Flora & Fauna

Sea spurge is a serious threat to dune ecosystems. Probably arriving on ocean currents - it must be eradicted before it establishes. Photo: R. SmithEcologists and Environment Waikato staff have confirmed presence of sea spurge, Euphorbia paralias, on a West Waikato beach. This weed is a serious threat to indigenous sand dune vegetation and unvegetated fauna habitat, such as the nesting site for NZ Dotterels.

Two small infestations were found including around 65 flowering plants and over 100 seedlings. Sea spurge is native to western and southern Europe, but is widely naturalised in the coastal districts of southern Australia, and has also recently naturalised on Lord Howe Island. It is a long lived perennial plant 20-70 cm tall that dies back after flowering. The seeds are buoyant and can travel over long distances on ocean currents. The plant must be eradicated. If you see sea spurge, contact your Plant Pest Officer.

Muehlenbeckia growing next to a Beach Care access way at Whiritoa Beach (Photo John Barren)Pohuehue (Muehlenbeckia complexa)

Pohuehue is a low growing wiry vine that scrambles over rocks, dunes and other plants forming dense mats in the back dune area helping with dune stabilisation. Its white fleshy fruits provide food for geckos and skinks and the leaves and stem are food for other creatures such as Rauparaha copper butterflies a small brown native moth and a native mite.

The copper butterfly is relatively small, 24-34mm across with orange and black wings. It is often seen on pohuehue on the back dunes where it lays its eggs. When hatched the little green caterpillars (very hard to see) feed exclusively on the pohuehue leaves and flowers.

Copper butterflies have evolved a strategy for coping with New Zealand’s unpredictable climate. In every brood some larvae grow steadily towards maturity, but others stop feeding after just one molt and enter a resting stage (diapause) for several months before continuing their growth some months later. This increases the chance of survival for some offspring if harsh conditions suddenly develop.