Reports Search

Review of Soil Quality and Trace Element State of the Environment Monitoring Programmes

5269 RM 19-146 Review of Soil Quality and Trace Element State of the Environment Monitoring Programmes

Author(s): Jo Cavanagh, Kiran Munir, Stephen McNeill and Bryan Stevenson

Publication Date: 1 June 2017

Publication Number: 5269

Review of Soil Quality and Trace Element State of the Environment Monitoring Programmes

SedNetNZ modelling of sediment sources and loads in the Northern Hawke's Bay region

5001 RM 18-17 SedNetNZ modelling of sediment sources and loads in the Northern Hawke's Bay region

Author(s): Raphael Spiekermann, John Dymond, Harley Betts, Mike Marden

Publication Date: 1 June 2017

Publication Number: 5001

SedNetNZ modelling of sediment sources and loads in the Northern Hawke's Bay region

4941 Hawke's Bay Coastal Profile Monitoring 2016

Author(s): David Carruth

Publication Date: 1 June 2017

Publication Number: 4941

4941 Hawke's Bay Coastal Profile Monitoring 2016

4936 Taranaki Tsunami Inundation Analysis Update 2017

Author(s): Craig Goodier (MEng Civil, CPEng NZ)

Publication Date: 1 June 2017

Publication Number: 4936

4936 Taranaki Tsunami Inundation Analysis Update 2017

Tukituki Catchment State of freshwater wetlands 2016

Executive summary
Wetland is one of the most critically threatened ecosystems in Hawkeâ€™s Bay and in New Zealand. Hawkeâ€™s
Bay has lost 98% of its wetlands, which is proportionally more than the national scale of loss (90% loss
nationally). It is anecdotally evident that most remaining wetlands are now isolated, have gone through
modification of varying degrees, and they remain under threat of further decline.
Regional councils have responsibilities to maintain indigenous biodiversity under the Resource Management
Act 1991, and to protect the significant values of wetlands under the National Policy Statement for
Freshwater Management (NPS-FM 2014). Hawkeâ€™s Bay Regional Councilâ€™s Tukituki River catchment Plan
Change 6 (PC6) sets out improved and additional provisions to protect wetland values.
The primary purpose of state of the environment monitoring for wetlands is to produce a snapshot of their
state, and to monitor trends to detect early signs of decline or improvement. By doing so, monitoring results
could inform the effectiveness of national and regional statutory frameworks.
A pilot study was completed for the Tukituki catchment in which site selection framework, survey and
reporting methods were explored and field-tested. As a result, 10 freshwater wetlands were selected to
represent a range of wetland types typical of the Tukituki catchment, and baseline data for condition,
vegetation, soil and plant nutrient status, water level, and wetland birds (spotless crake and fernbird) were
compiled.
Half of the monitored wetlands were in good condition while others were more degraded. However, all of
the wetlands are subject to a high level of pressures, particularly from undesirable plant species such as crack
and grey willows. Either or both species of willow were present at 9 out of 10 monitored wetlands.
Fluctuation of water levels was particularly high in marsh compared to fens and in some of the swamps where
water level was relatively stable and lay just above or below the ground surface. Soil and foliage nutrient
showed the expected pattern, where fens are generally lower in nutrient status than swamps or marsh (see
Appendix C for descriptions of the characteristics of fen, swamp and marsh).
Most of the monitored wetlands supported either spotless crake or fernbird, both of which are threatened
species (At Risk â€“ Declining). This was despite the absence of predator control targeting non-possum
predators, except at Whatuma where mustelids, cats and rodents are actively controlled.
One of the key indicators for wetland condition is nutrient concentrations in soil and/or plant foliage. A
current snapshot of nutrient status showed patterns among wetland class and vegetation types. Most of the
soil nutrient concentrations were within the range of national thresholds, although a national threshold is
yet to be established for marshes. Combined with the nutrient status assessed as part of the Wetland
Condition Index, 3 of the 10 wetlands had particularly high nutrient status due to surrounding land use
activities and may require remedial actions in the near future.
The current bird survey method targets 2 species that are specialised in wetlands, albeit having different
habitat requirements. While these 2 species give an indication of habitat conditions (e.g. vegetation
structure, presence/absence of predators), a method targeting a small number of species misses other
wetland bird guilds such as water fowls, thus underrating some of the habitat values. The data does not give
an indication of the population size at a given site, making it hard to conclude if a wetland is doing well (or
not).
In conclusion, all of the monitored wetlands contribute to a representation of wetlands of the catchment but
they also are affected by key pressures such as undesirable species invasion and nutrient and sediment inputs
at a varying degree. Therefore it is recommended that efforts and attempts be made to maintain, restore, or improve the condition of these monitored wetlands. It is also recommended to review bird survey method to address the limitation described above.

Author(s): Keiko Habisha