CONSERVATION

The Humble Spekboom: Climate Change Saviour or Overrated Fad?

MAY 22, 2020  |  Written by Zoe Poulsen. Photos by Mike Powell and Zoe Poulsen.

Today we are celebrating the International Day of Biological Diversity, as proclaimed by the United Nations. This day aims to raise awareness of the world’s biodiversity and environmental issues. It was first created by the Second Committee of the United Nations General Assembly in late 1993 when the Convention on Biological Diversity first came into effect. This year for the first time the celebration of the International Day of Biological Diversity will be taking place primarily online, with this year’s theme being ‘Our solutions are in nature’. More information about the day can be found here.

The slogan ‘our solutions are in nature’ speaks to the fact that the COVID 19 crisis has called upon people to re-evaluate our relationship with nature, with the acknowledgement that we are completely dependent on healthy ecosystems for our wellbeing. It emphasises the importance of hope, solidarity and working together to build a life that it in harmony with the natural world. In this blog we are going to take a closer look at the spekboom, a South African shrub that has very much been in the spotlight this year.

This rather unassuming South African shrub has hit the news of late. The spekboom bandwagon has rolled into town and everyone is climbing on board, from travel magazines to municipalities, homeowners to game reserves. This shrub is appearing in almost every suburban garden, often jostling for position in the driveway with multiple 4x4s. So what is all the fuss about? Can one shrub save the world? Or is the spekboom trend all a lot of hot air?

So what is spekboom? Let’s take a closer look. Also known as Porkbush, the scientific name of the spekboom is Portulacaria afra. It is an evergreen succulent shrub or small tree that in the wild grows on rocky slopes in bushveld, thicket and Karoo scrub from the Eastern Cape northwards into Kwa-Zulu Natal, Mpumalanga and Limpopo, as well as being found in eSwatini and Mozambique. It is a highly favoured food for game including elephants and domestic livestock. It is edible to humans too, packed with Vitamin C and with a relatively tart flavour. Spekboom can be used in salads, preserves and chutneys and as an ingredient in traditional South African tomato bredie.

As the scale of the climate change crisis has hit home, the world has been looking for solutions. Research has shown that spekboom, as part of its indigenous ecosystems and in the climate to which it is adapted, is a superbly adapted indigenous species that is highly effective at sequestering carbon. When conditions are favourable, spekboom undertakes C3 photosynthesis. During drought conditions it switches to CAM photosynthesis (Crassulean Acid Metabolism), where the plant closes it pores (stoma) during the day to save loss of water.

As the scale of the climate change crisis has hit home, the world has been looking for solutions. Research has shown that spekboom, as part of its indigenous ecosystems and in the climate to which it is adapted, is highly effective at sequestering carbon. When conditions are favourable, spekboom undertakes C3 photosynthesis. During drought conditions it switches to CAM photosynthesis (Crassulean Acid Metabolism), where the plant closes it pores (stoma) during the day to save loss of water.

Despite this, the plant is still able to photosynthesise. This is made possible through the acid that has accumulated during the night which is stored as carbon dioxide. Through these processes spekboom is highly effective at capturing carbon. Spekboom is also highly drought tolerant and easy to propagate, rooting with little effort from cuttings. It has thus been cited by researchers as an important plant for use in carbon sequestering thicket restoration within its natural range.

We spoke to Mike Powell from the Rhodes Restoration Research Group, Department of Environmental Sciences, Rhodes University and he had the following to say:

“Spekboom (aka Portulacaria afra) is indeed a wonder plant, an ecosystem engineer and a significant part of the ecology of the Albany Thicket Biome. It has a pivotal role to play in the carbon sequestration strategies and restoration plans for the semi-arid and xeric thickets in the Eastern Cape and eastern parts of the Western Cape (NB – where thicket used to occur and has been lost due to poor management). Unfortunately the popularisation of spekboom as a symbol of carbon capture in South Africa has led to the false belief that planting this lovely species in your garden or in urban areas will make a significant difference towards mitigation of climate change. This is pure tokenism. Planting the species in natural areas (e.g fynbos) where it never occurred before or planting it in super saturated densities in thicket is a mild form of ecological terrorism..”.

Fast forward in time and much of the popular media have jumped into publicising the story of the spekboom, without letting the facts get in the way of a good story. This shrub has captured the imagination of South Africans, with promises that this ‘wonder plant’ will help save the earth from the climate change crisis. Many false and over-exaggerated claims about spekboom are flying around and being reproduced without fact checks, confusing the green and eco-minded public even further. It has been widely publicised that spekboom is a ‘wonder plant’ because it absorbs carbon dioxide and uses it to produce plant tissue. In fact, this is something that almost all plants on earth do.

Spekboom is making its way en masse into domestic gardens across the country, and even into nature reserves outside its natural range thanks to well-meaning people thinking they are ‘doing the right thing’. This has been further fuelled in 2020 as a result of the launch of the Spekboom Challenge. This social media movement has called upon people to plant ten or more spekboom in 2020 and post to social media about their efforts under the hashtag #SpekboomChallenge. Many organisations and individuals have joined in, thinking they are contributing to addressing the climate crisis.

The reality is that spekboom is not the ‘silver bullet’ it is purported to be for fighting against climate change, particularly when it is planted outside of its natural range. Also it contributes little for wildlife as a part of the indigenous garden when grown outside its natural range due to its intermittent flowering providing little for pollinators. If we really want to save the world from the climate crisis then we need to face some uncomfortable truths: We need to cut back on emissions and conserve those of our natural ecosystems that remain to best ensure their resilience and survival. Even grasslands have been shown to be highly effective carbon sinks. There are no shortcuts or easy fixes here.

We instead encourage you to garden your outdoor space with locally indigenous plants: Many of these are most effective carbon sinks when grown within their natural range. Within urban areas indigenous gardens provide an oasis for wildlife, supporting pollinators such as insects and birds. As diverse a range of plant species as possible offers interest from flowers and foliage throughout the year, providing blooms during differing flowering seasons to the benefit of people and wildlife.

We would like to wish you happy gardening!