History & Decline
It’s not known exactly when the first marmot ancestors arrived, but DNA evidence suggests that it was likely during the Illinoian glacial period (about 100,000 years ago). Sea levels fell during this period, creating land bridges between the mainland and Vancouver Island allowing marmots from the continent to travel to the newly accessible island. Once the glaciers melted sea levels rose again, isolating the island marmots and setting the stage for a new species to evolve. During subsequent glaciation periods, it is likely that while more mainland marmots journeyed to the Island but did not disrupt the speciation of the Vancouver Island marmot.
Marmots were important to many First Nations on Vancouver Island. A number of First Nations recall the importance of marmot fur and meat in their cultural traditions, and carried out annual hunts on the species. In the ‘Namgis Tradition Territory, there was “Papikatan” (similar to “Place of Marmot”) near present day Schoen Lake Provincial Park. While historic marmot populations can only be guessed at, the regular harvest by First Nations strongly suggest a much larger, and more widespread, population once lived here.
Recognizing a Species in Decline
By the mid-1980s, volunteer naturalist groups began voicing serious concerns about the state of the marmot population. In the 1990s, the marmot population began an even more rapid decline. By 1998, only 70 marmots were recorded in the wild, and with the exception of one lone colony on Mt Washington, all marmots were located in one small geographic area east of the Nanaimo Lakes.
The Mt Washington colony was the only surviving colony in the central and northern regions of the marmot’s historic habitat and the remaining marmot population south of Alberni Inlet was so small and fragmented that dispersing animals were unable to find mates. The Recovery Team determined that without active human intervention (captive breeding followed by the reintroduction of captive-bred animals back to the wild) the species would become extinct in the very near future.
Reasons for the Decline
We may never know with certainty why marmots disappeared from much of their historic range. It is especially concerning that marmots disappeared even from large protected areas, such as Strathcona Provincial Park. However, there are hints to the causes in both how marmot colonies occupy the landscape and what we have learned about marmot mortality in the south.
Marmots live in networks of colonies, which we call “meta-populations.” Colonies within these meta-populations regularly exchange young marmots with other. If a single a colony has a poor year – perhaps is particularly hard hit by predators – the survivors would rely on new marmots arriving from other nearby colonies. However, in many areas, the movement of marmots was disrupted, and colonies were increasingly isolated, and vulnerable. Even in large protected areas, this type of isolation can lead to local extinction.
In the south Island area, biologists had the opportunity to witness more of the species’ decline. There, radio telemetry studies identified predation as the most significant cause of recent mortality. From 1995-2005, predation by wolves (Canis lupus), cougars (Felis concolor) and golden eagles (Aquila chrysaetos) accounted for 80% of marmot mortality.
Research suggested that abnormally high levels of predation led to dramatic declines at some colonies in just a single year, and showed that colony-specific survival rates were spatially correlated (similar at closer locations) indicating that declines may have been caused by localized predation events. But predation is a natural and ongoing process the marmots have always been exposed to – so what changed?
It has been speculated that ongoing landscape changes on the Island had coinciding impacts on predator and prey populations as well as on Vancouver Island marmot populations. The boom and bust population dynamics of predators and prey may have been much more extreme over recent decades, exacerbated by the constraints of an island environment. In years with greater numbers of predators and fewer prey, this could have shifted “unnatural” pressures onto marmot populations.
Vancouver Island marmots were never plentiful enough to be the sole prey species for a predator population due to the scarcity of their habitat. Instead, marmots functioned as secondary prey species, and were killed opportunistically while predators hunted more plentiful species such as elk, deer or rabbit. But the impacts of an “unbalanced” predator-prey relationship and the network structure of marmot colonies may have been enough to drive this uniquely Canadian species to the brink of extinction.
Radiotelemetry will help us to answer some of our remaining questions. Marmots in the wild have radiotelemetry transmitters which send out pulses that our crew can detect using special equipment. The strength of the pulse helps us to track a specific location, and the speed of the pulse tells our crew whether the marmot is alive, dead, or hibernating. When a marmot has died, we retrieve its transmitter, and clues around the transmitter help us to determine its “cause of death”.
Future challenges await the marmot as well. Climate change threatens to allow forests to overgrow marmot habitat, as well to bring more extreme weather events. Our challenge is restore this species, and keep its habitat in good condition, in the face of a rapidly changing world.