Two Interconnected Grassland Mammals You May Never Have Heard Of
Species #1: The Black-tailed Prairie Dog
The Black-tailed Prairie Dog (Cynomys ludovicianus) is so rare in Canada it is only found in one place in Canada: Grassland National Park. The prairie dog was first documented in Canada 1938, when the first prairie dog “towns” were discovered. The nearest colonies are in Montana over 20 kilometres away — way too far for breeding between populations. There is thought to be about 3.6 adults in every hectare, and 12.6 juveniles in every hectare of grassland. This is not a lot of prairie dogs! In simpler terms, the number of prairie dogs are estimated to be between 6,000 to 9,000.
Historically, this species would have been considered a keystone species as it is a food source for species such as Swift Foxe (Vulpes velox), Ferruginous Hawk (Buteo regalis), Swainson Hawk (Buteo swainsoni), Prairie Falcon (Falco mexicanus) and Golden Eagle (Aquila chrysaetos). Their numbers have declined by 22 to 33 per cent over the years to the point that they cannot really be considered keystone. While the exact cause for decline isn’t fully understood, they are known to be susceptible to fleas, lice and ticks and prone to the zoonotic disease, sylvatic plague (bubonic) that these species can carry.
Despite no longer being a keystone species, their burrows do provide homes for Greater Short-horned Lizards (Phrynosoma douglassii) (another poorly known species), Prairie Rattlesnakes (Crotalus viridis), Burrowing Owls (Speotyto cuicularia) and Mountain Plovers (Charadrius montanus). So, they do continue to provide an important habitat service in Grasslands National Park.
But the story gets more complex. There is a unique predatory-prey system with two species at risk: the prairie dog and the Black-footed Ferret.
Species #2: Black-footed Ferret
The Black-footed Ferret is another grassland mammal that disappeared from Canadian grasslands in 1978. This species is nocturnal and an obligate carnivore — meaning it relies on a specific prey item, the prairie dog. This strange looking creature was lost due to the decline of prairie dogs, loss of grassland habitat, poisonings and sport shootings. Black-footed Ferrets also use the burrows of prairie dogs to give birth and raise their young.
Captive breeding programs for Black-footed Ferrets have been underway by Conservation groups like the Toronto Zoo for many years. The Black-footed Ferret recovery team has released 269 ferrets to Grasslands National Park since 1992. Calgary Zoo’s Wilder Institute has also been involved and released individuals in 2018.
Interconnected Survival
The Black-footed Ferret relies on a unique habitat and a very specific food source: thus, the number of prairie dogs will determine their ultimate success. If there are no prairie dogs, there are no Black-footed Ferret. Many other grassland species would be impacted as well.
The future of the Black-footed Ferret is unclear. The last Black-footed Ferret seen in the area was in 2013 and experts say there is strong evidence that it no longer exists in the wild. However, we can be hopeful that the efforts of Grasslands National Park to improve the habitat and prairie dog population so to release more captive ferrets that are ready and waiting to go home.
Grassland species have very intricate interspecies relationships, and thus conserving grassland habitat is vitally important to their survival.
To get a better sense of the landscape of Grassland National Park, check out the live webcam here.
Learn more about the work the Canadian Wildlife Federation is doing to help Canada’s native grasslands >
Tracey Etwell
Tracey Etwell, M.Sc, CERP, is a Restoration Ecologist with the Canadian Wildlife Federation. She supports the Rights of Way program helping restore pollinator meadows for Monarch Butterfly and other pollinators in eastern Ontario.
