Switch from cotton to livestock threatens key biodiversity area in Zimbabwe

An article by Ryan Truscott ,writer and nature journalist based in southern Africa 

Is cattle-farming in arid landscapes in parts of sub-Saharan Africa really better for biodiversity? The results from a study by a team of international and Zimbabwean researchers suggest the answer’s not that simple.

Small-scale farmers in the Zambezi Valley in northern Zimbabwe have switched in droves from cotton production to cattle, goats and other livestock over the past 13 years, attracted by better prices offered by middlemen from the capital Harare.

The research team revisited more than 140 households in Mbire in 2020 that had previously been surveyed in 2007. The numbers of cattle owned by these households had increased by 361%; numbers of sheep and goats by 405%.

But the effect on ecosystems in the arid, low-lying area of Mbire has been damaging — with a loss in natural vegetation cover doubling from 10% to 20%.

Loss of scrublands

This has serious implications for biodiversity, and Mbire is particularly rich in that. The area is home to more than 40 species of large mammals, 200 species of birds and 700 species of plants.

One of the solutions may be to promote the sustainable growth of cotton and other commodity crops, and to encourage farmers to manage grazing areas sustainably. Subsidies, generated from wildlife, could be used to encourage fodder production and conservation, said Frederic Baudron, a Harare-based agronomist who is also lead author of the study published in the journal Biological Conservation.

At the time of the study only around 6% of farmers were producing their own fodder. Sometimes this is done unsustainably by felling dominant tree species like mubvee (Kigelia africana) and mupumbu (Faidherbia albida) for their leaves during the dry season. And the opening up of land for livestock production has been at the expense of mostly scrub and shrublands, which are important for biodiversity conservation.

Rethinking wildlife revenues

CAMPFIRE, a long-running community-based natural resource management programme, may also need a rethink on how revenues generated from wildlife can influence local farming systems and promote coexistence between humans and wildlife, Baudron said.

Under CAMPFIRE revenue is generated via trophy hunting, though earnings from this dropped from $1.3 million in 2011 to less than half that amount in 2018. The decline in “trophy species” like elephants and buffalo could be partially responsible, the study says. Numbers of elephant, buffalo, impala, kudu, sable, waterback and other species all faced a downward trend during the period under study, though the researchers say they don’t have the data to definitively link this to reduced vegetation cover.

Drought could be one reason for it. Poaching another.

Simplistic narratives

The findings that livestock rather than crops have driven dramatic land cover change in Mbire may come as a surprise to some.  

Commodity crops, cotton included, are generally seen as a threat to biodiversity wherever they’re grown in the tropics. The need for palm oil drives deforestation in Indonesia and Malaysia; soya production drives deforestation in the Amazon.

But as the latest study in Mbire shows, the reality in other regions can be more textured.

“We need to go beyond simplistic narratives, often not driven by data, but by ideology, when it comes to the impact of agri-food systems on biodiversity,” said Baudron.

“We should be careful of simplistic messages of commodity crop production for the global market (as intrinsically bad) versus low input food crop production for local markets (as intrinsically good).”