Vegetation
On this rich floodplain, wildflowers are abundant, and the older parts of the floodplain forest have rare species in the herb layer, such as spring avens (Geum vernum) and Asa Gray’s sedge (Carex grayii). In the deep gravels close to the creek edge, sycamore and cottonwood dominate, while at the base of the slope are wetlands called fens where groundwater emerges in springs and seeps. This area once harbored fringed gentian (Gentianopsis crinita) and other rare plants. The forest vegetation on the steep slopes above Fall Creek varies with the aspect and rock exposure. Here, along the dry, south-facing slopes, the forest is dominated by oaks, hickories, white ash, and red maple. A dry, exposed bluff at the top of a landslide has many interesting, and some scarce, dry-site oak-woods species, such as the yellow false-foxglove (Aureolaria flava). The northernmost extension of this property – the mature oak woods near the golf course – is a habitat for adults of rare salamander species that breed in Bull Pasture Ponds.
Geology
The exposed strata at Flat Rocks are part of the uppermost layer of the Ithaca Formation. These outcrop-pings are highly resistant to erosion and form a nearly level terrace over which the creek flows. The deeper swimming areas mark breaks in this thin resistant layer, where there has been faster erosion of the underlying, weaker, rock. Some interesting and rare fossils have been found here.
Ecological Communities
Appalachian oak-hickory forest
A hardwood forest with more than 60% canopy cover of trees that occurs on well-drained sites, usually on flat hilltops, upper slopes, or south and west facing slopes. Dominant trees include one or more of red oak, white oak, and black oak. Mixed with oaks, are one or more of pignut, shagbark, and sweet pignut hickory. Common associates are white ash, red maple, and hop hornbeam. Small trees include flowering dogwood, witch hazel, shadbush, and choke cherry. Shrubs and groundlayer flora are diverse. Shrubs include maple-leaved viburnum, blueberries, red raspberry, gray dogwood, and beaked hazelnut.
Beech-maple mesic forest
A hardwood forest with sugar maple and beech co-dominant. Found on moist, well-drained soils, on north and east facing slopes, and on gently sloping hilltops of any aspect, this ecological community type rarely occurs in ravines. Common associates are basswood, American elm, white ash, yellow birch, hop hornbeam, and red maple. Characteristic species in the sub-canopy are musclewood, striped maple, witch hazel, hobblebush, and alternate-leaved dogwood. There typically are few herbs and shrubs, but tree seedlings may be abundant. There are many spring ephemerals.
Erosional slope/bluff
A sparsely vegetated community that occurs on vertical exposures of unconsolidated material, such as small stone, gravel, sand and clay, that is exposed to erosional sorces, such as water, ice, or wind.
Intermittent stream
The aquatic community of a small ephemeral streambed with a moderate to steep gradient where the water flows only during the spring or after a heavy rain. The streambed may be covered with mosses such as Bryhnia novae-angliae.
Riverside sand/gravel bar
A meadow community that occurs on sand and gravel bars deposited within, or adjacent to, a river channel. The community may be very sparsely vegetated, depending on the rates of deposition and erosion of the sand or gravel. Characteristic species include sandbar willow (Salix exigua), sand-cherry (Prunus pumila), dogbane (Apocynum cannabinum), switchgrass (Panicum virgatum), and poison ivy (Toxicodendron radicans).
Shallow emergent marsh
A shallow marsh is better drained than a deep emergent marsh; water depths may range from 15cm to 1m during flood stages, but the water level usually drops by mid- to late-summer and the substrate is exposed. Characteristic plants include bluejoint grass, reed canary grass, cutgrass, manna grass, spikerushes, bulrushes, sweetflag, wild iris, and water smartweed. Marsh communities occur on mineral soils or fine-grained organic soils that are permanently saturated. They are often found near the Finger Lakes or in wetlands near a drainage divide. Because water levels may fluctuate, exposing substrate and aerating the soil, there is little or no accumulation of peat.
Shrub swamp
A shrub dominated wetland that occurs along a lake or river, in a wet depression, or as a transition between wetland and upland communities. The substrate is usually mineral soil or muck. Alder, willows, or red-osier and silky dogwoods are common dominant species. Other characteristic shrub species include gray dogwoods, meadowsweet, highbush blueberry, winterberry, spicebush, viburnums, and buttonbush. A few red maple trees may be present. The herb layer is lush and diverse, and typically includes species found in sedge-grass meadows.
Successional northern hardwoods
A forest with more than 60% canopy cover of trees that occurs on sites that have been cleared or otherwise disturbed. Dominant trees are usually two or more of the following: red maple, white pine, white ash, gray birch, quaking aspen, big-tooth aspen, and, less frequently, sugar maple and white ash. Tree seedlings and saplings may be of more shade tolerant species. Shrubs and ground cover species may be those of old-fields. In abandoned pasturelands apples and hawthorns may be present in the understory.
Successional old field
A meadow on sites cleared, plowed, and then abandoned. The ragweed type occurs on fields 1 to 3 years after last cultivation; ragweed, daisy, Queen Anne’s lace, crab grass, golden foxtail, and chickweed are common. The goldenrod subtype occurs 3 – 15 years after last cultivation. Dominant species are perennial composites: goldenrods and asters. Other herbs include timothy, orchard grass, smooth brome, bluegrasses, quackgrass, sweet vernal grass, evening primrose, old-field cinquefoil, wild strawberry, and hawkweeds. Shrubs and trees represent less than 50% cover but include gray dogwood, arrowwood, raspberries, blackberries, sumac, red maple and white pine.
Successional shrubland
A shrubland with at least 50% cover of shrubs that occurs on agricultural fields 10 – 25 years after abandonment, following other disturbance, and especially on sites with restricted drainage. Characteristic shrubs include gray dogwood, raspberries, hawthorn, serviceberries, chokecherry, sumac, nannyberry, arrowwood and buckthorn. Herbs are those of old-fields. Seedlings of white pine, red maple and white ash are usually present.
Wetland headwater stream
The aquatic community of a small, swampy brook with a low gradient, slow flow rate, and cool to cold water that flows through a fen, swamp or marsh near the stream origin. Springs may be present. The substrate is clay, gravel or sand, with silt, muck, peat, or marl deposits along the shore. Characteristic plants include watercress, Chara. Persistent emergent vegetation is lacking.