Natural and historical variability in fluvial processes, beaver activity, and climate in the Greater Yellowstone Ecosystem

Auteur(s) et Affiliation(s)



Description :
The AA. used beaver-pond deposits as proxy records of beaver occupation to compare historical beaver activity to that throughout the Holocene. Carbon-14 (14C) ages on beaver-pond deposits from Grand Teton National Park indicate that beaver activity was episodic. These gaps in the sequence of dated deposits coincide with episodes of severe, prolonged drought, e.g. within the Medieval Climatic Anomaly. In contrast, many beaver-pond deposits date correspond to the colder, effectively wetter Little Ice Age. Abundant historical beaver activity in the early 1900s is coincident with a climate cooler and wetter than present. Reduced beaver populations after the 1920s, particularly in the northern Yellowstone winter range, are in part a response to elk overbrowsing of willow and aspen that later stemmed from wolf extirpation. Beaver populations on small streams were also impacted by low streamflows during severe droughts in the 1930s and late 1980s to present. Thus, both abundant beaver in the 1920s and reduced beaver activity at present reflect the combined influence of management practices and climate, and underscore the limitations of the early historical period for defining reference conditions.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 7, p. 728-750, nombre de pages : 23, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley