Paper authors: Watermeyer, K. E., Guillera‐Arroita, G., Bal, P., Burgass, M. J., Bland, L. M., Collen, B., Hallam, C., Kelly, L. T., McCarthy, M. A., Regan, T. J., Stevenson, S., Wintle, B & Nicholson E

Blog author: Kate Watermeyer

Citation: Watermeyer, K. E., Guillera‐Arroita, G., Bal, P., Burgass, M. J., Bland, L. M., Collen, B., Hallam, C., Kelly, L. T., McCarthy, M. A., Regan, T. J., Stevenson, S., Wintle, B & Nicholson E. Using decision science to evaluate global biodiversity indices. Conservation Biology.

*****

Simple measures of biodiversity, or indicators, are crucial conservation tools, for example to

• monitor states and trends,
• understand policy impacts, and
• evaluate progress towards conservation targets (like the CBD Aichi Targets or UN SDGs).

Many biodiversity indicators are already widely used. For example the IUCN Red List Index, which measures change in species extinction risk, is a suggested indicator for 12 of the Aichi targets and six of the SDGs.

But to use biodiversity indicators effectively, we really need to understand exactly how they work, and when they might not! Limited time and data mean that often indicators are simply drawn from those available, rather than being purpose-built. But are they fit for the jobs they’re doing?

In our new paper, we used a structured approach based on decision science (see Possingham et al. 2001 for more details, pdf) to evaluate nine commonly used biodiversity indicators against criteria related to: objectives; design; behaviour; incorporation of uncertainty; and constraints (e.g. costs and data availability).

We identified four key gaps:

1. pathways to achieving goals are not always clear or relevant to outcomes decision makers want to achieve;
2. index testing and understanding of expected behaviour is often lacking;
3. uncertainty is seldom acknowledged or accounted for; and
4. costs of implementation seldom considered.

These gaps limit utility of indicators, and are a problem when indicators are linked to conservation policy, biodiversity targets and sustainability goals.

Gaps can be addressed by:

• Making sure that index objectives are clear, and that design is underpinned by a model of relevant processes, would help to address these issues. These are both important steps in developing any new indicators.
• Making it clear how indicators behave (e.g. by performance testing, including impacts of data bias) and what uncertainties are involved.

Indicators with clear objectives, functioning, and limitations can be used with more confidence and deliver more value in guiding policy decision-making and monitoring. This is increasingly important as we rely more and more on biodiversity indicators to support national and global policy decisions, like the post-2020 global biodiversity framework of the Convention on Biological Diversity currently under negotiation.

If you’d like to talk about this work or to get a pdf of the paper, please get in touch!