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I I. I I I I I I I .. I I I I I I I. I I wet meadow has retained a diverse assemblage of native flora and is the only part ofTCAAP noted on Ramsey County's Natural Communities Map. Marshes are one of the most productive temperate-climate communities. They provide significant food for animals higher up the food chain, and the bigger the marsh, the bigger the food chain. Biological Components: Natural Plant Communities In all, the natural plant communities on TCAAP are not prime examples of undisturhed floral diversity. Much of the area was grazed and some was tilled (Figure 8). Native prairie remnants remain in two locations. The first is the wet meadow noted above. Another area is on the high ground of the kame, south of the gravel pit. This area is moderately disturbed. Scattered stands of variously disturbed prairie flora can also he found in the understory of oak woodlands, which appear to have been savanna. Oak woodlands with varying degrees of disturbance are scattered throughout TCAAP (Figure 9). The higher quality woodlands are distinguished by the continued presence of prairie ground cover, a vestige of theie former savanna status. Although oak savannas are extremely rare across Minnesota, those on the TCAAP kame are sufficiently disturbed not to be considered high-quality examples of this plant community. As such they are not noted on the Map of Natural Communities of Ramsey County developed by the Minnesota County Biological Survey. As a local resource, though, the oak woodlands should not be overlooked. Arden Hills would be well served by preserving them. Biological Components: Animal Communities The plant communities may not be distinguished, but the size of the site and its variety of vegetation, topography, and micro-climates supports a diverse array of animal species. TCAAP has long drawn the attention of birdwatchers, lepidopterists (persons who study butterflies), and other naturalists. The overall consensus of resource professionals is that size makes the difference: The bigger the open space area, the better for maintaining viable animal populations and plant comunities. No other open space areas of this size remain in the north most metropolitan area. Biological Components: Documented Rare Species Blanding's Turtle: For many years, resource specialists have known that Marsden Lake is home to a population of Blanding's turtles. Previous research strongly suggests that this state-listed threatened species has declined significantly throughout its range. Destruction of the upland breeding grounds surrounding resident wetland areas seems to be a primary cause of population decline. For the Marsden Lake population to be maintained, unobstructed movement between Marsden Lake and upland breeding habitat elsewhere must continue. At present, field research is being conducted to identifY the exact upland areas used by the Marsden Lake Blanding's population. Based on records made in the 1980s, this territory appears to extend from Karth Lake south ofCSAH 96 northward to the area around Turtle Lake School just east of Lexington Avenue and north of CR 1. Preliminary rmdings suggest that the sandy grassland area west of Marsden Lake is an important nesting area. Radio-monitored turtles are being tracked in the wetland complex northwest of Marsden Lake and south of Shamrock Park. At this point it is premature to conclude where additional active nesting areas or resident homes for Blanding's turtles might be, other than Marsden Lake. The National Wetlands Inventory map indicates that Marsden Lake (an old lake basin, now a deep marsh) is part of a large wetland complex surrounding Turtle Lake to the east. It is not beyond reason to suggest that the turtles originally nested not only in the sandy Chetek and Zimmerman soils west of Marsden, as they do today, but also in the sandy soil associations between Marsden and Turtle Lake. However, it Camiros, Ltd./SEH.lnc./LHDL. Ltd. TCAAP Framework Plan Page 16 Chapter II