Gravel beaches are discrete, irregularly separated habitats along New Zealand’s coasts. They are one of a diverse range of small, disparate, naturally rare ecosystems that tend to occur in extreme environments, and provide critical habitat for threatened, rare and endemic species. New Zealand’s gravel beaches are threatened by urbanisation, weeds, adjacent agriculture, introduced animals and predicted sea-level rise.
Species composition patterns and vegetation–environment relationships were quantified for montane volcanic outcrops on Banks Peninsula. The flora of these habitat islands comprises 346 vascular plant species including 82 exotic species and 52 species that are nationally rare, regionally rare, or regional endemics. Both MDS ordination analysis and TWINSPAN results illustrated the high compositional and environmental heterogeneity across the outcrops.