There are numerous streams within the Wellington urban area. Many of these have been piped and there is minimal historic information on their ecological health (habitat, macroinvertebrates and fish). Greater Wellington Regional Council (GWRC) has worked with Wellington City Council (WCC) over the last three years to better understand the ecological health of Wellington’s piped and open urban streams. This information will be used to inform WCC’s Natural Capital Strategy and GWRC’s Natural Resources Plan, which aim to maintain and improve freshwater ecosystem health values. The monitoring programme commenced in 2016 and has continued annually over summer until 2019. A range of open and piped urban streams across a gradient of urban impact were sampled to assess habitat condition, macroinvertebrate and fish populations to inform the design of a long term monitoring programme.
Urban streams within Wellington City support a range of ecosystem health values related to habitat, macroinvertebrate and fish values. Macroinvertebrate communities were generally in better condition with more sensitive taxa (e.g. EPT taxa) in streams with less urban land use and impervious surface in the upstream catchment. Barriers to fish movement are one of the major pressures influencing fish communities in Wellington urban streams. For example, the only fish species found upstream of piped sections of stream were climbing species (banded kōkopu, kōaro and eels). A piped stream ecological survey pilot study showed that some sections of piped streams have habitat which supports fish and macroinvertebrate life, however species richness and abundance is greater in open streams. Within piped streams only a subset of available taxa within catchments are able to persist there. Moving forward a long term monitoring programme will be implemented to determine trends in ecosystem health and responses to actions put in place to improve ecosystem health.