Year of Award

2013

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Geography

Department or School/College

Department of Geography

Committee Chair

Anna E. Klene

Commitee Members

Heather Almquist, Ragan Callaway, J. Stephen Shelly

Keywords

aerial photography, beavers, climate, peatlands, remote sensing

Abstract

Aerial photographs of nine peatlands along the Rocky Mountain Front, Montana, were analyzed in a GIS. The boundary of wetland extent was hand-digitized and the area within was classified into land-cover types including: total area, open fen, open water, woody vegetation, and non-wetland/agriculture. Changes in wetland extent and land-cover categories were evaluated from the earliest available imagery in 1937 to the last available imagery in 2009. Images prior to 1995 were orthorectified to correct inherent distortions. Results indicate little change in overall peatland area between 1937 and 2009 despite increasing air temperatures in the region. Open water area and the number of ponds increased over the study period, reflecting a rebounding beaver population. Agriculture in Pine Butte Fen, McDonald Swamp, and the Blackleaf Wetland Complex declined over the study period. Land purchases by the Nature Conservancy of Pine Butte Fen and McDonald Swamp have preserved the natural state of those peatlands, and they hold conservation easements for three of the other fens. One peatland is owned by the state and another is located within the Lewis and Clark National Forest. Conversely the sprawling Theboe Lake wetland has been heavily disturbed by ongoing agriculture since prior to 1937, and Bynum wetland has been heavily impacted since the middle of the study period.

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© Copyright 2013 Joseph Tyler Milbrath