 (3) ◽  
pp. 725-742 ◽  
Author(s):  
Petr Pyšek ◽  
Giuseppe Brundu ◽  
John Brock ◽  
Lois Child ◽  
Max Wade

Sign in / Sign up

Export Citation Format

Share Document