Bighorn genetic connectivity
Scat, dung, feces, poop...what's in a name? That which we call a pellet by any other name would still contain DNA.
In wildlife biology, scat can be a useful source of information, so it's best to not be squeamish about it. Our team certainly isn't. We've used scat, or pellets, from bighorn sheep for over two decades to learn about their genes. It's an efficient way to look at large-scale patterns of genetic diversity and gene flow - the exchange of genes between populations through movement and reproduction.
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Turning feces into fingerprints
Once we extract DNA from samples collected in the field, we look at DNA sections called microsatellites. Microsatellites have high mutation rates and often look very different from one individual to the next. Data from multiple microsatellites can act like a fingerprint to identify unique individuals. We call these genetic fingerprints genotypes.
Using genotypes we can:
- estimate genetic diversity or population isolation
- track the movements of individuals
- estimate gene flow between populations & flow changes over time
- model connectivity across large landscapes
Fragmentation & gene flowMany human-made barriers (shown in dark red on the map) limit bighorn movement and gene flow. This has split the desert bighorn metapopulation into subunits. Without these barriers, we would expect more gene flow between these subunits, so we're working with our partners to identify ways to restore this lost connectivity.
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Updating the connectivity map
Genetic connectivity can change over time, especially if conditions that influence animal movement change. We know that things like traffic density, human-made structures, and human activity in natural areas can affect wildlife behavior. In Southern California, all of these things have increased in recent decades.
In Joshua Tree National Park, for example, human activity has sky-rocketed. But the last collected bighorn samples & genotypes from the park date back to 2002 & 2003. Does bighorn movement and connectivity still look like it used to?
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We're investigating this question with new genetic samples from Joshua Tree and surrounding areas. The more samples we're able to gather, the more we can learn about the current trends in bighorn connectivity and habitat use. The Southern Mojave region is an especially sensitive area due to its low elevation and higher temperatures. It will be an important area to continue to monitor as climate trends push this region to even hotter and drier conditions.
COME BACK SOON AND FIND OUT HOW CONNECTED THE SOUTHERN MOJAVE METAPOPULATION IS TODAY