Mississippi Lake National Wildlife Area Management Plan: chapter 3

3. Management challenges and threats

3.1 Land use and development on Mississippi Lake and River

Mississippi Lake National Wildlife Area (NWA) is one of the few undeveloped areas along the shoreline of Mississippi Lake and River and provides a variety of habitats and refuge for wildlife in the surrounding area. It is important that the management of nutrient inputs to the lake continues, so that the health of the McEwen Bay ecosystem is not negatively impacted by development. High levels of phosphorus and nitrogen can increase plant growth, causing an ecosystem shift towards less desirable fish and invertebrate species that may include invasive species (EC, 2010).

There is increasing concern over potential long-term effects of multiple stressors on the Mississippi Lake subwatershed such as climate change, intensified urbanization and growth, pollution, and the introduction of exotic and invasive species (Symon, personal communication, 2012). In response to these concerns, the Mississippi Valley Conservation Authority (MVCA) in collaboration with Mississippi Lakes Association (MLA) initiated development of a Mississippi Lake Subwatershed Plan (MLSP) in 2011.The MLSP will identify adaptive strategies to maintain and improve water quality and water level management on Mississippi Lake (Symon, personal communication, 2012).

3.2 Public access issues

The effects of public access on wildlife and habitat have not been studied, and the types and frequency of prohibited activities are difficult to determine.

There is widespread support in the local community to protect Mississippi Lake NWA for wildlife, and to maintain public access to Mississippi Lake via the boat launch in the NWA. However, Environment Canada staff and contractor reports of damage to habitat and infrastructure indicate unauthorized access and prohibited activities are a common occurrence.  

The incidence of prohibited activities in the Mississippi Lake NWA, such as off-road all-terrain vehicle (ATV) and vehicle use, hunting, firewood collection and open fires, dogs off leash, camping, garbage dumping, vandalism, disturbance to wildlife, and fishing and boating in McEwen Bay (i.e., September 15 - December 15), creates additional pressures on resources required to prevent and mitigate effects.

Enforcement of prohibited activities and water access in McEwen Bay (September 15 - December 15) is a challenge due to lack of capacity (this is an unstaffed site) as well as the multiple access points to the NWA by water and neighbouring properties.

Misinterpretation of NWA boundaries and the prohibitions on access during fall migration, a lack of acceptance of the prohibition on public access and the designation as federally protected lands has occurred within the local community.

Public access to McEwen Bay and McIntyre Creek during the winter over the ice and water poses particular risks to human health and safety. Other hazards to visitors include Poison Ivy (Toxicodendron radicans) along trails.

Any increase in visitation to the NWA may require an increase in the maintenance of facilities (For example, parking lot, boat launch, access roads, trail and washroom), and actions to promote compliance and safe practices within the NWA.  

3.3 Non-native and invasive species

There are several non-native and invasive plant species at Mississippi Lake NWA, including Purple Loosestrife (Lythrum salicaria), Tartarian Honeysuckle (Lonicera tatarica), Scots Pine (Pinus sylvestris), Common Lilac (Syringa vulgaris) and Common Buckthorn (Rhamnus cathartica) (Hamill, 2009; Hamill and Thomson, 2012). Other non-native plant species such as Flowering-rush (Butomus umbellatus), European Frogbit (Hydrocharis morsus-ranae) and Eurasian Milfoil (Myriophyllum spicatum L.) have been reported in marsh areas within the NWA (Hamill and Thomson, 2012). The majority of these plant species currently do not present a management challenge: they create some competition with native plants for light and nutrients, but do not dominate. Problems may arise with more aggressive plant species that have the ability to rapidly spread, limit growth of native species and reduce habitat quality for wildlife. Other non-native and invasive species reported at Mississippi Lake NWA include Butternut canker (Ophiognomonia clavigignenti-juglandacearum), Earthworms (undetermined species), Double-crested Cormorant (Phalacrocorax auritus) and Zebra Mussel (Dreissena polymorpha) (Hamill, 2009; Hamill and Thomson, 2012). Vegetation and non-native and invasive species will be monitored regularly to identify the presence of non-native species, areas where species are expanding, and the effects on wildlife and habitat. Forecasting effective management options to reduce the spread and mitigate effects of these species is often hampered by limited knowledge and the ability of many of these species to adapt to Ontario growing conditions.

The Emerald Ash Borer (Agrilus planipennis) has made its way as far north as Sault Ste. Marie. Although it has not yet been confirmed in the NWA, its presence in surrounding areas suggests that it may soon become a threat. This insect kills all species of ash trees, including White Ash, a species found in the NWA (Canadian Food Inspection Agency [CFIA], 2011; White, 2008). The Emerald Ash Borer is able to fly several kilometres, although it is often spread through the transportation of wood products (CFIA, 2011). The CFIA has created wood and wood product movement restrictions to try and regulate the spread of Emerald Ash Borers (CFIA, 2011). These restrictions are not yet in place in Lanark County, but they are in place in the nearby Ottawa and the Leeds and Grenville regions (CFIA, 2011). Tree or wood products cannot be transported out of these regions, in an attempt to reduce the spread of this pest (CFIA, 2011).

There is a well-established Zebra Mussel (Dreissena polymorpha) population in Mississippi Lake (Lee, personal communication, 2011). Zebra Mussels have altered aquatic ecosystems within both Mississippi Lake and McEwen Bay (MVCA, 2008). At this time, there are no methods to stop the spread of Zebra Mussels once established, and the effects on wildlife and habitat within the NWA are unknown.

3.4 Feral and domestic animals, and overabundant wildlife

Wildlife such as Beaver, though native to Ontario, can become overabundant and create management challenges for NWA staff. Beavers cause damage to trees, and the construction of dams may alter hydrology within the NWA and neighbouring properties (Robinson, personal communication, 2012).

Other animals that can pose challenges for management of the site include feral cats, dogs, livestock, and wildlife such as skunks, raccoons, and groundhogs. These animals may be feral strays and in some cases are unwanted domestic pets (For example, turtles and fish), livestock from neighbouring properties or unwanted wildlife (For example, skunks and raccoons) that have been released illegally in the NWA.

While the number of feral and domestic animals on the NWA may be few and infrequent, these animals can exert significant predatory pressure on native wildlife through nest destruction and eating eggs and individuals (i.e., birds and turtles), transferring disease and pathogens to wild animals, as well as disrupting natural habitats through soil disturbance, and require ongoing active management.

3.5 Water level management on Mississippi Lake and River

The wetland habitat of Mississippi Lake NWA is dependent on the maintenance of water levels in the Mississippi River (OMNR, 2006). Water levels within McEwen Bay are directly affected by the operation of the dam at Carleton Place.

Studies examining water levels and flows and the potential impacts of climate change within the Mississippi valley watershed have indicated that stream flows could be 40% less than present by summer of 2099, with periods of intense rainfall, resulting in additional nutrient loading and decreased capacity to assimilate nutrient loads (Symon, personal communication, 2012; Bruce et al., 2000).  Mississippi Lake has a low flushing rate and is particularly susceptible to nutrient inputs from its extensive 2900 km2 upstream drainage area (Symon, personal communication, 2012).  

There is a need to develop adaptive management strategies to consider water level changes over time and other potential effects of climate change and variability on habitat and wildlife, and to identify whether habitat management practices to restore and protect water quality within Mississippi Lake NWA and the broader Mississippi Lake watershed are needed.

3.6 Multi-species conservation and Species at Risk

Multi-species conservation and recovery is an ongoing challenge in the Mississippi Lake NWA. Many species have complex habitat requirements that are not well understood, and small and/or widely distributed populations are often underrepresented in general research studies, and site-specific habitat requirements are unknown. It is anticipated that "critical habitat" (under SARA), necessary for the conservation and recovery of species at risk may be identified for a number of species on the NWA. A foreseeable challenge will be how to balance the varying habitat needs of multiple species: both common and species at risk.

3.7 Legacy issues

Ungazetted lands

Following the establishment of the NWA in 1977, Environment Canada Canadian Wildlife Service (EC-CWS) acquired two additional parcels of land totalling 15 ha, adjacent to the NWA. These lands are in the process of being gazetted and will be managed as part of the Mississippi Lake NWA. However, in the interim the Wildlife Area Regulations do not apply. This situation presents a management challenge to establish a consistent management approach for all NWA parcels.

Ownership and maintenance of fences are shared (between EC-CWS and neighbouring land managers). Once all lands are gazetted, boundaries and land and water management practices will be reviewed. It is anticipated that the continuation of shared ownership and arrangements for maintenance will need to be formalized to ensure responsibilities and commitments are documented. In some cases, boundary delineation at the field level needs to be clarified to promote management practices and land uses that are compatible with management objectives for the NWA as well as neighbouring land managers’ objectives. This situation is of particular concern along waterways, where it may not be feasible to post boundaries and restrict access, and adjacent to agricultural lands where buffers are narrow or non-existent, and habitats may be vulnerable to damage from adjacent land use practices.

National Wildlife Area and Migratory Bird Sanctuary boundaries

There is a long history of hunting and sport fishing within Mississippi Lake, both within and outside the NWA, prior to the establishment of the Migratory Bird Sanctuary (MBS) and NWA. Access to the NWA and recreational activities within it are restricted because a key conservation purpose is to provide undisturbed staging habitat for migratory waterfowl. Since the establishment of the MBS (1959) and NWA (1977), hunting is not allowed in the MBS and NWA, and recreational boating and sport fishing (no lead sinkers) are prohibited during a portion of the year.

The NWA and MBS boundaries are not identical; they extend on land and water, and sometimes cause confusion for neighbouring landowners and visitors (by land and water) regarding prohibited and authorized activities relative to the boundaries of the NWA and MBS. It is a particular management challenge to communicate boundaries along the water to visitors accessing the NWA by water.

Environmental site assessment

EC-CWS works with Environment Canada’s Contaminated Sites Program to conduct site audits to identify contaminants, assess risks and remediate contaminants on federal lands.

The Phase I and Preliminary Phase II (combined) Environmental Site Assessment at Mississippi Lake NWA was completed in 2008 by Environment Canada’s Contaminated Sites Program to assess legacy issues (For example, vacant structures, waste and debris) (Franz Environmental Inc., 2009). There was no need for further site investigation or remediation identified at that time (Franz Environmental Inc., 2009).

^dLevel of Priority: 1 (from 0 to 3 years); 2 (from 4 to 6 years); 3 (from 7 to 10 years)