“By 2050, the abundance of native wild species is increased to ….”. In this third clause, abundance is a measure of population status and is usually expressed as the number of individuals per unit area (e.g. square kilometre). ‘Native wild’ species are specified to make clear that the focus is on species that occur naturally in the wild in the area under consideration, and so excludes alien species and domesticated species. Alien taxa are defined by the Convention as " A species, subspecies or lower taxon, introduced outside its natural past or present distribution; includes any part, gametes, seeds, eggs, or propagules of such species that might survive and subsequently reproduce” (
https://www.cbd.int/invasive/terms.shtml). The inclusion of this element implies that broad-scale policies (for example, addressing habitat loss, restoration, and sustainability of production systems like agriculture, forestry and fisheries) are required to recover population abundance of all species, including those that remain common (but depleted) and widespread.
“… healthy and resilient levels” are not defined in the Framework, but this wording implies that species face no threat of extinction and their abundance is not substantially depleted in comparison with historical levels and is not diminished to a level that reduces their contribution to ecosystem structure and function. For practical purposes, one approach may be to measure the average population abundance of a suite of species compared with a baseline some decades ago. For example, the Living Planet Index has a baseline of 1970 (WWF 2022) and the Wild Bird Index for Europe uses a baseline of 1980 (Gregory and Strien 2010), although it should be noted that considerable biodiversity loss occurred before these dates. It could also be argued that ‘healthy and resilient levels’ imply that species’ populations are healthy throughout their native range and that no populations have been extirpated, which suggests that reintroduction or natural recolonisation would be required to meet this goal. This would be equivalent to a species being at least Viable (the equivalent of either Least Concern or otherwise Near Threatened and not declining), and ideally Functional, in each part of its native range, as defined in the IUCN Green Status of Species, which provides a framework for measuring species recovery (Akçakaya et al. 2018).
Target 4: urgent action for species
The inclusion of this target in the KMGBF demonstrates the value of timely policy-relevant research designed to address specific knowledge gaps. The Zero Draft of the KMGBF (CBD 2020a) was released on 6th January 2020 and contained six Targets to reduce pressures on biodiversity, but contained no target to undertake the management actions that are necessary for some species to recover. In response, Parties and Observers called for this gap to be filled, drawing on evidence provided by a preprint of Bolam et al. (2022
https://www.biorxiv.org/content/10.1101/2020.11.09.374314v1 preprint; not peer-reviewed), who showed that more than a third of species would require targeted recovery measures for their conservation status to improve. Subsequent drafts of the Global Biodiversity Framework included a target for undertaking urgent action. The final text adopted stated:
“Ensure urgent management actions to halt human induced extinction of known threatened species and for the recovery and conservation of species, in particular threatened species, to significantly reduce extinction risk, as well as to maintain and restore the genetic diversity within and between populations of native, wild and domesticated species to maintain their adaptive potential, including through in situ and ex situ conservation and sustainable management practices, and effectively manage human-wildlife interactions to minimize human-wildlife conflict for coexistence.”
There are presently 3,960 species that have threats requiring urgent management actions under Target 4 and that will not be addressed (or not addressed sufficiently) by actions under other Targets, according to the approach outlined in Bolam et al. (2023) (see Supplementary Material 1). The most significant threat that requires focussed recovery action is invasive non-native/alien species and disease, with 2361 species requiring urgent management actions to tackle such alien species and disease under Target 4 (Figure 2, see Supplementary Material). The mitigation of these threats does not guarantee recovery, and other actions, such as management of breeding sites, will be needed to promote an increase in species populations. Focussed recovery actions under Target 4 are also required for species that need particular species recovery actions and for species that have very small population sizes or very small ranges.