New Site For Water Brome (Amphibromus Fluitans) in the South Island
Until recently water brome (Amphibromus fluitans) had been known from the South Island from only two gatherings. The first of these was made by H.H. Allan in 1935 from the shores of Lake Tekapo, and the last in August 1991, when a few sterile scraps of an unidentified grass collected by P.J. de Lange from Mahers Swamp, north Westland, were identified as this species when they finally flowered in cultivation a few months later. At Mahers Swamp further surveys in 1992 and 1998 failed to find water brome and, while no one has specifically searched for water brome around Lake Tekapo, botanical surveys of that lakes admittedly extensive shoreline have so far failed to rediscover the elusive grass. Therefore, while no one was openly saying it, the general view was that water brome may well have gone extinct from the South Island. That situation changed, when, over the last summer staff and contract workers of the Department of Conservation’s Canterbury Conservancy began surveying the vegetation of kettleholes, and other wetlands for threatened plants. In one kettlehole surveyed near Lake Heron in late December 2005, Mr Markus Davis discovered water brome. The grass was found growing on muddy ground within the dried up centre of the kettlehole, and also, though much less frequently, in the marginal turf. Mr Davis estimated a percentage cover of 5% on the muddy ground where plants grew intermingled with Myriophyllum pedunculatum and Neopaxia linearifolia. Water brome was not recorded from any of the other kettleholes/wetlands surveyed in the area. Nevertheless its discovery strongly suggests that South Island botanists should now be keeping an extra vigilant eye out for this elusive, cryptic species.Posted: 17/05/2006