Evidence-Based Conservation

Historical development

The approach took shape around 2000. In 2004 William Sutherland and colleagues argued that most conservation practice rested on anecdote and habit, not evidence, and they founded the Conservation Evidence project at Cambridge, which summarises interventions that have been tested. Andrew Pullin and Teri Knight adapted the methods of the Cochrane Collaboration in medicine to found the Collaboration for Environmental Evidence (2007) and its systematic reviews.

At the same time, Hugh Possingham, Kerrie Wilson and others developed decision science and return-on-investment methods for deciding where conservation money should go. This led to the “triage” debate: should some species be let go so that the money can save more? The wider “new conservation” that Peter Kareiva and Michelle Marvier argued for around 2012 shared its pragmatism and its focus on results.

Principal claims

• Money and effort for conservation are scarce, so they have to be spent where they achieve the most.
• Many common interventions have never been tested, and some do not work. Practice should follow systematic evidence.
• The proper test of a conservation project is its results for species and ecosystems, measured against what would have happened without it.
• Decisions should state their aims, costs and trade-offs openly, including which species and places come first.
• Ideological commitments, whether to strict protection or to community control, should give way in each case to what the evidence shows.

Policy implications

The approach supports systematic monitoring and evaluation of impact, funding conservation by measured results, and tools that allocate money by expected return. It favours adaptive management that changes course when monitoring shows failure, and it is open to whatever works, from eradicating predators to paying for ecosystem services. It is wary of spending heavily on charismatic species when the same money would save more elsewhere.

Internal disagreements

Practitioners disagree about how far triage should go. Some say openly giving up on some species is honest, and others say it erodes public support for conservation. They disagree about whether outcomes should include human wellbeing, a question that pulls some toward community-based approaches. They also disagree about whether the standards of medical evidence, built for randomised trials, can be met in ecosystems, where controlled experiments are rare.

Criticisms and controversies

Critics from environmental justice and community conservation argue that a focus on total outcomes for nature ignores who pays the costs, and that cost-effectiveness rankings tend to favour cheap land, which is often the land of poor or Indigenous people. Ecocentric critics argue that triage treats species as interchangeable units of value. Others note that what is easy to measure is not always what matters, and that people who already favour an approach use evidence selectively.

Supporters answer that ignoring evidence wastes money that could save species, and that being open about trade-offs is fairer than hiding them.

Relationships to other traditions

Evidence-based conservation shares environmental pragmatism’s case-by-case method and gives it a quantitative, scientific form. Its use of cost-effectiveness and payment for results links it to market environmentalism and to the environmental economics that market approaches draw on. It underpins much of restoration-centred conservation and ecological engineering. It is in direct tension with environmental justice and rights-based conservation over whether outcomes for nature can be weighed separately from fairness to people.