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BOTANICAL EVALUATION OF THE GOAT ISLAND COMPLEX, NIAGARA FALLS, NEW YORK |
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THE MOSS AND HEPATIC FLORA The extensive representation of the pleurocarpous species in the genus Amblystegium and weedy species in Brachythecium in recent collections on Goat Island probably relates to the large expanses of lawns where grass is mown down to six inches or less, allowing for more sunlight than would occur naturally, and less competition for these mosses. Recent collections of the weedy acrocarpous species of Barbula unguiculata, Ceratodon purpureus, Pottia truncata, Phascum cuspidatum are present mainly in disturbed or gravelly soil by roadsides and at the bases of trees in lawn areas - the first two species are colonizing the open dolomite flats on the south side of Goat Island. The old collection of Dicranum montanum mentioned below was and is associated with the trunks of trees, especially old, dead or dying trunks. Since all woody material is and has been scrupulously removed from the Goat Island woods and slope areas, the habitat for this moss and many other similar organisms is absent. Depletion of species of fungi and lichens is also due to loss of rotting wood material. The presently described bryophyte flora of the Goat Island complex is an extension of the rich and unusual bryophyte flora of the Niagara River Gorge and consequently includes little that cannot be found there. The number of species and genera in the family Pottiaceae (Aloina, Barbula, Bryoerythrophyllum, Didymodon, Hymenostylium, Hyophila, Phascum, Pottia, Tortella, Tortula, Trichostomum and Weissia), the highest of any family represented on Goat Island and the lower gorge, is indicative of the alkaline seepages and substrates (dolomite and limestone) exposed or shallowly covered in that area, and for which these species have an affinity. In addition, species of the family Pottiaceae have an unusual ability to tolerate cycles of drying and rewetting, which is typical of non porous limestone environments. Many of these taxa are rare in New York State. Many mosses from the nineteenth century were collected at the base of Goat Island "ad Niagarae fluminis rupes humidas" or "ad rupes irriguas" or "irroratas" after the climb down the Biddle Stairs. Wet rocks supported moss communities in the sprayzones of the Horseshoe and American Falls. There also the lime-charged seepage at the top of the talus slope where the early paths were provided, supported, then as today, dense, soaking populations of Hymenostylium recurvirostrum and other typical mosses found in the gorge only in these areas (see discussion below). The station of Fissidens grandifrons, of which two still persist on Goat Island and in the sites referred to a century ago at the Hermit's Cascade and The Spring, seemed to fascinate visitors to Goat Island with an interest in mosses, as can be seen from the number of collections cited below. In 1874, Peck published another New York station at Chittenango Falls found by Judge Clinton, "at present ... our most eastern known station of this interesting ... moss." The presently taxonomically uncertain moss Didymodon luridus was also found at Chittenango Falls "as at Niagara Falls we here find this rare moss accociated with Fissidens grandifrons (Peck, 1874). In the Goat Island complex, the greatest species diversity occurs on the west end of the First Sister (23 mosses, three liverworts) followed by the west end of the Second Sister (19 mosses, two liverworts) and the east end of the Second Sister (12 moss species). The base of Goat Island has 21 moss species and one liverwort. The highest number of taxa in the complex corresponds with areas of little access (base of Goat Island) or areas which are not frequented by visitors and administration. The distribution of mosses may be significant in the interpretation of phytogeographic, paleoecological and geologic history, since they demonstrate slower rates of evolution than vascular plants (Miller, 1980; Birks, 1982; Fife, 1985). Rare and relictual species may contribute new information in a floristic phenomenon already rich in indicators of past floristic migrations, etc. Certain mosses are significant in pioneer stages of succession on exposed dolomite river-bed in solution or excavation cavities filled with sand, gravel, bits of shells and organic debris, algae. Mosses in these habitats compete with certain grasses and the young rosettes of Lythrum salicaria, or, in some cases, the establishment of these larger plants may precede that of mosses, which may colonize their roots. Nomenclature follows Crum and Anderson (1982) except in the case of Hymenostylium recurvirostrum (Hedw.) Dix. which is referred to as Gymnostomum recurvirostrum Hedw. by Crum and Anderson (1982). The taxonomic position of Didymodon luridus is in doubt, and these names may turn out to be Didymodon tophaceus or D. rigidulus, both common on the Niagara dolomite and limestones, if rare in New York State (Crum & Anderson, 1982). I would like to express my gratitude to Dr. William Buck, New York Botanical Garden for field collections and identifications undertaken for this report, and to Dr. Richard H. Zander, Buffalo Museum of Science, who collected extensively in the 1970's in the Niagara River Gorge, and kindly allowed his specimens to be a part of this survey. I am also grateful to Richard Zander, a specialist in the genus Didymodon, for examining the Drummond exsiccat and sharing his determinations with me. |