1 The effects of habitat degradation on the soil seed bank at La Perouse Ba
y, Manitoba are described. Foraging by lesser snow geese leads to loss of v
egetation, coupled with changes in soil abiotic conditions and an increase
in salinity.
2 The density of seeds and the relative abundance in the seed bank of speci
es characteristic of undisturbed sites decrease following degradation, whil
e the relative abundance of invasive species increases. Vegetation loss had
the greatest impact on seed banks of stress-tolerant species and the least
impact on species with many widely dispersed seeds.
3 The above-ground vegetation and below-ground seed bank were less similar
in undamaged plots than in disturbed plots. In spite of the low degree of s
imilarity, redundancy analysis of the data indicated that approximately hal
f of the variation in the soil seed bank could be explained by the vegetati
on data and vice versa.
4 More recently degraded soils had richer soil seed banks than those from o
lder disturbances. Site-specific factors not only influenced the species pr
esent but also the time lag between loss of vegetation and loss of the seed
bank. Seed banks in these impacted and fragmented sites do not recover qui
ckly.
5 Seed banks in sandy beach-ridges were less affected by degradation due to
the greater proportion of ruderals present in the original vegetation and
the absence of the high soil salinities that are characteristic of degraded
salt-marsh soils.