IUCN Green Status of Species

The creation of the Green Status system began with the formal call of the World Conservation Congress (WCC) in 2012 for the creation of "Green Lists" for ecosystems, protected areas and species based on a set of measurement systems for conservation success. In Resolution 41, the WCC noted that merely preventing extinction of species or loss of ecosystems, the goal of the Red Lists, was insufficient to retain biodiversity, preserve the valuable ecological services provided by ecosystems and species and maintain their resilience in the face of threats like those posed by climate change. Ultimately, the Green List of Species was developed separately from what became the IUCN Green List of Protected and Conserved Areas. In 2020, the IUCN decided to rename the Green List of Species the IUCN Green Status of Species due to methodological differences between it and the Green List of Protected and Conserved Areas and concern that having a species receive a Green "listing" might be perceived as implying that it is not at risk of extinction. The Green Status complements the Red List assessment but does not replace it: both assessments are performed by the IUCN for a given species and, with the exception of species extinct in the wild that would require reintroduction as a conservation measure and whose current Green Score is by definition 0%, one status does not determine the other. Pilot program As of April 2020, preliminary ==Assessment==

The score (Green Score) is an average of spatial units currently occupied or occupied in the past by a species weighted by their status. Spatial units are discrete segments of the species population, and all spatial units together define the species' indigenous range: the distrubution of the species prior to major human impacts on its abundance or distribution Spatial units can represent reproductively isolated populations or subspecies, areas where the species faces a unique threat, division by ecosystem types the species inhabits or may be based on geographical features with some barrier to dispersal. The definition and number of spatial units chosen by the assessor directly influences the Green Score and conservation metrics that are obtained. A Green Score of 100% is defined for a fully recovered or non-depleted species that is present in all parts of its indigenous range (prior to any major human disturbance), each with viable populations that are ecologically functional, a score that may not be realistically attainable for many species even if they achieve their Recovery Potential. Conservation metrics A Green Status assessment also includes four conservation metrics that represent predicted changes in Green Score in different conservation scenarios over periods of time. They can be used to help assess the effectiveness of past, current and future conservation measures. The first metric is Conservation Legacy, which measures the difference in estimated Green Score that would be expected at the time of assessment (the present) if no conservation actions had been undertaken (counterfactual scenario) to the actual Green Score at the time of assessment. If no past conservation actions had occurred, the Conservation Legacy would be 0%. Conservation Dependence, the second metric, assesses the change in Green Scores between the present and the short-term future, defined as three generations of the species or 10 years, whichever is longer, if no conservation actions are undertaken over that time and all current programs are immediately stopped. Conservation Gain, the third metric, is the change in Green Scores between the present and short-term future with current and planned conservation action. Finally, Recovery Potential is the change in Green Score between the present and the long-term future, defined as 100 years after present, in an optimal conservation scenario. The metrics can have zero and negative values. In the case of the Conservation Dependence and Conservation Gain metrics, values less than zero may be attributable to reliance on a static Green Score baseline that does not indicate whether the species is projected to decline or recover if threats to a species change in the short term. Version 2.0 of the Green Status of Species assessment introduced a dynamic current baseline that can be employed for the calculation of Conservation Dependence and Gain, using the predicted Green Score at 10 years given current conservation actions and those that are expected to go into effect within one year of the Green Status assessment. Species Recovery Category Species Recovery Categories are defined based on the Species Recovery Score (the Green Score at the time of the assessment), which is a point estimate (SRSbest), with a corresponding confidence interval (bounded by SRSmax and SRSmin). The Species Recovery Category at the time of the assessment is defined as follows: The conservation impact metrics are also each expressed as point estimates with their own confidence intervals and verbal descriptors. The conservation impact categories—high, medium, low, zero, negative and indeterminate—have criteria based on absolute change in Green Score (magnitude of the conservation metric), change relative to the baseline present-day Green Score or any benefit that prevents extinction, in cases of species with high conservation needs. While the Green Status and the Red List statuses showed a moderate negative correlation among species assessed in a Green Status pilot, with progressively more depleted species being more likely to be threatened with extinction, among conservation metrics, only Recovery Potential showed differences between IUCN Red List categories, with currently imperiled species generally possessing a higher Recovery Potential than the species of Least Concern. ==See also==