How butterflies benefit from coffee corridors

Published: 15 March 2017 at 15:28

Forest in Arba Minch, Ethiopia

Research led by Anglia Ruskin academic shows impact of deforestation in Ethiopia

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New research shows that coffee and timber plantations are providing a safety net for butterfly species in Ethiopia, as the country’s tropical forests are being destroyed at an alarming rate.

The research, carried out by academics from Anglia Ruskin University, the University of York and Jimma University in Ethiopia, has been published in Biotropica, the journal of the Association for Tropical Biology and Conservation.

Unlike in the UK where butterflies are associated with open habitats such as meadows and pasture, tropical butterflies have a much higher dependence on trees. Ethiopia has 376 species of tropical butterfly, many of which are endemic to the country.

Over a quarter of Ethiopia’s mountain forest has been lost since the turn of the millennium, with agriculture and logging the main driving forces. This new study is one of the first to look at how wildlife is faring across these human-altered landscapes in Ethiopia.

The research found that butterfly communities in coffee and timber plantations were dominated by forest species, sharing 90% of their species with the natural forest. On average, there were 14 different species recorded per hectare in the forest compared to 10 in the coffee and timber plantations. This figure fell to three species per hectare in cropland.

The average total number of butterflies recorded per hectare in cropland was only six, compared to 35 in timber plantations, 37 in natural forests and 41 in coffee plantations.

Dr Olivia Norfolk, Lecturer in Animal & Environmental Biology at Anglia Ruskin University, said:

“Ethiopia may conjure up images of barren savannah, but in reality much of the country consists of green highlands that were once dominated by tropical forest.

“Ethiopian highlands are renowned for the production of coffee, which was traditionally harvested directly from the forests and is now cultivated in semi-managed coffee forests that retain a thinned canopy. More recently the region has experienced an expansion of timber plantations and intensive agricultural practices such as croplands and pasture.

“Our study shows that tropical butterflies are strongly influenced by agriculture; they exhibit extreme declines when forest is converted into cropland and pasture, but are retained in relatively high numbers in coffee forests and timber plantations.

“These wooded agricultural areas are used by a high diversity of forest butterflies, but butterfly numbers decline with distance from natural forest, suggesting that agricultural land cannot support stable populations without the continued presence of forest.

“Planting trees in agricultural landscapes and encouraging wooded agriculture such as coffee forests may help to soften the impact and act as a corridor to allow movement of butterflies between isolated forest patches. However, protecting the remaining natural forest is essential for conserving Ethiopia’s diverse community of colourful butterflies.”