Pinery Provincial Park. Pinery Provincial Park contains a spectacular sequence of coastal sand dunes. A mosaic of cedar savanna, prairie, heath and barrens parallels the Lake Huron shore. Wet, calcareous meadows occur in several low interdunal depressions. Oak-pine woodlands and savannas cover the rolling dune landscape inland from Lake Huron. River floodplain habitats occupy the inactive channel of the Ausable River, which runs the length of this park (Lindsay 1982). Bakowsky (1990) presented a detailed analysis of the floral ecology of Pinery's different habitats.
Of these vegetation communities, oak savanna is one of the most significant. According to Bakowsky (1990), savannas are the rarest of Ontario's plant communities and at least two thirds of Pinery supports this vegetation type. In eastern North America, oak savanna formerly flourished along the boundary between the prairies of the Midwest and the northeastern deciduous forest region (Bakowsky 1990). The occurrence of this midwestern vegetation in Ontario, far from its main range, may be explained by the postulated hypsithermal period, when climate warmed between 4000 and 8000 years before present (Deevey and Flint 1957; Szeicz and MacDonald 1991).
This resulted in the vegetation of many upland areas in the northeast changing from deciduous forest to prairie. Subsequent climatic cooling reduced the extent of the grasslands, and the more recent clearing of land for agriculture left only a few pockets of the habitat in Ontario. Oak savanna covered 11-13,000,000 hectares of the midwestern USA at the time of settlement but, by 1985, only about 2,600 hectares, or 0.2% of this habitat remained (Nuzzo 1986). In Ontario, savanna is restricted mainly to isolated localities along the shores of the Great Lakes. Many of the regionally rare robber flies discussed below are associated with this habitat.
In recent years a dense population of White-tailed Deer (Odocoileus
virginianus(Zimm.)) has greatly reduced the understorey vegetation
in Pinery (Bakowsky 1990; Schweitzer 1993). Deer were culled in 1998 and
the vegetation is expected to recover. Presumably, these vegetation changes
will affect arthropod diversity and abundance. Karner Blue Sanctuary. The
Karner Blue Sanctuary is a small parcel of oak savanna in Port Franks that
was purchased by LWI to protect the last significant breeding population
of the Karner Blue Butterfly (Lycaeides melissa samuelis Nabokov)
in Canada. This butterfly was extirpated from Canada following the 1988
drought (Schweitzer 1993), but the habitat is in relatively good condition
and is protected from development. Planted pines are being removed from
the site and intermittent burns are planned to maintain the savanna habitat.
Unlike savannas in Pinery Provincial Park, this area has not had a large
deer population. Thus, although the general appearance of the habitat is
similar to oak savanna areas in Pinery, there are differences in arthropod
fauna attributable to the denser understorey (Skevington, unpublished data).
Port Franks Forested Dunes. In Port Franks (south of Pinery),
L-Lake and the surrounding area are protected as part of an Area of Natural
and Scientific Interest (ANSI) and are owned by the Ausable Bayfield Conservation
Authority and the Nature Conservancy of Canada. The Nature Conservancy
property, known as Port Franks Forested Dunes, is managed by LWI. Many
of the habitats are similar to those in Pinery, but there is considerably
less impact from humans and deer. Floodplain forests that differ from those
in Pinery dominate the lowlands on the east side of the property primarily
by the pronounced growth of herbaceous and woody understorey plants. In
addition to the lower deer numbers, frequent flooding of Mud Creek and
the associated nutrient wash contribute to this lush landscape. Insect
diversity here is noticeably different than in the floodplain forests of
Pinery. A series of old, stabilized sand dunes bisect the property to the
west of the floodplain forest. The eastern sides of the dunes contain oak
forests similar to those found in Pinery, the dune tops are typically cedar
savanna, and the western flank of some dunes give way to oak savanna. Eastern
White Cedar (Thuja occidentalis L.) and Eastern Hemlock (Tsuga
canadensis (L.)) fringe L-Lake on the western edge of the property.
Ipperwash Army Base. The Ipperwash Army Base is similar to the
adjacent Port Franks Forested Dunes. The most notable difference is the
presence of large coastal sand dunes. Jeff Skevington sampled from the
periphery of this area only because he could not get permission to sample
within the base. Overall, the fauna is likely analogous to that of the
Port Franks Forested Dunes, although the open sand dunes likley support