Invertebrate community assembly along proglacial chronosequences in the high Arctic

1. Invertebrate community assembly is described for two contrasting proglacial chronosequences (over 1900 years) at Kongsfjord, W. Spitsbergen, Svalbard. 2. Three hypotheses were tested: (1) community assembly is deterministic, directional and predictable; (2) succession is inextricably linked to plant community and soil development; and (3) dispersal is a rate-limiting factor for community assembly. 3. Communities, dominated by omnivores and detritivores, are more complex than supposed previously. Herbivore species were few but predators, parasitoids and hyperparasitoids were abundant. 4. Species fell within one of eight defined groups with respect to colonization. This relates to ecophysiological tolerances, need for facilitation or dependence on other species. Spiders, surface-active Collembola and drought-resistant cryptostigmatic mites arrived before vascular plants established and soils developed. Later colonizers required site facilitation through soil development or host availability. 5. Comparisons between the proglacial area of Midtre Lovenbre, a land-terminating glacier, and three Loven Islands, released from beneath a tidewater glacier, showed similarities in community composition and species abundance with respect to successional stage, suggesting determinism and direction in community development. 6. Most common species on Midtre Lovenbre colonized the Loven Islands rapidly, suggesting that dispersal does not seriously restrict community development on the time scales involved. Some minor species associated with older soils appear not yet to have reached the islands.