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Catedrática @Conacyt_MX - @Conabio. Tweets on Science (evolutionary bias), agricultura, code, ciclismo en la CDMX y feminismo. Dibujo en papel.

Dec 11, 2022, 45 tweets

Yesterday at #COP15montreal we had a side event on #GeneticDiversity and how to monitor it WITHOUT genetic data, so that it can be included it in the goals & targets. People wanted to know more, so here you have a summary THREAD! @GEOBON_org @gbike_cost @CoalitionConGen

First of all, what the hell is #GeneticDiversity? It is the variations within individuals and populations of a species. Or as @LindaLaikre put it: genetic diversity is the toolboox for evolution, adaptation and survival of species.

Loss of #GeneticDiversity can have similar effects as loss of species. Therefore #GeneticDiversity within species is as important as species diversity! --@LindaLaikre

High #GeneticDiversity can allow species to adapt to new changes, including climate change. Example: corals adapting to climate change thanks to genetic diversity, and kelp forests of high genetic diversity being less affected by a heatwave --@LindaLaikre

On the opposite side... low #GeneticDiversity can lead populations to local extinction --@LindaLaikre

So #GeneticDiversity is super important for nature to fight back in this changing, polluted and warmer world of us, but since genetic diversity is difficult to measure, it was historically excluded from the CBD implementation. This is a problem.

That's why @seanmhoban, @LindaLaikre and et al came up with 3 indicators of genetic diversity, that inform us about genetic diversity, but without necessarily requiring genetic data. OMG... HOW?

Instead of focusing on expensive and hard to get data, the indicators of #GeneticDiversity focus on the processes that can result in loss of genetic diversity. SO CLEVER, right?

If we lose a population, we lose the genetically distinct diversity of that population. So our indicator is the proportion of populations that remain / the populations that existed. Our goal: to maintain all genetically distinct populations.

Similarly, if populations are too small, we lose genetic diversity just because randomly only the most abundant variants will tend to pass to the next generation. Small populations tend to have all sort of problems for the same reasons you shouldn't have kids with your cousins.

Mathematically, we now that diversity REALLY drops if the effective population size (Ne) is < 500.

So our indicator is the proportion of populations with Ne > 500, i.e. populations large enough to prevent loss of genetic diversity.

Wait a second! What is this thing of "effective population size" (Ne)??? Worry not, @LindaLaikre explained it very simply...

The effective population size (Ne) is how a population "behaves" genetically. More or less it represents the individuals of a population that actually reproduce and pass their variation to the next generation. For most species, this is around 10% of the census size.

The effective population size (Ne) can be assessed with genetic data, BUT on the absence of it, it can INSTEAD be estimated as 10% of the census size of a population.

The third and last indicator refers to whether populations are being monitored with genetic methods or not, because that way we can see if human induced selection or spread of alien populations or human induced hybridization is happening.

Those are the three #GeneticDiversity indicators proposed by @seanmhoban @LindaLaikre et al

The #GeneticDiversity indicators are SMART, and not only because smart people proposed them ;)

As @seanmhoban next explained in our side event, these indicators are related to Goal A and Target 4 of the post 2020 GBF currently being discussed at #COP15montreal

We will now focus on the first 2 indicators of #GeneticDiversity, because at #COP15montreal we want to show parties that they can assess them for hundreds of species WITHOUT genetic data

The importance of presenting the feasibility the #GeneticDiversity indicators and the scientific rationale behind the them was beautifully summarized by Hesiquio Benitez, chair of SBSTTA

To exemplify that data are available and usable @seanmhoban summarized a Swedish study which found that data is available for THOUSANDS of species! and that genetic indicators make visible genetic loss that would otherwise not be seen

But what about other countries? Well, we are currently assessing the #GeneticDiversity indicators 100 species per country in 9 countries of every continent!

Jessica DaSilva from @SANBI_ZA, South Africa and myself, from @Conabio Mexico, shared how are we doing this at our countries based on different data sources, but both without genetic data

Jess assessed an endemic toadlet based on published scientific studies and @IUCNRedList data, none of which involved genetic data

Based on one published studies she found that only 2 out of 6 populations remained, so indicator 2 = 2/6

And based on another capture-mark-recapture study, Jess found that each population had less than 2,000 individuals. Applying the Ne = 10% Nc rule, we have that the number of populations with Ne > 500 is sadly 0

With similar existing data sources Jessica an her team are already evaluating lots of South African species

But what if there are no scientific studies published or the species haven't been assessed in red list?

Worries not. I showed an example using citizen science and experts or local knowledge, using the case of a mountain that grows at high elevation mountains.

First, using observations from scientific collections and @inaturalist we defined a population as a cluster of isolated mountains. If junipers were historically AND current observed we considered that population to still exists. Totaling for 15/17 populations still around

Then for each population we asked local botanists or park rangers if they knew approximately how many mature trees were at each population.

Importantly we didn't asked them to count individuals, it was enough if they could tell us if there were below or above the 5,000 threshold. Based on this we calculated the indicator, finding that 4 populations have Ne > 500

A similar approach can be used to include other sources of citizen science data, expert's knowledge and participatory monitoring. Including re-using data that was collected for other purposes like we are doing with the Mexican Agrobiodiversity @theGEF project

The #GeneticDiversity indicators can be estimated for all taxonomic groups, generating a country level indicator.

To help countries and researchers to estimate the indicators without creating a data mess, we developed a web form for standarized data collection. It includes useful metadata and ids to link it other databases, like @GBIF

We know filling forms won't create capacities by magic, so we created guidance documents and are giving workshops with detailed advice. E.g: Ecuador, Chile and Cuba are interested and we will meet in January!

With these examples we hope to have convinced you!

We can leverage existing biodiversity knowledge and monitoring data to include genetic diversity - one of the main components of biodiversity and of Goal A.

It was a fantastic side event, by an absolutely terrific extraordinary team of #GeneticDiversity friends @LindaLaikre @CristianoVernes @seanmhoban @ivanpazvinas and many more who couldn't come

Questions? Tweet them here, find us at our booth at #Cop15montreal o check our resources at coalitionforconservationgenetics.org/cbd

Thanks to our kind sponsors for $ for traveling, printing, translation (to Spanish, French, Arab and Mandarin)

Thanks to the more than 40 institutions co-hosting this side event and to the many researchers, practitioners, parties and young people who are supporting us!

Also thanks to @JillStats and @UNBiodiversity for their interest in #GeneticDiversity indicators at #COP15montreal @CBD_COP15

If you made it this far, you probably want to check out the pdf of the presentation we gave during the #GeneticDiversity indicators side event. Now available at coalitionforconservationgenetics.org/cbd

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