Vegetation recovery following fire in two Waikato peatlands at Whangamarino and Moanatuatua, New Zealand

Abstract

After fires in 1984 and 1989 at Whangamarino wetland, and in 1972 at Moanatuatua Bog, peatland flora and vegetation were monitored to determine rates and pattems of recovery. Species with rhizomes that survived the fires were able to resprout and grow rapidly in the initial post-fire period. Species that were eliminated had to re-establish from seed and so recovered more slowly. The vegetation at Moanatuatua took almost 12 years to recover to pre-fire condition, twice as long as at Whangamarino. Adventive and early colonising native species were prominent only in the first 1-2 post-fire years, probably because of temporarily increased availability of nutrients and/or open habitat. Ordination techniques arranged the plots and species in a sequence from shrub-sedgeland (Whangamarino), through Empodisma minus restiad rushland (Whangamarino), to Sporadanthus traversii/ Empodisma restiad rushland (Moanatuatua) following a gradient of decreasing fertility with time. Fires reset the bog development process but generally do not alter the recovery pathways. In the absence of future major disturbance, including invasion by troublesome adventive species, the younger Whangamarino peatlands are expected to develop eventually into floristically poor, oligotrophic raised bogs similar to those at Moanatuatua and elsewhere in the Waikato district.

Vegetation recovery after fire on a southern New Zealand peatland

“…Likewise, Timmins (1992) recorded the slow reappearance of Empodisma, fiom seed, and slow recovery of Gleichenia at Eweburn Bog. Similar observations at Whangamarino wetland were related by Clarkson (1997) to the probable susceptibility to fire of the erect rhizome and surface roots of Empodisma and the slender rhizomes, at or just below ground surface, of Gleichenia.…”

“…and Schoenus brevifolius in the Whangamarino wetland, Waikato (Irving et al 1984;Clarkson 1997), S. brevifolius in Kaimaumau gumland, Northland (McQueen & Forester 2000), B. teretifolia in south Westland (Mark & Smith 1975), and by sedges in Tasmanian wetlands (Kirkpatrick & Hanvood 1983). Dobson (1979) considered that persistently burned oligotrophic mires "have a rather monotonous vegetation of Sphagnum, Polvtrichum, Empodisma, Gleichenia, and Drosera".…”

Ecology and vegetative morphology of the carnivorous plantUtricularia dichotorna(Lentibulariaceae) in New Zealand

“…The appearance of U. dichotoma after fire was reported by Thomson (1876), Cockayne (190l), Carse (1901~ 1910. Cockayne & Laing (19IO), and recently by Clarkson (1997).…”

“…comm.). In the Whangamarino wetlands, U. dichotoma was recorded three months after a fire in 1984 (notes on CHR 422063, Irving, 16 Oct 1984;WAIK 1387, Irving, 14 Feb 1985 and after six months in 1989 (Clarkson 1997). After experimental bums at Whangamarino in 1994, U. dichotoma dominated briefly before the vegetation thickened, mosses became re-established, and U. delicatula replaced it (P. J. de Lange & D. A. Norton unpubl.…”

“…Timmins (1992) and Clarkson (1997) studied the role of fires in wetlands in New Zealand and noticed a rapid re-establishment of carnivorous plants such as Drosera and/or Utricularia. The appearance of U. dichotoma after fire was reported by Thomson (1876), Cockayne (190l), Carse (1901~ 1910.…”