Table 4. Percent difference between habitat conservation objectives based on energetic carrying capacity and typical duration of stay by waterfowl at each foraging threshold and a standard 50% food availability threshold as currently assumed by the Upper Mississippi River and Great Lakes Region Joint Venture in 4 wetland habitat types and overall in the Upper Midwest, USA.
| Habitat | Fixed Foraging Thresholds (kg/ha) | |||||||
|---|---|---|---|---|---|---|---|---|
| 25 | 50 | 75 | 100 | 125 | 150 | 175 | 200 | |
| Wet mudflat / moist-soil plants | -48% | -45% | -43% | -40% | -36% | -32% | -28% | -24% |
| Shallow semi-permanent marsh | -41% | -27% | -4% | 38% | 145% | 1,017% | * | * |
| Deep water marsh | -44% | -35% | -24% | -8% | 17% | 60% | 154% | 508% |
| Extensive open water | -45% | -38% | -29% | -18% | -2% | 21% | 59% | 130% |
| Overall | -42% | -31% | -14% | 16% | 87% | 625% | * | * |
* Foraging threshold exceeds food availability and value of wetland type as foraging habitat is negligible making difference not estimable.