Foraging Habitat for Shorebirds in Southeastern Missouri and its Predicted Future Availability

Water management to protect agriculture in alluvial floodplains often conflicts with wildlife use of seasonal floodwater. Such is the case along the Mississippi River in southeastern Missouri where migrating shorebirds forage in shallow-flooded fields. I estimated the current availability of habitat for foraging shorebirds within the New Madrid and St. Johns Basins based on daily river elevations (1943– 2009), under assumptions that shorebirds forage in open habitat with water depth \u3c15 cm and use mudflats for 3 days after exposure. The area of shorebird foraging habitat, based on replicated 50-year random samples, averaged 975 ha per day during spring and 33 ha per day during fall. Adjustments to account for habitat quality associated with different water depths, duration of mudflat exposure, intraseasonal availability, and state of agricultural crops, indicated the equivalent of 494 ha daily of optimal habitat during spring and 11 ha during fall. Proposed levees and pumps to protect cropland would reduce shorebird foraging habitat by 80 %: to 211 ha (108 optimal ha) per day during spring and 9 ha (\u3c3 optimal ha) per day during fall. Alternative water management that allows natural flooding below a prescribed elevation would retain nearly all existing shorebird foraging habitat during fall and about 60 % of extant habitat during spring. Supplementary Material (8) Supplement #1 Daily intra-basin water elevations (feet NGVD) for St. Johns Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover under historical flood conditions and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations (XLS 3041 kb) Supplement #2 Daily intra-basin water elevations (feet NGVD) for St. Johns Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover predicted under authorized flood reduction conditions upon completion of the St. Johns-New Madrid Project and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 3020 kb) Supplement #3 Daily intra-basin water elevations (feet NGVD) for New Madrid Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover under historical flood conditions and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 2784 kb) Supplement #4 Daily intra-basin water elevations (feet NGVD) for New Madrid Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover predicted under authorized flood reduction conditions upon completion of the St. Johns-New Madrid Project and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 2857 kb) Supplement #5 Daily intra-basin water elevations (feet NGVD) for New Madrid Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover predicted upon completion of the St. Johns-New Madrid Project but with water elevations allowed to exceed authorized elevations (Alternative 1; Table 3) and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 2858 kb) Supplement #6 Daily intra-basin water elevations (feet NGVD) for New Madrid Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover predicted upon completion of the St. Johns-New Madrid Project but with water elevations allowed to exceed authorized elevations (Alternative 2; Table 3) and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 2860 kb) Supplement #7 Daily intra-basin water elevations (feet NGVD) for New Madrid Basin derived from river elevations at the New Madrid gauge (MS115; navigation mile 889.0) on the Mississippi River, regional precipitation, topography, and land cover predicted upon completion of the St. Johns-New Madrid Project but with water elevations allowed to exceed authorized elevations (Alternative 3; Table 3) and projected areas of potential shorebird foraging habitat associated with these intra-basin water elevations. (XLS 2861 kb) Supplement #8 Geographic information system methodology used to determine basin-wide 3.05-cm (0.1 ft; decifoot) digital elevation models within the New Madrid and the St. Johns Basins in southeastern Missouri. (PDF 48 kb