Presentation Type

Presentation

Faculty Mentor’s Full Name

Ben Colman

Faculty Mentor’s Department

W.A. Franke College of Forestry & Conservation

Abstract

Like many streams in the northern Rocky Mountains, Ninemile Creek in Western Montana was degraded by placer mining. This type of gold mining leaves a legacy of physical transformation to the stream, characterized by a highly incised and straightened river channel disconnected from the floodplain. These changes to the physical structure cause low streamflow during much of the year which is then punctuated by increased pulses of water during spring snowmelt and even rainfall events. This combination of physical and hydrologic changes render the creek an unsuitable habitat for many invertebrates, fish species, and mammals, including beavers. Recently, restoration in the Ninemile Creek watershed led by Trout Unlimited (TU) has reintroduced sinuosity and increased floodplain interaction with the river channel in three reaches of the stream which were restored in 2014, 2016, and 2018. To expedite recovery of the biotic component of this newly constructed floodplain ecosystem, TU planted willows and used a native seed mix representative of riparian plant assemblages in the region. To evaluate the riparian vegetation recovery, soil characteristics, and beaver presence, a post-restoration monitoring effort was implemented in 2019 across all three restored reaches. Line point intercept (LPI) method was used to assess vegetation growth forms and surface types along transects perpendicular to the stream channel, beginning at the bank. Signs of moose and deer browse were also documented when observed within the transect. Soil samples were collected at a single randomly selected point on each transect and beaver structures were documented and mapped along the restored reaches. These measurements were taken at each restoration site, and at a reference reach which never experienced placer mining. The results show measurable differences in percent cover and distribution of vegetation types, predominant soil characteristics and beaver presence among the reaches. The data gathered will inform TU on how to more effectively restore and adaptively manage their current and future restoration activities on the Ninemile Creek and other similar restoration projects.

Category

Physical Sciences

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The Pace of Recovery of Riparian Ecosystem Structure in Restored Reaches of Ninemile Creek

Like many streams in the northern Rocky Mountains, Ninemile Creek in Western Montana was degraded by placer mining. This type of gold mining leaves a legacy of physical transformation to the stream, characterized by a highly incised and straightened river channel disconnected from the floodplain. These changes to the physical structure cause low streamflow during much of the year which is then punctuated by increased pulses of water during spring snowmelt and even rainfall events. This combination of physical and hydrologic changes render the creek an unsuitable habitat for many invertebrates, fish species, and mammals, including beavers. Recently, restoration in the Ninemile Creek watershed led by Trout Unlimited (TU) has reintroduced sinuosity and increased floodplain interaction with the river channel in three reaches of the stream which were restored in 2014, 2016, and 2018. To expedite recovery of the biotic component of this newly constructed floodplain ecosystem, TU planted willows and used a native seed mix representative of riparian plant assemblages in the region. To evaluate the riparian vegetation recovery, soil characteristics, and beaver presence, a post-restoration monitoring effort was implemented in 2019 across all three restored reaches. Line point intercept (LPI) method was used to assess vegetation growth forms and surface types along transects perpendicular to the stream channel, beginning at the bank. Signs of moose and deer browse were also documented when observed within the transect. Soil samples were collected at a single randomly selected point on each transect and beaver structures were documented and mapped along the restored reaches. These measurements were taken at each restoration site, and at a reference reach which never experienced placer mining. The results show measurable differences in percent cover and distribution of vegetation types, predominant soil characteristics and beaver presence among the reaches. The data gathered will inform TU on how to more effectively restore and adaptively manage their current and future restoration activities on the Ninemile Creek and other similar restoration projects.