Can the Solar Cycle and Climate Synchronize the Snowshoe Hare Cycle in Canada? Evidence from Tree Rings and Ice Cores

  title={Can the Solar Cycle and Climate Synchronize the Snowshoe Hare Cycle in Canada? Evidence from Tree Rings and Ice Cores},
  author={Anthony R. E. Sinclair and John M. Gosline and Gerald Holdsworth and Charles J Krebs and Stan Boutin and J. N. M. Smith and Rudy Boonstra and Mark R. T. Dale},
  journal={The American Naturalist},
  pages={173 - 198}
Dark marks in the rings of white spruce less than 50 yr old in Yukon, Canada, are correlated with the number of stems browsed by snowshoe hares. The frequency of these marks is positively correlated with the density of hares in the same region. The frequency of marks in trees germinating between 1751 and 1983 is positively correlated with the hare fur records of the Hudson Bay Company. Both tree marks and hare numbers are correlated with sunspot numbers, and there is a 10-yr periodicity in the… 
Demography of snowshoe hares in relation to regional climate variability during a 10-year population cycle in interior Alaska
The strength of these interactions may increase in importance if the asynchrony of environmental seasonality and life his- tory traits of snowshoe hares becomes more pronounced as the climate continues to change.
What Drives the 10-year Cycle of Snowshoe Hares?
The spectacular cycles of snowshoe hares and their predators have captured the attention of biologists as well as historians, and the challenge to biologists has been to understand the mechanisms behind these cycles, which has not been easy.
Solar Activity and Mammal Cycles in the Northern Hemisphere
It is shown that the amplitude of the cycle decreases at lower latitudes, and suggestions for this trend in amplitude range from changes in predator species and their numbers to differences in food productivity.
The solar cycle as a possible modulator of ecosystem functioning on the decadal time scale: new evidence from North American porcupine (Erethizon dorsatum) feeding scars and climatic data
Using North American porcupine (Erethizon dorsatum) feeding scars on trees as an index of past porcupine abundance, we have found that porcupine populations have fluctuated regularly over the past
Correlated cycles of snowshoe hares and Dall’s sheep lambs
Testing the hypothesis that the number of surviving lambs counted in mid-summer from a Dall’s sheep population on Sheep Mountain, Yukon, Canada, is correlated to the density of snowshoe hares in the surrounding boreal forest found no evidence of direct interactions.
The enigma of the 10-year wildlife population cycle solved? Evidence that the periodicity and regularity of the cycle are driven by a lunar zeitgeber
The hypothesis is presented that the 9.3-year nodal half-cycle of the moon is the zeitgeber (“time-giver”) of the 10-year wildlife population cycle, providing explanations for the regularity, periodicity, amplitude, distribution, and synchrony.
Solar Activity and Hare Dynamics: A Cross-Continental Comparison
The fur records of the Hudson Bay Company comprise an unusually long time series of population data. Since MacLulich (1937, 1957; Elton 1942; Elton and Nicholson 1942), population ecologists have
Mammal population cycles: evidence for intrinsic differences during snowshoe hare cycles
This hypothesis predicts that animal lineages bred from high and low phases of the population cycle should differ in reproduction and survivorship and suggests a mechanism for alternating population densities that could work synergistically with extrinsic causes like predation and food shortage.
Porcupine Feeding Scars and Climatic Data Show Ecosystem Effects of the Solar Cycle
The results suggest that the solar cycle indirectly sets the rhythm of population fluctuations of the most abundant vertebrate herbivore in the ecosystem the authors studied, which constitutes strong evidence for the possibility of a causal link between solar variability and terrestrial ecology at the decadal timescale and local spatial scale.
Chronology of Terrestrial Den Use by Polar Bears in Western Hudson Bay as Indicated by Tree Growth Anomalies
In a large polar bear denning area inland from the coast of western Hudson Bay south of Churchill, Manitoba, previous denning activity was determined by examining tree growth anomalies in the black


The Newfoundland ice extent and the solar cycle from 1860 to 1988
Sea ice conditions off the east coast of Newfoundland for the last 130 years are presented, forming what is believed to be the longest ice record for the northwestern Atlantic. Because of differences
Evidence of a 22-year Rhythm of Drought in the Western United States Related to the Hale Solar Cycle since the 17th Century
Families of Drought Area Indices (DAI) have been derived from tree-ring data for the entire U.S. west of the Mississippi River, for each year back to either 1700 or 1600 A.D., depending on the data
Analysis of a 290-Year Net Accumulation Time Series from Mt. Logan, Yukon
A 102.5-m mechanically continuous firn and ice core sequence retrieved from the Northwest Col of Mt. Logan (latitude 60°30'N; longitude 140°35'W; site location 5340 m a.s.l.) in the Yukon Territory,
A Closer Look at the Effect of the 11-Year Solar Cycle and the Quasi-biennial Oscillation on Northern Hemisphere 700 mb Height and Extratropical North American Surface Temperature
Abstract A recently discovered association between the 11-year solar cycle and the Northern Hemispheric low-frequency atmospheric circulation structure, which is most easily delectable when the two
Periodic 18.6‐year and cyclic 10 to 11 year signals in northeastern United States precipitation data
Evidence for a narrow band-limited signal with period near 18.6-years is found in 126 out of 136 yearly total precipitation records, and in 1531 out of 1668 monthly records in the northeastern United
Population biology of snowshoe hares. II. Interactions with winter food plants
It is suggested that snowshoe hares at Kluane did not experience an absolute food shortage in winter at peak densities, and that a relative food shortage was suggested.
Effect of climate change on fire regimes in northwestern Minnesota
Of all the impacts of projected climate change on forest ecosystems, perhaps the most difficult to forecast is the potential for altered fire frequency and intensity. Fire regimes in forests are
Ten-year periodicity in whooping crane census
Although the Whooping Crane (Grus americana) has received more public interest than perhaps any other endangered species in North America, amazingly little is known of the factors influencing its
During the winter in south-western Colorado, the porcupine feeds almost exclusively on the phloem layer of pinon pine (Pinus edulis) and western yellow pine (P. ponderosa) which is a favoured winter habitat for porcupines.
Association between the 11-Year Solar Cycle, the QBO, and the Atmosphere. Part II: Surface and 700 mb in the Northern Hemisphere in Winter
Abstract Sea level pressure, surface air temperature, and 700-mb temperature and geopotential height show a probable association with the 11-year solar cycle which can be observed only if the data