Riparian Zone Variability In the Foothills of Alberta



Abstract
Introduction
Data
Methods
Results
Discussion
Sources of error
References
Discussion

Topographic variation


Steeper and more rugged riparian forest floors could input woody debris more often, due to increased rates of treefall on unstable surfaces.   These areas may also contribute fallen wood from a larger source area than flatter areas would because dead trees and branches are more likely to roll down the banks.  The correlations show that these processes are more likely to occur in high elevation streams, so we could expect to find more abundant woody debris there than in my study reaches.   Streambed roughness also increases with elevation.  This could indicate an increase in slope, which would increase the liklihood of woody debris transport.  Alternatively, it could indicate complex streambed topography which would trap woody debris and prevent transport.  Oddly, streambed roughness cannot be reliably predicted by riparian zone roughness.

I find it interesting that stream order isn't a predictor of stream bed or riparian floor roughness at all; streams are frequently catagorized by order as if this reference system indicates something about their structure and ecology.  My results  seem to show that, in this system, this is not the case.

Forest analysis


I had expected to find fewer spruce riparian zones in low order, high elevation streams because spruce tends to prefer wet soil, and small upland streams don’t appear to affect soil moisture enough to encourage Spruce growth.  I expected fewer riparian zones in large streams that are subject to more frequent vegetation-destroying floods because in my experience these stream banks tend to be vegetated by alder and willow.  However, old growth spruce forests were not restricted to lower elevation reaches, and were not more common in medium-order streams.  Nevertheless, a significant proportion of riparian zones were forested with old growth Spruce stands, and could be considered comparable to my study sites.


Applications

Once zonal statistics have been completed for the remaining watersheds this website will act as interactive database of riparian conditions in the entire Hinton Wood Products Forest, providing landscape-wide riparian data at unprecedented resolution.  It will be made available to the Foothills Research Institute, where models of natural disturbance and fluvial reference conditions are being developed.


Further analysis

Most of the work that went into this project was to generate a huge riparian zone dataset for future analysis.  If time weren't so short, here are some things I would have liked to do:
  • Compare the proportion of old growth riparian forest between watersheds.
  • Combine old growth spruce and riparain roughness data to identify zones with both similar forest and similar topography to my study sites.
  • Create multiple buffer widths to see if the relationship between streambed and streamside roughness changes with distance.
  • Check for spruce distribution in higher elevation watersheds, like the Berland River, which borders the Jasper Park mountain range.
  • Compare riparian characteristics between a sequence of watersheds ranging from prairie to mountainous environments.

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Sources of error