TY - JOUR
T1 - Trophic Dynamics of the Boreal Forests of the Kluane Region
AU - Krebs, Charles
AU - Boonstra, Rudy
AU - Boutin, Stan
AU - Sinclair, A
AU - Smith, James
AU - Gilbert, B.
AU - Martin, Kathy
AU - O'Donoghue, Mark
AU - Turkington, Roy
PY - 2014
Y1 - 2014
N2 - The trophic dynamics of the Yukon boreal forest have been under investigation at the Kluane Lake Research Station since 1973. We monitored and conducted experiments on the major species in this ecosystem, except the large mammals (for logistic reasons). The central problem has been to determine the causes of the 9-10 year cycle of snowshoe hares, and to achieve this we carried out several large-scale experiments manipulating food supplies, predator pressure, and soil nutrient availability to test hypotheses that food, predation, or habitat quality regulate populations. The hare cycle is driven top-down by predators, and most hares die because they are killed by predators. Predators also cause stress in female hares, and the stress response seems to be responsible for the loss of reproductive potential in the decline and low phases of the hare cycle. Many of the specialist predators and some herbivores in this ecosystem fuctuate with the hare cycle. Arctic ground squirrels do, but red squirrels do not, being linked closely to white spruce seed masting years. Small rodents fuctuate in numbers in two patterns. Red-backed voles and four species of Microtus voles have a 3-4 year cycle that seems to be driven by food supplies and social behaviour. Deer mice, in contrast, have fuctuated dramatically in the 38 years we have monitored them, but not cyclically. White spruce seed production varies with temperature and rainfall, but was not affected by adding nutrients in fertilizer. Global warming and reduced hare browsing in the last 20 years have helped to increase the abundance of shrubs in these forests. It will be challenging to predict how this system will change as climatic warming proceeds, because even closely related species in the same trophic level respond differently to perturbations. We recommend continued monitoring of the major species in these boreal forests.
AB - The trophic dynamics of the Yukon boreal forest have been under investigation at the Kluane Lake Research Station since 1973. We monitored and conducted experiments on the major species in this ecosystem, except the large mammals (for logistic reasons). The central problem has been to determine the causes of the 9-10 year cycle of snowshoe hares, and to achieve this we carried out several large-scale experiments manipulating food supplies, predator pressure, and soil nutrient availability to test hypotheses that food, predation, or habitat quality regulate populations. The hare cycle is driven top-down by predators, and most hares die because they are killed by predators. Predators also cause stress in female hares, and the stress response seems to be responsible for the loss of reproductive potential in the decline and low phases of the hare cycle. Many of the specialist predators and some herbivores in this ecosystem fuctuate with the hare cycle. Arctic ground squirrels do, but red squirrels do not, being linked closely to white spruce seed masting years. Small rodents fuctuate in numbers in two patterns. Red-backed voles and four species of Microtus voles have a 3-4 year cycle that seems to be driven by food supplies and social behaviour. Deer mice, in contrast, have fuctuated dramatically in the 38 years we have monitored them, but not cyclically. White spruce seed production varies with temperature and rainfall, but was not affected by adding nutrients in fertilizer. Global warming and reduced hare browsing in the last 20 years have helped to increase the abundance of shrubs in these forests. It will be challenging to predict how this system will change as climatic warming proceeds, because even closely related species in the same trophic level respond differently to perturbations. We recommend continued monitoring of the major species in these boreal forests.
KW - boreal forest
KW - snowshoe hares (Lepus americanus)
KW - red-backed voles (Myodes rutilus)
KW - Microtus spp.
KW - Arctic ground squirrels (Urocitellus parryi)
KW - red squirrels (Tamiasciurus hudsonicus)
KW - grouse
KW - fertilization
KW - predation.
KW - Boreal forest
KW - Grouse
KW - Red-backed voles (Myodes rutilus)
KW - Fertilization
KW - Red squirrels (Tamiasciurus hudsonicus)
KW - Predation
KW - Snowshoe hares (Lepus americanus)
UR - http://www.scopus.com/inward/record.url?scp=84904254321&partnerID=8YFLogxK
U2 - 10.14430/arctic4350
DO - 10.14430/arctic4350
M3 - Article
SN - 0004-0843
VL - 67
SP - 71
EP - 81
JO - Arctic
JF - Arctic
IS - 5 SUPPL.1
ER -