It is important to protect biodiversity in regions such as East Africa, where many of
the poor rely on ecosystems for food and water, scientists stress.
An international team has identified which of the world's watersheds are priorities for protecting both nature's services and biodiveristy.
"The services we examined included providing water for drinking and agriculture and minimising the effects of flooding," said Associate Professor Gary Luck, an ecological researcher with the Charles Sturt University (CSU), Australia. He had worked with colleagues from the University of British Columbia in Canada and Duke University in the study.
"We found that these services were most needed in watersheds found in the world's poorest and most densely populated regions. Some of these regions are also 'rich' in biodiversity and we identified Southeast Asia and East Africa as regions with the highest priorities for protecting nature's services and biodiversity.
"Our research showed that a dollar spent protecting nature's services in many developing countries would have a greater relative benefit to humans than spending the same amount in developed countries such as Australia and the USA.
"People living in developing countries rely heavily on the services provided by local forests, wetlands and other ecosystems. In developing countries, land is relatively cheap to acquire for conservation and restoration and labour costs are lower than developed countries. Many of these areas are also under greater threat from land clearing, undermining the capacity of nature to provide services.
"Developing countries also often can't afford the alternatives to nature's services. For example, building water filtration plants, de-salinisation plants and levee banks can be too expensive in developed counties, so they must rely on these services from natural ecosystems.
"Many ecosystems in developing countries are also rich in species, so there is great opportunity to promote both biodiversity conservation and human wellbeing by protecting these ecosystems."
Professor Luck argues that focussing on the human need for nature's services, combined with knowledge of the world's most important biological regions, is a way of combining human development and conservation goals.
Published in the latest issue of the international journal Conservation Letters
, the research has implications for the employment of conservation and human development projects worldwide and for guiding investment decisions by global institutions such as the World Bank and World Wide Fund for Nature.
"Despite the accelerating loss of biodiversity worldwide, conservation is not a primary concern for many national or international development programs. By emphasising the human need for services that are underpinned by biodiveristy, we hope to encourage a greater conservation focus in future development projects."