Modelling the distribution of Aspalathus linearis (Rooibos tea): implications of climate change for livelihoods dependent on both cultivation and harvesting from the wild

Abstract

Aspalathus linearis (Burm. f.) R. Dahlgren (rooibos) is endemic to the Fynbos Biome of South Africa, which is an internationally recognized biodiversity hot spot. Rooibos is both an invaluable wild resource and commercially cultivated crop in suitable areas. Climate change predictions for the region indicate a significant warming scenario coupled with a decline in winter rainfall. First estimates of possible consequences for biodiversity point to species extinctions of 23% in the long term in the Fynbos Biome. Bioclimatic modelling using the maximum entropy method was used to develop an estimate of the realized niche of wild rooibos and the current geographic distribution of areas suitable for commercially production. The distribution modelling provided a good match to the known distribution and production area of A. linearis. An ensemble of global climate models that assume the A2 emissions scenario of high energy requirements was applied to develop possible scenarios of range/suitability shift under future climate conditions. When these were extrapolated to a future climate (2041–2070) both wild and cultivated tea exhibited substantial range contraction with some range shifts southeastwards and upslope. Most of the areas where range expansion was indicated are located in existing conservation areas or include conservation worthy vegetation. These findings will be critical in directing conservation efforts as well as developing strategies for farmers to cope with and adapt to climate change.

Climatic niche divergence and habitat suitability of eight alien invasive weeds in China under climate change

“…Hence, the AIWs may be closer to equilibrium in the invasive range than in the native range (Callen & Miller, ; Early & Sax, ; Strubbe, Broennimann, Chiron, & Matthysen, ). Niche divergence is strongly related to rapid evolution in the invasive range, disequilibrium in the native range caused by biotic interactions, dispersal barriers, and human activities (Ansong & Pickering, ; Dellinger et al., ; Guo, Lambertini, Li, Meyerson, & Brix, ; Lötter & Maitre, ; Marini et al., ; Martínez‐Cabrera, Schlichting, Silander, & Jones, ; Schmidt & Drake, ). Previous studies have shown that plant species for which dispersal ability is limited in native ranges could occupy wide climatic niche spaces enabled by genetic evolution and human activities (Donoghue & Edwards, ; Dellinger et al., ).…”

“…Lambertini, Li, Meyerson, & Brix, 2013;Lötter & Maitre, 2014;Marini et al, 2012;Martínez-Cabrera, Schlichting, Silander, & Jones, 2012;Schmidt & Drake, 2011). Previous studies have shown that plant species for which dispersal ability is limited in native ranges could occupy wide climatic niche spaces enabled by genetic evolution and human activities (Donoghue & Edwards, 2014;Dellinger et al, 2016).…”

“…Furthermore, the rapid adaptive evolution of the fundamental niches of species may result in climatic niche changes (Prentis et al 2008;Dellinger et al, 2016). Niche divergence often involves a period of introduction by human activity, such as agriculture, transportation, and trade, with some degree of plasticity, allowing for the establishment of individual plants at least temporarily and enabling subsequent evolution (Donoghue & Edwards, 2014;González-Moreno, Diez, Richardson, & Vilà, 2015;Guisan et al, 2014;Lötter & Maitre, 2014;Martínez-Cabrera et al, 2012). For example, A. retroflexus was introduced to China as agricultural feed and expanded via agricultural transportation.…”

Nodes and networks in the governance of ecosystem-based adaptation: the case of the Bergrivier municipality, South Africa

“…Commercial agriculture (particularly potato and rooibos tea farming), alien vegetation infestations, and extensive new housing developments are among the drivers of habitat transformation and biodiversity loss. Climate and impact models suggest that the increase in temperatures and decrease in winter rainfall predicted for could have far-reaching effects on the BM's terrestrial ecosystems, including reductions in water supply, sea level rise, species losses, and wildfire increases (Lötter et al 2014). As the municipality's economy is driven by agriculture and a growing eco-tourism sector, there is concern that climate change will have severe impacts on local livelihoods, compounded by the municipality's low literacy levels (70.5%) and the existence of very few alternative economic opportunities (BRM 2012).…”

Rooibos agro‐processing waste as herbal tea products: optimisation of soluble solids extraction from dust and application to improve sensory profile, colour and flavonoid content of stem infusions

“…Rooibos ( Aspalathus linearis ), an indigenous fynbos shrub of South Africa, is cultivated for the production of rooibos herbal tea, representing 10% of the global tea market . Demand surpasses production, a shortfall aggravated by drought and shrinking production areas as a result of climate change . This compels the industry to consider the potential of rooibos processing waste as a marketable product.…”