AQUATIC FORAGE RATINGS ACCORDING TO WETLAND TYPE: MODIFICATIONS FOR THE LAKE SUPERIOR MOOSE HSI

Abstract

Because aquatic macrophytes are recognized as a critical forage for moose in parts of North America, habitat evaluation for moose in these regions requires estimates of the availability of aquatic resources. The habitat suitability index (HSI) for moose of the Lake Superior region includes wetlands as a primary variable because they produce aquatic macrophytes. In northeastern Minnesota, representative samples of 10 wetland types were measured for areal cover and species composition of macrophytes, while biotic and physical variables that may serve to predict macrophyte presence were also recorded. Abundance of macrophytes favored by moose varied among wetland types, with slow streams and beaver ponds having higher levels than lakes and fast streams. We tested whether standard colour or black-and-white aerial photos (1:15,840) would reveal extent of submerged and floating aquatics, based on known, measured sites, and found the photos unreliable. We conclude that specifications in the Lake Superior moose HSI for measuring aquatic resources can be significantly improved by including a classification of wetlands that relates more closely to the limnological conditions that favor macrophytes.