Colonization constraints during primary succession on coastal Lake Michigan sand dunes

Lichter, J

J. Lichter, Colonization constraints during primary succession on coastal Lake Michigan sand dunes, J ECOLOGY, 88(5), 2000, pp. 825-839

65

INGLESE

Article

Environment/Ecology

JOURNAL OF ECOLOGY

0022-0477 → ACNP

88

5

2000

825 - 839

ISI

0022-0477(200010)88:5<825:CCDPSO>2.0.ZU;2-Q

1 Primary succession on coastal sand dunes has generally been presumed to b e driven by autogenic environmental change associated with dune stabilizati on and gradual soil development. 2 An extensive chronosequence of dune-capped beach ridges is found adjacent to northern Lake Michigan and the youngest 13 ridges (aged 30-440 years ol d) show a clear pattern of primary succession and development of a forest e cosystem. 3 Seed-addition and seedling-transplant experiments indicated that coloniza tion of young sand dunes by late-successional Pinus and Quercus species is constrained by limited seed dispersal, seed and seedling desiccation, and s eed predation rather than seedling success being constrained by low soil ni trogen availability. Their establishment may therefore depend on coincidenc e of chance seed dispersal, favourable weather conditions and low rodent de nsities. 4 In addition, episodic burial by sand prevents most species from colonizin g young dune ridges, while burial of seedlings by litter limits recruitment on older dune ridges with developing forest. The intensity of competition increases during succession. 5 Dune succession is better described as the transient dynamics of coloniza tion and competitive displacement rather than the result of gradual soil de velopment and competitive displacement.