Native plants have many advantages over exotic plants including water purification, nutrient cycling, carbon sequestration, pollinator support, soil formation, flood control and climate regulation.
Alien plants tend to take over native plant territory. Species like the floating aquatic water hyacinth can degrade catchment areas and freshwater ecosystems.
Experts have found that outbreaks of zoonotic diseases like Ebola, Swine and Avian Flu as well the Covid-19 pandemic are closely linked with the destruction of our natural habitats.
In a recent article in Deutsche Welle about coronavirus, experts said, “In the last century, tropical forests, home to around two thirds of the world's living organisms, have been halved. This profound loss of habitat has ripple effects throughout the entire ecosystem, including on the parts we tend to forget — infections.”
This destruction has dire consequences. David Quammen, author of Spillover: Animal Infections and the Next Pandemic, says “We cut the trees; we kill the animals or cage them and send them to markets. We disrupt ecosystems, and we shake viruses loose from their natural hosts. When that happens, they need a new host. Often, we are it.”
SAVING THE ECOSYSTEM
In East Africa, the bio-diversity of coastal areas is under threat. In the book A Garden Guide to Native Plants of Coastal East Africa, by Dr Anne H Outwater, Ilana M. Locker and Roy E. Gereau, the authors make an attempt to save the ecosystem, which is among the world’s 36 most ecologically endangered hotspots. The ecosystem stretches from Mozambique, Tanzania, Kenya to Somalia.
“The East African coastal forest mosaic is one of the world’s most biologically diverse areas and is home to a high number of endemic plant and animal species. However 90 per cent of the original vegetation here has been lost, and the destruction continues,” the authors say.
The book has a foreword by Jane Goodall the world renowned primatologist known for her studies of chimpanzees in Tanzania; and another from the former Tanzanian Minister of State January Makamba. In the foreword Makamba says, “Efforts such as this book will go a long way towards educating people about native plants…. Wherever there is room for a plant, it should be native species.”
Native plants have many advantages over exotic plants including water purification, nutrient cycling, carbon sequestration, pollinator support, soil formation, flood control and climate regulation.
Native plants like Phragmites mauritianus (reed grass) can clean sewage water. The authors offer gardening advice that can save water and invite soothing birds to your backyard. So you can repel the noisy foreign crows.
Plants along coastal east Africa include the ashoka tree, the bougainvillea, the allamander, the hibiscus, the melalauca, prickly pear and eucalyptus. Yet these plants aren’t native to East Africa and they do more harm than good.
Alien plants tend to take over native plant territory. Species like the floating aquatic Eichhornia crassipes (water hyacinth) can degrade catchment areas and freshwater ecosystems, negatively affecting the fishing, transport and hydroelectric industries; this prompted the Plant Protection Act (1997) of Tanzania. Other alien plants like the leucena thicket, which livestock mistake for food, is known to poison them.
A Garden Guide says South Africa has done research on the economic loss posed by alien plants, estimated at between $0.9 million and $16.7 million per square kilometre per year.
The practical part of the book has information on how to grow native plants and their benefits. And although the book is written in English, it includes the Swahili names of the plants making it instantly relatable to local landscapers.
The book provides a link to native plants from the region, and highlights 60 that are easily grown in our gardens and public spaces. They include the baobab, desert rose, lucky bean tree, ivy, African blackwood and tamarind.
LOSS OF HABITAT
The history of the degradation of the habitat goes back to colonial times. The gum copal tree used to cover much of Dar es Salaam and Zanzibar until the early 19th century. Then it was unsustainably cut down. Between 100 and 300 tonnes of gum copal were shipped out of Dar es Salaam every year from 1888 to 1907. Export continued through the 1940’s. The tree is now hardly seen in coastal East Africa.
The book goes on to share records of unsustainable lumbering of other native trees in the region by colonialists. Trees like Khaya anthotheca, Miilcia excelsa (mvule) and Afzelia quanzensis (mkongo) helped finance both World War I and II for the British Empire, with exports of up to 2,000 tonnes per annum.
A Garden Guide to Native Plants of Coastal East Africa is published by Dar es Salaam-based Mkuki na Nyota Publishers and can be bought online via www.mkukinanyota.com or Amazon.
