A new species of wirerush from the wetlands in northern New Zealand

Jul 09, 2012
This shows Beverly Clarkson assessing the ecological condition of an Empodisma robustum wetland. Credit: Steve Wagstaff and Beverly Clarkson

The northern part of the North Island of New Zealand is marked at approximately 38° S latitude by a distinct ecological boundary known as the "kauri line". This region forms the southern distributional limit of many plants and is the warmest part of New Zealand. A number of endemic plants are found there. Ecologists have recently discovered a new species of wirerush from peatlands north of the "kauri line".

Wetlands serve vital ecological functions by providing wildlife habitat, carbon storage, nutrient regulation and water balance. New Zealand has a number of wetland types. The peat-forming wetlands are dominated by a plant commonly known as wirerush (Empodisma, Restionaceae). The name Empodisma is derived from a Greek word meaning "to hinder". Both the common and the Greek name describe its dense scrambling growth form. Empodisma is in the southern hemisphere family Restionaceae.

This is a map showing the generalized distribution of Empodisma in Australia and New Zealand and the collection localities of the DNA samples included in our study. The approximate position of the kauri line in New Zealand is shown with a dashed line. Credit: Steve Wagstaff and Beverly Clarkson

The horizontal root systems of wirerush branch profusely forming finely divided rootlets with long-lived root hairs. In wirerush bogs, the underlying peat is formed largely from the remains of the root systems, stems bases and trapped plant litter. The peat mass absorbs water like a sponge. In peat bogs, incoming rainfall and atmospheric particles are the only source of nutrients. These are removed from the flow of water in the porous upper layers of peat. This may be an adaptive feature in nutrient-poor environments such as peat bogs.

Morphological characteristics of Empodisma robustum. A) Vegetative shoot with attached leaves and flowers (actual size) B) Rhizomes with emerging vegetative shoots (2.5× actual size) C) Vegetative shoot with attached pistillate flower D) Pistillate flower with attached bracts E) Gynoecium F) Mature nut G) Vegetative shoot with attached staminate spikelet H) Staminate flower with attached bracts I) Staminate flower. Scale bar = 1 mm. Credit: Steve Wagstaff and Beverly Clarkson

Steve Wagstaff and Beverly Clarkson recognize three of wirerush including the newly described species Empodisma robustum. Empodisma robustum is only found in peatlands in northern New Zealand, whereas E. minus is found in central and southern and eastern Australia, and E. gracillimum is restricted to western Australia. Their study provides an account of the origin, diversification and ecology of the genus with descriptive keys and illustrations.

Explore further: 'Red effect' sparks interest in female monkeys

More information: Wagstaff SJ, Clarkson BR (2012) Systematics and ecology of the Australasian genus Empodisma (Restionaceae) and description of a new species from peatlands in northern New Zealand. PhytoKeys 13: 39-79. doi: 10.3897/phytokeys.13.3259

add to favorites email to friend print save as pdf

Related Stories

Peat-based climate reconstructions run into murky waters?

Jul 06, 2012

Peatlands are globally important ecosystems that serve as archives of past environmental change. Peatlands form over thousands of years from the accumulation of decaying plants and hold water, or in some cases purely rainwater. ...

Nitrogen rain makes bogs contribute to climate change

Dec 11, 2006

High levels of nitrogenous compounds can make bogs give off more carbon dioxide, thereby adding to the greenhouse effect. This has been shown by the plant ecologist Hakan Rydin in an article published this week in the Proceedings of ...

Recommended for you

'Red effect' sparks interest in female monkeys

Oct 17, 2014

Recent studies showed that the color red tends increase our attraction toward others, feelings of jealousy, and even reaction times. Now, new research shows that female monkeys also respond to the color red, ...

Roads negatively affect frogs and toads, study finds

Oct 17, 2014

The development of roads has a significant negative and pervasive effect on frog and toad populations, according to a new study conducted by a team of researchers that included undergraduate students and ...

All in a flap: Seychelles fears foreign bird invader

Oct 17, 2014

It was just a feather: but in the tropical paradise of the Seychelles, the discovery of parakeet plumage has put environmentalists in a flutter, with a foreign invading bird threatening the national parrot.

Amphibians being wiped out by emerging viruses

Oct 16, 2014

Scientists tracing the real-time impact of viruses in the wild have found that entire amphibian communities are being killed off by closely related viruses introduced to mountainous areas of northern Spain.

User comments : 0