Land Deal

Cheaper can be better when it comes to conservation. That’s the message from a new study that examines the most cost-effective way to protect 10% of Argentina’s vast grassland ecosystem. The approach suggests that putting a premium on saving the most biologically-important lands may not always be the most realistic approach.

Global conservation groups often argue for reaching a goal of protecting at least 10% of threatened ecosystems, such as rainforests, within a nation or region. The most cost-effective way to reach that goal, however, is often unclear. Temperate grasslands, for instance, are one of the most unprotected habitats on Earth, with just 5% covered by parks or reserves. In Argentina, which has essentially all of South America’s grasslands, they once covered some 160 million hectares, but that’s now dwindled to 110 million. And less than 0.5% of that is protected. To see what it would take to boost that number to 10%, a research team took a close look at what it would cost to set aside one-tenth of the original habitat, or about 15.5 million hectares.

The researchers used biodiversity and land price data to compare three strategies: protecting the cheapest land (“minimize cost”); maximizing conservation benefit regardless of cost (“maximize benefit”); and maximizing conservation benefit per dollar (“return on investment”, or ROI). To run their study, which appears in the Proceedings of the National Academy of Sciences, they divided Argentina’s remaining grasslands into 53,000 parcels, evaluated the conservation value and risk faced by each parcel, and then estimated land prices, which ranged from $10 to nearly $40,000 per hectare.

Overall, they found that the costs of the different strategies varied dramatically, as did the resulting geographic distribution of protected land. The “maximize benefit” approach to protecting the best 10%, for instance, cost $18.7 billion and spread slivers of protected lands over a wide area. In contrast, the ROI approach cost $350 million, and the “minimize cost” strategy just $150 million. But you got what you paid for: spending less tended to clump protected lands, include fewer rare or at-risk ecosystems. Indeed, the cheapest option “yields a very poor conservation outcome,” the authors concluded.

The ROI approach, however, showed promise for stretching dollars – especially when budgets were limited. For instance, when the researchers capped total land-buying budgets at $100 million or $500 million over ten years, the ROI strategy protected “more, and typically many more, high-risk, rare, and total ecosystems than the two other strategies.” Although ROI cost twice as much as just buying the cheapest land, it achieved six times the conservation benefit. In contrast, ROI costs just 1/50th of the most expensive approach, but still delivers about half of the conservation benefit. The practical lesson, the authors write, is that the “ROI approach can yield enormous gains in conservation efficiency, which is of great importance in a world with limited resources devoted to conservation.”David Malakoff | November 23, 2010

Source: Murdoch, W., Ranganathan, J., Polasky, S., & Regetz, J. (2010). Inaugural Article: Using return on investment to maximize conservation effectiveness in Argentine grasslands. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1011851107

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