- 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 journal 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 the 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."
During the study, the team conducted 150 counts each at both natural habitat and mango orchard locations and measured aspects of habitat structure. Across all 300 survey points, a total of 14,278 birds representing 151 species were recorded. The results indicate that the lack of low level woody scrub in the mango orchards could account for the absence of some 26 insectivorous and nectarivorous species.
The diversity and abundance of bird species were both greater in natural habitats than in mango orchards, and whilst approximately a third of species recorded in the natural sites were unique to this habitat, there were no species unique to mango orchards.
Study author Yvette Ehlers Smith of the University of Exeter and The University of KwaZulu-Natal in South Africa added: "Our findings suggest that knowledge of habitat structure, along with species' life history traits can provide a predictive framework for effects that anthropogenic habitats may have on regional biodiversity, and allow management to reduce negative effects."
"The consequences of farmland management will have critical effects on conservation planning for biodiversity, as well as implications for food security. We recommend the inclusion of patches of natural vegetation, for example hedgerows, surrounding and within agricultural landscapes to increase habitat diversity and maintain natural levels of species richness."
'Response of avian diversity to habitat modification can be predicted from life-history traits and ecological attributes' by Yvette C. Ehlers Smith, David A. Ehlers Smith, Colleen L. Seymour, Elisa Thébault and F. J. Frank van Veen is published in the journal Landscape Ecology.
A copy of the paper can be found at: http://link.
About the University of Exeter
The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 10th in The Complete University Guide and 9th in the Guardian University Guide 2015. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was The Sunday Times University of the Year 2012-13.
The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is jointly owned and managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Marine Biology, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.
The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres - the Forum in Exeter and The Exchange at Penryn - together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for another £330 million of investment between now and 2016.
About the University of Exeter's Centre for Ecology and Conservation (CEC)
Staff at the Centre for Ecology and Conservation, based on the Penryn Campus, undertake cutting-edge research that focusses on whole organism biology. The CEC has three interlinked research groups: Behaviour, Ecology and Conservation, and Evolution which constitute 40 academics and over 100 early career researchers. It engages widely with businesses, charities and government agencies and organisations in Cornwall, the Isles of Scilly and beyond to translate its research into societal impact. Staff at the CEC deliver educational programs to some 500 undergraduate and 100 postgraduate students.
A new £5.5 million Science and Engineering Research Support Facility (SERSF) is currently under construction at the Penryn Campus. The facility will bring pioneering business, science and engineering together and will provide space for the growing CEC alongside the University of Exeter Business School, which is expanding into Cornwall, and the University's Marine Renewables team.
The University of Exeter and Falmouth University are founding partners in the Combined Universities in Cornwall (CUC), a unique collaboration between six universities and colleges to promote regional economic regeneration through Higher Education, funded mainly by the European Union (Objective One and Convergence), the South West Regional Development Agency and the Higher Education Funding Council for England, with support from Cornwall Council.