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Tim Pearce visits his favourite place in Kenya and finds out that plant life needs help

Tim Pearce is a regional co-ordinator at Kew’s Millennium Seed Bank partnership. Tim reflects on his most recent seed collecting trip to Kenya and talks about his concern for the unique plant life in the region.

View of Kenya: The Aberdare Mountains (Image: Tim Pearce, Kew MSBP)

My first ever trip to East Africa was as an Aberdeen University Botany student sharing three months in the modest "Fisherman's Camp" with four other botanists high in the Aberdare Mountains.

This was my first introduction to the bizarre Afro-alpine vegetation. The lower forests of Podocarpus and Juniperus, their branches dripping with the beard-like Usnea lichen eventually merging with hillsides of the thick mid altitude Mountain Bamboo (Arundinaria alpina), the floor of its galleries festooned with violets and balsams. Everywhere the tell tale signs of elephants and buffalo. 

Giant Lobelias
  • This plant is only found on the Aberdare ranges of Kenya
  • This plant has evolved to withstand extremely hot days and freezing nights by holding an "anti-freeze" liquid at the sensitive base of it's leaves
  • Like many alpine plant species, survival of the giant Lobelias of East Africa are under threat from global warming


Climbing the Aberdare Mountains

There is a special moment as you make your way out of the bamboo zone and follow the track up onto the rolling mid altitude heathland. Nothing like the heathlands of North East Scotland which was my University classroom; this is the home of forests of tree heather (Erica arborea), hillsides of centuries-old grass and sedge tussocks mixed with blood red Gladiolus watsonioides and a close relative of the Red Hot Poker, Kniphophia thomsonii.

Climbing still, you pass through the elphin-like forests of East African rosewood (Hagenia abyssinica) before you reach the true Afro-alpine zone with the giant Groundsel (Dendrosenecio battiscombei) and some equally impressive giant Lobelia (Lobelia deckenii ssp. sattimae) found only in the Aberdare Mountain ranges. Jomo Kenyatta International Airport is 4hrs away.

Whilst I have been back many times over the years to this, my favourite haunt in Kenya, a recent visit with my colleagues of many years from the East African Herbarium, partners in the Millennium Seed Bank was a special one. We were accompanied by a freelance journalist from the British Airways High Life magazine giving me an opportunity to enthuse about this place and its plants. Collecting seeds from a wild relative of the Aubergine (Solanum sp.), so new that it does not yet have a name but of great potential value economically, and the giant Groundsel (Dendrosenecio battiscombei), it's very survival at high altitudes threatened from our changing climate.

The “Fisherman’s Camp” cabin is still there though it’s now the “Fishing Lodge”, refurbished to a high degree and a much more effective money spinner for the Kenya Wildlife Service. What didn’t seem to have changed was the truly spectacular vegetation. No obvious signs of man-made habitat loss or degradation on the drive across the lowlands and rich agricultural areas around Nairobi.  

New threats from a changing climate

This apparently untouched ecosystem however is at the mercy of changing climate patterns. As the name suggests, the Afro-alpine environment is found only in Africa at altitude. That means from the mountains of Malawi in the South, the Virunga volcanoes of Rwanda and Burundi to the West and up through the high mountains of Kenya, Tanzania and Uganda to the high plateaus of Ethiopia. Whilst the Aberdare Mountains do not have permanent glaciers, Mount Kenya and Kilimanjaro in Tanzania certainly do. Or they certainly used to. Although I didn’t see any discernable changes in vegetation cover since my first visit 15 years earlier, this is not easily measured. Real changes in the size of mountain glaciers can be seen from space. In fact they can be seen by every visitor taking the day flights into East Africa or indeed from my hotel window in Nyeri. 

Working together to save plant life in Kenya

Teams of Kenyan and Kew botanists are now playing their part in a series of globally coordinated monitoring of vegetation change on high mountains.

Kew's Tim Pearce with giant groundsel (Dendrosenecio battiscombei)

What is clear is that the survival of species in these unique habitats is under threat. Just like the glaciers, the populations of giant groundsels and lobelias are retreating up the mountains, soon there will be nowhere left to go. 

We found the new species of Solanum with literally thousands of fruits, all unripe. An all too common result for seed collectors. All we could do was marvel at how many people must have driven past this rather common roadside shrub. A relative of the domestic Aubergine and Potato, completely new to science. 

It was particularly exciting when through the binoculars we were able to spot a distant forest of our target species of Dendrosenecio battiscombei, with many seeding and some flowering specimens; a seed collectors dream!

A brisk 45min walk across the grass tussocks, and a brief hailstorm later we were finally amongst giants. As our accompanying journalist snapped away with his camera, Patrick, Paul and myself, like boys in a sweet shop. We enthusiastically bagged tens of thousands of seed. 

How the Millennium Seed Bank is making a difference

As a result of our seed collecting trip, this botanical icon will not go extinct. But in reality, our work has only bought it some time. The processed seed collection will remain alive, at -20º in the National Genebank of Kenya and in Kew’s Millennium Seed Bank at Wakehurst Place, West Sussex, ready to repair and restore this unique natural system.

As I reminded our visitor, we seed collectors have the technical skill and know how to prevent almost any species of seed plant on the planet from going extinct. But with our unpredictable and changing climate, the next challenge we face is much larger. We need to find suitable habitats in which to put these plants back so they can flourish again. 

Help Kew save plant life for our future - save a plant species outright or adopt a seed for just £25

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7 August 2011
Fascinating: I googled 'Usnea' and was taken on a Kenyan field trip. Hope we can rise to the challenge of climate change. The changing landscape is blantantly evident here in Borneo too.
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6 December 2009
this is great!! Love your work, thanks for introducing me to these plants
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