On the 29th of January a groundbreaking scientific study was published by Nature, giving insight into global genetic diversity trends over a 34-year period. The results are an intricate, instructive guide on the human disturbances causing the most harm, as well as the conservation interventions proving most effective.
By applying a landmark meta-analysis methodology, the article reviewed genetic data from 141 countries and 628 plants, animal, fungi and chromista species. Led by an international team of researchers, the study filtered through over 80 000 scientific papers, sourcing data from 882 relevant articles.
While the study doesn’t shy away from the reality of unprecedented global genetic diversity loss, it also shines an empowering and proactive light on conservation solutions. Namely, the article suggests 5 conservation management strategies that have shown hopeful trends in slowing, stabilising or reversing genetic diversity decline. Considering the massive breadth of the meta-analysis, this information is extremely valuable.
So what is genetic diversity, and why should we give a toss?
Genetic diversity relates to the variety (or diversity) of different gene pools within a species population (IFAD). Genes are segments of DNA that are inherited from parent to child, and code for an individual's unique physical features and functioning (MedlinePlus). Importantly, the more diverse a populations gene pool, the more resilient that population will be to threats such as disease, invasive species and climate change (Australian Geographic). This is because populations with the same gene codes share the same genetic vulnerabilities, reducing the population's ability to adapt to environmental changes. Generally, the smaller a population is, the lower the genetic diversity, and the greater the risk of extinction by any one hazardous event. In a nutshell, without robust genetic diversity, species are less able to adapt to environmental changes and are at a far higher risk of extinction.
What’s the difference between Genetic Diversity and Biodiversity?
Genetic diversity and biodiversity are different but interrelated terms, with genetic diversity being imperative for overall biodiversity. According to the Convention of Biological Diversity, biodiversity relates to “the variety of life on our planet” and involves three main components:
- genetic diversity (the variations of species genes in a given population).
- ecosystem diversity (the variety of habitats in a given area)
- species diversity (the variety of species in a given area)
By this definition “biodiversity” can be seen as an umbrella term, with ecosystem, species and genetic diversity collectively contributing to the overall biodiversity of an ecosystem.
5 Standout Strategies in Improving Genetic Diversity:
- Supplementation (adding individuals)
Supplementation involves adding individuals to an existing population. By physically introducing new genes/ individuals to a group, supplementation can prevent inbreeding and it’s narrowing effects on gene pools. It is regarded by the study as the most empirically successful action, being the sole “statistically significant moderator of genetic diversity loss” out of all mentioned conservation interventions. These results were particularly prominent for bird species.
One success story can be found in a supplementation programme for the critically endangered Woylie (Bettongia penicillata ogilbyi), where genetic diversity markers returned “significantly higher following supplementation”.
- Population Control (removing individuals)
As a genetic diversity conservation strategy population control involves removing individuals from a given population to prevent inbreeding and domination by any one genetic lineage. [EW1]
- Restoration (rehabilitating natural areas)
Habitat restoration is another population-level conservation strategy, involving restoring or rehabilitating natural areas. Improving the quality of the natural environment ensures species have a larger quantity of suitable habitat, with positive implications for population size. This is significant for genetic diversity as larger populations generally support higher levels of genetic variation and gene flow.
The genetic impacts of restoration efforts can be seen in the Huron-Erie corridor (HEC) fish habitat restoration project. By constructing several artificial reef habitats, this project has helped stabilise the genetic diversity of Lake Sturgeon (Acipenser fulvescens) populations in the area.
- Feral and pest control
By controlling populations of feral and over-dominant species, competition and excessive predation can be reduced. This supports population growth for the vulnerable species being targeted and thus potentially improves their genetic diversity outcomes.
This strategy was used in a 2018 study in Sweden, where over-dominant Red Fox (Vulpes vulpes) populations were successfully controlled as part of an Arctic Fox (Vulpes lagopus) "genetic rescue” strategy.
- Conservation Introductions + Reintroductions
Conservation introductions involve establishing new populations at new sites – or, in the case of re-introductions, at sites where a population previously existed. As a strategy conservation introductions are logistically complex, requiring that any introduced population has a large gene pool to begin with.
While conservation introductions have had mixed results, genetic diversity has been successfully supported in cases such as the reintroduction of the golden bandicoot (Isoodon auratus) to 3 new WA locations.
How can we apply this knowledge?
Armed with the knowledge of declining genetic diversity, coupled with an understanding of actionable solutions, we’re able to make real change.
By planting native pollinator habitat, the B&B Highway is able to grow pollinator populations and thereby support the genetic diversity of these species. As it stands PlantingSeeds has increased biodiversity at our participating sites by 10%, through revegetating over 5506 square metres and counting! With 200 school B&B Highway locations so far, we’re helping to rehabilitate key corridors of pollinator migration.
By rehabilitating urban habitat with endemic plants, native stingless beehives, insect hotels and nesting boxes, we can help boost habitat connectivity and breeding between different sub-populations – a phenomenon known as “gene flow”. Clearly, there is massive genetic diversity potential that can be found in our own backyards, school yards and gardens.
While the latest genetic diversity report is alarming, it’s also empowering – we know what works and through actions like the B&B highway, we can chip away at change.
Article by Emma Whitmore