LE3 .A278 1975

1975

Dodds, Donald

Acadia University

Master of Science

Masters

Biology

Biology

Gilbert Island is an alluvial island in the St. John p River, approximately 7 miles south-east of Fredericton, New Brunswick. The island, like other near by river islands, provides valuable wetlands and woodlands habitat for waterfowl and several other wildlife species. The agriculture history of the island dates back to the late 1700's and since 1962 it has been operated by the New Brunswick Government as a community pasture. The 660 acre island is covered by 170 acres of cleared grassland, 345 acres of deciduous woodland and 145 acres of sloughs vegetated with aquatic plants. It is surrounded by 70 acres of river marshland. Floral descriptions of these island regions are presented. Ninety-eight bird species including 11 waterfowl species and 10 species of mammals were observed during the study period, May to September, 1972 and 1973. The findings of systematic surveys conducted to determine the importance of Gilbert Island to nesting and brood rearing waterfowl and observations of mammals and bird species other than waterfowl are reported. In 1972, 276 cattle were pastured on Gilbert Island, but the number was lowered to 218 the following year. The location and movement of cattle on the island was monitored throughout the 1973 season. Cattle grazed primarily on the grassland until early July, but moved to the woodlands for forage when the grassland forage became scarce. During the previous year, they also grazed extensively on the slough marshlands. Floral descriptions of 10 exclosures and 10 control areas are p~esented for comparsions to demonstrate the effects of grazing on the flora. Nearly all effects of the grazing were interpreted as being detrimental to the native flora and contributing to downgraded habitat quality for wildlife. These are reported on and discussed. It appears that cattle could be pastured on Gilbert Island without causing these undesirable effects if the grassland was properly managed.

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