Northern Prairie Wildlife Research Center
Before the refuge was established in 1935, land use in the area was primarily native pasture and cropland (Wm. Schultze, pers comm, USF&WS, Columbia, S.D.). However, in the 1930s the area was devastated by wind erosion magnified by a combination of drought, extensive agricultural land use, and fine soil types (USDA 1993). Conservation efforts, such as the shelterbelt program (established in 1937 by South Dakota Soil Conservation District Law), began during this period (USDA 1993).
Executive Order 7169 established the SLNWR in 1935 as a "refuge and breeding ground for migratory birds and other wildlife." Active management in the form of low head dam construction began in 1937 with the initiation of the Mud Lake Dam project. In 1938, construction began on the Columbia Dam. Both dams were completed in June 1939. Numerous control structures were also built at different locations on the refuge to enhance waterfowl production, and many dike systems and nesting islands were constructed. These early management strategies have changed the landscape of the refuge to what it is today.
Vegetation has greatly changed since refuge establishment. Refuge narratives (1936) document efforts to propagate bulrush (Scirpus spp), burreed (Sparganium eurycarpum), and duck potato (Sagittaria spp). To transplant these wetland plants to different locations on the refuge, there must have been an on-site source. However, at present very little Scirpus or burreed occur on SLNWR.
Shelterbelt planting was a priority during early refuge establishment. Photographs from 1936 show no trees. However, by 1937, Civilian Conservation Corps (CCC) workers had established nearly 1.5 million seedlings in tree nurseries that would be used as wildlife food and cover (SLNWR 1937). During the entire time the CCC crews worked at SLNWR, nearly 500,000 trees were planted, including Russian olive (Eleagnus angustifolia), Siberian elm (Ulmus pumila), cottonwood (Populus deltoides), green ash, American elm (Ulmus americana), Tatarian honeysuckle (Lonicera tatarica), and honey locust (Gleditsia triacanthos).
Early refuge managers apparently collected biological data on the refuge in the form of cover maps and vegetative classifications. About 2,000 plant specimens had been collected for the herbarium. Unfortunately this information and the plant collection no longer exist.
Perhaps the most obvious floral change on the refuge came with the conversion of terrestrial habitats. Prior to refuge establishment, the primary terrestrial habitat was wet meadow, often used for hay by landowners. Native prairie pasturelands were also evident. Refuge narratives state that seeds were collected from native plants including buckbrush (Symphoricarpos spp). This suggests the presence of native upland areas prior to conversion and invasion by tame grasses.
All of these vegetational changes have restricted or in some instances enhanced certain vertebrate species occurrences on the refuge.
One bird species which has been extirpated from the refuge but is still present in low numbers in the Hecla Sandhills east of the refuge is the greater prairie chicken. In narratives from 1938, managers stated that there are "splendid concentrations of prairie chickens...." By 1944 there was no mention of this species nesting or wintering on the refuge. Refuge managers recognized this decline: "it is believed that when more of the land reverts to native vegetation that then and only then will we see a material increase of (prairie chickens)" (SLNWR 1938-39).
Some native bird species that were common nesters in the 1940s were not found nesting on SLNWR during this study. The short-eared owl was the most abundant nesting owl, and the northern harrier was the most abundant nesting raptor. Upland nesting shorebirds such as willets and marbled godwits commonly nested on the refuge in "typical prairie nesting cover" (SLNWR 1938). Of all these species, only the northern harrier was seen during this study, and then only occasionally.
Lack of native cover was recognized by early managers as a potential problem for endemic bird species. Managers wrote that "we will not have an increase in native upland (birds) on this refuge so long as we continue the encouragement of exotic birds by so much farming" (SLNWR 1939).
Native vegetation fragmentation resulted in an increase in bird species diversity on the refuge. The brown-headed cowbird became established. Populations of eastern and western kingbirds, orchard orioles, brown thrashers, and catbirds also increased when woodland habitat increased. Endemic grassland species, including the sharp-tailed sparrow and LeConte's sparrow, also were rather numerous.
Wetland birds have remained relatively static throughout refuge history. However, upland nesting shorebirds have declined drastically. Species recently increasing in abundance include the exotic cattle egret, first observed on the refuge in 1961. Nesting was first documented in 1977. Presently, an estimated 1,000 cattle egrets nest on the refuge.
American white pelicans and double-crested cormorants historically have nested on the refuge. With destruction of islands and lack of suitable nesting substrates, these species have declined in abundance although they still are found nesting. The double-crested cormorant currently nests in trees throughout the refuge.
Herptiles on the refuge were seldom documented in past refuge narratives. A record of a female garter snake was the first herp record. A "grass snake" was mentioned on two occasions. In 1958, it was reported that a few snapping turtles were seen. Fish species have generally benefited from permanent water sources on SLNWR, and species diversity remains somewhat similar to that at refuge establishment.