Barbary Sheep and Desert Bighorns

Barbary sheep (Ammotragus lervia)  aoudad

This handsome fellow is an aoudad (Ammotragus lervia), aka a Barbary Sheep. These caprids are approximately the same size as domestic goats and weigh from 40 to 140 kg (88 to 300 lb).  Their original range was the desert and arid scrubland of Northern Africa–the northern margins of the Sahara in Algeria, Tunisia, northern Chad, Egypt, Libya, northern Mali, Mauritania, Morocco, Niger and Sudan–however as the Sahara expands and grows hotter and more dry, the aoudad is going extinct in its home range.

Desert Bighorns (Ovis canadensis nelsoni)

This is where the issue becomes morally complex.  Bestiary keepers and gentleman hunters of previous eras imported populations of Barbary sheep to other parts of the world which more closely resemble the now vanished ancestral scrublands of the Sahara.  Thus Aoudads might be going extinct in North Africa, but they are flourishing in Texas.  Their success comes at the expense of the endangered native caprid of Texas, the desert bighorn sheep (Ovis canadensis nelsoni) a desert subspecies of bighorn which once dwelt in Texas in thriving herds before over-hunting, disease, and habitat loss nearly wiped them out.  The Aoudad is larger and more aggressive (and requires less water) than the bighorn.  The invader is out-competing the native, and Texans are up in arms about it–quite literally, since they are renowned as a gun-toting people.  Aoudads, so precious in their original home in North Africa, are being blasted away as invasive pests in Texas.

My interpretation is that climate change is making West Texas more like the Sahara used to be (and making the Sahara more like the Atacama…or like the sunny side of the moon). Although, there are lots of factors at play when it comes  to whether an organism is successful in an ecosystem, climate change affects a lots of these variables.   Aoudads and bighorns have a relationship sort of like the round goby and the mottled sculpin (remember them) although the Aoudads don’t actually eat the bighorns’ eggs, they just run the males off and pointlessly hoard all of the bighorn ewes.  We are going to see more of these situations involving invasive creatures and we are going to have to start thinking now about how to best manage climate refugee species.  Do we want Aoudads to go extinct in the wild? Do we want the deserts of Texas to have no wild caprids?  Maybe we need to start releasing desert bighorns in Arkansas or Rhode Island?  What even is a natural habitat in a world where humankind has changed every habitat?