Threatened Aquatic Moss Found in An Eel Tank!
Fissidens berteroi (Mont.) C.Muell., a distinctive, large aquatic moss is currently known in New Zealand from only two geographic areas, Auckland City and on the western side of Lake Wairarapa. In Auckland only one population is now known, that resides at the mouth of a large outlet pipe draining a spring in the middle of suburbia near down town Onehunga. Here amidst the rubbish and pampas grass this tiny population just manages to hang on during times of chronic water shortages. Its habitat is presumed to be a relict of the once important Onehunga Springs which helped (and still do at times) supply the growing Auckland City’s water needs. Another population, located in dank water draining the Auckland Zoo in 1994, disappeared almost as mysteriously as it was discovered. As far as is known it is now extinct there. The Wairarapa locations occupy equally precarious habitats, just two small roadside populations where plants grow in shaded pools and slow flowing water underneath road bridges. Discovered there in the 1970s by the aptly named Tom Moss, who was then in the process of checking out nesting Welcome Swallows, they remain in a serious situation - should the streams flood too much these populations will be lost, should the streams dry up, as they are prone to do, then again the species will be lost.
Just why Fissidens berteroi should be so scarce defies current understanding. Herbarium records show that it was once more widespread here with at least four other locations (all collected prior to 1940) spanning from Northland to Nelson and Marlborough. Though it may still occur in these areas, recent surveys have failed to find plants. Of its status in the South American and Australian part of its range we know very little.
Thus it came as somewhat of a surprise to find a large thriving population of F. berteroi gracing the stone walls of the Eel Tank in Kelly Tarltons Underwater World, Okahu Bay, Auckland City. Here upwards of 50 distinct patches grow submerged in the semi-shade of a tank supporting two huge short-finned eels and a koi carp. Although rarely fertile the moss is thriving, so much so that it is occasionally trimmed back by the Kelly Tarlton Staff. Inquiries as to the origins of the plants have so far been unsuccessful. Those responsible for the Eel Tank maintenance are as mystified as the person who spotted the occurrence in the first place NZPCN Vice President Peter de Lange. Mr. Andrew Christie of Kelly Tarltons states that the only item introduced into the tank, some ten years ago, was a large log removed from a local stream. Unfortunately records were not kept of where exactly the log came from, and the staff member responsible has moved on. Even more notable is that the log does not support the moss, only the artificial rock wall does. So whether the log initially had small plants on it or spores when it was obtained is unclear. What is good news though, is that this highly threatened moss is being successfully cultivated, and says Mr Christie, koi carp don’t eat it.
Kelly Tarlton staff pride themselves on their conservation ethic and world leading aquatic animal management but they now can add to their expertise that they are apparently the first people to successfully - albeit it unwittingly - cultivate a thriving, sexual and recruiting population of Fissidens berteroi in New Zealand.
Posted: 14 September 2005