Tuesday, September 26, 2017

Analysis of the impacts of a water channel diversion wall on waterbirds inhabiting the western end of Lake Rotoiti, Bay of Plenty, New Zealand

TitleAnalysis of the impacts of a water channel diversion wall on waterbirds inhabiting the western end of Lake Rotoiti, Bay of Plenty, New Zealand
Publication TypeJournal Article
Year of Publication2015
AuthorsSmith, D, Bycroft, C, McClellan, R, Gillies, R, Shaw, W
JournalNotornis
Volume62
Issue4
Pagination184-191
Type of ArticleFull article
KeywordsBird counts, Lake Rotoiti, little black shags, Phalacrocorax melanoleucos, water diversion, waterfowl
Abstract

Cyanobacterial blooms in Lake Rotoiti have been linked to nutrient flows from Lake Rotorua via the Ohau Channel. To mitigate this, a diversion wall was constructed in 2008 that was designed to redirect water entering Lake Rotoiti from Lake Rotorua into the Kaituna River. One concern was whether the presence of the diversion wall might have adverse impacts on the abundance of birds using the lake. Monthly bird counts were undertaken at 8 sites in Lake Rotoiti, over 8 years, and which spanned the period before, during and after construction of the wall. Generalised linear mixed effect models and AIC were used to investigate any effects of the wall on 6 bird species. There was no apparent impact of the wall on 5 of the species. The sixth species, little black shag (Phalacrocorax melanoleucos), was more abundant in sites surrounding the wall post-construction, and appeared to be using the wall for roosting and to hunt for smelt.

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