Insidious alien species threat to livelihoods, biodiversity

Lazarus Sauti

After habitat destruction, invasive alien plant and animal species are proving to be the biggest threat to biodiversity in Zimbabwe as they are altering intact habitats, placing ecosystems at great risk as well as displacing indigenous species that are beneficial to an environment.

Multiple species of armyworm moths, for instance, are putting down to waste huge areas of farmland across Zimbabwe, threatening livelihoods and food security in the country still wobbling from a ravaging spell of drought.

These moths raze like swarms of locusts, a fact supported by the United Nations Food and Agriculture Organisation (FAO), which reports that the invasion includes both the native African armyworm (Spodoptera exempta), plus the vicious fall armyworm (Spodoptera frugiperda) – alien species that originated in the America’s.

Entomologist, Dr. Godfrey Chikwenhere, says these invasive non-indigenous species can lay six generations of around 50 eggs in a single location, leading to rapid colonisation, as well as destruction of territory.

In Matabeleland South Province, an invading thorn shrub Cactus Rosea (Opuntia Fulgida), which originated from South Africa and was first detected in 2010, is also ravaging the environment, claiming close to 3 000 hectares of land in Gwanda, Matobo, Beitbridge, Bulilima, Insiza and Mangwe.

The shrub, according to the Environmental Management Agency (EMA), is deadly as it reproduces vegetatively and holds back the germination and growth of all native flora under its canopy.

Farmers in Matabeleland and other areas are losing their livestock, thanks to this noxious shrub, further entrenching them into dire poverty.

The impacts of alien invasive species such as the fall armyworm and Cactus Rosea are massive, dangerous and permanent, says researcher, Vengai Badza, adding: “Some of the infamous plant culprits are Lantana camara – a noxious terrestrial weed, and water hyacinth (Eichhornia crassipes) – an aquatic nuisance that blankets water bodies, especially if accompanied by eutrophication.”

EMA adds that the water hyacinth occurs in most parts of the country’s polluted water bodies like Lake Chivero as well as Manyame River in Harare and Shagashe River in Masvingo.

As for Mutare-based ecologist, Sheila Mutize, the proliferation and assault of invasive alien species in the vein of Pinus, Eucalyptus, Acacia and L.camara in the Eastern Highlands of Zimbabwe have killed thousands of trees, especially Eucalyptus trees – famously known as gum trees in the country.

“Eucalyptus and other tree species in Eastern Highlands, as well as some parts of Zimbabwe are in serious trouble, thanks to an onslaught of invasive alien pests first detected in 2015,” she says. “These alien pests affect almost all growth stages of the tree.”

The Zimbabwe Forestry Commission blames climate change for the surge in invasive alien species that are ravaging the country’s immaculate forests and plantations, a fact supported by the Ministry of Environment, Water and Climate, which adds that Zimbabwe has a deforestation rate of 330 000 trees per year.

From 2015, estimates the ministry, at least 43 000 eucalyptus trees and close to 24 000 trees of other species surrendered to invasive forest pests alone.

Fast becoming the new drivers of desertification, says environmentalist, Edson Nyahwa, insidious alien species come in the form of plants, animals and microbes that have been introduced into an area from other parts of the world.

“The spread of these alien species is also strongly linked with human activities such as urbanisation, disintegration of the natural environment and agriculture,” he adds.

Invasive species not only cause environmental damage and crop loses, but also impact schooling as children, especially from poverty-stricken families are forced to help with weeding.

According to the United Kingdom’s Centre for Agriculture and Bioscience International (CABI), rural women and children in most developing states like Zimbabwe spend about 200 hours per year weeding out persistent alien species from family farms.

The economic and social brunts of invasive alien species, notes economist Kudzai Manyanga, are negative impacts on health, over and above decreases in economic production of activities based on biodiversity.

Zimbabwe is not the only country in southern Africa that is battling invasive alien species as Zambia is also vulnerable to invasive pests, according to Moses Mwale of the Zambia Agricultural Research Institute.

Invasions of different alien species have also been reported in Namibia and Malawi, and David Phiri, FAO Subregional Coordinator for Southern Africa, adds that such invasions could potentially have a devastating impact on food security.

Despite their social, economic and environmental impacts, avows Badza, Zimbabwe still lacks information on the presence and distribution of invasive allien species as well as the strategies and policies needed to properly manage this increasingly urgent menace.

“This low public concern about alien plants and animal species is hampering conservation efforts in the country as communities battle the rapid decline of pristine habitats,” he adds.

Consequently, agronomist Rudo Muteeri believes controlling invasive allien species will play a crucial part in protecting the country’s biodiversity, as well as achieving the second Sustainable Development Goal which aims to end hunger, achieve food security and improve nutrition.

“This, therefore, means policy development, capacity building and coordination among researchers, scientists and stakeholders in the environment sectors are needed if the country is to effectively control the threats of invasive alien species and protect the environment,” she adds.

Muteeri also urges the government, scientists and other development partners to invest in research and development programmes that help farmers, especially in remote parts of the country to either defeat or adapt to the presence of invasive allien species.

“In everything, prevention is better than cure; the country, therefore, needs funds for research, development and technology to get the job done properly,” she adds.

Development practitioner, Stancelous Mverechena, adds that there is urgent need to develop bio-security measures to prevent the invasive alien species problem from becoming more serious.

He also urges the country to look for scientific solutions that are environmentally friendly and affordable for poorer communities.

“The private sector, non-governmental organisations, the media and literate farmers should partner the government in developing ‘knowledge banks’ so as to share experiences and research findings,” he adds.

Agriculturalist, Dickson Matenda, believes biological controls can be safe, sustainable and economically feasible options to manage persistent strange species that are destroying the environment and fueling foot shortages in the country.

“Safer pest control is possible,” he says, but its implementation will require political will and support from the donor support.

Matenda also says agriculturalist and entomologists working with invasive species need better training on how to communicate the risks posed by invasive allien species so as to effectively educate the people living with and using alien plants or animals every day.

He also strongly encourages the government to collaborate with researchers and scientists in the country and thrive to meet global targets to invasive alien species, such as the Aichi Biodiversity Target 9, which notes that by 2020, invasive allien species and pathways should be identified, prioritised, controlled or eradicated.