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USGS2020

Remnant hardwood forest mapping within the Upper Mississippi River floodplain

Executive Summary The primary objective of the project was to locate previously unknown stands of mast-producing hardwood forest trees in the Upper Mississippi River floodplain using existing information. We located and mapped 399 previously unknown hardwood forest stands within the Mississippi River floodplain area of navigation pools 9, 10, and 11. Using color infrared images in combination with true-color imagery was useful for identifying hardwood forest stands. We recommend our result be refined by visiting the forest stands we identified to evaluate our classification rate and determine which stands are regenerating. In combination with regeneration information, our results can help better inform flood inundation modeling, which will help improve the efficacy of restoration design. Although we had some success using the best available information, to obtain more relevant observations, we recommend acquiring color infrared aerial imagery during the late fall season if providing detailed mapping of forest stands is a management priority. Imagery of this type collected in the fall, when trees may be distinguished by their differing senescence, has the potential to uniquely identify individual species or perhaps even individual trees. Gaining a better understanding of forest diversity and developing conservation strategies to preserve that diversity is timely because remaining aging trees, established before lock-and-dam installation on the Mississippi River, are nearing the end of their life expectancy.

Iowa, Minnesota, Wisconsin↗

USGS2015

Host–parasite behavioral interactions in a recently introduced, whooping crane population

The whooping crane Grus americana has a long conservation history, but despite multiple attempts across North America, introduction success is lacking. Recently introduced, captively reared whooping cranes have had periods of poor reproductive performance in central Wisconsin that sometimes coincided with black fly (Diptera: Simuliidae) emergences. Sandhill crane Grus canadensis reproductive performance in central Wisconsin is approximately double that of whooping cranes. We used comfort behaviors as a measure of black fly harassment to infer whether behavioral differences existed between nesting sandhill cranes and nesting whooping cranes and between successful and unsuccessful whooping crane pairs. To further explore the interaction between black flies and incubating whooping cranes, we examined differences in behaviors between incubating birds and their off-nest mates. Compared to their off-nest mates, incubating whooping cranes exhibited elevated comfort behaviors, suggesting a bird at a nest may experience greater harassment from black flies. Sandhill cranes had elevated head-flicks over whooping cranes. Whooping cranes exhibited more head-rubs than sandhill cranes, and successful whooping crane pairs had elevated head-rubs over pairs that deserted their nests. Behavioral differences between sandhill cranes and whooping cranes as well as differences in reproductive performance, could be explained by exposure to local breeding conditions. Whereas sandhill cranes have nested in the area for hundreds, if not thousands, of years, whooping cranes were only recently introduced to the area. Behavioral differences between the species as well as those between successful and unsuccessful whooping crane pairs could also be explained by the effect of captive exposure, which could affect all whooping crane introductions.

Wisconsin↗