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Vignettes
Learn more about the relevance of ecology and evolution to issues that matter to you:
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Canada is a focal point for climate change, with shifts over the past few decades and the coming years exceeding those in most other places in the world. Research conducted with NSERC Discovery Grant funding has generated fundamental insights into how organisms might respond to these changes and thereby influence biodiversity and ecosystem services in Canada’s future. Examples include changes in the seasonal timing of northern animals and the ability of phytoplankton to uptake carbon dioxide. Changes in seasonal timing are studied by many Canadian scientists, with one example coming from the work of Dr. Denis Réale (Univ. du Québec à Montréal), Dr. Stan Boutin (Univ. of Alberta), Dr Andrew McAdam (University of Guelph), and Dr. Dominique Berteaux (Univ. du Québec à Rimouski). By tracking a population of red squirrels in the Yukon for many years, something only possible given the consistency of Discovery Grant funding, the researchers showed that red squirrels have advanced the timing of their reproduction to match levels of food supply (spruce cones) that is linked to climate. Some of this response was purely behavioral but some of it was also evolutionary. The phytoplankton work was conducted in the laboratory of Dr. Graham Bell (McGill Univ.). With his student Sinéad Collins, Dr. Bell determined how these small uni-cellular aquatic algae would respond to the increasing levels of carbon dioxide that accompany climate change. This work showed that phytoplankton did not evolve a greater ability to uptake carbon. This result is critical in showing that evolution in aquatic primary producers, such as phytoplankton, will probably not greatly increase the rate of carbon sequestration in the ocean – which had been suggested as a potential counterbalance to the increased human-mediated atmospheric carbon. These two studies highlight need for additional basic research on which organisms will and will not evolve in response to particular environmental conditions. Discovery Grant funding is the backbone of this work.
Contributed by A. Hendry
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A Canadian red squirrel (photo: Andrew Hendry) and changes in reproductive timing in response to climate warming (from Réale et al. 2003 - Proceedings of the Royal Society of London B 270: 591-596).
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The livelihood of many Canadians depends directly or indirectly on the harvesting of wild populations. Research conducted with NSERC Discovery Grant funding has shown that evolutionary change in these populations can have important consequences for the value and sustainability of these harvests. Examples include bighorn sheep on Ram Mountain in Alberta and Atlantic cod off the east coast of Canada. The bighorn sheep population is studied by David Coltman (Univ. of Alberta) and Marco Festa-Bianchet (Univ. de Sherbrooke). This population is managed for trophy hunting, such that only the largest individuals can be harvested each year. The investigators showed that this selective harvesting caused the evolution of smaller horn size in the population, which reduces the value of the resource to hunters. The Atlantic cod situation is studied by several Canadian scientists including Jeff Hutchings (Dalhousie Univ.). Atlantic cod are famous for their precipitous collapse in the 1980s, which led to the loss of livelihood for many Atlantic fisherman and individuals with fishing-related businesses. The researchers have shown that the collapse in cod stocks was coincident with an evolutionary decrease in growth rate, age-at-maturity, and size-at-maturity of the cod. These life history changes may have contributed to the collapse and may now be hampering population recovery. In short, the work on bighorn sheep and Atlantic cod has revealed the need to consider potential evolutionary changes in management plans, and has thereby tied the basic science done through NSERC Discovery Grants into the lives of Canadians and the resources of Canada.
Contributed by A. Hendry
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A bighorn sheep with a relatively small horn size (photo: Andrew Hendry) and changes in horn size through time in the Ram Mountain bighorn sheep population (from Coltman et al. 2003 - Nature 426: 655-658).
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Long-term research on individually-marked mammals has
contributed much to our knowledge of the ecology, evolution and
conservation of these economically important animals. Thanks
mostly to NSERC, Canada is a world leader in this field, with
decades-long monitoring programs on programs on individually
marked wolves, caribou, polar bears, squirrels, bighorn sheep and
mountain goats. Among other things, long-term monitoring of
marked individuals has shed light over the predator-prey
relationship. Canadian researchers have shown that wolf
predation on woodland caribou increases when clearcuts provide
forage to sustain high moose densities, or when roads, pipelines
and snowmobile trails allow easier travel by wolves, Because of
habitat destruction and artificially enhanced predation, woodland
caribou are now a Threatened species in Canada. Long-term
research on bighorn sheep has also revealed a complex
relationship with cougar predation. In most years, cougars do not
prey on bighorns and specialize on deer and elk. Occasionally,
however, an individual cougar will ‘discover’ that sheep are
highly vulnerable to ambush predation. In Alberta, NSERCsupported
research by Marco Festa-Bianchet and a team of
international colleagues has shown that individual cougars that
specialize on bighorns cause drastic declines in sheep
populations, with a substantial risk of extirpation if ‘sheep
specialists’ live many years. Usually, however, cougars have no
impact on sheep populations. Individual specializations in large
predators has many implications for ecology and conservation,
and can be applied to the protection of endangered species and
livestock. It also illustrates how the balance of predator and prey
must be considered over long times and wide areas. In humanaltered
environments or in small protected areas, a predator-prey
balance may be difficult to achieve.
Contributed by M. Festa-Bianchet
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A bighorn lamb wounded by a
cougar (photo: M. Festa-Bianchet)
and decreases in the number of
bighorn sheep in 3 populations
during years of ‘specialist’ cougar
predation (black bars) (From Festa-
Bianchet et al. 2006 – Proceedings
of the Royal Society of London B
273: 1537-1543).
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| In mountain habitats, temperatures approach freezing almost nightly, and it can snow or hail on any summer day. In such conditions, humans need a winter-rated sleeping bag for a comfortable rest, but small 20 to 40g songbirds can survive and maintain their eggs at almost 40º C sitting on their ground nests above the permafrost for about 19 hours/day. Although little is known about how well songbirds live at high elevation, over 90 bird species and many mammals and herptiles breed successfully in the often inhospitable mountain habitats. The main hypothesis being tested is that as elevation increases, mountain birds adopt a slower lifestyle where they produce fewer offspring each year compared to birds at low elevations, but they live longer and thus have more years to breed.
Kathy Martin (UBC) conducts Discovery Grant-sponsored research aimed at understanding the ecological secrets and conservation status of animal life on high. Some alpine populations differ genetically and may thus represent new sub-species or new species. For many songbirds, such as horned larks, with rapid population declines at low elevation across North America, mountains may represent critical refuge habitats. Since alpine habitats are experiencing globally significant warming, it is critical to determine the vulnerability of alpine birds to climate change.
Research on songbirds in western Canada has revealed some secrets to alpine living. High elevation songbirds are larger and have up to 20% higher annual survival than the same species living in lower elevation habitats. Their offspring also have high survival and a strong tendency to return to their birth sites. Thus, most birds living in alpine habitats are not inferior individuals but have developed a slow lifestyle and live and breed successfully.
With a slow life style, alpine birds may be reasonably buffered against extreme weather events that cause breeding failure every few years. Nevertheless, climate change impacts that reduce the survival of adults could be catastrophic for alpine birds. More information is available at the Centre for Alpine Studies Website: http://www.forestry.ubc.ca/alpine
Contributed by K. Martin
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Fig 1. Alpine in summer on Hudson Bay Mountain (HBM), Smithers,
British Columbia; Inset shows HBM after snow storm on 4 July 2002.
Fig 2. Hungry horned lark nestlings in the alpine.
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