Chatham Islands, New Zealand

Until the close of the last century very little was known and next to nothing published about the mosses of the Chatham Islands. Although the first moss gatherings were made by Henry Travers in the 1860's it was not until 1997 that Landcare Research staff visited the islands to specifically study mosses and liverworts. Since then, partly to assist with the preparation of upcoming New Zealand Flora treatments on bryophytes, mosses and liverworts have also been gathered from Chatham Islands by scientists from of the National Institute of Atmospheric Research and Department of Conservation. From these aggregated collections we now have a reasonable idea of the Chatham Island moss flora.

Currently c.199 different mosses have been recorded from the Chatham Islands. Only one, Macromitrium ramsayae is endemic.  A small number, perhaps six species, are naturalised and the remainder are indigenous to New Zealand, Australasia or the wider Pacific. Of these mosses the majority are widespread species found throughout the main islands of New Zealand.

However, a small number follow a pattern already evident with the islands flowering plants and ferns, which is that some mosses previously only known from northern and southern New Zealand, are now known to occur on the Chatham Islands.

Lichens are by definition any fungus and alga (or a cyanobacterium - oft known as blue green alga) living in symbiotic association. This overly simplistic description serves to explain away a vast amount of New Zealand's biodiversity. There is an estimated 2000 different kinds of lichen in New Zealand of which formal descriptions exist for no less than 1706! As a rule most people ignore lichens, often mistakenly confusing them with the very different mosses and liverworts "as just lichens". This is unfortunate, and increasingly we are beginning to appreciate that we do this at our peril. Lichens are proving to be the botanical equivalent of the canary in the cage, often providing the first warning signs of deteriorating air quality, pollution and temperature changes. Lichens too are proving useful in dating geological phenomena such as landslides and earthquakes, and lichens are major nitrogen fixers, contributing for example, 10 kg N per ha per year in the average New Zealand temperate rainforest ecosystem.

New Zealand has about 10% of the worlds lichen flora, 23% of which are treated as endemic (i.e., found nowhere else but New Zealand).For our size this is an impressive figure, Australia which is many times larger has for example an estimated 35% of its lichen flora endemic. While our knowledge of New Zealand lichens is rapidly growing we are still unclear of what is present over large parts of the subcontinent. One key area of lichen ignorance is the Chatham Islands. The current lichen flora (Galloway 2007) records just 48 species for the islands. Yet despite that, the Chathams are the type locality for three species, one of which, Caloplaca maculata is endemic to the islands.