Radio New Zealand - Te Reo Irirangi o Aotearoa

Show notes for Thursday 29 January 2009

On This Programme

Female kakapo Alice feeds her 12-day-old chick. Image courtesy of Don Merton/Department of Conservation

It's summer and the world's 90 remaining kakapo have breeding on their mind. The Department of Conservation's Kakapo Recovery Team is optimistic that this could be an outstanding kakapo breeding season on Codfish Island-Whenua Hou, and with the first mating of the season taking place on the night of Christmas Day, their optimism appears well-founded.

Kakapo are the world's heaviest parrots. They are flightless, nocturnal vegetarians, and are unique to New Zealand. Once widespread throughout the main islands of New Zealand, their numbers declined following the arrival of humans, the clearance of much of their forest home and the introduction of mammalian predators such as stoats, cats and rats. By the 1950s they were feared extinct, until a remnant population of a few males were rediscovered in Fiordland. In the late 1970s a breeding population of several hundred birds was rediscovered on Stewart Island, but when this was threatened by feral cats the entire population was captured and relocated to safe offshore islands, including Little Barrier Island and Codfish Island-Whenua Hou.

To find out more about kakapo, have a look at the Kakapo Recovery Programme and the Department of Conservation's kakapo page.

In this programme, Kakapo Recovery Programme managers Deidre Vercoe and Daryl Eason talk about what they are expecting this year and how they might deal with hand-rearing up to 60 chicks. Over the coming weeks we will explore how intermittent mass rimu fruiting triggers irregular kakapo breeding, kakapo genetics, the implications of low genetic diversity and inbreeding, and artificial insemination as a way of increasing the number of rare Fiordland genes in the kakapo population.

Diloma snails feeding on bull kelp. Image courtesy of Alison Ballance

Bull kelp (Durvillaea antarctica) is the very large tough brown seaweed that thrives on rocky surf beaches in the south of New Zealand. It has leaves that can be up to 10 metres long, and the plant is attached to the rock by a strong base, or holdfast, that 'glues' the plant onto the shore. The leaves of bull kelp are honeycombed and filled with air spaces, so if a plant breaks off in the waves it can float. Lots of small creatures such as crustacea and snails live within the holdfast, so if the kelp plant floats away, it takes all these creatures, becoming their floating 'hotel and restaurant'.

A team of biologists from the University of Otago (Crid Fraser, left, Jon Waters and Raisa Nikula, left, pictured with a bull kelp holdfast that had washed up on a beach) has been looking at how bull kelp is distributed around the Southern Hemisphere, the genetics of the plant, and the creatures that live within it, and they have come up with some unexpected results. Find out more about their research.

About 55.5 million years ago, the Earth experienced a global warming event unique in its speed and magnitude - leading to what is often described as Greenhouse Earth. Scientifically, this period is known as the Palaeocene-Eocene Thermal Maximum or PETM.

With the help of ancient rocks from a Canterbury river bed, a team of palaeontologists and geochemists, led by GNS Science's Chris Hollis (pictured with Matt Huber, right, of Purdue University, Indiana) has found that the surface temperatures of the oceans surrounding New Zealand at the time exceeded 30 degrees Celsius. They presented their findings at a conference about Greenhouse Earth.

New research suggests that current cancer therapies may be targeting the wrong cells by focusing on the rapidly-dividing cells that form the bulk of the tumour rather than a small population of cancer stem cells.

Stem cells are found in healthy tissue and organs. There, they never stop dividing, and with each division they form two distinct daughter cells - one that remains a stem cell and one that turns into the cells that build the tissue or organ.

Stem cells (or more specifically, cells that have most of the properties of stem cells) have now also been discovered in a number of cancerous tumours, including tumours of the breast, brain, prostate, colon, pancreas, ovary, lung as well as melanoma. They are thought to drive the uncontrolled growth via their modified daughter cells, while remaining in such low numbers themselves that they escape standard cancer treatments such as chemotherapy and radiation.

Mike Berridge, who heads the Mallaghan Institute's Cancer Cell and Molecular Biology Group, and Melanie McConnell explain their research effort to stimulate the immune system to recognise and target these cells in melanoma tumours.