Scientists warn of species loss due to man-made landscapes

  • Study found 35% fewer bird species in agricultural habitats
  • Researchers say farmland is a poor substitute for natural areas but simple improvements could make a difference to biodiversity conservation

Research led by the University of Exeter has found a substantial reduction in bird species living in cultivated mango orchards compared to natural habitats in Southern Africa. The results, which are published today in the journalĀ Landscape Ecology, highlight the value of assessing habitats prior to land use change to predict the impact of agriculture on biodiversity.

The researchers monitored bird populations across cultivated mango orchards and natural habitats in theĀ Kruger to Canyons Biosphere region in South Africa. They found that replacing a natural habitat with an agricultural landscape can result in a substantial decline in the richness of species living within the region.

The scientists were aiming to ascertain whether agriculture could add novel habitat elements and thereby support additional bird species complementary to those already present in the natural areas – but found that in contrast, there was a loss of 35% of the bird species within the farmed land.

One of the study’s authors, Dr Frank Van Veen of the Centre for Ecology and Conservation at the University of Exeter, said: “Mango orchards are missing the low level woody scrub found in natural vegetation and the birds missing from the orchards are exactly those that have a life-style that depends on this layer of vegetation. These results show that simply measuring the vertical vegetation structure can help to predict negative effects of agriculture on biodiversity and suggest ways to mitigate these.”

“This loss of richness has implications for the preservation and provision of the ecosystem, in particular pest control, seed dispersal and pollination. It is thus crucial for policy makers in countries such as South Africa, where natural habitats remain the predominant landscape features, to identify management strategies that provide the best balance between crop productivity and biodiversity conservation in the context of sustainable agriculture.”

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