Seed rain in successional vegetation, Port Hills Ecological District, New Zealand

Patterns in vegetation and seed rain were measured in an abandoned agricult ural scrubland/forest system in lowland Canterbury to test relationships be tween patterns of seed rain and succession in seral scrub and established l ow forest. indicator species analysis separated four distinct vegetation ty pes which formed a successional chronosequence confirmed by air-photo inter pretation and analysis of vegetation composition. Vegetation biomass (appro ximated by summed species importance scores) and species richness (mean spe cies plot(-1)) both increased with successional stage. Although there was a significant difference in seed rain density among vegetation types, the re lationship between seed rain and succession was clouded by individual speci es fecundity. There was a significant positive relationship between success ional stage and seed rain species richness. The proportion of seed species present in seed rain but absent from extant vegetation was greater in less advanced vegetation. This relationship was determined by low species richne ss in the vegetation and a suite of highly mobile seed species, typical of more mature forest, common to all vegetation types. We conclude that forest recovery is not dispersal limited in the forest and seral scrub vegetation we investigated, and that with the continued absence of grazing pressure f orest recovery should be rapid.