Management
Iroquois National Wildlife Refuge is actively managed to provide the best possible habitat for the widest variety of wildlife. Over one half of the refuge is wetlands including marshes, shrub-scrub wetlands and forested wetlands. The remaining habitats are upland and include grasslands, shrublands and forests.
Wetlands
Before the addition of fifteen impoundments, over 5,000 acres of the refuge was normally inundated in 
the spring and mostly dry in the fall. A system of dikes (man-made barriers) and water control structures were created to regulate water levels to mimic the flood and drought cycle in a natural, undisturbed marsh and to reduce local flooding. Over time the quality of the marsh will decline. Plants which provide food and shelter are eaten out or trampled down forming expanses of open water. Periodic draining of the impoundments (draw downs) allows the re-growth of plants that provide for wildlife.
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n year one of the cycle, the water is drained from the pool as soon after the peak of the spring waterfowl migration as possible. The relatively cool soil in April and early May favors the germination of annuals such as smartweed, Bidens spp. wild millet, and several other species whose seeds will provide waterfowl food when the pool is re-flooded in the fall. Organic material from several years of dead marsh vegetation is exposed to oxygen and thus oxidizes (breaks down) and becomes nutrients for the growth of new marsh plants. As more of the water evaporates the bottom "firms up" and provides a rich bed for the new plant roots. Some perennials, such as cattail and bur-reed, germinate and grow. These plants usually will remain in the understory but play an important role in future years of the cycle. If the water is drained off later when the soil is warmer (late May to June) it is likely that purple loosestrife will germinate. That was formerly a problem, but the expanding population of Galerucella beetles seems to be capable of controlling most of the loosestrife when it does germinate.
The second year of the cycle is a growth and re-colonization year. Residual seeds from the annuals provide a rich carbohydrate food source for the northward migrating waterfowl. The dead, and now partially decomposing, stalks of those plants become a food source for many kinds of invertebrates that, in turn, provide a critical protein source for the northbound birds, particularly for female ducks that will soon lay eggs. The cattails and bur-reed grow vigorously, and soon become colonized by muskrats which utilize the perennials as both a food source and a material for construction of their houses. The cover from the perennials, interspersed with openings newly created by the muskrat’s activities, provides ideal conditions for waterfowl broods and migrating waterfowl as well as nesting rails and bitterns.
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n subsequent years of the cycle, as the perennials are used by muskrats and are stressed by higher, more constant water levels, the arrangement of emergent vegetation and small irregular water areas creates habitat conditions suitable to marsh-nesting birds. As the impoundment becomes more open, it becomes ideal for least bitterns. As the pool gets to a 50:50 mix of vegetation and open water, nesting black terns, a species of special concern, may be attracted to it. The terns seem to favor old, sunken muskrat houses as nesting platforms. Eventually conditions become too open and the habitat value is greatly reduced for waterfowl and most marsh nesting species since there is now not as much cover and food sources. At this pont the drawdown cycle repeats. A "typical" cycle may last 4 to 6 years.
Forested Wetlands
Forested wetlands are located along Oak Orchard Creek and Seneca Pool. Oak Orchard Creek feed
s many of the refuge’s marshes as it meanders east to west through the refuge en route to Lake Ontario. Wood ducks, hooded mergansers and prothonotary warblers are just a few of the species found in the forested wetland along its banks or bordering marshes.The refuge does little to actively manage the forested wetland and associated marshes along the creek but rather allows it to remain a natural, free flowing area.
Grasslands
Grasslands provide nesting habitat for migratory birds such as Savannah sparrows, bobolinks, Eastern meadowlarks, upland sandpipers and some species of waterfowl. To keep grassland open the refuge employs a combination of mowing, spraying, haying and prescribed (controlled) fire.
Fire is a natural part of the ecosystem that revitalizes the landscape. Fire has been used to maintain habitats for centuries by Native Americans and today has become a valuable tool on National Wildlife Refuges. Some plant species rely on fire for reproduction and survival. Fire has been used to maintain habitats for centuries by Native Americans.
On Iroquois NWR, prescribed fire is used to remove woody plants and non-native species from grasslands. In addition to returning valuable nutrients to the soil, fire removes dangerous fuels such as dried grass and other plant debris which can lead to wildfires. As the name implies, prescribed fires are highly managed. Before a burn can take place air temperature, wind speed and direction, fuel moisture and other factors must be within specified limits. Otherwise the burn cannot take place. Highly trained employees ensure that burns are conducted with human safety as a top priority. At Iroquois NWR, burns are generally scheduled every three to five years for each field. Not all fields are burned in the same year.
Before Fire 
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During a Fire
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Two Weeks After Fire
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Forests
Maples, elms, ashes, aspens, oaks and beech dominate the 1,738 acres of upland forest much of which is in second growth (re-grown after the original forest was harvested). These forests are homes to a variety of songbirds, mammals and game birds. Several natural and rare hemlock stands are found in small pockets on the refuge. Forest are permitted to go through their natural cycle of succession with very little active management.
Images are USFWS unless otherwise noted.
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