Coastal Restoration Trust of New Zealand

Coastal Dune Ecosystem Reference Database

Wave riders: using seed dispersal characteristics to develop the surveillance programme for Euphorbia paralias (sea spurge) in New Zealand Other Publication

Frances Velvin
Publisher / Organisation
Ministry for Primary Industries
Euphorbia paralias, sea spurge
sea spurge, MPI, environmental impact, weed, water dispersal
Poster Sea spurge (Euphorbia paralias) is a coastal weed that has the potential to cause significant environmental impact to coastal sand dunes. Juvenile and mature plants (Fig. 1) were detected in 2012 on the west coast of the North Island and an eradication programme was initiated by MPI soon after. Activities included management of the detection site to prevent further seed production and coastline surveys to prevent establishment of new populations. Sea spurge seed can float and survive in sea water for over a year giving this species the ability to spread on coastal and ocean currents. To establish a new population seed must be deposited on land well above the high tide mark where there is sufficient time for germination, flowering and seed development before being washed back in to the sea during subsequent storm events. Seed washed off these sites may then be deposited further along the coastline. This is likely to have occurred at the detection site due to erosion of the seaward embankment (Fig. 2). The objective of the surveillance programme was to detect new populations of sea spurge on the coastline near the original site before seed development could occur, thus minimising propagule pressure from local sources.