Wildflower farming on the Agulhas Plain : fynbos management and conservation

[摘要] ENGLISH ABSTRACT: The Agulhas Plain is a constituent of the Cape Floristic Region, internationally known as a global biodiversity hotspot. The species-rich Agulhas Plain consists mainly of fire-prone fynbos shrublands of which sandstone fynbos covers a significant surface area. This lowland region is characterised by mostly infertile soils yet has unique floristic complexity and contains a high amount of threatened lowland species. Natural vegetation on the Agulhas Plain has been prone to large scale land transformation activities, mainly attributed to the extent of alien plant invasions, urbanisation and agricultural expansion. Fynbos wildflower farming, specifically from natural vegetation, is an important economic activity and contributes to the region‟s agricultural sector. Farmers harvest large quantities of commercial fynbos species and supply these to the market in an attempt to sustain a livelihood. Certain wildflower farming practices (burning, ploughing and broadcast sowing) are applied to natural vegetation in an attempt to increase the abundance of commercial species (i.e. augmentation). Numerous farming practices are used in the industry and the application of these methods can be dynamic and divergent. Furthermore, the implementation of farming practices manifest as anthropogenically induced disturbance events and are a concern for conservation. Previous investigations suggest that farming practices could establish monocultures of commercial wildflower species by reducing species richness and plant diversity of wildflower vegetation. Although the impact of natural disturbance regimes (e.g. fire) and flower harvesting activities have been researched, the impact of farming practices on fynbos structure and composition remains largely unknown.This thesis reports on various aspects related to wildflower farming on the Agulhas Plain. Firstly, by administering a questionnaire, the extent and application of farming practices was investigated. Additionally, the opinion of wildflower farmers (referred to as landholders) about the impact of farming practices on wildflower populations was explored. Secondly, a vegetation survey aimed to assess the impact of farming practices on various structural (regeneration mode and growth form) and compositional attributes (plant family, dominant and rare species) of fynbos.Results from the questionnaire indicate that the application of farming methods are seasonally restricted, often used in varying combinations and relatively small in spatial extent. Furthermore, results show that wildflower farmers have an ecologically acceptable knowledge base and awareness of fynbos management and conservation. Secondly results, obtained from the vegetation survey, imply that natural vegetation subjected to particular farming practices differ from pristine fynbos vegetation by having both altered structural and compositional attributes. However, the impact of farming practices on rare species was less apparent.The conflict between commercial and conservation objectives are apparent from consultation with landholders. Nonetheless, landholders are optimistic about fynbos conservation and conservation can build upon these positive sentiments. Importantly, there is a need to communicate locally with landholders if a sustainable wildflower industry is a priority to stakeholders on the Agulhas Plain. Furthermore, fynbos ecosystems naturally entail complex ecological interactions. Wildflower farming practices reduce the ecological integrity (i.e. altered plant diversity, growth form and plant composition) of wildflower vegetation, at least at the local scale. These farming practices ultimately result both in distorted competitive interactions and disturbance regimes. Therefore, from a conservation perspective, the implementation of these farming practices (ploughing and broadcast sowing) should be cautioned against.

[发布机构] Stellenbosch University