9.0 Historical Changes in the Land-Use and Wetland Availability in Old Norfolk County

9.2 Changes in wetland availability in old Norfolk County

9.2.2 Characteristics of old Norfolk Counties inland wetlands

Table 9.4 Provincially Significant (Class 1-3) and other Locally Significant Wetlands (Class 4-7) in Old Norfolk County, as classifed by OMNR.

The Norfolk Sand Plain is well drained by several creeks and tributaries and contains few wetlands compared to counties with less pervious soils, such as Haldimand. With the exception of a few small Grand River tributaries in the north, all the streams in old Norfolk County drain directly south to Lake Erie, and primarily into Long Point Bay (Heathcote 1981). That point where the watersheds divide in the north is probably where wetlands are the most prevalent. Oxbow wetlands can also be found in valleys along stream corridors.

Swamps are the most common natural wetland class in southern Ontario, and old Norfolk is no exception. However, the tobacco farms of old Norfolk County generally require extensive irrigation. This has resulted in most tobacco farms having constructed at least one irrigation pond or dam to facilitate irrigation (Francis et al. 1985). Aerial surveys over the old Norfolk Sand Plain indicate that these manmade ponds and dams are by far the most prevalent type of waterbody, followed by swamps. While marsh habitat can be found on some impoundments, natural marshes are virtually non-existent.

From a waterfowl production standpoint, swamps and ponds have considerably less ecological value than most marshes. This is because ponds are often too small, with stagnant water, and with limited aquatic vegetation, pair-space, and brood-rearing habitat, as well as often being at some distance from neighboring ponds. Swamps are generally wooded wetlands, which support trees, tall shrubs, herbs and mosses. While they are substantially more productive than ponds, some lack the submerged aquatic vegetation necessary for foraging waterfowl, while many also lack the emergent vegetation used for nesting and brood rearing. However, wooded swamps within old Norfolk County that contain standing water throughout the year are used fairly extensively by pre-nesting and nesting Mallards and Wood Ducks (G. McCullough, personal communication). In contrast to ponds, marshes have less clearly defined boundaries due to fluctuating water levels. These ever-changing water levels cause them to be highly productive, supporting a diverse flora and fauna. Old Norfolk County contains very low wetland densities, and many of those that are represented are poorly suited for waterfowl reproduction. Old Norfolk's most significant wetlands are listed as follows (Table 9.4). There are, however, substantially more class 3-7 wetlands in old Norfolk than this table depicts, as only wetlands that have been evaluated by OMNR are listed.

Table 9.4 Provincially Significant (Class 1-3) and other Locally Significant Wetlands (Class 4-7) in Old Norfolk County, as classifed by OMNR.