We are Sean Hoban, Linda Laikre, Cristiano Vernesi, Catherine Grueber, Ancuta Fedorca, Alice Hughes, David O’Brien, Myriam Heuertz, Sibelle Torres Vilaça, Alejandra Lorena Goncalves, Abdeldjalil Aissi, Jess da Silva, and Alicia Mastretta Yanes, and we are posting on behalf of a large group of conservationists, including members of G-BIKE and the Coalition for Conservation Genetics. We write our post about the indicators for conserving genetic diversity within species, including Headline Indicator A.4. This is an update to our previous post above (September 2023).
CONTEXT:
The GBF Goal A and Target 4 is supported by a headline indicator - A.4: Proportion of populations within species with an effective population (Ne) size > 500. An effective size of 500 is important for maintaining genetic diversity “within populations” for the long term. Genetic diversity is essential for species’ populations to adapt to new conditions, climate change, and diseases. For example, genetic diversity has helped seagrass meadows recover after extreme heat waves, and is helping some species adapt in contemporary time, from rhesus macaques to collared flycatchers.
Because Target 4 commits to conserving genetic diversity “within and between populations”, there must be an indicator on between populations genetic diversity. This is the complementary genetic diversity indicator - Proportion of populations maintained within a species. This indicator is important because diversity among populations maintains a diverse range of options across a species' distribution. For example, populations found in parts of a species range that experience a warmer climate may have physical traits adapted to those locations. This kind of genetic diversity can help coral adapt to warmer temperatures, for example.
Since 2020, these indicators have been refined via stakeholder consultation, pilot projects, and scientific progress. A recent paper (open access, free to read) highlights how these indicators can be calculated, even in the absence of genetic data
https://doi.org/10.1111/conl.12953.
WHAT’S NEW:
In 2022-2023 we applied these indicators in nine countries (Australia, Belgium, Colombia, France, Japan, Mexico, South Africa, Sweden, USA), including megadiverse regions from the Global South. The detailed results of this multinational effort are now available in a free to access article:
https://ecoevorxiv.org/repository/view/6104/. It was possible to use existing data and resources within countries to calculate the indicators. In this pilot testing approximately 100 species per country were assessed, totalling >900 species. In less than a year, we assessed around 5,000 populations. Data were obtained from very diverse sources: national inventories, local monitoring, local knowledge, consultation with knowledge holders, citizen science, species management plans, and other sources. A complementary paper explains the advantages of the indicators in more detail
https://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biae006/7625302.
PRELIMINARY RESULTS SUMMARY:
Headline indicator: We found that in 58% of species assessed, all populations were below Ne 500 (too small to retain genetic diversity); indicator value = 0. In 19% of species, all populations were large enough; indicator value = 1. In the remaining species (23%) only some populations were large enough; indicator value between 0 and 1.
Complementary indicator: We also found that most populations were maintained (overall indicator value = 0.90), though 40% of species have lost more than 1 in 10 populations.
These findings highlight that many species are at a critical threshold for maintenance of genetic diversity. Many populations need intervention, management and monitoring to improve their genetic diversity status and allow adaptation in a changing planet. We also note that even some species considered as IUCN Least Concern or Near Threatened can have low genetic diversity indicator values indicating that even if they are not threatened with extinction, they have low or decreasing genetic diversity.
SUMMARY
In summary, genetic diversity indicators are critically important, scientifically sound, affordable, fast, and feasible. The diverse data sources and flexible methodology make them adaptable to each country’s capacity. Genetic data/ expertise are not needed. The publications linked above provide further detail.
A quickstart video on the basics of the indicators is here (scroll down a little on the page):
https://www.coalitionforconservationgenetics.org/sbstta25. On this same page you can find a policy brief in multiple languages
Webinar presenting our results to the European Commission Knowledge Center for Biodiversity:
https://www.youtube.com/watch?v=r8KLqagcwl0We are also here to help! If you are interested in more information on the indicators or would like help to start assessing them in your country please contact us
https://www.coalitionforconservationgenetics.org/resources-database/have-questions-or-need-translations-related-to-cbd-materials Sean Hoban, The Morton Arboretum, USA
Linda Laikre, Stockholm University, Sweden
Cristiano Vernesi, Foundation Edmund Mach, Italy
Catherine Grueber, University of Sydney, Australia
Ancuta Fedorca, National Institute for research and Development in Forestry Marin Dracea, Romania
Alice Hughes, University of Hong Kong, China
David O’Brien, NatureScot, UK
Myriam Heuertz, INRAE (National Research Institute for Agriculture, Food and the Environment), France
Sibelle Torres Vilaça, Vale Institute of Technology, Brazil
Alejandra Lorena Goncalves, Universidad Nacional de Misiones, Argentina
Abdeldjalil Aissi, University of Batna, Algeria
Alicia Mastretta-Yanes, CONABIO, Mexico
Jessica da Silvia, South Africa National Biodiversity Institute
And many members of the Coalition for Conservation Genetics (
https://www.coalitionforconservationgenetics.org/)