Regional councils now have another tool in their kit to help identify natural wetlands, thanks to research shared by NIWA’s freshwater ecology specialist Paul Champion.
Mr Champion led two, two-day workshops in March, showing regional council staff how to identify characteristics of rushes, sedges and grasses, the dominant vegetation of wetlands in New Zealand.
Wetland plant species knowledge is in demand following the release of the National Policy Statement for Freshwater Management 2020.
The policy requires regional councils to be responsible for identification, protection and encouragement of restoration of natural wetlands.
The policy included a guide with protocols to identify wetlands using hydrology, soils and vegetation.
“Determining the type of vegetation can help regional councils work out if indeed a site is a natural wetland or not,” Mr Champion said.
“But just as important is the ability to identify threatened species which must be managed under the same policy.”
Mr Champion co-authored An Illustrated Guide to Common Grasses, Sedges and Rushes of New Zealand, published in 2012.
A workshop to revise and update the information in the guide was timely given the interest in wetland management among regional councils and the rural sector.
“Rushes and sedges are very difficult to identify, some are threatened, some are non-native and some are weeds,” Mr Champion said.
“Many are specific to certain habitat types so when you are trying to classify wetlands, they are a good indicator species.
“There is also a biosecurity aspect. We need to be able to correctly identify non-native plants or those causing problems in other parts of New Zealand.”
Mr Champion ran one workshop at the University of Waikato and the other at NIWA’s Christchurch office.
He grew his own seed specimens for the workshops and collected others from Waikato, Central Plateau in the North Island, as well as Canterbury and the West Coast in the South Island.
“We were able to examine some common species and their range across the country as well as the most threatened species.
“There is a site near the Napier-Taupo Road (State Highway 5) where there are only about 20 plants of a certain species and they are incredibly rare.”
Megan Royal is a catchment management officer for the lower Waikato River, working for the Waikato Regional Council.
She was among 16 staff from North Island regional councils who attended the workshop at the University of Waikato.
“I spend a lot of time talking with farmers about their restoration planting needs for riparian and wetland areas.
“Being able to identify plants correctly will help determine what the ecology of the environment will be like at different times of the year.
“This will help select the correct plants for each site based on their preferred habitat requirements.”
Ms Royal said the workshop showed her how to correctly identify different species of rushes, grasses and sedges.
“By using a microscope and botanical key I learnt how to distinguish between the different characteristics of leaves and fruiting structures.
“I can identify the fruiting structures of Juncus, grasses and Carex species and their subgenus vignea.”
By the end of the workshop she was able to identify the tiny fruiting capsule of the rushes with their minuscule seeds.
She also learnt that the fruit of the sedge is actually a nut, albeit a collection of very tiny ones and she was able to see the fruiting grains of the grasses. “Since the course I now have a heightened appreciation of the sheer diversity of these flora, especially after hearing how Paul and his team collected the plant material from all over New Zealand.”
