The Impacts Of Invasive Alien Plants

Chapter 1

Research on the impacts of invasive alien plants (IAP) on biodiversity, ecosystem services and processes have been well documented in the literature. Furthermore, the primary focus of this research was the negative impacts associated with IAPs when there are some benefits associated with these plants. Limited research has also addressed the issue of IAP impact on the livelihoods and well-being of local land-users. Seeing that limited resources are available to address the issue of IAP at large, quantification of stakeholder perception is needed to maximise IAP management.

Through this thesis, an investigation into the spread and impacts of IAPs in the rural parts of the Agulhas Plain as well as the perceptions, uses, costs and benefits associated with IAPs and the importance of these plants to the livelihoods of the local communities was carried out. The purpose of this research is to provide a better understanding of the possible impacts of invasive plant species on the livelihoods of people. This local knowledge can aid researchers by providing context specific information about impacts, which can then be used for future conservation actions.

Motivation

The detrimental effects of IAPs on ecosystems and biodiversity, ecosystem goods and services the economy of human enterprises and human health have been well documented in the literature (e.g. Geesing et al. 2004, Nel et al. 2004, Shackleton et al. 2007). Invasion by alien species have been reported as a major threat to the biodiversity and functioning of sensitive ecosystems (Turpie et al. 2003, Richardson and Van Wilgen 2004, Van Wilgen et al. 2008). It has been shown that invasive species are very successful in competing for resources with native species and can modify fuel loads by changing the amount of litter fall (Behenna et al. 2008). Invasive alien plants are also capable of altering the natural nutrient fluxs by shifting the nitrogen content due to changes in the litter fall (Behenna et al. 2008). Dense stands of acacias along the rivers in the Western Cape replace and exclude native fynbos species (Blanchard and Holmes 2008). Invasive alien plants also pose one of the greatest immediate threats to floral diversity in the fynbos and have the ability capture vast amounts of water (Turpie et al. 2003). In contrast, research exploring the effects of IAPs on the livelihoods of local, rural communities has received little attention (McGarry et al. 2005, Shackleton et al. 2007).

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Not all of the impacts exerted by IAPs are negative as these plant species is a source of both costs and benefits (Bardsley and Edward-Jones 2006). Various plants have been introduced to South Africa for a variety of purposes (Van Wilgen et al. 2001). These include species intrudes for crop production, timber and firewood, garden ornamentals, for dune stabilisation and hedge plants (Van Wilgen et al. 2001). Several of these have become naturalized and some of the naturalized species are now invasive (Van Wilgen et al. 2001). Costs are experienced when these invasive species impede the functioning of social and ecological systems (Bardsley and Edward-Jones 2006). Benefits, on the other hand, are experienced when the same traits (such as hardiness and high fecundity) that lead to these species becoming invasives, contribute to their usefulness (Bardsley and Edward-Jones 2006).

Rural communities are exposed to IAPs in different ways (Shackleton et al. 2007). The outcome is that that these communities have to weigh up the trade-offs between the possible positive benefits of IAPs as a natural resource and the negative impacts exercised by these species on ecosystem goods and services and in turn on human livelihood (Shackleton et al. 2007). It is generally accepted that the negative effects of IAPs on ecosystem goods and services are transferred directly to human well-being (Shackleton et al. 2007). This has been proven otherwise by researchers such as de Neergaard and others (2005), Shackleton and others (2007) and Kull and others (2011) who illustrated that IAPs can be integrated significantly by local communities in their lifestyles as either a source of tannins and timber, for firewood, building material, as well as for medicinal extractions and financial income by selling of firewood.

Working for Water (WfW), an IAP eradication programme, was launced in 1995 with the aim of restoring natural capital by controlling invading species and enhance water security (Van Wilgen et al. 1998). Simultaneously, the programme aims to alleviate poverty by providing employment to underprivileged communities (Van Wilgen et al. 1998). To date, the WfW programme has developed into one of the biggest conservation projects in Africa with regard to manpower, costs and impact (Ndhlovu 2011). Immense sponsorships have contributed towards extensive areas being cleared and a large numbers of individuals being employed (Binns et al. 2001, Turpie et al. 2008). Conversely, the socio-economic benefits of the WfW programme have not been wholly assessed regardless of the programmes extensive activities and substantial sponsorships associated with it (Turpie et al. 2008).

Additionally, the use of these plants by rural communities is not well understood and seldom integrated into eradication programmes as stated below:

The lack of information on the socio-economic impacts of IAS has been singled out as a major barrier to the implementation of comprehensive national IAS management programmes and as one of the main reasons for the failure of IAS issues to feature prominently in the mainstream agenda of most countries (Peter, 2009).

Quantification of stakeholder perception on the impacts of IAPs is essential in order authorize an argument for the control and management of invasive plant species (Peter, 2009). Though it is vital to understand anthropogenic impacts on landscapes and ecosystems through ecological knowledge of invasive species, an improved understanding of the social processes is also required to inform both species management and conservation policy (Peter 2009).

There is a shortage of information regarding the socio-economic impact of alien species presently found in South Africa. Even in well studied areas such as the Cape Floristic Region, the range of the impact of invasive plants is poorly understood. Additionally, limited research has also been done with regard to the socio-economic impacts of alien eradication programmes in the Western Cape. Consequently, there is a need for comprehensive research that investigates the holistic impacts (both negative and positive) of IAPs on the livelihoods and well-being of local communities.

Goals and Objectives

Considering the above, the objective of this study was to assess the effects and impacts of IAP infestation on human well-being, with the focus on the effects of IAPs on the livelihoods of rural land users in the Western Cape, South Africa. The main research question that directs the study is as follow: What are the impacts of invasive alien plants on the livelihoods of rural land users? This research question was broken down into seven key questions. These key questions were adapted from the literature (see McGarry et al. 2005).

Key Questions

What is the significance of the natural environment to the community?

What are people’s attitudes towards and perceptions of IAPs ?

How important are IAPs for human well-being and livelihoods?

Are the IAPs used for sustenance, for domestic requirements, etc.?

Are IAPs sold to provide an income?

Does the local community perceive IAPs as having a positive or negative impact on spirituality, culture and/or aesthetics?

How do IAPs in the area affect the supply of (other) ecosystem goods and services which are important to people’s livelihoods?

What are people’s attitudes towards IAP management?

What are the impacts of IAP eradication programmes on livelihoods?

What is the impact of IAP distribution on land-use practices?

What are the long-term and short-term gains and losses for human well-being and livelihood as a result of IAP impact?

The study site is highly dependent on areas where rural communities are still highly reliant on generating an income from the land. Additionally, the study site must also comply with the use of IAPs by the local community and in the same light IAPs must be potentially regarded as a problem by the local community.

The Agulhas Plain, situated within the Cape Floristic Region (CFR), has been selected as the focus area for this study as it meets the above mentioned criteria.

Study area

The Agulhas Plain (AP) is located within the CFR which is internationally known as a global biodiversity hotspot (Turpie et al. 2003). The CFR, known for its Mediterranean type climate, is the most floristically rich of the seven diverse biomes allocated in South Africa with an estimated 9600 plant species of which 70% are endemic (Richardson and Sekhran 2009). The AP, comprising an area of 270 000 ha, is located at the southern-most tip of South Africa and is a species-rich area known for its fire-prone coastal lowland fynbos and infertile soils (Richardson and Sekhran 2009, Treurnicht 2010). It is internationally recognised as a “centre for endemism” (Treurnicht 2010).

This area is however increasingly threatened by habitat transformation and alien plant invasion (Turpie et al. 2003), the latter being the focal point of this study. Fynbos wildflower farming and harvesting, particularly from natural vegetation, forms an integral part of this area’s economic activity and contributes immensely to this region’s agricultural sector (Treurnicht 2010). This has been shown Turpie and others (2003) who stated that natural fynbos vegetation are estimated to be accountable for 57.6% of the CFR’s turnover, which were equal to R90.5 million in the year 2000. The Agulhas Plain is practically responsible for the largest part of this turnover (Turpie et al. 2003).

Study limitations

It was not possible to do a systematic and exhaustive research in all the areas on the Agulhas Plain were IAP infestation occurs due to the time limitation of this study. It was thus decided to do a detailed and comprehensive micro focus i.e. case study on the socio-economic impacts of invasive alien plants and to gather as much consistent information as possible by means of interviews. Elim and the surrounding farming communities were accordingly selected as the study group.

Study site selection

Elim and the surrounding farming communities were chosen as the best suitable study site according to the following reasons:

It was established during the visits prior and during the pilot study that this rural settlement and its neighbouring farms still relies on woody IAPs as either a primary or a supplementary source of energy.

It was noted during field visits that the areas surround the settlement as well as the neighbouring farms are invaded to a substantial degree.

There has been active alien eradication programmes in the area since 1998 i.e. Working for Water as well as LandCare under the departments of Water Affairs and Agriculture respectively.

Thesis outline

Chapter 1 – Introduction

Chapter 2 – Literature Review

Chapter 3 – Methods, Results and Discussion

Chapter 4 – Implications for management and policies