Satellite imagery paints picture of New Britain’s disappearing forest birds
Analyses of satellite images have revealed for the first time the extent of deforestation occurring on the island of New Britain, Papua New Guinea, indicating that many more bird species are threatened with extinction than previously feared.
An eighth of lowland forest on the island –a stronghold for a number of birds found nowhere else on Earth- disappeared between 1989 and 2000, largely driven by a rapid and uncontrolled expansion in global demand for palm oil.
The findings, published in the journal Biological Conservation mean that the total number of threatened or ‘near threatened’ birds on the island will almost double to 21.
Conservationists are now calling for an effective system to adequately protect the crucial lowland forests that remain on New Britain.In the paper, scientists from the RSPB (BirdLife in the UK), BirdLife International, Conservation International, an independent consultancy and Institute of Environment and Sustainability, EC JRC, analysed ‘before-and-after’ high resolution images of New Britain, showing that approximately 12% of forest cover was lost between 1989 and 2000, including over 20% of forest under 100 m altitude, with substantial areas cleared for commercial oil palm plantations.
“Examining the satellite images of New Britain, we were struck immediately by the clear and extensive loss of forest in many parts of the island”, explained Dr Graeme Buchanan of the RSPB and lead author of the paper. “Deforestation was particular severe in the flat coastal lowlands.”
The authors of the paper then overlaid the maps of forest loss with known habitat preferences of New Britain’s birds. These analyses suggested that extensive habitat loss will have forced significant declines for 21 of the island’s bird species, bringing some to the edge of extinction.
“By comparing this information against the altitudinal ranges of each of the birds that live in New Britain, we estimated the potential effects on species – a ‘before and after’ of disappearing habitat, and of disappearing populations”, said Buchanan.
The novel study represents the first time that that the use of satellite imagery (‘remote-sensing’) has been used to determine the likely threat status of a complete set of birds present in a given region or locality.
“The findings show that New Britain’s endemic birds are being driven to extinction by our thirst for palm oil” —Stuart Butchart, BirdLife’s Global Species Programme Coordinator
The technique has potential for use in other places where field-data are lacking in areas that may be too extensive or too difficult to survey on the ground, as is the case on New Britain.
The island of New Britain is a hotbed of rare and unusual bird species, home to 37 endemic (occurring nowhere else on Earth) or ‘restricted-range’ bird species. Species most affected by deforestation on the island are those which cannot tolerate degraded or non-forest habitats, and that only occur in the lowlands.
The paper reports that hardest hit is the strikingly iridescent Bismarck Kingfisher Alcedo websteri –a specialist of lowland forest streams- which lost a fifth of its habitat during the ten year period.
Other birds to suffer include the Green-fronted Hanging-parrot Loriculus tener, which lost 18% of its habitat in the same period.
Southeast Asia’s largely unregulated and expanding palm oil industry –fuelled by increasing global demand- is highlighted as the main factor behind the extensive lowland forest loss on New Britain.
“The findings show that New Britain’s endemic birds are being driven to extinction by our thirst for palm oil, which is widely used in foodstuffs and industry.” said Dr Stuart Butchart, BirdLife’s Global Species Programme Coordinator and co-author of the paper. “After wiping out the lowland forests of Malaysia and Indonesia, companies are now moving eastwards, to New Guinea and Melanesia, where they now threaten a whole new suite of species”.
Based on further analysis of the satellite images, an estimated 320 km2 (11%) of the land cleared had already been converted to plantation, mainly for palm oil. Much of the remainder is likely to be planted up in the next few years: “it is likely that oil palm plantations will continue to increase rapidly: by 2001, oil palm estates at just two sites totalled c.295 km2 with one company planning to expand its plantations on New Britain to 800 km2 by 2014.” the authors assert.
The paper recommends potential areas to designate as protected areas, concluding “there is clearly a pressing need to survey these areas to confirm that they are refuges for New Britain’s endemic fauna, and to ensure their immediate and effective protection.”
Buchanan, GM, Butchart, SHM, Dutson, G, Pilgrim, JD, Steininger, MK, Bishop, KD, Mayaux, P 2008 Biological Conservation 141: 56-66