Planted Riparian Buffer Zones in New Zealand: Do They Live Up to Expectations?
Article first published online: 17 NOV 2003
2003 Society for Ecological Restoration International
Volume 11, Issue 4, pages 436–447, December 2003
How to Cite
Parkyn, S. M., Davies-Colley, R. J., Halliday, N. J., Costley, K. J. and Croker, G. F. (2003), Planted Riparian Buffer Zones in New Zealand: Do They Live Up to Expectations?. Restoration Ecology, 11: 436–447. doi: 10.1046/j.1526-100X.2003.rec0260.x
- Issue published online: 17 NOV 2003
- Article first published online: 17 NOV 2003
- water quality
Abstract River and stream rehabilitation projects are increasing in number, but the success or failure of these projects has rarely been evaluated, and the extent to which buffers can restore riparian and stream function and species composition is not well understood. In New Zealand the widespread conversion of forest to agricultural land has caused degradation of streams and riparian ecosystems. We assessed nine riparian buffer zone schemes in North Island, New Zealand that had been fenced and planted (age range from 2 to 24 years) and compared them with unbuffered control reaches upstream or nearby. Macroinvertebrate community composition was our prime indicator of water and habitat quality and ecological functioning, but we also assessed a range of physical and water quality variables within the stream and in the riparian zone. Generally, streams within buffer zones showed rapid improvements in visual water clarity and channel stability, but nutrient and fecal contamination responses were variable. Significant changes in macroinvertebrate communities toward “clean water” or native forest communities did not occur at most of the study sites. Improvement in invertebrate communities appeared to be most strongly linked to decreases in water temperature, suggesting that restoration of in-stream communities would only be achieved after canopy closure, with long buffer lengths, and protection of headwater tributaries. Expectations of riparian restoration efforts should be tempered by (1) time scales and (2) spatial arrangement of planted reaches, either within a catchment or with consideration of their proximity to source areas of recolonists.