Shingle beaches
Shingle beaches are comprised of water-smoothed gravels. We sample the potential vegetated component which is that portion of shingle beaches occurring inland from the foreshore (i.e. the berm and backdune), with a substrate comprised primarily of a mixture of sand, gravel and cobbles. Within the top 10 cm of the surface, > 50% of the volume comprises particles > 2mm in diameter (upper size of sand). No greater than 50% of the surface can be covered with boulders (rocks > 256 mm). Gravel/shingle beaches occur where rivers deliver large quantities of gravel to the coast or where gravel is being eroded from the coastal cliffs. They often rise to a ridge that is rarely disturbed; a lagoon may be impounded behind.
From 2006-08 we completed sampling plants and invertebrates on 61 shingle beach sites around the New Zealand coast. Many of the sites we sampled are highly modified by exotic plants and animals, but some still have a significant, and often distinctive, native component. Our observations have allowed us to develop a preliminary conceptual model of what the plant composition and structure of these dynamic systems would have been before human disturbance. Invertebrate biodiversity highlights include the discovery of a rare egg laying peripitus (velvet worm), Ooperipaltellus veridimaculatus from one of the few shingle beaches on the South Island West Coast. This site also supports a highly diverse array of invertebrates, particularly macro invertebrates belonging to Coleoptera (e.g.,predatory carabids, arachnids (e.g., predatory salticids and Lycosids), native and introduced species of formicids, hemiptera etc.) Shingle beaches on Canterbury coast (e.g., Napenape) are particularly rich in ground/soil hunting carabids and staphylinid beetles including a potentially new species of rove beetle genera Paradiglotta and Ianmoorea, and new species of harpalanid carabids.