Cheyenne Bottoms

Cheyenne Bottoms is the premier wetland of Kansas. Located in the center of the state, it is considered to be among the most important wetland sites for migration of shorebirds and waterfowl in North America (Zimmerman, 1990). The bottoms occupy a large, oval-shaped depression (~166 km2) that is the terminal point for an enclosed drainage basin (Fig. 14-15). Cheyenne Bottoms is managed in part by the Kansas Department of Wildlife and Parks and partly by The Nature Conservancy (TNC) as well as by other private landowners. Beginning in the early 1990s, TNC started to acquire land in the upstream portion of Cheyenne Bottoms, north and west of the state wildlife area (Fig. 14-16). The management goal of TNC is to protect habitat for shorebirds and waterfowl through reclamation of natural marshes, wet meadows, mudflats, and adjacent grassland. In pursuing this goal TNC has undertaken substantial alterations of the previous agricultural land use in the areas it owns and manages.

An important concern of recent years was the expansion of cattail (Typha sp.) thickets during the 1990s, which threatened to overspread open marshes and mudflats, thus rendering the habitat less suitable for many migratory birds. Cattail may be controlled in several ways. However, TNC lacked heavy equipment for mechanical removal, had no means to artificially regulate water levels in the marshes, and rejected herbicides in this sensitive environment. Thus, TNC adopted a patient strategy to exploit recurring drought episodes, when dead cattail thatch might be removed, as the primary means to control cattail

FIGURE 14-15 Satellite image of Cheyenne Bottoms and surroundings in central Kansas, United States. CBWA = Cheyenne Bottoms Wildlife Area managed by the state of Kansas. Landsat false-color composite based on Thematic Mapper bands 2, 5, and 7 color coded as blue, green, and red; 10 July 1989.

FIGURE 14-16 High-resolution, natural-color Ikonos satellite image of Nature Conservancy land in the northwestern portion of Cheyenne Bottoms, Kansas, United States. TNC marshes are subjects of long-term SFAP observations. A mixture of moist and dry mudflats, active and dormant vegetation, and residual water pools is visible in this typical mid-summer, drought scene, July 2003.

FIGURE 14-16 High-resolution, natural-color Ikonos satellite image of Nature Conservancy land in the northwestern portion of Cheyenne Bottoms, Kansas, United States. TNC marshes are subjects of long-term SFAP observations. A mixture of moist and dry mudflats, active and dormant vegetation, and residual water pools is visible in this typical mid-summer, drought scene, July 2003.

FIGURE 14-17 Healthy cattail thickets (dark green) cover much of TNC marsh study site prior to drought. View toward west, May 2002. Taken from Aber et al. (2006, fig. 4).

infestation of its wetlands. SFAP was utilized to monitor TNC marshes over a period of several years (Aber et al., 2006) and to provide improved ground truth for better interpretation of satellite images and conventional airphotos.

The spring of 2002 marked the end of the favorable period for cattail expansion, and thickets filled much of TNC marshes (Fig. 14-17). Later in 2002, a two-year drought began, and much of the emergent wetland vegetation, including most cattails, had died by the early summer of 2003 (Fig. 14-18). By the spring of 2004, the marshes were largely dry and most emergent wetland vegetation had died.

FIGURE 14-18 Partially dead cattail thickets, June 2003. (A) Normal color shows that small patches and narrow zones of cattails survived (green), particularly around the margins of thickets. Taken from Aber et al. (2006, fig. 6). (B) Color-infrared close-up view highlights active zone of emergent vegetation (red).

FIGURE 14-18 Partially dead cattail thickets, June 2003. (A) Normal color shows that small patches and narrow zones of cattails survived (green), particularly around the margins of thickets. Taken from Aber et al. (2006, fig. 6). (B) Color-infrared close-up view highlights active zone of emergent vegetation (red).

FIGURE 14-19 Dry conditions and dead cattails (reddish brown) in TNC marsh study site. Areas treated by mowing (m) and burning (b). View toward west, May 2004; compare with Figure 14-17. Taken from Aber et al. (2006, fig. 7).

At this time, TNC conducted an experiment in removal of the dead cattail thatch. Both mowing and burning were attempted with limited success (Fig. 14-19). Soon after, heavy rains and runoff flooded the marshes (Fig. 14-20), and by spring of 2005 a healthy mixture of emergent wetland vegetation had become established, including great bulrush (Scirpus validus), blunt spike rush (Eleocharis obtusa), and

FIGURE 14-20 Revegetation of former dry mudflat by blunt spike rush (Eleocharis obtusa), which appears dark green at scene center. Muddy water from recent flooding fills the marsh in the foreground, and cattle are grazing on wet meadow in the background, July 2004. Taken from Aber et al. (2006, fig. 8).

FIGURE 14-20 Revegetation of former dry mudflat by blunt spike rush (Eleocharis obtusa), which appears dark green at scene center. Muddy water from recent flooding fills the marsh in the foreground, and cattle are grazing on wet meadow in the background, July 2004. Taken from Aber et al. (2006, fig. 8).

small stands of cattail (Fig. 14-21). At this point in time, it appeared that TNC strategy was partly successful for restoring open-water marsh and mudflat habitats attractive for migrating shorebirds and waterfowl.

Later in 2005, another dry period began. This drought continued and became severe by the autumn of 2006, and TNC marshes were completely dry. Based on previous limited success, TNC staff launched a more ambitious experiment to simulate the impact of heavy buffalo (Bison bison) grazing on the marsh complex. Dry mudflats were disked (plowed) up and dead vegetation thatch was mowed down (Fig. 14-22).

The spring of 2007 brought heavy rain, the marshes rapidly filled to overflowing (Fig. 14-23), and rains continued well into the summer leading to flooding of historic magnitude. Cheyenne Bottoms was inundated and became a huge, shallow lake for several months. By 2008, the bottoms once again became accessible via roads, although water levels remained high (Fig. 14-24).

As water receded and emergent wetland vegetation grew up, it became apparent that marsh treatments (disking and mowing) in the fall of 2006 had been successful for limiting cattail infestation. TNC staff found that periodic SFAP was the best means available to them for evaluating the impacts of their management techniques. However, continued maintenance will be necessary in future years, as cattails are remarkably hardy plants.

FIGURE 14-21 Mosaic of emergent wetland vegetation types with extensive open water in Nature Conservancy marsh. Superwide-angle view, May 2005. Kite flyers are visible in lower right corner. Taken from Aber et al. (2006, fig. 9).
FIGURE 14-22 Severe drought conditions culminated with completely dry marshes in October of 2006. Main image: A, vegetation thatch is being mowed, and B, mudflats are disked (plowed). View northward; kite aerial photo by SWA and JSA. Inset image: detail of the tractor mowing the thatch.
FIGURE 14-23 Waxing flood conditions at TNC marshes in the spring of 2007 following disking and mowing of previous autumn. Compare with picture above. View northward; kite aerial photo by SWA and JSA, May 2007.
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