Christchurch City Council

Herbicides are a vital tool to reducing weed competition during the establishment phase of revegetation plantings. However, there is limited information on herbicide tolerances of native species, hindering the ability to develop effective weed-management plans. In a pilot study, tolerances of five New Zealand native species (Coprosma propinqua, Griselinia littoralis, Hoheria angustifolia, Prumnopitys taxifolia, and Cyperus ustulatus) were tested against the herbicides clopyralid, haloxyfop-P-methyl, triclopyr, glufosinate-ammonium and glyphosate at label rates, and to a dilute glyphosate treatment used to simulate drift from spraying around native plants. Treatments were sprayed directly onto plants, with survival and growth over four months compared to a control group. Clopyralid caused significant damage to H. angustifolia and G. littoralis, but increased growth in Cyperus ustulatus. Haloxyfop-P-methyl did not damage any species. While glyphosate and glufosinate-ammonium at label rates caused significant mortality, a low dose of glyphosate did not damage any species except Coprosma propinqua. Triclopyr also caused significant mortality or damage even in non-dicotyledonous plants, possibly due to small plant sizes. These results identify broader than expected susceptibility to triclopyr and clopyralid, suggesting additional caution with these herbicides may be required. The findings from this study also indicate that spraying glyphosate carefully around these species is unlikely to cause harm, except to Coprosma propinqua.

Conventional tourism risk-to-life analyses require data that are often unavailable, inaccurate or out-of-date. Thus tourist fatalities can occur where risk analyses have not been completed, as at Whakaari/White Island volcano, New Zealand in 2019, when 22 people on commercial tours died because of a sudden eruption. Even where risk analyses have been carried out (as at Piopiotahi/Milford Sound, New Zealand, a World Heritage Site where thousands of lives are endangered by coseismic landslide-triggered tsunami) unacceptable risks remain because (i) analyses can be misinterpreted, (ii) risk calculations change with time, and (iii) sociopolitical factors influence risk management decision-making. Herein we (i) develop a methodology for reconnaissance ("average") risk-to-life assessment, to indicate where more complete assessments are required, and (ii) test this against (a) the empirical acceptability of risks following a disaster and (b) a series of risk analyses where no disaster has yet occurred. We develop an “average” risk-to-life assessment for Whakaari/White Island, and compare its outcomes with existing risk analyses for Piopiotahi/Milford Sound. It agrees with post-event risk acceptability at Whakaari/White Island, and with pre-event risk analyses at Piopiotahi/Milford Sound. We update the “average” risk analysis for Piopiotahi/Milford Sound by incorporating vulnerabilities of cruise ships and improved hazard data - the societal risk-to-life is unacceptable by several orders of magnitude. The only feasible strategy for achieving acceptable risk is drastically reducing visitor numbers. Socio-economic considerations suggest that this may not be societally practicable, which calls into question the way in which risk is used in planning to reduce tourism fatalities.

The hihi/stitchbird (Notiomystis cincta), an endangered New Zealand endemic species, has one self-sustaining population not subject to human intervention, located on Little Barrier Island (Te Hauturu-o-Toi), in the Hauraki Gulf, Auckland. All other hihi populations have been derived from Little Barrier Island and all require active management. Changes in the population of hihi on Little Barrier Island are, therefore, of great conservation interest.

A destructive earthquake of 7·1 magnitude struck Christchurch, New Zealand in September 2010. A second, more violent and much more damaging earthquake with multiple fatalities occurred in February 2011, followed by a sequence of strong aftershocks centred around the city throughout 2011, 2012 and into 2013. This paper offers an insight into how the national, international and local agencies and, most importantly, communities came together to deal with this destructive sequence of events. It explores the impact of the events on the community and then the recovery planning for a wide range of essential infrastructure services and their effects on daily lives in a modern city with a population of some 350 000 people.

One approach in toxicity testing using microalgae is to assess the modulation of light energy absorbed as a result of exposure to contaminants. In this study, four strains of microalgae were isolated to obtain a variety of taxa for testing from sites receiving various levels of environmental stressors around Christchurch, New Zealand. The strains were characterized by partially sequencing rbcL, a routinely used gene in plant phylogenetics with a large existing database of strains. Based on morphological observation and gene sequences, the strains were identified as Chlorella sp., Neochloris sp., and Choricystis minor. The isolates were exposed to the herbicide glyphosate and the metal zinc, and their responses were measured using the ToxY-PAM system. Chlorella sp. was the most sensitive. Two strains of Choricystis minor were isolated from different ponds in an effluent gradient at a sewage treatment plant. Analysis of variance indicated that the isolate from the least contaminated pond was more sensitive to zinc (although regression analysis did not show this result). This suggests that the selective pressure exerted on algal strains by a contamination gradient over short a distance is detectable by both genetic and physiological methods, with implications for sourcing appropriate indicator organisms from the environment.