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Benthic macroinvertebrates were sampled (seven Surber samples per site) in 88 rivers throughout New Zealand in "runs" (velocity 0.4-0.8 m s" 1 , depth = 0.3-0.6 m), under autumn baseflow conditions (Q < median). Medians and 10-90 percentiles for the following community level characteristics were: taxa richness, 14 and 7-20(0.7 m -2 ); Shannon Diversity (H'), 1.33and 0.80-1.90; total density, 1900 and 230-6700 nr 2 ; and total biomass, 0.608 and 0.112-2.932 g AFDW nr 2 . Invertebrate abundance and taxonomic richness were lowest in rivers with beds of silt or sand, or cobbles overlain with sand deposits. Comparisons of environmental factors between sites grouped by TWINSPAN indicated that the degree of catchment development to improved pasture, water temperature, and level of enrichment (indicated by increased nutrients and periphyton biomass) are important factors affecting invertebrate community structure in New Zealand rivers. Mayflies, stoneflies, and predatory caddisflies were associated with cooler, less enriched, steeper, and more elevated sites than snails, crustaceans, chironomids, and worms. Stonefly biomass was minimal at sites having mean annual temperatures >13°C. The following community characteristics emerged as useful indicators of the level of water enrichment: the Macroinvertebrate Community Index (MCI) and its quantitative analog (QMCI); the presence of some species (e.g., Zelandoperla decorata and Bereoptera roria), and the densities of some widely distributed taxa (e.g., M90014Received 5 March 1990; accepted 23 May 1990 Deleatidium spp. and Psilochorema spp.); percentage predator biomass; and the number of ephemeropteran, plecopteran, and trichopteran taxa (EPT). Sites did not separate out clearly into ecoregions, although rivers with "clean-water" faunas were more predominant in the South Island than in the North Island. This is thought to reflect the greater degree of development of the North Island catchments.

SummaryBackgroundStents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy.MethodsThe International Carotid Stenting Study (ICSS) is a multicentre, international, randomised controlled trial with blinded adjudication of outcomes. Patients with recently symptomatic carotid artery stenosis were randomly assigned in a 1:1 ratio to receive carotid artery stenting or carotid endarterectomy. Randomisation was by telephone call or fax to a central computerised service and was stratified by centre with minimisation for sex, age, contralateral occlusion, and side of the randomised artery. Patients and investigators were not masked to treatment assignment. Patients were followed up by independent clinicians not directly involved in delivering the randomised treatment. The primary outcome measure of the trial is the 3-year rate of fatal or disabling stroke in any territory, which has not been analysed yet. The main outcome measure for the interim safety analysis was the 120-day rate of stroke, death, or procedural myocardial infarction. Analysis was by intention to treat (ITT). This study is registered, number ISRCTN25337470.FindingsThe trial enrolled 1713 patients (stenting group, n=855; endarterectomy group, n=858). Two patients in the stenting group and one in the endarterectomy group withdrew immediately after randomisation, and were not included in the ITT analysis. Between randomisation and 120 days, there were 34 (Kaplan-Meier estimate 4·0%) events of disabling stroke or death in the stenting group compared with 27 (3·2%) events in the endarterectomy group (hazard ratio [HR] 1·28, 95% CI 0·77–2·11). The incidence of stroke, death, or procedural myocardial infarction was 8·5% in the stenting group compared with 5·2% in the endarterectomy group (72 vs 44 events; HR 1·69, 1·16–2·45, p=0·006). Risks of any stroke (65 vs 35 events; HR 1·92, 1·27–2·89) and all-cause death (19 vs seven events; HR 2·76, 1·16–6·56) were higher in the stenting group than in the endarterectomy group. Three procedural myocardial infarctions were recorded in the stenting group, all of which were fatal, compared with four, all non-fatal, in the endarterectomy group. There was one event of cranial nerve palsy in the stenting group compared with 45 in the endarterectomy group. There were also fewer haematomas of any severity in the stenting group than in the endarterectomy group (31 vs 50 events; p=0·0197).InterpretationCompletion of long-term follow-up is needed to establish the efficacy of carotid artery stenting compared with endarterectomy. In the meantime, carotid endarterectomy should remain the treatment of choice for patients suitable for surgery.FundingMedical Research Council, the Stroke Association, Sanofi-Synthélabo, European Union.

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(1991) Microhabitat preferences of benthic invertebrates and the development of generalised Deleatidium spp. habitat suitability curves, applied to four New Zealand rivers, New Zealand Journal of Marine and Freshwater Research, 25:2, 187-199, DOI: 10.1080/00288330.1991 Marine and Freshwater Research, 1991, Vol. 25: 187-199 0028-8330/2502- velocities, Potamopyrgus antipodarum and Chironomidae low to moderate velocities (0.0-0.75 m s -1 ), and all three were associated with a broad range of substrates. Deleatidium spp., Olingaferedayi, Hydrobiosidae, and Aphrophila neozelandica were found in a wide range of habitats. Velocity, depth, and substrate suitability curves developed for Deleatidium in each of the four rivers also demonstrated the broad habitat tolerances of this genus. Generalised suitability curves formed by enveloping, rather than averaging, curves from each of the rivers performed favourably when compared to models based on suitability curves developed for each river individually. Correlations between Deleatidium abundance and the joint suitability function, calculated from the generalised velocity, depth, and substrate curves, were significant but poor (r = 0.44-0.69) in each of the four rivers. The intercepts of the linear relationships between Deleatidium abundance and the joint preference factor were not significantly different from zero for three of the four rivers, suggesting that the preference functions are applicable to in-stream flow assessments.

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We develop a high-resolution conservation prioritization analysis for New Zealand's rivers and streams that simultaneously consider both the present state (representation) of ecosystems, and the prioritization of management actions designed to mitigate ongoing human impacts on their expected future state (retention). As input we used information about the geographic distributions of river ecosystem groups and their compositional similarity, species richness, present condition as compared to their estimated pristine state, and upstream and downstream connectivity. Candidate management actions included riparian planting, establishment of wetlands on tile-drain outflows, and use of riparian buffer strips in plantation forests. The analysis, carried out at a 1-ha resolution for a study area of 22,000 km 2 in Southland, New Zealand, demonstrates a credible range of options for management intervention, particularly in lowland streams under serious threat from agricultural intensification. The proposed analysis can be replicated elsewhere for terrestrial, freshwater, or marine systems using publicly available software.

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