LONG-TERM VEGETATION CHANGES IN A SNOW GOOSE NESTING HABITAT

Vegetation in a small section of nesting habitat in a Lesser Snow Goos e colony was mapped in 1976 and again in 1993. During the 17-year peri od, ground cover changed dramatically from being dominated by salt-mar sh graminoids and short grasses to being dominated by willows and area s of bare sediment. Lyme grass, Elymus arenarius, a plant strongly fav oured by Snow Geese when selecting their nest sites, which covered 15% of the ground in 1976, had completely disappeared by 1993. Although t he area had contained 79 Snow Goose nests in 1976, no nests remained i n 1993. Degradation of the nesting habitat is caused by foraging activ ities of the geese themselves during the prenesting and nesting phase: salt-marsh graminoids and short grasses are removed by grubbing and t he sediment is exposed; E. arenarius plants are removed by shoot pulli ng. Both clutch size and hatching success can be negatively affected b y the decline in available food plants, and, presumably as a consequen ce, the area was abandoned by breeding geese. This habitat destruction and subsequent abandonment of nesting areas by breeding geese is a pr ocess similar to that documented for brood-rearing areas of Lesser Sno w Geese.