Phragmites Infestation in the Bear Creek Wetland
Phragmites Infestation within the Bear Creek Provincially Significant Wetland Complex
By David Featherstone, Senior Ecologist
March 31, 2020
Project objective
Phragmites australis subsp. australis (hereinafter “Phragmites”) is considered one of the “dirty dozen” invasive species in the NVCA watershed. Initial Phragmites colonization is often associated with seed dispersal. As seeds enter tributary and drainage systems, downstream colonization may occur. Once established, it spreads aggressively from its extensive root systems and also releases toxins from its roots, hindering the growth of native plants. Dense stands create a poor habitat for native marsh vegetation and wildlife. Seeds and root fragments attached to vehicles are a likely spread vector particularly when they are released (inadvertently) to disturbed areas.
Phragmites infestation has been noted along the edges of transportation corridors in the Bear Creek Wetlands, a Provincially Significant Wetland.
The purpose of this project is to approximate the degree of infestation of invasive Phragmites along the various edges of the Bear Creek wetland complex. This project dovetails with the NVCA Invasive Species Strategy and assists with Rick Irvin (local resident) and other community partners who are spearheading local Phragmites initiatives.
Bear Creek Wetlands
The Bear Creek Wetlands is a provincially significant wetland complex that lies astride the boundary of the Lake Simcoe Region Conservation Authority (LSRCA) and the Nottawasaga Valley Conservation Authority (NVCA). Bear Creek Wetland was evaluated in 1984 by the Ministry of Natural Resources (MNR) as Class IV (regionally significant wetland). At the time, it was considered the second largest wetland complex within the NVCA watershed (998.1 ha). In 1992, NVCA and the Brereton Field Naturalists (now Nature Barrie) requested that MNR undertake a re-evaluation of the wetland. MNR undertook the re-evaluation in 1993, resulting in an upgrade of the complex to a Class II provincially significant wetland.
This wetland supports the headwaters of Bear Creek including sensitive coldwater brook trout streams. A variety of reptiles and amphibians, including Species at Risk, inhabit the wetland complex. Often in combination with contiguous upland natural areas, Bear Creek wetland provides deep, core forest habitat which supports a variety of wildlife species that require this core habitat to thrive.
Much of the Bear Creek wetland complex lies within or proximal to a rapidly urbanizing area associated with the City of Barrie as well as areas proximal to major road corridors such as County Road 90 and County Road 27. Land use conversion associated with development and road construction/improvement has and continues to impact the wetland. NVCA monitoring data has confirmed that Bear Creek tributaries have been negatively impacted by urbanization.
Methodology
Throughout 2019, Phragmites was documented via a presence/absence survey along roadways that bisect the Bear Creek Wetland Complex and GPS points in addition to photos were collected along the various roadways that bisect the wetland complex. Brief walks were conducted along publicly accessible paths within and adjacent to the Bear Creek Eco Park, located just east of Ferndale Drive south of Tiffin Street. Phragmites points away from roads were also included and consist of stormwater ponds, utility right-of-ways, disturbed sites visible from road and from past site visits. Figure 1 illustrates the distribution of Phragmites documented through these surveys.
Figure 1: Phragmites Observations 2019.
Field-based observations
Phragmites was common to ubiquitous along the majority of roads bisecting the PSW complex. Particularly significant infestations were present along:
- County Road 90 east and west of County Road 27,
- County Road 27 south of County Road 90,
- Ferndale Drive, and
- Tiffin Street (LSRCA).
Infestations are concentrated along roadside ditches along these thoroughfares. Although not formally measured as part of this project, infestations in the order of 200 m to in excess of 300 m long are present along portions of County Road 90 and County Road 27 and it is postulated that the infestation is centred at the intersection of these two roads.
Phragmites infestations were also observed in the following areas:
- Stormwater facilities (off County Road 90 and Ferndale Drive),
- Disturbed properties off County Road 90,
- Marshes north of Dunlop Street (LSRCA), and
- Off-road wetlands north of Ardagh Road and Bear Creek Eco Park.
Approximate location and extent of infestations are shown in Figure 1. This figure also outlines the Bear Creek wetland complex, including areas mapped by Ministry of Natural Resources and Forestry (MNRF) as well as wetlands mapped by NVCA proximal to these wetlands. The watershed divide between NVCA and LSRCA is also identified. Photos associated with these areas will be circulated to recipients via Dropbox.
Correlation with Recent Developments
Phragmites infestations appear to have a correlation with recent construction/development in the area including:
- County Road 90 improvements post-2008,
- County Road 27 improvements post-2002,
- Ferndale Drive construction post-2002,
- Post-2002 stormwater facilities off County Road 90 and Ferndale Drive, and
- Post-2002 disturbed areas off County Road 90 and north of Summerset Drive.
Road right-of-way and utility corridor maintenance activities may also be a contributing factor.
These findings align with known vectors/suitable conditions for spread of this invasive species. Initial Phragmites colonization is often associated with seed dispersal. As seeds enter tributary and drainage systems downstream colonization may occur. Seeds and root fragments attached to vehicles are also a likely spread vector, particularly when they are released (inadvertently) to disturbed areas. Once established, Phragmites spread is often associated with extension from its extensive rhizome (root) system.
Recommendations
Phragmites is a challenging issue within the Bear Creek Wetlands. The infestation is well-established and it is envisioned that established roadside stands may colonize further into the interior of the wetland. Continuing development and road and right-of-way improvement/maintenance pose ongoing risks for Phragmites colonization. Over time, this has the potential to significantly impact wetland biodiversity and associated fish and wildlife functions associated with this provincially significant wetland.
The following recommendations are informal and do not denote any responsibility for any agency (including NVCA) to follow through or manage this extensive problem; however, I offer the following:
- Implementation of clean vehicle protocols (private sector, public sector) would be helpful to minimize spread of Phragmites (please refer to the Ontario Invasive Plants website)
- Other education and outreach opportunities should be explored. Here are some examples.
- Disturbed areas should be restored to vegetation cover (including use quick-growing nurse crops) as soon as possible to minimize time available for Phragmites to colonize disturbed and exposed soils.
- Work with the City of Barrie to initiate a community project to address Phragmites stands in Bear Creek Eco Park, as well as an opportunity to better define extent of Phragmites through field work in this important and popular local natural area.
Potential opportunities to further refine Phragmites mapping throughout the study area, including but not limited to refinement of roadside stand polygons and grading; mapping of right of way stands and other public lands within the wetland, etc.
For more information or for a copy of this document in an alternative format, please contact NVCA at 705-424-1479 or admin@nvca.on.ca