Introduced aquatic macrophytes can dominate small agricultural waterways in summer and autumn becoming a significant management problem. Excessive growth can clog waterways, causing drainage issues and reducing agricultural productivity while in‐stream velocities are reduced and sedimentation increased. Consequently, water managers remove them by mechanical clearance, chemical spray and cutting which can be costly and have neg...

Excessive macrophytes can cause significant problems in agricultural waterways requiring active management. Conventional control techniques can have a range of adverse effects. We investigated several control tools in two experiments: firstly, we tested eight treatments at a small‐scale (2 m × 2 m). We found intensive hand weeding, weed mat and herbicide spraying to be effective treatments, reducing macrophyte cover to

Arsenic, often found in gold deposits, can enter aquatic systems. The toxicity of arsenate (As(V)), the most common valence state of arsenic in freshwater, was assessed on the larvae of four freshwater insect taxa from naturally acidic (pH 5.9) and circumneutral (pH 7.4) New Zealand streams. Insects from the acidic stream were more sensitive to arsenate‐spiked water than those from the circumneutral stream. Early instars ( Del...

Canterbury mudfish ( Neochanna burrowsius ) are endemic to a small region of Canterbury, South Island, New Zealand and classified as nationally endangered. We reviewed data from the New Zealand Freshwater Fish Database and trapped fish in July 2006, and January and February 2007 in the Waianiwaniwa Valley, Canterbury to determine the importance of this catchment for mudfish conservation. Mudfish were found in 19 of the 28 site...

At the catchment scale, braided rivers are recognised as physically unstable, dynamic landscapes, yet at finer spatial scales they are a mosaic of micro‐habitats including physically unstable braided channels and more stable spring‐sources, spring creeks, and groundwater zones. We investigated benthic invertebrate communities at 103 sites in braided channels, springs and hillslope streams in the Waimakariri River, New Zealand...

Okeover Stream, on the University of Canterbury campus in Christchurch, New Zealand, has been the subject of restoration efforts since 1998. Our study focused on quantifying the response of this urban stream to current restoration efforts. Initially, physico‐chemical conditions and biological communities at three sites along the Okeover Stream were compared with three physically similar sites on each of nearby Waimairi Stream...

Deforestation is a global phenomenon threatening the biodiversity of many unique forested ecosystems. The volcanic calderas of Banks Peninsula, New Zealand, experienced widespread deforestation from 1860 to 1900 when >98% of the indigenous forest was removed. Streams on the Peninsula possess several regionally‐endemic species. The objective of this study was to assess the effect of historic deforestation on stream faunas by su...