8 Evaluation of significant wildlife habitat
Evaluation is the process of determining if wildlife habitat should be considered significant under the Natural Heritage Features and Areas Policy and therefore warrants protection under the Planning Act. Specific wildlife habitats are compared to evaluation criteria to determine if they should be considered significant. Appendix Q provides lists of evaluation criteria for significant wildlife habitat. The evaluation process can be used to determine if a habitat meets a minimum standard for significance. The evaluation criteria can also be used to compare one potential significant wildlife habitat to another, if they need to be ranked. This may be necessary where there are several potential sites and the planning authority wants to place the greatest emphasis on the best sites.
The evaluation process is an important step for designating lands for protection. It can also be used to identify sites that merit further study because of their apparent conservation value or to identify suitable candidates for future restoration efforts. Evaluation allows a planning authority to focus its time and resources on sites that are most likely to be significant. The degree of representation of significant natural heritage features and areas within a planning area is a very important element of evaluation. In order to achieve a comprehensive Natural Heritage System, all natural heritage features and areas should be well represented, or at the very least opportunities for restoration should be identified.
Not all identified wildlife habitats will prove to be significant for the purposes of the Natural Heritage Features and Areas Policy. In landscapes that are still very natural, there are more likely to be some habitats that, although they have value for wildlife, will not be considered significant because they are well represented in the planning area. In areas with very little natural cover remaining, it is more likely that a high proportion of the identified habitats will be considered significant.
8.1 Evaluation criteria and guidelines
The evaluation process involves examining a number of criteria that describe key ecological functions of the habitat. Table 8-1 provides a list of criteria for evaluating wildlife habitat. They provide a comprehensive overview of the most common evaluation criteria used by wildlife and conservation biologists. More specific criteria are presented in Appendix Q.
The criteria listed in Table 8-1 have not been weighted, although this can be done as part of a ranking process (see Chapter 9). However, a high emphasis should be placed on representation. It is expected that for many of the wildlife habitats listed in this guide, the application of the criterion current representation of the wildlife habitat in the planning area will be sufficient to determine that a specific habitat is at least locally significant. If a particular type of habitat is poorly represented in the planning area, then it is very likely all examples of this habitat should be considered significant. There may not be a need to apply every criterion to a particular habitat if it has already been determined to be significant. Some further examination may be beneficial in situations where there is a desire to determine what aspects might be improved at some point in the future. A planning authority may also consider breaking their planning area into physiographic units for determining representation within the planning area. Some physiographic features are unique, such as the Oak Ridges Moraine or Niagara Escarpment, and representation within that feature may make more sense than representation within the planning area as a whole.
In general, habitat evaluation should not be a costly and time-consuming exercise. It should first concentrate on criteria that can be evaluated using existing information. Some criteria can be applied using aerial photographs and topographic maps. If the habitat is deemed significant using these criteria, it may not be necessary to conduct a field survey. However, there may be situations where fieldwork is necessary.
Extensive searches for hard-to-find habitats, such as snake or bat hibernacula are not recommended, particularly if the species is unlikely to occur in the planning area. In areas where particular species have been recorded, but critical habitats have not been found, some potential sites can be indicated on maps so that future investigations can be focused on these areas.
The difficulty of finding precise locations of the significant wildlife habitats of some species emphasises the value of adopting some of the basic principles of a landscape approach to planning, discussed in Chapter 2. This includes ensuring that there is adequate representation of all habitat types within the planning area. Although this approach cannot guarantee that all critical portions of habitat of a particular species will be adequately protected, there is a greater probability that these important habitats will be protected than if some habitat types are not included in the Natural Heritage System.
| Criteria | Definition and implications |
|---|---|
| Current representation of wildlife habitat, species, or natural features in the planning area |
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| Abundance |
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| Species diversity |
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| Presence of species of conservation concern (e.g. rare, vulnerable, threatened, endangered, declining, uncommon, sensitive, endemic species) |
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| Ability of the site to meet the known habitat requirements of target species |
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| Condition/quality of site |
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| Potential for long-term protection of site/habitat |
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| Provision of several significant wildlife habitats |
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| Size of habitat/site |
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| Shape of habitat/site |
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| Location of habitat/site |
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| Habitat diversity/complexity |
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| Evidence of use |
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| Other perceived values |
|
8.2 Field investigations
At times, there will be a need for field investigations to collect important habitat information pertaining to some of the evaluation criteria (habitat quality, species richness). More than one visit to a site is not encouraged, unless necessary, such as to obtain seasonal information. If a site is visited during identification, then sufficient information should be collected at that time for evaluation. Appendix D describes the types of information that should be collected during a field investigation.
The following Sections (8.3 to 8.6) discuss important factors to consider when evaluating specific wildlife habitats.
8.3 Evaluation of habitat of seasonal concentrations of animals
Table Q-1 in Appendix Q lists criteria and suggested guidelines for evaluation of seasonal concentrations of animals. The following section describes key factors to consider during the evaluation of seasonal concentrations of animals. It expands on some of the criteria and provides additional detail that is not in the table. In general. for determining significance, the greatest emphasis should be placed on the following:
Representation - this can include representation at the large scale, such as habitat for species that are provincially rare, or it can include representation at the local level
Abundance - habitats supporting high numbers of animals relative to other habitats of the same species within the planning area
Rare Species - the presence of rare species (or species of conservation concern) in an animal concentration area, adds to the probability it will be significant
Multiple Benefits - these are habitats that not only provide habitat for a seasonal concentration of animals, but also other significant wildlife habitat as well, such as rare vegetation communities, specialised habitat for wildlife, habitat for species of conservation concern and/or and animal movement corridor.
Not all sites identified as candidates for protection will be significant. In some cases, there will be better examples of the same habitat within the planning area. Some habitats may not be sustainable due to serious habitat limitations that were not identified earlier. Some habitats may not meet a minimum standard for habitat quality and sustainability. For example, a winter deer concentration area may have been identified. However, the site may support only a very small number of deer in winter. Although any concentration of deer may be important, the number of deer using the concentration area may be too small to be considered significant in the context of land-use planning.
Habitat evaluation can be difficult. One difficulty is in finding some of the habitats. This has been discussed in Chapters 2 and 4. Another difficulty is determining the degree of significance of some of the criteria for the identified habitats. Examples include knowing the relative importance of a winter deer yard to the local deer population and knowing the relative importance of a colonial bird nesting site to the local population. The planning authority may not have the expertise to be confident in making a decision on these criteria. Many government agencies and non-government organisations have knowledge of many of these species and their habitats. These organisations should be consulted whenever possible. Appendix F provides a list of agencies and their areas of expertise. Appendix G lists information sources for seasonal concentrations of animals. This information will be helpful when using the evaluation criteria.
See Chapter 4 for a detailed description of seasonal concentration areas and their functions.
8.3.1 Winter deer yards
The OMNR is responsible for managing deer in Ontario. Staff responsible for deer management, are aware of most deer winter habitat and should be consulted about the relative importance of deer yards to the planning area.
The significance of a particular deer yard depends on its context in the landscape. In areas where deer populations are high (and there are a number of large deer yards distributed across the landscape), some of the smaller yards may not be considered significant with respect to the application of the Natural Heritage Features and Areas Policy. That is not to say those small deer yards do not have value. All winter habitat for deer has value. It simply means that not all areas will be designated as significant wildlife habitat. In areas where deer are not as abundant and wintering deer are found in a limited number of small yards, all of the deer yards may be considered significant.
Deer management goals can also be used to determine significance. In many parts of Ontario, deer provide high numbers of recreational opportunities, both for viewing and for hunting. Revenue generated from these opportunities is not only important to the local economy, but to the province as a whole. This contrasts to some urban areas where too many deer may be considered a hazard on the roads and a nuisance to landowners. These areas are often not open to hunting.
Deer yard quality is determined from field investigations. Deer yard surveys can be used to determine the quality and extent of the conifer cover, the amount of food available and the relative density of the deer population with respect to the carrying capacity of its habitat.
The planning authority must work cooperatively with the Ministry of Natural Resources in setting deer management objectives. If there are numerous complaints about crop depredation or concern about high numbers of deer-motor vehicle accidents, the Ministry can set higher harvest targets to keep numbers down.
8.3.2 Moose late winter habitat
The OMNR is responsible for the management of moose in Ontario. The Ministry conducts aerial moose inventories once every three years for each Wildlife Management Unit having moose populations. The inventories are normally conducted in January and early February. Although the surveys are not conducted specifically in late winter, OMNR staff may be aware of locations of late winter habitats. They should be contacted for information about the relative importance of any late winter moose habitat.
If moose are common in the planning area, the planning authority should be aware there might be late winter moose habitat that has not been identified. This may be of greatest concern when associated with the shorelines of lakes where there may be potential for conflict with cottage development.
It is recommended that the planning authority contact the OMNR to find out the location and importance of any known late winter moose habitat on Crown land within their jurisdiction, particularly those areas of Crown land that are closely associated with private land where there could be potential conflict.
8.3.3 Colonial bird nesting sites
Agencies such as OMNR, Canadian Wildlife Service, and Bird Studies Canada have information on colonial nesting species. Staff at these agencies can be consulted as well as reference texts such as the Atlas of the Breeding Birds of Ontario to determine the relative importance of colonial nesting species in a particular planning area. Nesting colonies that are poorly represented should be considered most significant.
Nesting colonies that support rare species and species that are highly sensitive to disturbance should be considered significant. Higher priority should be given to rarity at the larger scale, such provincial rarity, than rarity at the local level.
Often when evaluating and ranking more than one colony, the number of nests in the colony is one important criterion used to compare colonies. This criterion should also consider whether the colony is expanding or declining. A new colony that is expanding may have a greater chance of long-term sustainability, than a colony that is declining.
Historical use of a colonial nesting site can be an important criterion. Colonies with a long history of use are highly significant. The evaluator should also consider new and expanding populations. Some populations may be recovering due to improvements in water quality or habitat. Colonies for some of these species may not have a long history of use, but they are still very important.
In some cases, potential habitats may also be considered for protection, particularly for species with expanding populations or for species that are forced to move periodically (such as herons where the nesting trees fall down).
Some colonial nesting species can be considered a nuisance when their populations get too high. Examples are ring-billed gulls and double-crested cormorants. These birds and their nesting habitats are protected under the Migratory Birds Convention Act. The planning authority must decide if the colonies in their jurisdiction require additional protection through the Planning Act.
8.3.4 Waterfowl stopover and staging areas
Generally, the most significant areas support the greatest number of birds and/or species in the planning area. The best areas tend to be very large wetlands. These are often associated with lakes, but that is not always the situation. The best wetlands generally have a diversity of vegetation communities interspersed with open water. Many of the marshes along the Great Lake shorelines are particularly valuable as waterfowl migration stopover habitat because they have an excellent mix of deep open water and shallow marsh habitat.
The Canadian Wildlife Service (CWS) is the lead agency for waterfowl management in Canada. They routinely conduct migration surveys in late fall and early winter. CWS staff are knowledgeable of most of the major migration stopover sites. OMNR conservation officers check waterfowl hunters in the fall and are often aware of locally significant staging habitat. These staff may also know if some uncommon species frequently use certain wetlands. OMNR staff is frequently involved in waterfowl management projects, such as projects associated with the Eastern Habitat Joint Venture. OMNR wetland evaluations include the degree of use of the wetland by migrating waterfowl. Staff at these agencies should be contacted for advice on the relative importance of waterfowl migration stopover and staging habitat.
The amount and distribution of staging areas within the planning area may determine the significance of some locally important staging areas. Some planning areas will have very few large wetlands with open water that can be used by staging waterfowl. All of these wetlands may be very important. Other planning areas may have several locally important staging habitats and the planning authority may want to use the criteria in Appendix Q to determine which areas are best.
Appendix G, the wildlife habitat matrices, lists the habitat requirements of migrating waterfowl. Knowledge of waterfowl staging habitat requirements is important when determining which sites are most significant.
The permanency of wetlands should be considered. Some wetlands, such as new beaver floods, may be temporary. Some of these ponds may be very attractive to locally staging waterfowl for a few years, but when beaver leave the pond they may no longer support staging waterfowl. The highest significance should be placed on permanent wetlands and wetlands that have provided habitat for staging waterfowl for many years.
8.3.5 Waterfowl nesting habitat
Marshes and swamps have greater value to nesting waterfowl than bogs and fens because they are more productive and have more permanent open water. However, bogs and fens are important to certain waterfowl species, and should not be ignored as potential significant waterfowl nesting habitat. Large wetlands and clusters of small wetlands located close to one another usually support greater waterfowl production than single small wetlands.
A number of agencies such as the OMNR, Canadian Wildlife Service, and Ducks Unlimited are very actively involved in waterfowl management in Ontario. Some of these agencies routinely conduct brood surveys in late spring and early summer. OMNR has completed about 2000 wetland evaluations in southern Ontario. Each of these evaluations provides an estimate of the relative value of the wetland for waterfowl nesting. These agencies should be contacted for advice on the relative importance of waterfowl nesting habitat in the planning area.
In 1996, a group of waterfowl experts assembled to develop criteria for determining the significance of waterfowl breeding habitat. Their report is included as Appendix K.
In general, the most significant sites will consistently support large concentrations of nesting waterfowl, species of conservation concern, or a variety of species. All known nesting habitat for ruddy duck, gadwall, northern pintail, green-winged teal, American wigeon, and northern shoveler should be given high priority for protection. These species are uncommon nesters in Ontario. Black duck populations have declined in many parts of North America, in large part due to hybridisation with mallards. In southern Ontario, wetlands supporting black duck nesting should be considered significant. Due to the decline of waterfowl, populations in North America, Canada and the U.S.A. signed the North American Waterfowl Management Plan. Considering the continental objectives for waterfowl, sites with high concentrations of more common nesting species, such as mallards and blue-winged teal, should also be considered significant.
A good distribution of nesting habitat should be protected across the planning area. In parts of the planning area where no large highly diverse wetlands remain, some smaller wetlands should be considered significant because they add to the diversity of the planning area.
8.3.6 Shorebird migratory stopover sites
There are a number of sources that can be consulted for information on shorebird stopover habitat (see Appendices A and F). Agencies that have knowledge of important shorebird stopover habitat include OMNR, Canadian Wildlife Service, Bird Studies Canada, and The Federation of Ontario Naturalists. Staff with these agencies and other information sources should be consulted to determine the relative importance of shorebird habitat in the planning area.
The Great Lakes shorelines provide some of the best habitat for migrating shorebirds. Many of these sites have been used for many years and should be considered significant.
High quality shorebird stopover habitat is often in short supply. If a site is lost, birds have no alternate habitats to use or may be forced to use inferior sites which results in increased mortality and subsequent population declines.
Most significant shorebird stopover habitats have a long history of use. Many local birdwatchers will be knowledgeable of these areas.
If there is little information about shorebird stopover sites for a planning area, an examination of aerial photographs and topographic maps will be helpful in determining the relative importance of a site.
Natural, permanent sites are generally more significant than artificial sites such as sewage lagoons or temporarily flooded or exposed areas such as mudflats. An exception would be where natural sites do not exist in the planning area and the only sites available are artificial.
The level of threat to a site should also be considered during evaluation. This is particularly important when considering the Lake Ontario and Lake Erie shorelines. Large portions of these shorelines have been developed, especially near large urban areas. Those sites that remain are extremely important and should be considered significant.
8.3.7 Landbird migratory stopover areas
There are a number of information sources on migrating landbirds (see Appendix F). There are also a number of agencies involved in the protection and management of landbirds. These include Canadian Wildlife Service, Bird Studies Canada, Federation of Ontario Naturalists, and the Ontario Ministry of Natural Resources. The sources and staff from these agencies should be consulted for information on the relative importance of stopover sites in a planning area.
Many significant landbird stopover sites are located within 2 to 10 km of Great Lake shorelines because migrating birds follow these shorelines moving to narrow crossing points to continue their migration. The Niagara Escarpment forms a natural corridor for migrating birds from Niagara Falls to the Bruce Peninsula and onto Manitoulin Island and northern Ontario. Sites with a high diversity of habitat types are best.
Sites that consistently support high numbers of birds, as well as a high diversity of species, including rare species, should be considered significant. Many of these sites will have a long history of use. This type of information can be obtained from local birdwatchers.
8.3.8 Raptor wintering areas
Many raptor wintering areas are used year after year. Few agencies actually monitor these habitats and they will have little information on the relative importance of a particular site. It is important to ensure there is good representation of this habitat in the planning area. Often local naturalists will be aware of sites that consistently attract raptors. Site visits in winter may be necessary to confirm that an area is used by wintering raptors. If a Christmas bird count is conducted in the area, the coordinator of the count should be contacted to find out where raptor concentrations occur.
Raptors frequently hunt over large areas and, as winter progresses, prey populations decline. Therefore, it is important to protect sites that are large enough to support wintering raptors for the entire winter. The best sites should be at least 25 to 30 ha in size.
Sites that consistently support large numbers of birds should be considered significant. The presence of large numbers of birds throughout the winter is a good indication that there are abundant prey populations and there is the right mix of food and cover.
The landuse of a site should be noted. Sites that are most likely to remain unchanged for several years are preferred. Cattle pastures often remain unchanged for many years, whereas hay fields can be cultivated and different crops planted that make the site unsuitable. Sites that are least disturbed are preferred and sites that are part of a rural landscape are preferred to those surrounded by urban development.
8.3.9 Wild turkey wintering areas
The OMNR has responsibility for wild turkey management in Ontario. Staff from the OMNR should be contacted for advice on the relative importance of wild turkey winter roosting habitats to the local planning area. Sites that consistently support large numbers of birds are most significant.
The amount of potential roosting cover is an important consideration when determining significance. In some parts of a planning area, conifer cover may be in short supply. It is common in these situations for the birds to move a considerable distance from their daily feeding area to their nighttime roosting cover. These roosting sites are very important and should be protected. Areas of potential roosting cover can be identified on aerial photographs and these can be compared to the distribution maps from the local OMNR.
At times, turkeys will roost close to houses and people. These birds are susceptible to disturbance. Activities such as snowmobiling and free-running dogs can prevent turkeys from using a suitable area. Greatest significance should be assigned to the least disturbed sites.
8.3.10 Turkey vulture summer roosting areas
These habitats are not easy to identify. Large numbers of birds may not observed using a roosting site every day. Often birds can be observed in the daytime soaring in search of food. They range over broad areas, often returning to their roosts at night. Any sites where roosting birds have been reported should be checked to note the characteristics of the site. Suitable known sites will likely be poorly represented in the planning area and should be considered significant. Sites that consistently support the largest numbers of roosting birds and are exposed to the least amount of disturbance are most significant.
8.3.11 Reptile hibernacula
All sites of locally rare or uncommon species should be considered significant. There should also be representation of sites for more common species, such as the garter snake. This species uses habitats with a good mix of open grassy habitat mixed with forest stands. This type of habitat is also used by many other species.
The most common situation will be where certain species are known to exist in the planning area, but hibernacula have not been located. These species are very important to the biological diversity of a planning area. Areas of suitable habitat for these species should be identified and representative examples should be protected. Areas of suitable habitat can be identified by referring to Appendix G and reference texts. Areas with the greatest potential for having hibernacula should be identified and subsequent investigations can focus on these areas.
The criteria listed in Appendix Q (Table Q-1) can be used to evaluate reptile hibernacula. Areas of suitable habitat should be examined using different criteria. For example, the highest significance should be assigned to:
- sites that are known to have populations of snake or turtle species that concentrate in winter
- the largest areas containing suitable habitat. These are most likely to contain critical features such as hibernacula.
- sites containing the greatest diversity of habitat types
- the least disturbed areas, as they have the greatest probability of maintaining snake or turtle populations. Many snakes and turtles are killed on roads, especially in spring and fall when they are attracted to warm asphalt or are moving to nesting areas. Also, many people do not like snakes and will destroy them.
8.3.12 Bat hibernacula
All known sites should be considered significant. Potential habitats can be identified from geological maps and from the Ministry of Northern Development and Mines. Individuals who explore caves recreationally are known as spelunkers. They commonly map caves and note their characteristics. Information about the size of the cave opening, depth of the cave, presence of water in the cave, winter air temperature and humidity, and evidence of any bat use would be helpful in determining the potential of the cave to supply winter hibernation habitat. Potential sites should be investigated by someone knowledgeable of bats who would know where to look and what species they might encounter. Bats should not be disturbed in winter and that is another reason why someone with expertise should conduct any investigations. University researchers may know of potential habitats that can be investigated.
Appendix Q (Table Q-1) lists criteria for evaluating identified bat hibernacula. Potential habitats such as caves, if they are found in the planning area, should be considered significant. These habitats are uncommon in Ontario and they provide a unique habitat, not only for bats, but other species as well.
8.3.13 Bullfrog concentration areas
The OMNR has responsibility for managing bullfrog populations in Ontario. They have knowledge of local populations and distribution of the species. Staff at the OMNR should be consulted for advice on the relative importance of bullfrog concentration areas in the planning area.
The planning authority should ensure there is good representation of this habitat in the planning area. The criteria listed in Appendix Q (Table Q-1) can be used to evaluate bullfrog concentration habitats.
Greatest significance should be assigned to sites that consistently support the highest number of bullfrogs. Bullfrogs are very vocal and easy to observe. Surveys should be conducted in mid-May to late June, when they are concentrated and males are in full chorus. Field investigations should include information on the relative abundance of bullfrogs; a description of the habitat, including size, vegetation species and shoreline cover; adjacent land uses and any other potential concerns, such as water-level fluctuations.
In areas where bullfrogs have declined and there is potential for population recovery, even small concentrations of bullfrogs may be considered significant. This is especially the case in planning areas where there is poor representation of bullfrogs and bullfrog habitat. Sites supporting low densities of bullfrogs may be significant if they are near the limits of the species’ range.
8.3.14 Migratory butterfly stopover areas
Agencies such as Agriculture Canada (Ottawa) and the Federation of Ontario Naturalists monitor some populations of butterflies and have a particular interest in monarch butterflies. Also, individuals devote considerable time tracking monarch butterflies each fall and spring. Staff at the above agencies, as well as Ontario Parks staff at provincial parks along the shorelines of lakes Erie, Ontario and Huron can be consulted for advice on the relative importance of identified butterfly stopover areas. They may be able to offer advice on the historical use of sites and on the relative numbers of butterflies using sites.
The criteria listed in Appendix Q (Table Q-1) can be used to evaluate identified butterfly stopover habitats. Large sites are usually most significant because they contain the greatest diversity of plant species.
8.4 Evaluation of rare vegetation communities
All provincially rare vegetation communities (S1 to S3 ranking) as described by Bakowsky (1996) in the planning area should be considered significant. The precise locations of many of them are known and the planning authority should contact the OMNR ecologist for more specific information. See Appendix J for a list of the provincially rare vegetation communities and Appendix M for of some of their locations.
Table Q-2 in Appendix Q lists criteria that could used to evaluate potentially rare vegetation communities. One of the most important criteria is current representation of the community in the planning area based on its area relative to the total landscape or the number of examples of it within the planning area.
Geomatics International Inc. (1991) used the criterion of five or fewer documented locations of a community type within Halton Region to define remnant habitat. Brownell and Larson (1995) prepared a preliminary list of regionally rare communities found in the Region of Ottawa-Carleton based on the area of each community; each of these communities represented less than one percent of the remaining natural area of the municipality. In addition, the OMNR has recommended that any forest cover type comprising less than five percent of the forest group to which it belongs (deciduous, coniferous, mixed) should be considered uncommon and significant. The Nature Conservancy in the United States considers vegetation communities rare if they represent less than three percent of the remaining natural area in the planning area and/or are found in five or fewer locations.
In addition to the criteria of rarity and representation, other criteria such as the rate of loss or degradation of a specific community and its value to wildlife might also be used to evaluate its level of significance. For example, in many areas, riparian areas that not only support rare vegetation communities, but often other significant wildlife habitats, are disappearing because of shoreline development along some lakes and rivers. Early successional fields that support rare vegetation communities and provide important nesting habitat for several species of birds are being lost to development or natural succession. Recognition of these important sites, followed by their protection, will safeguard many species.
Key information to know
- significant sites identified by local naturalists, Federation of Ontario Naturalists, Agriculture Canada (Ottawa)
- current representation of the rare community in the planning area
- presence of species of conservation concern
- presence of other significant wildlife habitats
- level of disturbance in the community (least disturbed sites often are of higher quality and contain more species of conservation concern)
- age of woodland (mature woodlots often contain more species of conservation concern than younger woodlots)
- level of threat to community
Additional information
- size of the site and amount and distribution of suitable habitat
- quality of the vegetation community (level of disturbance from human activities such as off-road vehicle use; number of non-native, invasive plant species; agriculture, cattle grazing)
- species diversity and abundance
8.5 Evaluation of specialised habitats for wildlife
Many species have special habitat requirements. Some species have specific requirements for the size of the habitat patch they need. For others, the critical element is the amount of total suitable habitat in the general area that is required to make it suitable for them. Specialised habitats can also refer to special habitat structure, such as cavities for nesting or rotting logs that provide a source of food. It can also refer to unique habitats that provide specialised conditions, such as springs and seepage areas.
Evaluation of some of these habitats is difficult. Many may not have been identified and, in some cases, the planning authority may have to choose the most significant habitats from a number of potential habitats that have been identified in Chapter 5. Table Q-2 in Appendix Q lists criteria that can be used to evaluate specialised habitats. The criteria in Table Q-2 are not prioritised, although it is suggested that the “current representation in the planning area” is probably the most important criterion. The planning authority may choose to prioritise the criteria in Table Q-2 according to needs and priorities for their planning area.
It should be noted that there is overlap between some specialised habitats. For example, old growth or mature forests may also contain interior habitat for area-sensitive species, areas of high diversity, and seeps and springs. Each of the habitat types is discussed and evaluation criteria provided in Table Q-2 because they are not necessarily found in the same sites and it is important to understand the diversity of ecological functions that a site may possess. Chapter 5 summarises the ecological characteristics of specialised habitats for wildlife.
8.5.1 Sites supporting area-sensitive species
Generally, the planning authority can best protect local populations by protecting the largest, unfragmented forests, the largest grasslands (which may include unimproved pasture or early succession fields) and the largest wetlands. In some planning areas, the largest sites that remain may not meet the area requirements of all the area-sensitive species that could potentially use this type of habitat. However, it is still important to protect the best of what remains. These habitats will be used by some species and by protecting them, there may be opportunities to improve these habitats.
The planning authority should have an idea of the structure and composition of the habitat. This can be determined from aerial photograph interpretation and FRI maps for forest stands. Natural forest stands containing a diversity of forest tree species and structure would be more significant than the same sized forest stand composed of a single species.
A number of agencies are actively involved in the monitoring and protection of area- sensitive species especially birds. These include the Canadian Wildlife Service, Ontario Ministry of Natural Resources, Bird Studies Canada, and the Federation of Ontario Naturalists. The information sources listed in Appendix F and the staff at the above agencies should be contacted for advice on the relative importance of habitats, both in the context of the planning area and the greater landscape.
Habitat shape is also an important consideration when determining the significance of a potential habitat. Habitat shapes that maximise the amount of interior habitat, such as circular or square shapes are best.
Some species require larger blocks of habitat than others (see Appendices C and G). Greatest significance should be assigned to those habitats that support species with the largest habitat requirements or that support species of conservation concern (Section 8.6).
Minimum habitat thresholds apply to species that require a minimum amount of suitable habitat within the general landscape before they will use that habitat, although their territorial requirements may be much smaller. In order to address minimum habitat thresholds, a landscape approach must be applied. A specific amount of habitat must be protected. This has been addressed somewhat by the recommendations in this guide to maintain good representation of all habitat types in the planning area.
8.5.2 Forest stands providing a diversity of habitats
The most significant stands contain a diversity of features, such as tree cavities, fallen logs, abundant forest structure (in terms of topography as well as species composition and age structure of the forest stand), soil moisture conditions, and food plants for wildlife. Table Q-2 in Appendix Q lists criteria that can be used to evaluate forest stands that provide a diversity of habitats. Following are some general considerations:
- Large, older, undisturbed forest stands provide the most significant habitat. The size of stands can be determined from aerial photographs, topographic maps, and satellite imagery maps. Stand ages and composition can be obtained FRI maps.
- OMNR and conservation authority staff may be knowledgeable of the forest stands in the planning area and may be contacted for advice on the relative importance of stands. It should be stressed that this significance determination is based on the stand’s diversity of wildlife habitats and not necessarily on its timber production value. OMNR staff may also be aware of the management history of the stand.
- Stands containing species of conservation concern and a large number of cavity- dependent species (see Appendix G) should be considered significant.
- Stands that contain other specialised habitats for wildlife should also be considered significant. Examples include the presence of candidate old growth stands and the presence of springs and seepage areas. Stands with a variety of vegetation communities of different age classes will support a high diversity of wildlife species.
8.5.3 Old growth or mature forest stands
Since true old growth forest stands in southern Ontario are very rare, the maturest stands in the planning area should be considered most significant. The best stands are those that exhibit the greatest number of old growth characteristics. These stands can be identified by consulting OMNR forestry staff and using FRI maps. Candidate sites should be checked in the field and characteristics of the stand noted. OMNR staff may be able to provide information on management history.
Greatest significance should be placed on the least disturbed forest stands. The closed canopy and moist growing conditions allow some very sensitive species to grow and these are vulnerable to trampling.
Stands that provide habitat for species of conservation concern should be considered significant.
8.5.4 Seeps and springs
Agencies such as the OMNR, conservation authorities and the Ontario Ministry of Environment (OMOE) may be aware of areas with seeps and springs, particularly those associated with the headwaters of cold water streams and wetlands. No specific ranking system exists for these features. However, staff with these agencies may be contacted for advice about the relative importance of seeps and springs and their value for maintaining cold water habitat for fish. This is also an important consideration.
Planning authorities should ensure they protect a good representation of this type of habitat.
Seeps and springs that are part of a forest or some other natural vegetation community should be assigned greater significance than those that are isolated or in disturbed habitats. Those that are important to other natural heritage resources, such as fish habitat, should be considered significant.
It may be necessary to conduct field investigations of identified seeps and springs. Wildlife species at these sites can be recorded as well as the characteristics. Appendix G provides a list of wildlife species known to use seeps and springs. The permanency of these features can be determined by checking them in the summer. Some dry up in summer and others maintain a moist environment throughout the year. Greatest significance should be assigned to sites that support species of conservation concern and to sites that provide year-round moist conditions.
8.5.5 Woodlands supporting amphibian breeding ponds
It is unlikely the planning authority will find an expert to provide advice about which woodland ponds are most significant. There may be naturalists in your area that are knowledgeable about amphibians. These people should be contacted for information on species occurrence and abundance. The primary consideration is to ensure there is good representation of this type of habitat in the planning area. Generally, the most significant sites will be associated with large woodlands associated with some type of riparian habitat.
It may be necessary to conduct field investigations in spring, when species using the ponds can be identified. The characteristics of the ponds should also be recorded. This would include such information as a description of the forest stand in which the pond is located (species, size, abundance of rotting logs on the forest floor, etc.), diversity of vegetation in the pond, shoreline vegetation, water quality, and degree of disturbance. The permanency of ponds may also be a consideration. The greatest significance would be assigned to ponds that support a high diversity of species, species of conservation concern, and high numbers of amphibians.
8.5.6 Special woodland feeding habitat
Most special woodland feeding habitats will not be identified and ranked. OMNR forestry staff may be aware of some particularly valuable stands and may be consulted. Some stands may be identified on FRI maps. The planning authority should ensure there is good representation of this type of habitat in the planning area. Large forest stands containing a diversity of mast producing trees would generally be most significant.
Any forest stands that are used consistently year after year should be assigned a higher level of significance. In many cases, this will not be known. The exception is some areas of black bear range, where evidence of bear use, especially in stands of beech trees, is obvious.
It may be necessary to investigate some sites in the field. Field investigations should collect information of the species and age of the trees (vigorous, full-crowned trees are the best producers). Field investigators should also record any signs of use by wildlife.
8.5.7 Osprey nesting habitat
Ospreys may be considered a species of conservation concern (see Sections 6.0 and 8.7). Ospreys are often considered an indicator of good water quality. It is recommended that all known Osprey nests be considered significant.
Nesting records that are not recent should be verified in the field. Sometimes nest trees fall down and the birds use another site close by. It is common for new nesting pairs to nest in the same general area.
In areas where Osprey populations are expanding, some potential habitat should be identified and protected. Sites with the greatest potential are undisturbed shorelines, with large trees close to productive shallow water feeding areas.
8.5.8 Turtle nesting habitat
Few turtle nesting sites have been identified. It is common to see turtles along roadsides attempting to lay eggs in the gravel shoulders of the roads. Obviously, these are not preferred sites. There is considerable risk to females and young as they cross roads. Turtle eggs suffer high mortality due to predation by raccoon and skunk. In some areas, virtually all eggs are lost each year. This problem becomes worse as turtles are forced to concentrate in fewer and fewer sites. Greatest significance should be assigned to sites that are natural, least disturbed and are closest to their habitat. The most significant sites should have safe movement corridors between the nesting and aquatic habitat.
The most significant sites will be those that are used by species of conservation concern and that consistently support the most nesting turtles. To ensure good representation of turtle nesting habitat, some potential habitats should be protected, even if it is not known to what extent they are used.
8.5.9 Special moose habitats–aquatic feeding areas, calving sites and mineral licks
Table Q-2 in Appendix Q lists criteria that can be used to evaluate moose aquatic feeding areas.
The OMNR may be aware of some of these special habitats, especially moose aquatic feeding habitats. They should be consulted for advice on the relative importance of any of these identified special habitats to the planning area. Very few calving sites and mineral licks have been identified. Therefore, any identified sites should be considered significant. The least disturbed aquatic habitats are most significant.
Movement corridors to these special habitats should be identified and protected. Moose are strongly attracted to aquatic feeding areas and mineral licks. New roads constructed near these sites may result in increased mortality to moose and a high risk to people.
Habitat adjacent to any special moose habitats should be identified and described. For example, the loss of the conifer resting cover adjacent to an aquatic feeding area may make it useless for moose.
8.5.10 Mink and otter feeding/denning sites; marten and fisher denning sites
Few of these specialised habitats have been identified. First, it is necessary to know which species occur in the planning area. Then, the planning authority should ensure it identifies and protects a good representation of suitable habitat for those species. This is an example of where a landscape approach to planning would be best. If these species are present in the planning area and large blocks of suitable habitat are represented in the Natural Heritage System, there is a good probability these species will continue to survive.
Natural shoreline habitat should be protected for mink and otter. High quality aquatic habitats are required that produce an abundance of fish, crustaceans and insects. Natural, undisturbed habitats are best.
Large, unfragmented blocks of forest are preferred by marten and fisher. Many of these forest stands will have a number of other values as well, such as interior forest habitat.
Sites that are the most natural and have the least amount of disturbance are the most significant.
8.5.11 Areas of high diversity
Often the most highly diverse sites contain several different vegetation communities and numerous microhabitats. Large, natural sites have a greater likelihood of having more diversity, although this is not always the case. Disturbed sites often have less vegetative structure, sensitive species are frequently missing, and non-native species can reduce the diversity of natural species.
A higher level of significance should be assigned to sites that contain rare species or vegetation communities.
Some potential sites may have been identified from existing reports or from input from local naturalists. It may be necessary to conduct field investigations to verify and update information. This information can be used when applying the evaluation criteria listed in Table Q-2 in Appendix Q. During field investigations information should be collected on species occurrence, vegetation community identification, soils and topography.
8.5.12 Cliffs and caves
Many planning areas do not have cliff or cave habitat. In areas where cliffs have been identified, the planning authority should ensure there is good representation of this habitat.
Greatest significance should be assigned to cliffs that provide habitat for rare species or rare vegetation communities. It may be necessary to conduct field investigations to verify or update information. Information should be recorded on species occurrence and vegetation communities. Physical characteristics of the cliff should also be recorded. This would include height, bedrock type, surrounding landuse, potential for human disturbance, etc. Cliffs that support other significant habitats or functions should be considered significant. Examples include nesting habitat for birds, roosts for turkey vultures, or talus slopes.
Any caves that provide winter habitat for bats should be considered significant. These habitats are rare, and any sites are very important.
8.6 Evaluation of habitat of species of conservation concern
Section 6.1 defines species of conservation concern and Section 6.3 describes what species should be considered and an approach that could be used to identify their habitats.
Refer to Table Q-3 in Appendix Q for criteria and guidelines for the evaluation of these habitats, and Appendix G for critical habitat requirements of many of these species.
Many habitats for these species will be under-represented within the planning area and therefore should be considered significant. Habitats that support large populations of a species of concern should be considered significant.
Key information to know
- current representation of habitat/species in the planning area
- critical habitat requirements
- member of a species group/guild
- location of habitat (in seasonal concentration area or rare or specialised habitat)
- size of population
Additional information
- sensitivity of species to specific environmental conditions, disturbance
- habitat quality
8.7 Evaluation of animal movement corridors
In general, the evaluation of the significance of animal movement corridors is based on an assessment of physical characteristics of a corridor:
- length
- width
- continuity
- habitat structure and type of corridor
- condition of corridor
- distance between the natural areas that the corridor connects
- actual or potential use of the corridor by wildlife
- whether the corridor meets the basic needs of the target species or group of species that reputedly use it
Several criteria and guidelines that can be used to evaluate animal movement corridors are outlined in Table Q-4 in Appendix Q.
Intuition and/or professional judgement is often required to evaluate animal movement corridors because knowledge about their actual effectiveness and use by wildlife is limited. Also, animal movements may occur quickly, often under certain weather conditions, or at night. However, sometimes their importance can be accurately inferred from existing information. For example, if a rare species of salamander is known to occur in a forested area and there is only one pond near the forest where females can lay their eggs, it is a safe assumption that salamanders use the corridor between the pond and the forested area.
Animal movement corridors must be evaluated within the context of the local landscape; therefore, the local characteristics of the landscape must be considered. In municipalities with little remaining forest cover, relatively narrow and somewhat fragmented hedgerows or small streams with some riparian vegetation may be considered significant. In natural regions, significant animal movement corridors should be of higher quality and provide wider, unfragmented links to important natural areas.
Significant corridors will usually be wider (the wider it is, the fewer edge effects will occur), without roads (to provide safer movement), and structurally and compositionally diverse. Often, they will be part of a known wildlife migratory route (deer movement from their winter yard to summer range). Sometimes, significant corridors will link two or more important natural areas within or outside the planning area. In densely populated parts of Ontario, significant corridors may be among the few remaining natural areas. Fence and hedgerows should not be considered significant unless they provide the only animal movement corridors in the planning area.
Key information to know
- location of important natural areas (forest, undisturbed grassland patches, wetlands)
- location of remnant and disjunct habitats
- location of seasonal concentration habitats and presumed home range habitat for target species
- relative location of roads and potential corridors
- list of species that are dependent on corridors (see wildlife habitat matrices in Appendix G)
- possible hazards facing wildlife moving in potential corridors
- provision of other important wildlife habitats
- presence of species of conservation concern
Additional information
- description of important corridor characteristics (vegetation structure and composition, approximate width and length, presence of roads across or in corridor, degree of fragmentation and size of gaps in the corridor)
- description of adjacent land uses
- level of human disturbance in and adjacent to the potential corridor
- evidence of use by wildlife
- diversity and abundance of species using the corridor