Biodiversity is not distributed evenly on the planet. The best areas for biodiversity conservation for Protected and Conserved Areas (PCAs) must be prioritised to be effective and efficient.
Representation is a useful concept in selecting PCAs. Representation means including viable populations of the full variety of biodiversity of different biological realms (freshwater, marine and terrestrial through all the ecoregions) and biological scales (ecosystems, species and within-species variation) within a system of PCAs. Identifying areas of particular importance for biodiversity can be considered at different scales – from Global Biodiversity Hotspots to Key Biodiversity Areas to regional, national or subnational identification systems.
Although national-level planning is essential, it is also important to develop this in the context of the global significance of a species’ population at a site, to avoid spending effort conserving globally abundant species that may be rare in a particular country because they are at the edge of their range. Conservation biologists also advise building some functional redundancy into the PCA system to ensure that omissions are minimized and there is some insurance against loss of critical sites. In some cases, locally rare species common elsewhere may have cultural or spiritual significance that means they also deserve special attention.
Why 30% might not be enough and what that means right now
Given the current bias in the type of ecosystem represented in protected areas, achieving representation by any measure (ecoregions, bioregions, ecosystems or species) will require more than 30% area-based conservation. This is true for biodiversity and ecosystem services conservation as a whole: analysis suggests that almost 80% of remaining natural vegetation is needed to meet the full range of issues identified in four United Nations’ resolutions (UNCCD, UNFCCC, CBD and the Sustainable Development Goals).
This means that PCA efforts, which may expand in future with a larger target, need to focus on the most urgent needs now. It is also important to understand what can effectively be conserved in the wider landscape and seascape; this is context-specific and depends largely on the extent to which area-based conservation is integrated into the rest of the landscape and seascape.