Valuing The Arc Linking Science With Stakeholders To Sustain Natural Capital

Home Our Work About Us The Eastern Arc Mountains Reports & Publications Project Partners & Links Contact Us

The Challenges...

There is growing global recognition of the importance of protecting ecosystems, not just for the variety of life they contain, but also for the contribution they make to improving or maintaining human well-being through the provision of ecosystem services.

Despite emerging recognition of the enormous benefits people get from wild nature - ranging from food and fibres, to climate stability and clean water - decision-makers continue to behave as if ecosystems have little or no value.

Efforts to reverse losses of wild habitats and wildlife populations by integrating ecosystem services into mainstream decision-making face real challenges: a lack of data at relevant scales; the fact that many beneficiaries (such as downstream water users) live far from the places where services are produced; and the tendency of the market to reward short-term, private gains and so encourage the conversion rather than conservation of remaining natural capital.

Thanks to The Leverhulme Trust, we embarked on a five-year programme to explore fundamental conceptual and empirical challenges for ecosystem service assessment. This work is conducted in collaboration with the Natural Capital Project and the KITE project.


Sunset In The Mountains


Our field research focuses on the Eastern Arc Mountains, Tanzania...

There are few places in the world that are as important as the Eastern Arc Mountains in terms of numbers of unique and endangered species, as well as providing direct human welfare benefits locally, nationally and globally. This is one of the richest areas for biological diversity on the entire planet. Together, 13 disjunct mountain blocks contain around 200 vertebrate species of conservation concern and around 500 plant species found nowhere else.

But the mountains are vital for people too. Collectively, they provide water for farming, hydroelectric power, and almost 3 million domestic water users in Dar es Salaam; fuel, food, medicine, and timber for nearby villagers; and carbon storage and sequestration for the global community.

To date, arguments based on biodiversity alone have failed to halt the conversion of the Eastern Arc to farmland: less than 30% of the original forest cover now remains. We have investigated whether including ecosystem service values can bolster the case for conservation of these important mountains.

Principal Findings

We developed a framework for evaluating ecosystem services that tackles major theoretical and practical concerns, which can be successfully applied even in a developing country context. This framework has since been adopted by the UK National Ecosystem Assessment and the TEEB initiative.

Careful analysis of local data reveals that the forests and woodlands of the Eastern Arc store considerably more carbon than was previously thought, though conversion and degradation are continuing to cause significant CO2 emissions.

The Arc’s remaining forests and woodlands are a substantial source of timber (much of it illegal) as well as charcoal, firewood, building poles and thatch. However harvesting in the lowlands is unsustainable, causing net emissions of carbon and threatening local livelihoods.

International intervention to enhance farm yields and the efficiency of fuel use and thereby lower demand for habitat conversion would reduce carbon emissions at a competitive price.

Our results on carbon storage in the Arc, and how to safeguard it, have helped Tanzania become a pilot country for the major UN REDD programme aimed at reducing emissions from deforestation.


A Baobab Tree

Policy Impacts

Information provided by Valuing the Arc is by far the most extensive evidence-based analysis of the various values of Tanzanian natural capital and how they have changed in land managed in different ways, and hence has considerable credibility with both policy-makers and NGOs.

Our carbon mapping work has provided sustained input to the development of Tanzania’s national REDD strategy. Our early carbon results were used by the Tanzanian Government’s delegation to the 2009 Conference of the Parties to the UN Framework Convention on Climate Change in Copenhagen. Particular use has also been made of our paper on the opportunity and implementation costs of REDD in Tanzania, within Tanzania and within the broader UN-REDD programme globally.

Our work on mapping and valuing charcoal, NTFPs, tourism, timber and water has fed into a series of exercises aimed at understanding the impact of Tanzania’s national Forest Policy and Water Policy, and their associated Acts and Regulations.

This in turn led to information from Valuing the Arc forming the basis of the speech made by the Tanzanian Minister of Environment at the Rio+20 meeting in Rio de Janeiro in June 2012.

That showcasing has allowed WWF-TZ (a partner in Valuing the Arc) to develop its work on the so-called Green Economy, and it is now engaged in discussions with UNEP and various parts of the Tanzanian government to take this agenda forward. Our research outputs are also being used to inform similar discussions in Mozambique, Kenya and Uganda, as these countries start to take seriously the issue of ecosystem services and the contribution of natural capital to national development.


Valuing the Arc has generated more than 60 peer-reviewed publications so far, including one book, one paper each in Nature, Nature Climate Change and Nature Geoscience, and two papers in PNAS. The programme has also led to six PhDs and 8 Masters theses.

Valid HTML 4.01 Transitional

Updated 05/05/13