CARDEN PLAIN
IMPORTANT BIRD AREA
(IBA)

INTRODUCTION

Image Copywrite Terry Bradt

The Carden Plain is an attractive blend of unique habitats that offer an unspoiled panorama of grassland and shrubland birds, a blaze of wildflowers and vegetation with prairie affinities, and a wide array of butterflies and insects, many of which are restricted to this area. Large expanses of grassland, occasionally interspersed with shrubs and savannah, lend a subtle, but yet distinct flavour of Africa. If you look carefully, and are lucky, you will spot an Eastern Loggerhead Shrike (Lanius ludovicianus migrans). This Endangered species, along with a large assemblage of grassland species, call the Carden Plain home during the spring and summer months.

Situated amongst the unpopulated backroads in Carden Township, Carden Plain has been a favourite haunt of birders, botanists, and naturalists, all drawn to the area by its curious and impressive array of habitats and wildlife. As its natural features were documented, parts of Carden Plain were recognized as a globally-significant, rare habitat: an alvar.

SITE HISTORY

14,000 years ago.

The Carden Plain is characterized by very shallow limestone bedrock, which in most places is relatively flat. Calcareous remains of billions of sea creatures settled to the bottom of the vast, warm tropical waters which occupied this area hundreds of million years ago, and were gradually compressed into these resulting layers of limestone.

About 14,000 years ago, when humans first entered North America, all of Southern Ontario and northern parts of U.S.A. were covered by the Wisconsian Glacier. Ice level up tree Kilometers thick exerted a huge pressure on the earth.

Around 13,000 years ago, global warming began. The melting glacier formed a large lake called Algonquin which initially drained south down the Mississippi. As the glacier retreated the land was released from the pressure raising up to 600 feet (called isostatic rebound) cutting off drainage outlets and replacing them with others newly exposed. Around 11,200 years ago the glacier withdrew past the Kirkfield Outlet through the Kawartha Lakes, through the Trent Valley and on to the Hudson River.

11, 200 years ago.

This phenomena washed the Carden Plain clean in contrast to the Canadian Shield. A few abandoned beach ridges and offshore sand and gravel deposits remain from this era, such as the gravelly ridges which can be found along Wylie Road just north of County Road 6.

The original forest of the Carden Plain appears to have included some good stands of White Pine, and considerably more Tamarack than now occurs. However, the northern parts of Carden Plain were also recorded by the first surveyors to include open areas, often described as rock barrens or spruce plains.

According to Chapman and Putnam (1984), the population peak on the Carden Plain was reached during the lumbering era, when farms could sell local produce such as beans and pigs to the lumber camps. In 1881 there were about 3,300 people and 470 occupied farms on Carden Plain; by 1941 there were only 1,700 people and 280 farms. The decline in agriculture, which followed forest clearing and wildfires, continued in later years, with average farm size becoming significantly larger to an average of 200 hectares in 1981. Over 70 percent of the farmed areas is rough pasture, requiring more than 5 hectares to support each unit of livestock.

Over the past 50 years, the overall population of the Carden Plain has stabilized, with most of the new residential development taking place around Lake Dalrymple and Canal Lake.