The Marshall Nature Preserve is found in the Wye River watershed and forms part of a corridor of habitat linking the Midland Little Lake Provincially Significant Wetland with the Lalligan Lake Life Science ANSI. A number of ecosites are contained within the property's boundary. A large portion of the property is dominated by a white cedar coniferous forest. There is also a sugar maple deciduous forest and three pockets of white pine plantation of varying size. Dividing the property is a thin band of a poverty oat grass meadow. At the southwest boundary there is a non-native deciduous thicket swamp that is part of a larger wetland beyond the property boundaries. There are two species at risk found present on the property, the wood thrush and the Canada warbler, with potential for others.