BOTANICAL EVALUATION OF THE GOAT ISLAND COMPLEX, NIAGARA FALLS, NEW YORK
F. THE OLD RIVER MARGIN HABITATS: The flora of recently abandoned river channels.
Note that on the Kindle-Taylor geologic map (1913) there were a series of lowered water level events, not simply one, with younger and younger communities developing outward from older river and glacial deposits in the center of the complex.
Since these geological-hydrological events were caused by fluctuating water levels in the Great Lakes, and in the same floristic region, similar plant communities should be found in many areas of the region.
Along the river the presence of conifers fringing the lower margins of the deciduous forest of the talus slopes above them may also be due to the relative youth of the exposed river bank due to lower Great Lakes water levels and corresponding lowered water levels in the river, and to the effects of ice-scour and sudden inundation in this essentially dry bedrock habitat. This conifer woods seems best developed where a ledge of bedrock has been exposed, such as at the Whirlpool, especially on the Canadian side. Shortness of duration of sunlight, cool moisture from the foaming rapids and long periods of cold in spring due to ice continuing to be brought down the river from Lake Erie upstream also contribute to conditions favoring a conifer element.
Cedar Island, an island in the Queen Victoria Niagara Falls Park in Ontario, destroyed by 1913 by commercial exploitation of the water channel between it and the mainland near the brink of the Horseshoe Falls, was reported to have possessed the following characteristics:
"[It consisted] ... largely of gravely soil, enriched by leaves and silt washed from the river. The Legumes are well represented here. Some beautiful shrubs, and towards autumn, the asters and golden rods decorate the attractive island. Several varieties of St. John's Wort and masses of wild Bergamot [Monarda sp.] cover many spots" (Panton, 1890).
The following catalogue is a representation of the flora of this lost island derived from the literature of the period, and specimens in the Queen Victoria Park School of Horticulture (NFO):
Anemone cylindrica LONG-FRUITED ANEMONE. 1890.
Carex lupulina HOP SEDGE. "Near Cedar Island," Cameron 1892 (NFO).
Decodon verticillatus SWAMP LOOSESTRIFE. 1893.
Equisetum variegatum VARIEGATED SCOURING-RUSH. 1891.
Hieracium scabrum ROUGH HAWKWEED. 1893.
Hypericum canadense CANADIAN ST. JOHN'S-WORT. 1893.
Hypericum kalmianum KALM'S ST. JOHN'S- WORT. "On Cedar island, in the vicinity of the bridge crossing to the mainland on the way to Dufferin Islands" (Panton, 1890).
Monarda fistulosa BERGAMOT. "Very common on Cedar Island, wild" (Panton, 1890).
Physostegia virginiana FALSE DRAGON-HEAD. 1890.
Ranunculus aquatilis var. capillaceus WHITE WATER CROWFOOT. 1891.
Shepherdia canadensis CANADIAN BUFFALOBERRY. "Very common along the paths on the islands, especially Cedar island" (Panton, 1890).
* Vicia sativa VETCH. "There are no doubt many other species of legumes which have escaped the writer's notice as yet. The Bean family is well represented in many parts, but especially in Cedar Island, where its representatives line the beautiful pathways through this sylvan spot" (Panton, 1890).
The recently abandoned channel floors have a particular flora: soils will be relatively immature, possibly with coarse sediments and consequently well drained (Kindle & Taylor, 1913). There will be seepage in places from drainage out of contiguous older glacial moraine or riverine sediments onto the exposed riverbed, such as at the Spring on Goat Island, and the flat land adjacent to the crest of the gorge in the park on the Canadian side, and periodic inundations with fluctuating river levels. There exist many fine nineteenth century drawings and photographs of these habitats showing the Canadian side, especially at the brink of the Horseshoe Falls. There will be ice-scour and water scour at the water's edge due to storm surges. River gravels will build up as on Cedar Island and the islands in the American Channel and support trees - colonizing evergreens on the immature, shallow soils which dry out quickly - especially Arbor Vitae, which appear to be able to tolerate both extremes. Areas of poor drainage may occur, as in what is now Queen Victoria Park in Ontario, where in 1799 "there was still a pond north of Table Rock House with cedar and ash swamps between it and the bluff, [that is, the Niagara Moraine]" (Tiplin, 1988).
But it is the area of exposed riverbed by the brink of the Horseshoe Falls which calls to the imagination certain habitats and their floras, some of which have been eliminated from Goat Island. On the Ontario side there was a "small patch of low lying wet soil, extending from Table Rock to Cedar Island. This is one of the richest areas in the whole park. It abounds with flowers of many varieties. It is largely swampy but shallow. Here can be found forms peculiar to dry areas where such exist and all the varieties found in wet places. There are three Loosestrifes here, and the attractive Lobelia kalmii. On one occasion we gathered twenty species of purple flowers in this comparatively small area which may be well considered an "Eldorado" for botanists" (Panton, 1890).
This description most closely resembles the rock-flora of the remnant of the Terrapin Point Complex as it occurs at the extreme tip of what is now called Terrapin Point: Gentianopsis procera, Gerardia, Lobelia kalmii (see section on Terrapin Point).
It also suggests the grassy mats on the Second Sister, east side. Since most of the purple flowered species are conspicuous in summer and fall, it was probably then that Panton saw his purple flowers: species of Gerardia, Gentian, of Lobelia and Aster, and species of the mint family.
The last population of Linear-leaved or Four-flowered Loosestrife (Lysimachia quadriflora) in New York State occurs in a habitat such as this on Goat Island, as does the more generally distributed Fringed Loosestrife (Lysimachia ciliata). The Tufted Loosestrife (Lysimachia thyrsiflora) has been reported several times from the wet areas near the Falls (Day, 1888; Panton, 1890); Cameron, 1895).
The second floral component of these recently exposed river channels is the conifer shore-line forests.
As recently as seven hundred years ago, the cataracts existed just north of Goat Island, presenting one continuous crestline (Otis, 1982). The level of water in the river reached up to at least the base of the sedimentary bluff on Goat Island's west end. This was at a time when the forest at this end of the island was a shoreline, not a crestline, as would be the case for the aboriginal crest forests all along the present seven mile length of the Niagara Gorge. Two shorelines were created as the gorge extended southward -one along the shore of the Niagara River above the falls, later to become abandoned as a crestline, the other being created at the base of the gorge and extending south with the lengthening of the gorge.
At the river margin the presence of conifers fringing the lower margins of the deciduous forest typical of the upper talus slopes may be due to the relative youth of the exposed river bank due to lower Great Lakes water levels and corresponding lowered water levels in the river. The effects of ice-scour, sudden inundation followed by periods of dryness and warmth due to shallowness of soil may have been tolerable to these trees, as the deciduous element favored areas of deep sediment (morain on the upper banks, talus on the lower slopes). Shortness of duration of sunlight, cool moisture from the foaming rapids and long periods of cold in spring due to ice continuing to be brought down the river from Lake Erie upstream also contribute to conditions favoring a conifer element at the extreme base of the gorge.
This scenario is well depicted in the pre-camera paintings, drawings, engravings, etc., made of the cataract and gorge landscapes when these forest communities were still relatively intact (see the Pictorial Tradition and Terrapin Point sections). The two pictures by Cockburn drawn around 1833 discussed in the first of the two chapters just mentioned, suggests that the physiognomy of the crestline and the basal area forest of the talus slope in the gorge were the same, composed of evergreen trees behind which occurred the typical deciduous forests of the region, including the talus slopes above the basal evergreen community. Depictions showing deciduous forest with scattered evergreens perhaps are later modified or replace-ment mixed forest communities.
As has been stated elsewhere in this manuscript, the crest areas were among the first forests to be cleared along the gorge rim, due to their use as prospect areas.
This scenario should still exist in some areas in the Great Lakes region and can be tested on the rocky shoreline pavements there, provided the natural relationships are truly analogous, including the genesis of bedrock flats areas at lake water-boundaries (from lowered water levels or exposure from isostatic rebound on northern lake rims). This phenomenon may be only related to the hydrology of lakes and major rivers and not, e.g. communities along the Niagara Escarpment.
In the testimonials and old depictions, the evergreen trees may have been White Pine on the drier areas and gorge crests, such as at Whirlpool Park (see discussion, Crest Woods) and parts of the Three Sisters. Hemlock may have occurred in the spray areas and protected habitats such as Dufferin Islands and the western end of the Second Sister (28 Ann Rep Comm, 1912) - there are still a number of these to be found at the base of the talus slope in the gorge. On rocks in the plunge pool near the cataracts, Arbor Vitae (Thuja occidentalis) may have favored the river margins as well, and Red Cedar (Juniperus virginiana) above, in the open, successional areas on the southeastern side of Goat Island, and the ridge of slopes and bluffs, as at Wintergreen Flats above Niagara Glen, Ontario today. It is possible that these areas visually contributed a great deal to the original prospect at Niagara. This reconstruction takes into account the illustrated caricatures of Hennepin's written description of the falls (see series in 16 Ann Rep Comm, 1900).
One interesting characteristic of these plant communities associated with lowered water levels was the development of vegetation mats of various sizes with plant communities composed of species with similar growth form and habit arranging themselves in concentric zones, from minute species in the outer extremities in toward shrubs and young trees in the center. Probably the best expression of these mats and the concentric zonation on them occurs on the east end of the Second Sister. The nuclei around which such mats may originate might be investigated in the exposed riverbed near the eastern ends of the Three Sisters, and the succession studied.
This peculiar zonation may have also occurred and be still occurring on the little islands in the present channels of the American and Horseshoe Falls. When Louis Agassiz (1850) noted seven tree species: Arbor Vitae, Red Cedar, Hemlock, Basswood, Chestnut-Oak, White Pine and Maple, growing on "the little islet (only a few feet in extent)" called Ship Island in the American channel, it is difficult to imagine how these species with their different habitat requirements for light, shade, moisture and good drainage, arranged themselves in such a tight space, if not in some pattern, such as concentric zonation, with the deciduous trees, at least, in the center.
It would be interesting to note how the soil is or was stratified as to depth and sediment size, and whether this could have had an effect on community structure, and whether the soil was developed as a result of processes of succession or of river or glacial deposit.
The nucleus for the development of these mats from nothing may start with a solution cavity or vug in the dolomite river channel. After an accumulation of clam, crayfish, etc. shells, such as those discarded by gulls, and sediment and algae, occasionally a rather large plant establishes itself, such as a willow, or recently Purple Loosestrife (Lythrum salicaria). The roots of this plant become "pot-bound" coiling up in the cavity and consequently anchoring itself against the rather swift, if occasional, current. Around these roots then moss, such as species of the pleurocarpus genus Amblystegium, establish themselves. Within the moss substrate succession from smaller to larger species begins to take place. Once the mat is established, it increases its area at the margins mainly by the moss community fixed there - if wet margins, then mosses of the acrocarpous genus Philonotis may become introduced. As the moss population becomes extensive, the next life-form group extends itself into it outward from the center. The biggest size groups occur at the center, consequently contributing more biomass, creating conditions for the introduction of the next largest life-form group - the ultimate being a tree -presently willow or ash.
In the aboriginal condition, conifer trees may have formed a part of this process, especially the Arbor Vitae, after which several of Niagara's islets have been named.
Numbers of individuals of any species are most numerous in the tiniest, shortest plants in the outer zones, decreasing inwards with increase in species size and height with usually one tree or one shrub at the center.
Not all vegetated mats and islets seem to follow this hypothetical process, however, especially those recently developed in the flats areas on the south side of Goat Island. Brother Island, never accessible to the public, does not seem to show this zonation. Perhaps only mats begun from solution cavities develop this way, as if there were another form of succession.
It is for this reason that if more riverbed is exposed through lower water levels, it is here recommended that lawn-scapes not be established, as they have been on the south side of Goat Island and at Terrapin Point, but that nature be allowed to construct an ecosystem out of this land, as has been and is being done in the southern flats area and elsewhere in the complex.
For further discussion see section on the Second Sister.