Constructed Borrow-Pit Wetlands as Habitat for Aquatic Birds in the Peace Parkland, Canada

The Peace Parkland, Alberta, Canada is part of a continentally important region for breeding and migrating aquatic birds. As a result of resource development and agricultural conversion, many wetlands have been lost. Road construction in the area results in the creation of borrow pits, <3？ha ponds created when soil is removed to form the road bed. We surveyed 200 borrow pits for aquatic birds in May through August 2007. We examined patterns of occurrence and richness, categorizing ponds based on surrounding landscape type: agriculture (0–33.3% forest within 500？m), mixed habitat (33.4–66.6% forest), and forested (66.7–100% forest). Principal Component Analysis indicated that pond environments differed based on local and landscape features. Twenty-seven species of aquatic birds used borrow pits, with 13 nesting. Nonmetric Multidimensional Scaling and Indicator Species Analysis of birds observed in each month revealed assemblages characteristic of agricultural ponds, including horned grebe, lesser scaup, American coot, and mallard, and of ponds with >33.3% forest, including bufflehead, ring-necked duck, green-winged teal, and American wigeon. Because borrow pits were used by a variety of dabbling and diving aquatic birds in repeatable assemblages across the breeding season, we propose that these wetlands be integrated into avian conservation strategies. 1. Introduction Constructed ponds are used by aquatic birds for several purposes. They can function as temporary resting and refueling stops in spring and fall for birds en route to more northerly breeding areas or southerly wintering areas. Birds may also settle and breed on them. Drought conditions negatively affect the availability of breeding habitat for aquatic birds in western Canada, and it is likely that migrating birds move northward seeking deeper, more permanent wetlands when preferred habitat is nonexistent in dry years on the prairies [1]; constructed ponds may meet their needs. Constructed wetlands may add habitat to the landscape when many natural sites have been destroyed or degraded. Since the 1950s, agricultural expansion in western Canada, and especially in Alberta, has resulted in wetland degradation and destruction, and accompanying declines in populations of breeding waterfowl [2]. At least 64% of marshes have been lost as a result of development in the settled south and central regions of Alberta [3]. Development due to oil and gas extraction in boreal Alberta is proceeding rapidly, involving large-scale habitat fragmentation, road construction [4], and tremendous wetland loss in the