I am, as you can imagine, quite excited about the fact that I have uploaded 5 images from our recent island journeys. What of course I should have done and will remember to do next time is to put one up at a time and that way I will be able to title them all!
The first 3 are of Rangitoto Island which is very close to us. In fact when we are on Cheltenham Beach we could almost swim to it. The last 2 are of Tiritiri Matangi which is about an hour by ferry from Auckland.
I have been so excited by these 2 islands and my Biology and Geography colleagues will understand why. On a personal level they were both incredibly beautiful and visually exciting but for someone who teaches succession, speciation, competition, transpiration etc they were a living classroom.
You can see from the pictures that they are very different and Fogg has described their history briefly I think. Rangitoto is hot and unforgiving, the black lava is hard and dry and it would be hard to imagine anything living on it let alone the massive pohutukawa tree. Yet over time (geologically and biologically a very short 400 years) mosses and lichens have covered the lava and when they died their remains have filled the nooks and crannies between the lumps of lava. This has provided a foothold for ferns and grasses, whose spores and seeds have blown in from neighbouring islands. The roots of the grasses have held the embryonic soil and allowed larger flowering plans and shrubs to get a foothold. Finally there has been soil enough for the trees which now cover an enormous percentage of the island. In places, however, the succession is still in its early stages and the only organisms visible are mosses or grasses. There is no water on the island, the lava is very porous and the rain water runs straight through to form a freshwater reservoir on top of the seawater under the island. On these open areas of lava temperatures rise as the black rock absorbs the sun's energy and so there is very little animal life except small birds which can shelter in the undergrowth and feed on the seeds and the few insects that are available. The survival of the pohutukawa also depended on the eradication of the possums and wallabies that had been introduced to the island in the 1880s.
Tiritiri Matangi is not a volcanic island and has plenty of running water. It has supported both Maori settlements (Kawerau and later Ngati Paoa) and European farmers and all of this occupation and farming resulted in most of the original bush being lost. When it was made into a sanctuary a massive amount of work had to be done to replant and reintroduce birds who could breed and survive without predation by possum, rats, cats, stoats etc. This has now happened and the rules about entering the island are very strict to ensure that no stray predators get back. The same applies to seeds of plants (weeds) that would compete too strongly with the indigenous plants. The plant life on the island is lush and green and allows the visitor to walk through shady tracks and boardwalks and listen to the birdsong and spot some of the most endangered species of birds in New Zealand. It is a magical place as you can see from the pictures and the birds are beautiful. Some special ones to mention are the Stitch Bird, The North Island Saddleback, The North Island Robin, The Whitehead, The Tui and of course the Takahe and The Kokako. Unfortunately we did not see the latter or the Blue Penguins which nest on the coast but we were so pleased to have spent such a wonderful day that it did not matter.
I leave you with this picture (as with all I must credit Fogg) of Greg. He is not the prettiest bird in the world, but because he is a Takahe one of the most endangered and therefore one of the most significant that we saw on Tiritiri.
With very best wishes
Phileas
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