| Title: |
Differing influences of natural and artificial disturbances on riparian cottonwoods from prairie to mountain ecoregions in Alberta, Canada |
| Authors: |
Samuelson, Glenda M.; Rood, Stewart B. |
| Source: |
Journal of Biogeography ; volume 31, issue 3, page 435-450 ; ISSN 0305-0270 1365-2699 |
| Publisher Information: |
Wiley |
| Publication Year: |
2004 |
| Collection: |
Wiley Online Library (Open Access Articles via Crossref) |
| Description: |
Aim Ecoregions represent biophysical zones where environmental factors enable the development of particular plant communities. Ecoregions are generally large but abrupt transitions occur in areas with rapid physical change. A particularly abrupt transitional sequence occurs in the Rocky Mountain region of south‐western Alberta where fescue prairie, aspen parkland and mountain ecoregions occur within 15 km. To investigate plant adaptation across ecoregions, our study investigated the influences of a natural disturbance (flooding) and an artificial disturbance (cattle grazing) on reproductive and population processes of black cottonwood ( Populus balsamifera subsp. trichocarpa , Torr. & Gray), the dominant riparian tree. Location We studied cottonwoods throughout their elevational range along two free‐flowing, first‐order streams, Yarrow and Drywood creeks. Cottonwood was the only prominent tree in the prairie ecoregion, the dominant riparian tree in the parkland and extended upward through the montane ecoregion where it was a pioneer species for the mixed coniferous–deciduous woodland. Cottonwoods did not occur in the higher elevation sub‐alpine ecoregion. Methods Thirty‐six cross‐sectional sampling transects were located across the three ecoregions with cottonwoods, and in ungrazed and grazed areas of each ecoregion. Rectangular 100 m 2 tree and 2 m 2 seedling quadrats were positioned along the transects, and substrate and vegetation were assessed. Historic hydrological data were analysed relative to flood recurrences and seasonal flow patterns. Results Overall, the cottonwoods displayed a sawtooth shaped ‘punctuated progressive age structure’ with many young trees, progressively fewer older trees, and about four pulses of increased recruitment over the past century. This was considered to provide a healthy cottonwood population and recruitment pulses were apparently associated with flood events with appropriate peak timing and magnitude and a gradual post‐flood stage recession. However, analyses of ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1111/j.0305-0270.2003.01052.x |
| Availability: |
https://doi.org/10.1111/j.0305-0270.2003.01052.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.0305-0270.2003.01052.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0305-0270.2003.01052.x |
| Rights: |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
| Accession Number: |
edsbas.7EC7EBC5 |
| Database: |
BASE |