Sustaining ecosystems in the post-2020 world

By Jessica Rowland, IUCN CEM Young Professional.

As we near the end of the Decade on Biodiversity, it’s time to take stock of achievements and shortcomings in conserving biodiversity. What is clear is that significant changes are needed to bend the curve of biodiversity declines. A new set of ambitious targets are necessary to meet the Convention on Biological Diversity (CBD) vision for 2050:

“By 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people.”

The targets for the post-2020 framework of CBD are yet to be finalised, and a science-based target on halting declines and restoring ecosystems is undoubtedly critical to achieving a biodiverse and healthy planet. Healthy ecosystems are vital in supporting biodiversity and human society alike. They provide our supply of food, freshwater and energy, regulate the climate, and have enriched our society and culture for a long time.

What should we be measuring?

Science-based targets require biodiversity indicators to measure progress towards them. Much discussion has surrounded the indicators that should support the post-2020 targets. Mace and colleagues identified three key indicators to capture changes in species biodiversity. These include an indicator of species extinction risk (Red List Index), species population abundance (Living Planet Index) and biotic integrity or ‘health’ (Biodiversity Intactness Index). Ecosystems are complex, so measuring the change in ecosystems is challenging. Yet comparable metrics for ecosystems capturing ecosystem collapse risk, area and health may be a valuable addition.

Fortunately, indicators exist that may fit the bill. The Red List Index of Ecosystems follows the approach used for species to show ecosystem collapse risk. Changes in ecosystem area can be a useful proxy for the carrying capacity, niche diversity and spatial partitioning of resources within an ecosystem to support the native species.Some indicators capturing changes in ecosystem area include the Wetland Extent Trends Index and the Ecosystem Area Index.

Indicators of ecosystem health are a greater challenge — requiring substantial data and a clear link between what the indicator is measuring and the health of the ecosystem. Such indicators may aim to capture the integrity of the ecological community, the degree of environmental degradation or proximity of ecosystems to collapse. Many indicators have been proposed, such as the Biodiversity Intactness Index, Human Footprint Index, Ecosystem Health Index, Forest Integrity Index, amongst others, but these need to be tested to ensure they provide reliable information.

Traits of indicators to support targets

Narrowing down the list to a workable set of indicators that give the essential information is key. Clear criteria to select the indicator ensures that they are fit for purpose. Some basic criteria may include:

  1. Reliability: captures the status of the biodiversity element of interest in a predictable and interpretable way.
  2. Coverage: can be calculated for all ecosystem types.
  3. Data availability: there must be time-series data of ample length and quality to reliably discern temporal trends for the diversity of ecosystems around the world.
  4. Disaggregation: can be calculated for different groupings of ecosystems, including at different spatial scales. For example, indicators may be calculated to reveal global trends, or a national scale to measure changes in ecosystems nationally and thus measure the contribution of individual countries to the global effort.
  5. Direction: can capture both degradation and ecosystem recovery.

Setting targets and selecting suitable indicators goes hand-in-hand. Setting targets can help us define what we care about measuring but knowing what we can measure can allow for targets that we can achieve. Without apt indicators, it is an impossible feat to see whether we are meeting our biodiversity conservation goals. Thinking carefully about the indicators that exist and those that may be required to measure our progress will be vital to support the post-2020 biodiversity agenda.


Ms Jessica Rowland is a Research Assistant with Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, Australia.

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