Northland soft fern Christella dentata

Christella dentata
Christella dentata

Many of New Zealand’s threatened ferns are found in warmer climates on landmasses north of New Zealand, with New Zealand representing their southern distribution limits. These species tend to be restricted to northern areas of the country and occupy coastal and geothermal sites. Other species are restricted to habitats such as wetlands, which have suffered drastic modification and loss, or are palatable to stock and feral animals.

Key Features

  • Bright green, terrestrial ferns, erect or creeping, with soft, hairy fronds on pale brown stalks. Fronds are pinnate, with two rows of lobed leaflets, the lowermost leaflets being much shorter than those at the middle of the frond.

Distribution and Habitat

  • Swampy sites in Northland, particularly remnant kahikatea stands or the edges of hot streams and pools in the Rotorua/Taupo thermal area.

Threats

  • Competition with exotic weeds.
  • Habitat loss and modification.

Management Opportunities and Methods

  • Survey for new locations.
  • Protection of habitat:
    • Avoid hydrological changes to swamps and thermal wetlands containing Christella (e.g. drainage; flooding to create water supply for fire control)
    • Exclude cattle (trampling is damaging)
  • Weed control.
  • Establish new populations of Christella in suitable sites within its range.

Monitoring Options

  • Check existing populations annually.
  • Report new locations to DOC, NZPCN.

Further Information and Support

  • New Zealand Plant Conservation Network (NZPCN). http://www.nzpcn.org.nz
  • Weed management - Department of Conservation, Regional Councils.
  • References:
    • Brownsey, P.J. & Smith-Dodsworth, J.C. (2000). New Zealand Ferns and Allied Plants. David Bateman, Auckland.
    • Dopson, S.R.; de Lange, P.J.; Ogle, C.C.; Rance, B.D.; Courtney, S. & Molloy, J. (1999). The conservation requirements of New Zealand’s nationally threatened vascular plants. Threatened Species Occasional Publication 13. Department of Conservation, Wellington.
    • Peter de Lange, Peter Heenan, David Norton, Jeremy Rolfe and John Sawyer (2010). Threatened Plants of New Zealand. Canterbury University Press, Christchurch. 472 pp.