The 2023 Nature Talks programme starts this month on Tuesday, February 21. Colin Ogle, well-known both in Whanganui and nationally as an outstanding botanist and conservationist, will give a talk titled ‘Our native coastal plants: What have we lost, and what about the rest?’. At the Coastal Restoration Trust of New Zealand’s most recent conference, held in Whanganui in March 2021, Colin was awarded the trust’s Pingao & Toheroa Award in recognition of his exceptional contribution to coastal restoration. The upcoming Nature Talks presentation is an extension of the one that Colin gave to the conference.
The Manawatū-Whanganui coastal plain is unique in that it contains the largest dune field in New Zealand, just under 1000 square kilometres and extending up to 20km from the current coastline. It contains a variety of special habitats for plants and animals, many species of which are solely or largely confined to it. Much of the land has been transformed for agriculture and forestry, with only a few remnants of native vegetation persisting away from the coast.
Colin’s talk will focus on three surviving components of this system: the coastal dunes themselves; the dune lakes and remnant coastal forests alongside them; and the coastal cliffs west of Whanganui. All three have been and continue to be modified to varying degrees by human activities (eg. settlement, agricultural and forestry land use, and recreation), natural forces (eg. wind and water erosion; changes in sand supply), and the spread of invasive plants.
Such changes and the gradual reduction in size of the remaining less affected areas has resulted in the complete loss of some species and the near-extinction of others. They include the sand gentian Sebaea ovata, last observed in the Tapuarau Conservation Area near the mouth of the Waitōtara River, and the sand daphne Pimelea actea, now known only from a tiny population near Himatangi Beach (it once occurred at Castlecliff, but is probably extinct there now). Likewise, the button daisy, Leptinella dispersa ssp. rupestris, a form that perhaps ought to be considered a full species, is now confined to a few eroding cliffs and cliff ledges along the South Taranaki-Whanganui coast, and a few scattered locations further north.
In this richly illustrated talk, Colin will discuss these and other species, and the wider communities of which they are part, outlining the threats they face and what can be done to protect them. His talk will be given in the Davis Lecture Theatre at Whanganui Regional Museum on Tuesday, February 21, starting at 7.30pm. Entry is free, although a koha would be appreciated to help cover the costs of hiring the venue.
