Projects and Research
Habitat management at Wallkill River focuses largely on controlling natural succession, and manipulating water levels to provide waterbird habitat. In early spring, snow melt and rains yield high water levels in the Liberty Marsh impoundments, benefitting thousands of migratory waterfowl. As spring progresses, water levels are lowered to produce open mudflat habitat for shorebirds. Remaining pockets of water provide foraging areas for the great blue and green herons that nest on the refuge. By late summer, any remaining water is held for the fall waterfowl migration. In most years, seasonal rains raise the water level before winter’s freeze sets in.
Natural succession threatens habitats that are considered “early successional”. Without management, these areas would revert to forest and be lost to species depending on them for nesting and foraging habitat. Grassland management is facilitated by a cooperative program in which local farmers hay the fields after the nesting season. Farmers benefit from the use of hay, and the refuge benefits from assistance in keeping the fields open. In other areas, biologists wish to maintain old fields in scrubby, shrub habitats desirable for a different suite of breeding birds, raptors and pollinators. These fields are cut every 3-5 years to prevent the establishment of trees.