Effects of human pressure

As the ultimate integrators of catchment activities, large rivers and their floodplains are subject to a range of impacts from human activities. These impacts include:

  • Flood control measures such as stop-banking which have truncated hydrological interaction with floodplains and associated lakes and wetlands
  • Proliferation of invasive species such as koi carp which can cause habitat modification and water quality degradation
  • Changes to shore-zone habitats through the planting of willows and use of riprap
  • Creation of impoundments and flow regime modification for hydro-electric power generation;
  • Riverbed excavation of sand and gravel
  • Drainage of floodplain wetlands
  • Effluent discharges
  • Development of catchments for agriculture.


Current projects

Ongoing work is investigating the effects of invasive fish on floodplain lake food-webs to understand the cascading effects on invasive fish management on other trophic levels. In addition, we are investigating the effects of modifying floodplain vegetation cover and connectivity on the generation of zooplankton during inundation events.

Contact: Kevin Collier (kcollier@waikato.ac.nz)


Completed projects

We have conducted studies on the effects of land use pressures on boatable rivers around New Zealand. In addition we have investigated the effects of stabilising river banks with riprap on shore-zone fish and invertebrates, and have examined the cumulative influences of organic, sediment and thermal discharges on macroinvertebrates in the lower Waikato River.

  • Collier K.J.; Hamer, M.P.; Moore S.C. In press. Littoral and benthic macroinvertebrate community responses to contrasting stressors in a large New Zealand river. New Zealand Journal of Marine and Freshwater Research.



  • Collier, K.J.; Clapcott, J.E.; David, B.O.; Death, R.G.; Kelly, D.; Leathwick, J.L.; Young, R.G. 2013. Macroinvertebrate pressure relationships in boatable New Zealand rivers: influence of underlying environment and sampling substrate. River Research and Applications 29: 645-659.



  • Collier, K.J.; Clapcott, J.; Young, R. 2009. Influence of human pressures of large river structure and function. CBER contract report 95, prepared for the Department of Conservation. The University of Waikato, Hamilton. http://cber.bio.waikato.ac.nz/PDFs/CBER_95.pdf