The decline of large carnivores, including wolves, in North America and around the world has disrupted ecosystems, causing cascading changes that have resulted in a decrease in biodiversity and created artificially inflated ungulate populations as documented in Yellowstone and Banff National Parks (3,34).
Where wolf populations have been extirpated or exploited in North America, a cascade effect is observed in which small mammals, fish, insects, birds, amphibians, ungulates, tree species and vegetation all suffer (3,34,36). The impoverished ecosystem in Yellowstone without wolves has since been dramatically reversed through the re-introduction of wolves into their native area, however not all wolf reintroduction efforts are successful (34, 40).
As the number of grey wolves declines, a cascade effect is observed in which small mammals, fish, insects, birds, amphibians, ungulates, tree species and vegetation all suffer. As wolves’ decline, ungulate density increases and adversely affects the growth of aspen and willow, with reduced plant biomass resulting in a reduction of active beaver lodges, which in turn negatively affects songbird abundance and diversity (21, 33, 34, 36, 39, 40).
Although wolves were returning naturally to Yellowstone National Park (Wyoming USA) and the surrounding area gradually since their extirpation in the 1920’s, the relocation of wolves from northern BC and Alberta in 1995/96 bolstered what has been referred to as the “greatest ecological restoration project in North American history”. Researchers William J. Ripple and Robert L. Beschta (2012) have documented changes to the entire Yellowstone ecosystem since wolves began enriching the landscape through a return of their presence.
Several indirect effects were documented with the return of wolves to this system, including mesopredator control. Ripple and Beschta also theorize that the mere presence of wolves on a landscape can affect the behaviour of ungulates, influencing vegetation growth, stream morphology, and overall biodiversity. In an article that appeared in Bioscience August 2004 Vol. 54 No. 8, Ripple and Beschta coin the question “Wolves and the Ecology of Fear: Can Predation Risk Structure Ecosystems?” Watch this video to find out how they CAN!
The combined role of the wolf pack as an umbrella and keystone species merits added protection for this species, as ecological studies have shown that loss of a keystone species is more apt to cause a series of linked extinction events, resulting in a degraded ecosystem where biological diversity suffers.
The Ecology of Fear
Image below from National Geographic Magazine©, March 2010.
Hebblewhite’s 1995 PhD Thesis titled “Wolf and Elk Predator-Prey Dynamics in Banff National Park” provides evidence and information on how wolves can control ungulate populations. However, the longest ongoing predator-prey study in history on Isle Royale shows that the relationship between wolves and moose in a simple system are unclear. Wolves on Isle Royale are now facing an extinction vortex, with numbers so low that inbreeding pressure has become a major threat to their survival. Learn more about this situation and the Wolves and Moose of Isle Royale
Biologist Chris Darimont urges that conservation of wolves and ecosystems requires maintaining not only viable populations, but also naturally-functioning populations.
Dr. Linda Rutledge’s research in Ontario’s Algonquin Provincial Park indicates that this may even benefit ecosystems more; “fitness is likely to be optimized when evolutionary adaptation is driven by natural rather than artificial (ie human mediated) selection pressures” (37 and Rutledge pers. comm.).
Rutledge and others (2010) state that this “social component may stimulate natural regulation at other trophic levels” and is “evolutionarily important”.
Canada is an important stronghold for wolves, as the species has been decimated or completely extirpated from many areas of its former range. Merely having wolves present is one thing, but preserving the species as part of a functioning ecosystem is a more challenging yet sound management decision.
Paul Paquet is a world renowned large carnivore specialist and senior scientist with Wolf Awareness Inc. and the Raincoast Conservation Foundation. He is a wolf expert who fuses ethics with conservation. Indeed, the two should be inseperable but often this is not the case.
Paquet has published countless peer-reviewed scientific articles and dedicated much of his life to exposing the true nature of wolves, researching them all over the word. Paul Paquet contributed greatly to the Central Rockies Wolf Project and is a strong proponent for Buffer Zones. Most of the research Paquet has done on BC’s coastal wolves is available on the Raincoast Conservation Foundations’ website.
The unique behaviour and ecological role of coastal wolves has also been extremely well documented by the Raincoast Conservation Foundation. Unlike wolves around the rest of the world, coastal wolves depend upon the ocean to make their living. Coastal wolves also contribute to nutrient cycling in the rainforest, bringing rich Nitrogen from salmon into the forest to enrich the soil and the trees. Grizzly bears and black bears, including the white Spirit Bear, or Kermode bear, also perform this important role in natures intricate web of life.
Read selected articles by Dr. Paul Paquet:
- Wolf Stories, Environmental Ethics
- The Practices of Wolf Persecution, Protection and Restoration in Canada and the US
Social chaos vs. pack stability
A disruption of wolf social structure often leads to increased conflicts with humans and livestock, similar to people reacting to war zone (stealing, cheating, killing). Disrupting stable wolf family units can even effect the ecological role of the wolf PACK as an apex predator, as documented by Dr. Linda Rutledge and her team in Ontario’s Algonquin Provinical Park.
Ecological & Ethical Arguments for Wolf Conservation
Rutledge et al (2010) state that this “social component may stimulate natural regulation at other trophic levels” and is “evolutionarily important”.
- “Lethal control” of wolves breaks social structure, and can lead to: changes in age composition; group size; survival rates of other wolves; pack hunting abilities; territory size and stability; social behaviour; genetic identity and diversity; a higher proportion of young, breeding pairs and litters due to lack of structure which regulates breeding (Wallach et al. 2009, Rutledge et al 2010).
- Packs experiencing control and/or hunting had higher mortality rates and thus pack sizes are smaller, home ranges less stable and occupied at variable times, more pups produced (Hayes and Harestad study)
- Packs dominated by young more likely to attack domestic stock (inexperience)
- May breed earlier and produce more pups in exploited population
- Growing pups have greater energy requirements and must consume more.
If an alpha, or leading parent, is killed by human influences, there will more likely be dispersering wolves. Territories may dissolve. Learning of young pups or jeuvenilles may be lost (the chance to pass on important information is taken or disrupted). This can lead to cause an alteration in social behaviour eg. cooperative hunting techniques, location and reuse of denning sites.
Dr.’s Gordon Haber, Chris Darimont, Paul Paquet, John Theberge and Linda Rutledge are among several wolf biologists whom urge that conservation of wolves and ecosystems requires managing the species at the level of the family unit. This will require maintaining not only viable populations, but also naturally-functioning populations where “fitness is likely to be optimized when evolutionary adaptation is driven by natural rather than artificial (i.e. human mediated) selection pressures” (Rutledge et al 2010 and personal communication).
The stability of wolf packs may be as important to their role as a keystone species as population size, but this critical factor is not often considered in conservation-management plans for wolves in North America.
- Wallach et al. (2009) indicated that the longer an area was allowed to recover from lethal control of dingos, the more they returned to using indicators of social stability (scent marking and howling). These indicators for social communication were lost in areas with high persecution.
(Note; scent marking through urine, scat, ground raking communicates pack size and composition, individual social and breeding status, and helps define territory).
- Rutledge et al. (2010) provided evidence through research on Eastern wolves in Agonquin provincial park (following implementation of Buffer Zones 2001) combining ecological and genetic data to show that reducing human-caused wolf mortalities (through hunting and trapping) restored the natural structure of wolf packs (kin-based families) without a marked increase in population (natural mortality replaced human caused deaths).
- Groups stopped recruiting ‘foreigners” when not exploited and Rutledge and team saw a reduction in unrelated adopted animals in 17 packs (80% pre-ban unrelated vs. 6% post-ban unrelated) (Rutledge et al 2010).
- provides evidence that even protected areas can act as sinks if not large enough, and with non-stable social units less able to adapt to evolutionary changes and function in ecological role (fitness benefits accompany social unit, experience and learning are important).
Predator-prey systems are becoming more rare across the globe.
“It is the caribou that feeds the wolf, but the wolf that keeps the caribou strong”. -Inuit saying.
84% of BC’s endangered species are at risk because of the loss of the places they need to live, find food and raise their young. Habitat loss is not only the greatest threat to species at risk in BC, it is also the greatest threat to species at risk in Canada and right across the world from Mountain gorillas to Siberian tigers. Although habitat loss is the most significant issue, species are also under huge pressure from toxins/pollution ( eg. frogs) , over-harvesting (eg. eastern wolverine and eastern wolf), invasive species (eg. bull trout), and climate change (eg. polar bears).
What is Biodiversity?
The dictionary defines “Biodiversity” as the variety of life on earth, shown in the variety of ecosystems and species, their processes & interactions & differences at the species level.
The more biodiversity there is in a natural area, the more chance things have of surviving extreme changes such as weather patterns, fires and floods. This spice of life makes an area more resilient, or able to adapt to and live through changes. It also offers benefits on a massive scale such as cleaning air and water.