North American porcupine (Erethizon dorsatum) feeding scars on trees were used as an index of past porcupine abundance in the Bas St. Laurent region of eastern Quebec, Canada. The frequency distribution of scars revealed that porcupine populations have fluctuated regularly over the past 130 years in the Bas St. Laurent region, with superimposed periodicities of 11 and 22 years. This porcupine population cycle has closely followed the 11 and 22-year solar activity cycles. An analysis of local temperature and precipitation data revealed a close relationship between fluctuations in annual precipitation and both the solar cycle and the porcupine cycle. These results suggest that the solar cycle has sufficiently important effects on the climate along the southern shore of the St. Lawrence estuary to influence terrestrial ecosystem functioning to the point of setting the rhythm of porcupine population fluctuations. This is the strongest available evidence of a top-down cascading effect of solar variability on ecological systems at the decadal time scale and local spatial scale. These results confirm and extend those obtained by others at greater temporal and spatial scales and provide exciting opportunities for future research on the extensively debated topic of solar variability and its impact on our planet.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.78395 |
| Date | January 2002 |
| Creators | Klvana, Ilya |
| Contributors | Berteaux, Dominique (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001985314, proquestno: AAIMQ88230, Theses scanned by UMI/ProQuest. |
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