Peter J. de Lange

24 posts
Associate Professor (Botany, Ecology, Plant Conservation, Biosystematics) at Unitec in Auckland and a former Department of Conservation scientist. Peter has been visiting the Chatham Islands since 1996 and is a current member of the Chatham Islands Conservation Board.
Chatham Island forget-me-not ([i]Myosotidium hortensia[/i]) (left) shares a common ancestry with a northern hemisphere Mediterranean herb called navel wort ([i]Omphalodes verna[/i]) (right)

New paper explores the origin of Chatham Islands native flora

A major paper (Heenan et al. 2010) examining the origin of the Chatham Islands native flora has just been published in the June 2010 issue of the New Zealand Journal of Botany. The paper written jointly by staff of Landcare Research, Department of Conservation, and Universities of Auckland, Lincoln and Otago explores the origin and diversification of 31 endemic land plants (ferns and flowering plants) of the Chatham Islands archipelago using DNA sequences pooled from a variety of independent unpublished studies.

Hooker's spleenwort ([i]Asplenium hookerianum[/i]) plants growing amongst hoho ([i]Pseudopanax chathamicus[/i]) root plate with two other ferns - maidenhair fern ([i]Adiantum cunninghamii[/i]) and [i]Rumohra adiantiformis[/i] - Waipaua Stream - Rangiauria (Pitt Island). The plants in this image represents both the finely divided frond race sometimes known as Colenso's spleenwort (A. colensoi or A. hookerianum var. colensoi) and the more common less divided frond race of Hooker's spleenwort (A. hookerianum or A. hookerianum var. hookerianum). Image: P. J. de Lange

Little fern provides cryptic proof of ongoing New Zealand to Chatham Islands plant dispersal

Hooker’s spleenwort (Asplenium hookerianum) is not a particularly common fern on the Chatham Islands.  By far the largest population the Department of Conservation knows about is one that was discovered in November 2008 along the banks of the Waipaua Stream, Pitt Island. Hooker’s spleenwort looks superficially like a smaller version […]

[i]Caloplaca maculata[/i] - the only lichen known to be endemic to the Chatham Islands seen here growing on hard tuff. Image: Peter de Lange/DOC

Chatham Island lichens

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.