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Background setting: The presumption that family violence will repeat and escalate is embedded in practices including risk assessment and case management. However, there is limited evidence that further episodes are inevitable, or that subsequent episodes will increase in severity. Therefore, we need to better understand temporal patterns in aggressor behavior to inform how risk is conceptualized in practice. Methods: For a sample of 2115 family violence aggressors who came to police attention in Integrated Safety Response catchment areas in Aotearoa New Zealand, we collected information New Zealand Police routinely recorded about reported harm between 2018 and 2020. We used a hidden Markov model to estimate the latent (i.e., unmeasurable) states behind the information reported to police, and modeled aggressors' movement between those states over time. Results: We identified three latent states. The first contained low or no reported harm, the second contained low probabilities of reported harm, and the third involved a high probability of reported verbal abuse and a moderate probability of reported physical violence. We identified four pathways through the latent states over the two-year follow-up period, which we called No reported harm, High reported harm, Low reported harm, and De-escalation. Conclusions: The findings add to the body of research indicating that family violence aggressors do not inevitably repeat or escalate their harmful behavior, and that a small subset of cases account for a large proportion of reported harm. This study demonstrates how information that police routinely collect can be used to estimate aggressors' latent behavioral states and model pathways communicating the probability that they will continue to come to police attention for family violence, contributing to improved risk assessment and practice. [ABSTRACT FROM AUTHOR]

Braided rivers can provide substantial recharge to regional aquifers, with flow exchange between surface water and groundwater occurring at a range of spatial and temporal scales. However, the difficulty in measuring and modelling these complex and dynamic river systems has hampered process understanding and the upscaling necessary to quantify these fluxes. This is due to an incomplete understanding of the hydrogeological structures that control river–groundwater exchange. In this paper, we present a new conceptualisation of subsurface processes in braided rivers based on observations of the main losing reaches of three braided rivers in Aotearoa / New Zealand. The conceptual model is based on a range of data, including lidar, bathymetry, coring, particle size distribution, groundwater level and temperature monitoring, radon-222, electrical-resistivity tomography and fibre-optic cables. The combined results indicate that sediments within the recently active river braidplain are distinctive, with sediments that are poorly consolidated and better sorted compared with adjacent deposits from the historical braidplain that become successively consolidated and intermixed with flood silt deposits due to overbank flow. A distinct sedimentary unconformity, combined with the presence of geomorphologically distinct lateral boundaries, suggests that a "braidplain aquifer" forms within the active river braidplain through the process of sediment mobilisation during flood events. This braidplain aquifer concept introduces a shallow storage reservoir to the river system, which is distinct from the regional aquifer system, and mediates the exchange of flow between individual river channels and the regional aquifer. The implication of the new concept is that surface water–groundwater exchange occurs at two spatial scales: the first is hyporheic and parafluvial exchange between the river and braidplain aquifer; the second is exchange between the braidplain aquifer and regional aquifer system. Exchange at both scales is influenced by the state of hydraulic connection between the respective water bodies. This conceptualisation acknowledges braided rivers as whole "river systems", consisting of channels and a gravel aquifer reservoir. This work has important implications for understanding how changes in river management (e.g. surface water extraction, bank training and gravel extraction) and morphology may impact groundwater recharge (and potentially flow, temperature attenuation and ecological resilience) under dry conditions. [ABSTRACT FROM AUTHOR]

Alcohol is an influential drug that has extensive societal impact. In Aotearoa New Zealand, there are a number of worrying trends related to alcohol consumption including rates of alcohol‐related harm and violence and heavy episodic drinking. To understand and address these issues, alcohol consumption rates and related trends need to be understood. A wastewater‐based epidemiology study was carried out over the course of six months (April–September 2021), sampling one week per month from ten catchment areas covering ~40 % of the national population. The average alcohol consumption was found to be 12.2 mL/person/day. Temporal and geographical trends in alcohol consumption were found; there was higher alcohol consumption on the weekends compared to weekdays, alcohol consumption was inversely related to settlement size, there was increased alcohol consumption due to public holidays and alcohol consumption was not seen to increase during COVID restrictions, however there was a notable change in the weekly trend during lockdowns. This application of alcohol WBE to Aotearoa New Zealand represents a comprehensive national study to understand alcohol consumption and its influences. The knowledge obtained will allow appropriate services and public policies to be reviewed to best serve communities. [ABSTRACT FROM AUTHOR]

Freshwater-limited fish populations are often tightly constrained by river drainage boundaries. As a case in point, the distribution of lineages within New Zealand's diverse Galaxias vulgaris complex is broadly structured by geographic barriers, reflecting tectonic processes. However, several drainages of the Central Otago region have been locally modified by past gold-mining activities, with artificial water races connecting formerly isolated headwaters of distinct river drainage systems. Here we synthesise published genetic data to highlight the role of anthropogenic catchment modification in redistributing fish diversity. These data show that several local phylogeographic anomalies for stream-resident Galaxias fishes are closely linked to anthropogenic connections across major drainage divides. While these anthropogenic translocations may parallel natural geologically-driven mixing events that occur on deeper time scales, they nevertheless have potential conservation implications given the increasing fragmentation of native fish populations. Our review also highlights the role of sub-catchment units in shaping the hierarchical structure of intraspecific biodiversity. [ABSTRACT FROM AUTHOR]

Braided rivers can provide substantial recharge to regional aquifers, with flow exchange between surface water and groundwater occurring at a range of spatial and temporal scales. However, the difficulty of measuring and modelling these complex and dynamic river systems has hampered process understanding and the upscaling necessary to quantify these fluxes. This is due to an incomplete understanding of the hydrogeological structures which control river-groundwater exchange. In this paper, we present a new conceptualisation of subsurface processes in braided rivers based on observations of the main losing reaches of three braided rivers in New Zealand. The conceptual model is based on a range of data including: lidar, bathymetry, coring, particle size distribution, groundwater, temperature monitoring, radon-222, electrical resistivity tomography, and fibre optic cables. The combined results indicate that sediments within the recently active river braidplain are distinctive, with sediments that are poorly consolidated and better sorted compared to adjacent deposits from the historical braidplain, which become successively consolidated and intermixed with flood silt deposits due to overbank flow. A distinct sedimentary unconformity, combined with the presence of geomorphologically distinct lateral boundaries, suggests that a "braidplain aquifer" forms within the active river braidplain through the process of sediment mobilisation during flood events. This braidplain aquifer concept introduces a shallow storage reservoir to the river system, which is distinct from the regional aquifer system, and mediates the exchange of flow between individual river channels and the regional aquifer. The implication of the new concept is that surface water-groundwater exchange occurs at two spatial scales. The first is hyporheic and parafluvial exchange between the river and braidplain aquifer. The second is exchange between the braidplain aquifer and regional aquifer system. Exchange at both scales is influenced by the state of hydraulic connection between the respective water bodies. This conceptualisation acknowledges braided rivers as whole "river systems", consisting of channels, and gravel aquifer. This work has important implications for understanding how changes in river management (e.g., surface water extraction, bank modification and gravel extraction) and morphology may impact groundwater recharge, and potentially river flow, temperature attenuation, and ecological resilience during dry conditions. [ABSTRACT FROM AUTHOR]

Larval behaviour for many of New Zealand's diadromous freshwater fish is inadequately described. Diadromy for many amphidromous species is not obligatory however, and where conditions are suitable, freshwater larval rearing may be facilitated. Where this occurs in lakes, opportunities to document the composition and conditions supporting larval rearing exist. Boat trawling was undertaken across nine lowland lakes in the Lower Waikato over four consecutive winters with a focus on larval galaxiids. Galaxiid larvae were captured in surface water habitats in all but one lake, with banded kōkopu (Galaxias fasciatus) and giant kōkopu (Galaxias argenteus) the most common species detected. One lake, Lake Waahi, consistently resulted in the most galaxiid captures for effort expended. Analyses of larvae from this and other lakes indicated that two sizes predominated in catches and that larger, older larvae were predominantly G. fasciatus while smaller, younger larvae were predominantly G. argenteus. Stomach contents indicated that two non-native zooplankton species predominated in the diet of larvae, the Holarctic daphnia, Daphnia galeata, and the Australian calanoid copepod Boeckella symmetrica. This study provides new information regarding the timing, movement and predicted recruitment of native fish species in this river basin that has important implications for lake and river management. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the effect of land use change (LUC) implemented to meet nutrient load targets for a freshwater lake in New Zealand. We used the Soil and Water Assessment Tool (SWAT) model in combination with a non-parametric statistical test to determine whether afforestation of 15% of a subcatchment area was adequate to meet assigned nutrient load targets. A regional management authority set nutrient load targets of reduction in total nitrogen (TN) by 0.9 t yr−1 and reduction in total phosphorus (TP) by 0.05 t yr−1 to avoid eutrophication in the receiving waters of a freshwater lake. The load reduction was designed to be achieved through 200 ha of LUC from pasture to trees. Analysis of nutrient loads before, during, and following LUC shows that a 15% increase in forest cover decreased the annual flow (7.2%), TP load (33.3%), and TN load (13.1%). As flow and water quality observations were discrete and at irregular intervals, we used a parametric test and the SWAT model as different lines of evidence to demonstrate the effect of afforestation on flow and water quality. Policymakers concerned with decisions about LUC to improve the quality of receiving waters can benefit from applying our findings and using a statistical and numerical modelling framework to evaluate the adequacy of land use change to support improvements in water quality. [ABSTRACT FROM AUTHOR]

Examining the links and potential feedbacks between tectonics and climate requires understanding the processes and variables controlling erosion. At the orogen scale, tectonics and climate are thought to be linked through the influence of mountain elevation on orographic precipitation and glaciation; the only documented erosional processes capable of balancing rapid rock‐uplift rates are glacial erosion or coupled river incision and landsliding. Our 20 new 10Be derived catchment‐averaged denudation rates from the Western Southern Alps of New Zealand generally range between 0.6 and 9 mm/yr, within the same order of magnitude as fault‐throw rates, exhumation rates, and erosion rates estimated from suspended sediment yields and landslide inventories. Combining our data with previously published 10Be denudation rates, we find that the proportion of catchment area in the 1,500–2,000 m elevation window is the variable that best explains denudation rate variability and the disparity between rock‐uplift rates and denudation rates. This correlation indicates that enhanced erosion likely occurs at 1,500–2,000 m above sea level, where periglacial and paraglacial processes have been proposed to be most active. We find that these temperature‐controlled erosional processes, which are also elevation‐dependent, can play a greater role in modulating erosion during interglacials than precipitation or glaciation. Our data suggest that temperature‐controlled peri‐ and paraglacial erosion could be efficient enough to balance some of the fastest rock‐uplift rates on Earth. Hence, temperature‐controlled erosion could contribute to limiting orogen elevations and modulating the erosion rates dictated by rock‐uplift, playing an essential role in linking tectonics and climate. Plain Language Summary: The shape and evolution of the Earth Surface depend on how the tectonic forces that build up mountains interact with the processes that wear them down through erosion. These erosional processes are often regulated by climate; for example, erosion is commonly more efficient where there are glaciers or in the wetter side of mountain ranges. We present 20 new 10Be concentrations, which are commonly used as a proxy for how fast drainage basins erode, from the Western Southern Alps of New Zealand, one of the fastest‐eroding places on Earth. We find that the rate at which these drainage basins erode is best predicted by the proportion of their drainage area that falls within the 1,500–2,000 m above sea‐level elevation window. This elevation range had previously been suggested to be where rocks are damaged and eroded through freeze‐thaw cycles. It is also the elevation window from which glaciers are currently retreating or have recently retreated, which can intensify erosion. Both freeze‐thaw cycles and glacier retreat depend on elevation and are related to temperature; therefore, we infer that temperature‐controlled erosional processes have likely dominated erosion for the last decades to hundreds of years. Key Points: Twenty new 10Be denudation rates of Western Southern Alps catchments are in the range 0.6–9 mm/yr, and likely >9 mm/yr for two glaciated catchmentsThe proportion of catchment area at 1,500–2,000 masl is the variable that best correlates with observed denudation‐rate variabilityElevation sensitivity of denudation is most likely due to peri‐ and paraglacial processes that modulate the tectonic control on erosion [ABSTRACT FROM AUTHOR]

Although some migratory fsh species are broadly distributed across large-spatial scales, they might only attain high abundance in certain areas. This can be attributed to local habitat conditions and variation in recruitment strength, which can be related to distance from spawning or larval-rearing habitats. The presence of pelagic compartments in riverine systems can enhance the abundance of some migratory fsh species by providing abundant food and habitat for larval development. In this study, we examined the composition and fne-scale abundance of migratory Galaxias brevipinnis Günther, 1866 (Teleostei: Galaxiidae) and non-migratory Galaxias spp. in relation to the presence and absence of downstream lakes and upstream distance of sites from lakes. Fish abundance and microhabitat use were estimated from randomly selected point samples (about 1 m²) from twenty-two streams in South Island, New Zealand. The total length of G. brevipinnis individuals was also measured to examine possible changes in their size-frequency distribution with increasing distance from lakes. Galaxias brevipinnis was found in almost all of the stream reaches surveyed upstream of lakes, while none were recorded in no-lake stream sites. The mean abundance of G. brevipinnis was considerably higher than non-migratory Galaxias species at sites upstream of lakes. Lotic habitats closer to the lakes also supported a higher abundance of G. brevipinnis than habitats sampled further away from the lakes, suggesting that recruitment limitation with distance from the larval supply is more important than the effect of microhabitats for this species. Furthermore, G. brevipinnis size-distribution patterns differed greatly with distance upstream, with a higher proportion of smaller (younger) individuals found mainly within 2 km upstream of lakes, suggesting strong recruitment of this species close to lake recruitment sources. Although non-migratory species made up all of the Galaxias species caught in non-lake streams, they also occurred in streams upstream of lakes, but only at low abundance in stream sites close to the lakes. However, their abundance tended to be higher at sites further away from lakes, where G. brevipinnis was less abundant. Declining recruitment of G. brevipinnis with distance inland from lake, and competitive interactions with non-migratory species, are likely the main determinants of the adult abundances and composition of these stream fsh at large spatial scales, and these effects may outweigh the role of microhabitat characteristics and preferences in such river basins. [ABSTRACT FROM AUTHOR]

Land Use and Land Cover (LULC) properties give vital information about pollution signatures in rivers, and they help develop best management practices (BMPs) for effective water resource management. This work employs multivariate statistical methods, receptor modeling, connectivity analysis, and univariate trend analysis to investigate pollution sources across spatiotemporal scales in the Manawatu River, New Zealand. A positive matrix factorization (PMF) method was applied to interpret possible contamination sources. A 25-year dataset (1989–2014) comprising 12 water quality variables from three sites was used. Runoff connectivity analyses identified high-producing grassland (HG) as the most dominant pollution class in all sub-catchments. Univariate analyses revealed that nutrients and sediments were higher than in the initial monitoring years. The PMF analysis found possible pollutants causing impairment, which required attention from waste managers. PMF also showed that point, natural, and agricultural sources significantly contributed to pollution downstream of the river. In the midstream, the erosion, point, and agricultural sources were significant contributing factors. Agricultural pollution and soil erosion were the main contributors to the upstream sub-catchment area. This study suggests that BMPs with a high retention capacity are needed in specific locations in the catchment area to filter high concentrations of pollutants generated. [ABSTRACT FROM AUTHOR]

Climate and land use changes impact catchment hydrology and water quality (WQ), yet few studies have investigated the amount of land use changes required to meet specific WQ targets under future climate projections. The aim of this study was to determine streamflow and nutrient load responses to future land use change (LUC) and climate change scenarios. We hypothesized that (1) increasing forest coverage would decrease nutrient loads, (2) climate change, with higher temperatures and more intense storms, would lead to increased flow and nutrient loads, and (3) LUC could moderate potential nutrient load increases associated with climate change. We tested these hypotheses with the Soil and Water Assessment Tool (SWAT), which was applied to a lake catchment in New Zealand, where LUC strategies with afforestation are employed to address lake WQ objectives. The model was calibrated from 2002 to 2005 and validated from 2006 to 2010 using measured streamflow (Q) and total nitrogen (TN), total phosphorus (TP), nitrate (NO3-N), and ammonium (NH4-N) concentrations of three streams in the catchment. The model performance across the monitored streams was evaluated using coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) metrics to provide a basis for model projections. Future scenarios incorporated LUC and climate change (CC) based on the Representative Concentration Pathway 8.5 and were compared to the baseline streamflow and WQ indicators. Consistent with our hypotheses, Q, TN, and TP loads were predicted to decrease with afforestation. Specifically, afforestation of 1.32 km2 in one of the monitored stream sub-catchments (subbasin 3), or 8.8% of the total lake catchment area, would result in reductions of 11.9, 26.2, and 17.7% in modeled annual mean Q, TN, and TP loads, respectively. Furthermore, when comparing simulations based on baseline and projected climate, reductions of 13.6, 22.8, and 19.5% were observed for Q, TN, and TP loads, respectively. Notably, the combined implementation of LUC and CC further decreased Q, TN, and TP loads by 20.2, 36.7, and 28.5%, respectively. This study provides valuable insights into the utilization of LUC strategies to mitigate nutrient loads in lakes facing water quality challenges, and our findings could serve as a prototype for other lake catchments undergoing LUC. Contrary to our initial hypotheses, we found that higher precipitation and temperatures did not result in increased flow and nutrient loading. [ABSTRACT FROM AUTHOR]

Glacial landscapes preserve records of past climate change. Investigating the glacier–climate system over the Late Quaternary provides information about past climate change and context for present‐day glacier response to climate warming. Using 28 beryllium‐10 (10Be) surface exposure dates and snowline reconstructions, we present glacier fluctuations and climate changes for the Antarctic Cold Reversal in the Ahuriri River catchment, Southern Alps of New Zealand (44°7′50″S, 169°38′29″E). Prominent terminal and lateral moraine features from the upper right tributary of the Ahuriri River valley have exposure ages of 14.5 ± 0.3, 13.6 ± 0.3 and 12.6 ± 0.2 ka, suggesting retreat of the glacier during the Antarctic Cold Reversal. Maximum elevation of lateral moraines (MELM) and accumulation area ratio (AAR) suggest snowline elevations at these ages were ≤700, ≤630 and ~360 m lower than today, respectively. This equates to air temperatures ≤3.9, ≤3.5 and 2.3 ± 0.7 °C lower than today (1981–2010), assuming no changes in past precipitation. Ice‐sculpted bedrock surfaces bound by a lateral moraine at nearby Canyon Creek have an age of 13.1 ± 0.3 ka, indicating the moraine correlates with those in the Ahuriri upper right tributary. MELM and AAR reconstructions from the Canyon Creek suggest that snowline elevations at 14.5–13.6 ka were ≤500 or ~380 m lower than today, corresponding to air temperatures ≤2.8 or 2.4 ± 0.7 °C lower than the present‐day (1981–2010). Our results provide insight into the structure of the Antarctic Cold Reversal in the Southern Alps, showing that the largest glacier advance occurred at the start of this interval at c. 14.5 ± 0.3 ka and was followed by gradual retreat. We hypothesize that the early cooling and glacier readvance in New Zealand at the onset of the Antarctic Cold Reversal were triggered by a latitudinal shift of the Southern Hemisphere westerly wind belt. [ABSTRACT FROM AUTHOR]

The hill country of west central North Island, west of Te Kuiti and Otorohanga, is recognised to be slowly uplifting and relatively stable. The New Zealand national seismic hazard model shows the area to be in a low-risk zone and the New Zealand active faults database recognises no active faults in the region. However, dated evidence provided by speleothems in a cave near Waitomo indicates the intermittent movement of the Okohua fault from before the Last Interglacial until around 38 kyrs ago. Evidence of older movement along the Waipa Fault near Te Kuiti is also apparent from the vertical displacement of the Ngaroma ignimbrite (1.55 Myrs) by about 150 m in the interval prior to the deposition of the Ongatiti ignimbrite at 1.21 Myrs. Net uplift in the West Waikato Hills and Ranges, by about 0.1 mm/yr in the Late Quaternary, is accommodated in a series of NNE-trending faults and transverse faults, resulting in a staircase of fault-bound blocks rising westwards from Waitomo to the western watershed of the Waipa basin. Geomorphologically fresh cliffed lineaments on the Okohua and Hikurangi faults convey evidence of mid to late Quaternary fault activity. [ABSTRACT FROM AUTHOR]

Monitoring for mass flows on volcanoes can be challenging due to the ever-changing landscape along the flow path, which can drastically transform the properties and dynamics of the flow. These changes to the flows require the need for detection strategies and risk assessments that are tailored not only between different volcanoes but at different distances along flow paths as well. Being able to understand how a flow event may transform in time and space along the channel is of utmost importance for hazard management. While visual observations and simple measuring devices in the past have shown how volcanic mass flows transform along the flow path, these same features for the most part have not been described using seismological methods. On 18 March 2007, Mt. Ruapehu produced the biggest lahar in Aotearoa / New Zealand in over 100 years. At 23:18 UTC the tephra dam holding the Crater Lake water back collapsed causing 1.3×106 m3 of water to flow out and rush down the Whangaehu channel. We describe here the seismic signature of a lake-breakout lahar over the course of 83 km along the Whangaehu River system using three three-component broadband seismometers installed <10 m from the channel at 7.4, 28, and 83 km from the Crater Lake source. Examination of three-component seismic amplitudes, frequency content, and directionality, combined with video imagery and sediment concentration data, was carried out. The seismic data show the evolution of the lahar as it transformed from a highly turbulent out-burst flood (high peak frequency throughout), to a fully bulked-up multi-phase hyperconcentrated flow (varying frequency patterns depending on the lahar phase), to a slurry flow (bedload dominant). Estimated directionality ratios show the elongation of the lahar with distance down the channel, where each recording station depicts a similar pattern but for differing lengths of time. Furthermore, using directionality ratios shows extraordinary promise for lahar monitoring and detection systems where streamflow is present in the channel. [ABSTRACT FROM AUTHOR]

Stream bank erosion has been anecdotally identified as an important source of sediment in New Zealand catchments, however, there have been few attempts to quantify its contribution. Here we use a radionuclide-based sediment tracing approach to determine the relative contribution of stream bank- and hillslope-derived sediment within three catchments in the upper North Island of New Zealand. Both lithogenic (radium-226 and radium-228) and fallout radionuclides (caesium-137 and excess lead-210) were used to differentiate sediment derived from stream bank and hillslope sources. The relative contribution of stream banks and hillslopes to fluvially transported suspended sediment were predicted using a mixing model approach. Our results indicate that both fallout and lithogenic radionuclides provide good source differentiation. We demonstrate that stream bank erosion can contribute very high proportions of sediment within New Zealand catchments. We used independent assessments of bank erosion from each of the study catchments to support the sediment source fingerprinting results. Further work is required to determine the spatial and temporal variability of the contribution of sediment from stream banks. Information on the importance of different sediment sources is needed to target limited catchment rehabilitation resources where they will have the most impact. [ABSTRACT FROM AUTHOR]

Rugby union is a popular team sport, with a high rate of concussions. In adolescents, concussions are further complicated by issues of under-reporting. To encourage more responsible concussion behaviours, it is imperative to understand the factors that influence youth players' behaviours, including the attitudes and behaviours of their coaches and parents. The aim of this study was to explore concussion-related behavioural intentions and behaviours that may influence effective concussion management across a youth rugby system. The study adopted a pragmatic, descriptive qualitative design and included high schools from four youth rugby catchment areas in New Zealand. Nineteen focus groups and 2 individual interviews were conducted with n = 75 players, n = 22 parents, and n = 8 coaches (N = 105) during the 2018 rugby season. A thematic analysis was conducted, guided by a system's approach and the Theory of Planned Behaviour. The themes generated reflected a 'tug-of war' between various behavioural intentions and reported behaviours present in a youth rugby system. Additionally, the behavioural intentions and reported behaviours of coaches, parents, players and their teammates are intricately linked and collectively influence effective concussion management. Being aware of concussions and caring about their management and consequences was a strong theme present across the system. However, these favourable attitudes and behaviours were countered by players, parents and coaches disregarding the system, downplaying the seriousness of concussion, being competitive and driven to win, regardless of the risks. In players the warrior mentality theme, which included bravado, being tough, and playing through the pain further complicated effective concussion management. The findings suggest that there is not always a strong, favourable network in place that would facilitate similarly favourable concussion-related behaviours. To effect change, a system-wide approach, that takes the unique needs of each stakeholder into account and ultimately aims to reconcile performance and brotherhood with positive concussion related behaviours, is needed. [ABSTRACT FROM AUTHOR]

Climate change impacts on water resources and increasing demand for renewable electricity will have significant impacts on the management of hydroelectric power catchments globally. In New Zealand, where 55% of electricity currently comes from hydroelectricity generation, rainfall over the major South Island hydroelectric power catchments is expected to increase in coming decades, and the seasonality and volatility of that rainfall is expected to change. This paper uses a change factor methodology linked to a model cascade to estimate changes to hydroelectric power catchment inflows in 12 regions of New Zealand. These future river flows are then put through an all of New Zealand electricity system model to examine impacts on flows downstream of the hydroelectric power stations, lake storage, and spill in the large South Island hydroelectric power catchments. An overall 2% increase in annual hydroelectric power catchment inflows over the whole of New Zealand is projected between 2020 and 2050. Seasonal impacts are projected to be larger, with total New Zealand inflows projected to be 10% higher in winter and 6% lower in summer by 2050. Projected changes to inflows are equivalent to between -3% of current total summer New Zealand electricity generation and +5% of winter generation. The four main snow-fed hydroelectric power catchments in the Southern Alps (Pukaki, Tekapo, Clutha, and Manapouri) are predicted to get higher inflows than currently in winter, and lower inflows in summer, with a small increase in annual flows. Modelled changes to inflows and catchment management results in, on average, higher modelled lake storage levels in the snow-fed hydroelectric power catchments in the South Island, which are predicted to spend more time at full lake levels and less time at low lake levels in 2050 than in 2020. The changing inflows, combined with higher storage levels and changes in the electricity system, results in a potential doubling of modelled spill from the large South Island hydroelectric power scheme lakes by 2050. These significant seasonal changes to inflows will better match electricity demand, but the increase to annual spill levels is projected to more than offset any increases in annual inflows over the study period. [ABSTRACT FROM AUTHOR]

Monitoring for lahars on volcanoes can be challenging due to the ever-changing landscape which can drastically transform the properties and dynamics of the flow. These changes to the flows require the need for detection strategies and risk assessment that are tailored not only between different volcanoes, but at different distances along flow paths as well. Being able to understand how a flow event may transform in time and space along the channel is of utmost importance for hazard management. While visual observations and simple measuring devices in the past have shown how lahars transform along the flow path, these same features for the most part have not been described using seismological methods. On 18 March 2007 Mt. Ruapehu produced the biggest lahar in New Zealand in over 100 years. At 23:18 UTC the tephra dam holding the Crater Lake water back collapsed causing 1.3 x 106 m3 of water to flow out and rush down the Whangaehu channel. We describe here the seismic signature of a lake-breakout lahar over the course of 85 km along the Whangaehu river system using three 3-component broadband seismometers installed < 10 m from the channel at 7.4, 28, and 83 km from the crater lake source. Examination of 3-componennt seismic amplitudes, peak frequency content, and directionality combined with video imagery and sediment concentration data were used. The seismic data shows the evolution of the lahar as it transformed from a highly turbulent out-burst flood (high peak frequency throughout), to a fully bulked up multi-phase hyperconcentrated flow (varying frequency patterns depending on the lahar phase) to a slurry flow (bedload dominant). Estimated directionality ratios show the elongation of the lahar with distance down channel, where each recording station shows a similar pattern, but for differing lengths of time. Furthermore, using directionality ratios shows extraordinary promise for lahar monitoring and detection systems where streamflow is present in the channel. [ABSTRACT FROM AUTHOR]

This study investigates factors contributing to the unexpected loss of a recreational Chinook salmon fishery in a reach of the Rangitata River in Canterbury, New Zealand. The Rangitata is one of only 14 rivers nationwide in which flows are protected by water conservation orders to provide for instream values in the face of competition from extractive uses. However, the river has experienced significant water abstraction or takes for irrigation and hydroelectricity generation, even recently. In this study, local fishers determined flow requirements and conditions for successful fishing based on historical catch data and gauged flows. Relationships between preferred and historical flows were examined using scenario analyses to identify the cumulative impacts of water takes on the conditions required for fishing. An irrigation take of 19.6 m3/s beginning in 2013 was found to have severely reduced the duration of flows in a 30 m3/s flow range that previously supported fishing success. A recently proposed further take of 10 m3/s will completely remove any remaining flows from this preferred flow range. These results show that cumulative takes of water from river systems may have profound and unintended consequences when the flow regimes that support recreational uses are not well understood and retained or protected. Impact assessments that address both cumulative takes and flow-specific values are needed to reliably detect and manage adverse effects. In this case, additional controls are required to maintain the values specifically recognized by the water conservation order. [ABSTRACT FROM AUTHOR]

The Westland petrel (Procellaria westlandica) is a 1200 g medium-sized seabird whose breeding colonies are dispersed across 700 ha of forest on the western coast of South Island, New Zealand. These birds represent the sole landscape-scale lowland remnant of formerly widespread petrel and shearwater colonies in mainland New Zealand and provide an opportunity to investigate maritime species' impact on terrestrial ecosystems characteristic of pre-human New Zealand. This review develops a conceptual model of biogeochemical processes influenced by Westland petrels from a single burrow to individual colonies and thence to a catchment scale. Results show the distinctiveness of the Westland petrel system, with colonies moving around the landscape in response to local damage by earthquakes and storms. Based on monitored streams in forested landscapes elsewhere, storms also control N and P fluxes to streams. Non-seabird temperate forests are dominated by mycorrhizal plant-soil interactions, but the high N and P status of Westland petrel colony soils minimises the role of fungi in soil processes, including trace element (Se) uptake. The more N-rich C:N ratio in tree foliage within habitat occupied by the colony may provide nutritional support for terrestrial herbivorous animals, including those whose ranges extend beyond the colony. Overall, the review emphasises the spatial and temporal dynamics of the Westland petrel terrestrial ecosystem, and highlights potential ecological linkages that connect colonies to the wider landscape. [ABSTRACT FROM AUTHOR]

Although water-borne viruses have important implications for the health of humans and other animals, little is known about the impact of human land use on viral diversity and evolution in water systems such as rivers. We used metatranscriptomic sequencing to compare the diversity and abundance of viruses at sampling sites along a single river in New Zealand that differed in human land-use impacts, ranging from pristine to urban. From this, we identified 504 putative virus species, of which 97 per cent were novel. Many of the novel viruses were highly divergent and likely included a new subfamily within the Parvoviridae. We identified at least sixty-three virus species that may infect vertebrates—most likely fish and water birds—from the Astroviridae, Birnaviridae , Parvoviridae , and Picornaviridae. No putative human viruses were detected. Importantly, we observed differences in the composition of viral communities at sites impacted by human land use (farming and urban) compared to native forest sites (pristine). At the viral species level, the urban sites had higher diversity (327 virus species) than the farming (n  = 150) and pristine sites (n  = 119), and more viruses were shared between the urban and farming sites (n  = 76) than between the pristine and farming or urban sites (n  = 24). The two farming sites had a lower viral abundance across all host types, while the pristine sites had a higher abundance of viruses associated with animals, plants, and fungi. We also identified viruses linked to agriculture and human impact at the river sampling sites in farming and urban areas that were not present at the native forest sites. Although based on a small sample size, our study suggests that human land use can impact viral communities in rivers, such that further work is needed to reduce the impact of intensive farming and urbanisation on water systems. [ABSTRACT FROM AUTHOR]

Prediction of the time for perennial outflow from a natural basin to recede from the mean to some low flow value is an important practical and difficult problem in water resource management. This study aims to gain further understanding of this complex problem and to put forward new practical and accurate methods for predicting flow recessions between nominated limits in both gauged and ungauged basins. For a gauged basin, a three parameter recession model is employed to estimate the recession time, from day‐to‐day, as flow recedes from mean flow using previously measured site recession curves and a library of recession curve shapes generated by the RObust Parameter Estimation algorithm. The model is tested using data from 10 New Zealand basins which are diverse in low flow hydrological behavior and yields a Median Absolute Error (MAE) of 1 day. Another new model is also developed to predict recession time in an ungauged basin using catchment characteristics and information from master recession curves in a suite of 10 reference basins geologically and hydrologically similar to the ungauged basin, as assessed by a Random Forest model. Model performance is robust with a MAE of 1 day and the models advance the use of past flow records to enable more accurate predictions to be obtained. They can be applied elsewhere with confidence although further testing is desirable. Key Points: A methodology for successive prediction in real time of the fall recession curve ranging from mean flow values is presentedAccess to a library of modeled recorded as well as generated possible recession curves enables close matching of real time measurementsPrediction of recession time at an ungauged site is achievable by using information from reference basins of similar hydrological character [ABSTRACT FROM AUTHOR]

A hydrological framework encompassing nitrogen (N), phosphorus (P) and microbial (E. coli) transfer from land to water was developed to provide a consistent and rapid approach for assessing the potential impacts of land activity on water quality in New Zealand. A flow partition approach was used to route precipitation via surface and subsurface pathways from land to water. The framework included a typology-based inventory that estimates annual yields of transportable N and P from land, a regional-scale spatial layer that attenuates N in groundwater, and literature-based estimates of E. coli concentrations in surface runoff and artificial drainage. Application of the framework in four catchments highlighted the importance of local catchment knowledge of dominant hydrological processes that was needed to ensure flow partitions derived were a realistic representation of transport processes. While the approach was promising, additional refinements are needed to improve process representation (e.g. effects of groundwater lags) and ensure input data (e.g. soil attributes) have appropriate resolution to describe hydrological pathways. We contend that such a framework would provide a consistent and relatively rapid approach for identifying contaminant transfer pathways from land to water that can inform assessments of the potential consequences of land use change and intensification. [ABSTRACT FROM AUTHOR]

How should the success of river and floodplain restoration be assessed? What should we be restoring? We contend that the benchmark for restoration should be the river in its "natural," that is, quasi‐equilibrium condition prior to deliberate modification. The pre‐modification condition of the river represents a quasi‐equilibrium state in which the river accommodates and adjusts to catchment water and sediment fluxes, whether in a pristine or modified catchment. The resulting assemblage of river landforms (e.g., bars, channels, backwaters) is in balance with the prevailing flood and sediment regime. Furthermore, equilibrium channel forms can adjust to changes in, for example, flood magnitude and frequency via for example, channel expansion or contraction. A restored river system is one that once was anthropogenically restricted, but now has regained capacity to adjust its form. River restoration needs understanding of the history and trajectory of pre‐modification channels, so that the "right" river type can be restored. To assess the scope and success of restoration, we propose using a natural character index (NCI). The NCI is the ratio between a parameter which describes the form and function of a river now (observed) and the same parameter measured at a point or points in time past (expected). Exemplar parameters include sinuosity, floodplain width, active channel width, bar area (at a given flow) and riparian vegetation. Measurement of these parameters utilizes a combination of aerial photos, archive maps and LiDAR‐derived terrain models, the availability of which necessarily limits and determines what parameters can be used in NCI assessment. LiDAR is a useful tool providing an opportunity to comprehend pre‐modification river and floodplain character. We illustrate the NCI concept and its potential for use in assessing restoration effects using examples from New Zealand, Spain and Croatia. The result is an index of use as a "first cut" preliminary assessment for river practitioners. [ABSTRACT FROM AUTHOR]

Pressures on braided river systems in New Zealand are increasing due to anthropogenic stresses such as demand for irrigation water, braidplain conversion to farmland and invasive vegetation, as well as extreme natural events associated with earthquakes and climate change. These pressures create issues around preserving braided river physical environments and associated ecosystems, and managing hazards such as floods, aggradation and erosion. A need for more robust understanding and quantification of braided river morphodynamic processes underpins many of these issues. Here, we present eight morphodynamic research challenges to service this need. The first four research challenges relate to managing aggradation‐related flooding hazards; the last four address issues stem largely from recent dairy expansion, which has created huge pressure to take land and irrigation water from the alp‐fed braided rivers and to alter flow regimes at their mouths. Hāpua, the freshwater lagoons found where most braided rivers meet the coast, show complex morphodynamic behaviour in response to the interplay of river and coastal processes, and their special ecosystems are sensitive to river flow and sediment load changes. We discuss how physical laboratory experiments and novel numerical modelling can help to understand the morphological processes braided rivers undergo, and we show how those research advances could inform planning and legal decisions to regulate land rights and irrigation water allocation on New Zealand's braidplains. We illustrate these environmental and engineering issues and research challenges with examples from the Kowhai, Waiho, Waiau, Rangitata and Hurunui Rivers. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Australian and New Zealand Standard Research Classification (ANZSRC) 2020 decision on disciplinary categories has profound implications for journalism as a research discipline. Journalism Practice and Professional Writing retain their six digit Field of Research (FoR) code within the Creative Arts and Writing Division, a new six digit FoR of Journalism Studies has been created in the Division of Language, Communication and Culture, and three new FoR codes of Literature, Journalism and Professional Writing have been created for Aboriginal and Torres Strait Islander, Māori and Pacific Peoples within the new Indigenous Studies Division. This categorisation confirms Journalism as a sovereign and independent discipline distinct from Communication and Media Studies, which has been in bitter contention for more than two decades. The ANZSRC confirmed its 2008 policy that the sole and definitive criterion for categorisation was methodology. This article explores the welcome ramifications of this decision for Journalism within Australasian university-based journalism and charts some of the issues ahead for journalism academics as they embark on the long overdue and fraught path to disciplinary self-recognition as an equal among the humanities and social sciences. [ABSTRACT FROM AUTHOR]

Knowledge of the types and impacts of contaminants occurring in the freshwater wetlands of the Great Barrier Reef catchment area (GBRCA) is limited. The present study examined the presence and concentrations of pesticides occurring in 22 floodplain wetlands, situated in moderate to high‐intensity land uses in the GBRCA. The dominant land use within 1 km of the wetlands was sugar cane for 12 wetlands, grazing for 6 wetlands, plantation forestry and conservation for 2 wetlands, and one with an equal mix of land uses. Fifty‐nine pesticides and pesticide degradates were detected in the wetlands during 2 consecutive early wet seasons. These included 27 herbicides, 11 herbicide degradates, 11 insecticides, 8 fungicides, 1 nematicide, and 1 pesticide synergist. Each wetland sampled contained between 12 and 30 pesticides with an average of 21 pesticides detected per wetland sampling. Temporal differences existed in the number, types, and average concentrations of pesticides detected. No exceedances of Australian and New Zealand water guideline values were found during the first sampling season, while 10 wetlands had concentrations of at least 1 pesticide exceeding the guidelines during the following sampling season. For 1 wetland, concentrations of 4 pesticides were greater than the prescribed guideline values. Individually, the vast majority of aquatic species would be protected, but in some wetlands, diuron would affect 49% of species and atrazine up to 24% of species. Statistically significant correlations between the number of pesticides and the percentage of intensive land use, primarily sugar cane growing in a 1 km radius of the wetlands, were found. Integr Environ Assess Manag 2020;16:968–982. © 2020 SETAC KEY POINTS: This is the first wide‐ranging study of the presence and concentrations of pesticides in freshwater floodplain wetlands located across the Great Barrier Reef Catchment area.This study shows that pesticides are pervasive in these wetlands, and the number of pesticides detected is correlated with the area of sugarcane within a 1 km radius of a wetland.There are temporal differences in the number, types, and average concentrations of pesticides detected.Given the complex mixtures of pesticides occurring in the monitored wetlands, the risk posed by pesticides may be underestimated. [ABSTRACT FROM AUTHOR]

Sustaining ecosystem services (ES) is a key interest in the management of land use in multifunctional landscapes (i.e. ES that support ecosystem function and sustain human livelihoods). In making land management decisions, it is important to understand the relationships and spatial distributions of multiple ES, and the synergies and trade-offs between them. We analysed nine ES in a catchment in the Bay of Plenty region, New Zealand, to identify areas in the catchment are high (hotspots) and low (coldspots) in supplying multiple ES, the relationships among ES, and where ES trade-offs and synergies occur. We found ES hotspots occurred mainly in indigenous forest. Synergies occurred among provisioning services (milk and meat) and dis-service nitrogen leaching as well as synergies with carbon sequestration and wood supply. Trade-offs occurred between regulating services and a supporting service. We identified ES bundles (services that occur repeatedly together) of provisioning services and those associated with exotic forest. Spatial concurrences and relationships of different ES provide a way to optimise the supply of multiple ES. These results may be used to guide landscape management whereby spatial prioritisation can be used to conserve areas of high ES supply or bundles of ES. [ABSTRACT FROM AUTHOR]

Determining the factors driving population dynamics of stream salmonids across broad landscapes is important for understanding stream ecosystem functioning and for the management and conservation of the populations of such fish. A few studies have described the determinants of the early life history of salmonids across catchments, but none of them have examined how this spatial variation develops temporally.We hypothesised that: (1) spatiotemporal dynamics of young‐of‐the‐year (YoY) trout populations vary within the catchment, with loss rates (emigration plus mortality) being higher in lower elevation, downstream reaches than in higher elevation, upstream ones; and (2) loss rate would be density dependent, leading to reduced intra‐ and inter‐cohort competition and supporting establishment of resident populations.We tested the first hypothesis by examining relationships between geomorphic characteristics of spawning streams and temporal dynamics of YoY brown trout density, loss rate and biological traits through an austral summer across the catchment of New Zealand's fourth‐longest river, the Taieri River. To test the second hypothesis, we examined whether initial YoY density in spring and other biotic determinants affected loss rate and cohort structure dynamics, resulting in density‐dependent self‐thinning of YoY fish to avoid resource limitation.Spring YoY density and subsequent loss rate was higher in low elevation sites, corresponding to stream accessibility to migratory spawners. These significant correlations of YoY density and related biotic variables with elevation disappeared later in the season, indicating that regardless of their origin, brown trout YoY tend to form stream resident populations with multicohort structure and densities low enough to limit intraspecific competition.Our findings provide evidence that geomorphological features of the landscape affect temporal dynamics of YoY trout populations driven by density‐dependent self‐regulatory mechanisms that can control the abundance of growing fish. [ABSTRACT FROM AUTHOR]

Data on spatial and temporal patterns of deposited fine sediment (DS) cover in New Zealand rivers are rare and this makes it difficult to assess DS trends and quantify links between sediment and ecological effects. A rapid, semi-quantitative method for characterising DS cover using class-based visual assessment was applied annually for 6 years (2005-10) at 30 sites in the Motueka River catchment, to explore spatial and temporal variation in DS cover and its relationship with sediment load and trout numbers. Deposited fine sediment cover was low at most sites, apart from some small tributaries with erodible granite geology near to the sampling site. Most sites had little change in DS over time. Large floods or forest harvesting caused discernible, but small, increases in DS cover at some sites. Local delivery of sediment and stream morphology were more important drivers of spatial patterns of DS cover than annual sediment load or characteristics of the upstream contributing catchment. For some sites there was a relationship between temporal variation in sediment load, caused by floods or forest harvesting, and DS cover. While trout abundance in the Motueka River varied considerably between 2005 and 2010, there was little relationship with DS cover. Sampling bias, assessed by repeating measurements at five sites on five days, was not significant indicating the method is highly repeatable. However, there was consistent significant bias between results from two different observers implying the visual assessment method requires training to be reliable. [ABSTRACT FROM AUTHOR]

The presence of the amino acid a-aminoisobutyric acid (Aib) within Cretaceous/Paleogene (K/Pg) boundary clay in the Raton and Powder River basins in Colorado and Wyoming, respectively, has been described as compelling evidence that extraterrestrial Aib survived the high-energy Chicxulub impact. Based on contemporary experiments and simulations, however, it is highly unlikely that extraterrestrial Aib survived the impact, which had peak impact pressures and temperatures in excess of 600 GPa and 10,000 K, respectively. In other words, the amino acid signature of the carbonaceous chondritic asteroid that impacted Chicxulub was undoubtedly destroyed upon impact during formation of the vapor plume or so-called "fireball." The only organisms known to produce Aib are the suite (more than 30 genera) of cosmopolitan saprotrophic filamentous fungi that include Trichoderma Pers., which has recently been hypothesized to have thrived during the K/Pg mass-extinction event. Therefore it is proposed that the Aib horizon in the K/Pg boundary clay in the Raton and Powder River basins correlates with the K/Pg boundary fungal spike, which thus far has only been observed in New Zealand (Southern Hemisphere). This proposition is based upon superimposing the Aib horizon on the well-known iridium and fern-spore spikes, as its stratigraphic position precisely matches that predicted by the fungal spike. If correct, this hypothesis alters the conventional perspective on the tempo and mode of terrestrial ecosystem recovery in western North America, as the heavily sampled K/Pg boundary section in the Raton Basin was instrumental in shaping the traditional narrative of the rapid recolonization of a denuded landscape by ferns via wind-blown spores in the immediate wake of regional deforestation caused by the K/Pg impact event. Perhaps more importantly, it could present an alternative to traditional palynological approaches for locating the fungal spike in other terrestrial K/Pg boundary sections and could provide additional support for the generalization that global mass-extinction events are frequently accompanied by fungal spikes. [ABSTRACT FROM AUTHOR]

Near-coastal marine sediments often provide high-resolution records of various anthropogenic influences such as the release of heavy metals, which pose a potentially negative influence on aquatic ecosystems because of their toxicity and persistence. In places, the gradual onset of man-made heavy metal emission dates back to ~ 4500 years BP and is difficult to distinguish from potential natural sources. New Zealand offers a perfect setting for studies on anthropogenic impact due to its well-defined three-step development: pre-human era (until ~ 1300 CE), Polynesian era (~ 1300–1800 CE) and European era (since ~ 1840 CE). However, hardly any information exists about the degree of heavy metal input to New Zealand's coastal areas and the 'pristine' natural background values. This study determines the natural background contents of lead (Pb) and zinc (Zn) in marine sediments of the Firth of Thames, a shallow marine embayment on New Zealand's North Island, and investigates anthropogenic inputs in historic times. Eight sediment cores were analysed by X-ray fluorescence (XRF) for their element composition and temporally resolved by a pollen and radiocarbon-based stratigraphic framework. Sharp increases in Pb and Zn contents occurred simultaneously with the onset of goldmining activities (1867 CE) in the nearby catchment area. The contents of Zn (Pb) increase from very stable values around 60 (13) ppm in the older sediments, interpreted to reflect the natural background values, to an average maximum of 160 (60) ppm near the core top, interpreted to reflect a significant anthropogenic input. These findings unravel the history of contamination in the Firth of Thames and provide an urgently needed database for the assessment of its current ecological state. [ABSTRACT FROM AUTHOR]

Hysteresis in the relationship between suspended sediment concentration and flow during run‐off events is commonly used to inform on sediment sources and hydrological pathways. Less attention, however, has been paid to comparing the water and sediment hydrographs, which provide a more direct appreciation of in‐event sediment dynamics and their relationship with the upstream catchment characteristics. The aim of this study is to better understand the catchment and hydrological controls on the phasing of water and sediment discharges during events and, in particular, to explore what controls sediment concentrations late on event recessions. Continuous records of flow and turbidity data (calibrated to suspended sediment concentration) were collected from 17 catchments across New Zealand for this purpose. Relationships between event sediment yield and peak flow showed, as anticipated, higher event sediment loads were generated in pasture compared with forested catchments and were also higher from catchments in more erodible terrain. One novel result was that these differences were greater during smaller, more frequent events, whereas the loads from larger flood events tended to converge between pasture and forest catchments. Another novel result was that event sediment load tends to be evenly split between rising and falling stages of the hydrograph in pasture catchments, but forested catchments yield more of their event loads on flood recessions, probably because of delayed erosion or more sediment sources remote from the channel network. Land cover, distance of the sediment sources from the monitoring site, and size of the catchments control sediment concentrations late on event recession. Pasture‐dominated and more erodible catchments show longer sediment recessions and therefore stay dirtier for longer time periods. In addition, the size of previous flood events appeared to control the extent of sediment exhaustion after the flood peaks in some catchments. [ABSTRACT FROM AUTHOR]

The nuisance species Didymosphenia geminata is thought to have been spread by humans across North and South America and New Zealand. This diatom is of interest for its ability to form thick benthic mats in streams, altering ecosystem properties. Little is known, however, about its historic distribution and the parameters that are associated with its growth in absence of human influence. Although it is considered to be native to Arctic regions, its status at lower latitudes is uncertain. We measured the concentration of D. geminata cells in a sediment core from Beauty Lake, WY, a record that dates back to the Late Pleistocene. From approximately 11,233–8750 years before present (ybp), a Didymosphenia maximum persisted, with peak concentrations of 3774±20 valves/mg dry sediment (9985 ybp). The period corresponded to low flux of Al, Fe, and P within the sediments, supporting the importance of low P in controlling distribution. Furthermore, we demonstrate that D. geminata arrived in Beauty Lake shortly after deglaciation of the watershed. This species arrived without the aid of human introduction, implying an inherent ability for dispersal. We also examined the sediment record of nearby Yellowstone Lake, WY for the presence of D. geminata during the same time interval, but cells were not detected. The Yellowstone caldera is composed of rhyolite, a rock rich in silica (Si) and modest amounts of P. We conclude that both watersheds were exposed to the potential colonization by D. geminata, but just as the North Island of New Zealand has not been able to support this diatom because of P concentrations exceeding a threshold, the Yellowstone watershed is not able to support it either. [ABSTRACT FROM AUTHOR]

Chemical contaminants, such as pesticides, pharmaceuticals and industrial compounds are ubiquitous in surface water and sediment in areas subject to human activity. While targeted chemical analysis is typically used for water and sediment quality monitoring, there is growing interest in applying effect-based methods with in vitro bioassays to capture the effects of all active contaminants in a sample. The current study evaluated the biological effects in surface water and sediment from two contrasting catchments in Aotearoa New Zealand, the highly urbanised Whau River catchment in Tāmaki Makaurau (Auckland) and the urban and mixed agricultural Koreti (New River) Estuary catchment. Two complementary passive sampling devices, Chemcatcher for polar chemicals and polyethylene (PED) for non-polar chemicals, were applied to capture a wide range of contaminants in water, while composite sediment samples were collected at each sampling site. Bioassays indicative of induction of xenobiotic metabolism, receptor-mediated effects, genotoxicity, cytotoxicity and apical effects were applied to the water and sediment extracts. Most sediment extracts induced moderate to strong estrogenic and aryl hydrocarbon (AhR) activity, along with moderate toxicity to bacteria. The water extracts showed similar patterns to the sediment extracts, but with lower activity. Generally, the polar Chemcatcher extracts showed greater estrogenic activity, photosynthesis inhibition and algal growth inhibition than the non-polar PED extracts, though the PED extracts showed greater AhR activity. The observed effects in the water extracts were compared to available ecological effect-based trigger values (EBT) to evaluate the potential risk. For the polar extracts, most sites in both catchments exceeded the EBT for estrogenicity, with many sites exceeding the EBTs for AhR activity and photosynthesis inhibition. Of the wide range of endpoints considered, estrogenic activity, AhR activity and herbicidal activity appear to be the primary risk drivers in both the Whau and Koreti Estuary catchments. [Display omitted] • Bioassays applied to assess chemical contamination in two New Zealand catchments. • Strong responses at sites impacted by landfill, stormwater and wastewater effluent. • Most sediments extracts were toxic to bacteria, estrogenic and induced AhR activity. • Polar water extracts exhibited significant estrogenic and herbicidal activity. • Estrogenic, AhR and herbicidal activity were the main risk drivers in the catchments. [ABSTRACT FROM AUTHOR]

In the New Zealand landscape, the mahika kai sites (resource gathering areas) are marked through place names, which act as central reference points (whai take) for a wider ecosystem catchment area and indicate changes over time. The traditional ecological knowledge, awakened through place names, informs and influences the way Māori realise cultural, social, environmental, and economic aspirations and practices (past and present). This paper will draw from a research project in Te Wai Pounamu (South Island), New Zealand that utilises traditional ecological knowledge (TEK) surrounding the place name, Matainaka, which indicate places where Kāi Tahu (South Island Māori tribal group) gathered whitebait (īnaka, Galaxias maculatus): an important fresh water species. A major focus of the research project is the knowledge around socio-cultural tipping points that will impact directly on the future cultural, social and economic sustainability within a specific catchment location, the Waikōuaiti River. The river has spawning and fishing sites for the īnaka mahika kai and comes under the mana whenua (recognised traditional authority) of the Māori tribal group, Kāti Huirapa Rūnaka ki Puketeraki. Traditional ecological knowledge kōrero (speech) explains the importance of Matainaka and its contribution to the surrounding catchment area, and - in contemporary times - works alongside that of scientific knowledge. The project merged TEK and science to find ways to improve future planning and adaptation for habitat restoration and modification, and to lessen impacts on īnaka spawning sites from the expected impacts of climate change. [ABSTRACT FROM AUTHOR]

The first New Zealand National Park was a gift from Māori, but subsequent management of National Parks has largely reflected a utilitarian European perspective. The Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 confers 'legal personality' on the entire Whanganui River catchment, recognising it as a 'living whole' that 'supports and sustains' the people. The Act is founded on holistic and long-term values shared by Māori and ecological science. During the three decades since the founding of the Department of Conservation in 1987, three major transformations in environmental thinking and practice are founded in similar values: (1) increased respect for nature as a community to which people belong; (2) cities as a major focus for ecological restoration; and (3) rapidly growing scale in landscape restoration. We build on these values and developments to propose the concept of National Park Aotearoa, a whole-of-nation vision for bicultural ecological restoration. [ABSTRACT FROM AUTHOR]

Although the freshwater environments of New Zealand once comprised an extensive interconnected network of rivers, lakes, and wetlands, their extent, condition, and connectivity have been reduced since human settlement, with consequent impacts on ecosystem functioning and the species that reside within them. An imbalance in the protection of freshwater ecosystems, with significant under‐representation of lowland freshwater ecosystems, makes these the most threatened ecosystems in New Zealand.Recent policy initiatives are attempting to take a whole‐catchment view, i.e. 'from the mountains to the sea'. There is also an increased focus on the restoration of vulnerable water bodies that still support moderate values, in preference to previous long‐term restoration programmes for the most degraded freshwater sites. The outcomes of these programmes have been less certain, with opportunities lost for systems that are declining in condition but have not yet reached the threshold of degradation for investment.This work demonstrates the gains that can be made through the use of spatial conservation prioritization software to identify priority catchments for freshwater restoration, emphasizing the representation of a full range of ecosystems and species, while also taking account of longitudinal‐connectivity constraints within catchments.Third‐order subcatchments were the most suitable scale for this prioritization, to capture the most important components within the largest river catchments. Populations of important native fish populations and the locations of major terrestrial conservation projects were also considered when assessing priorities; iteratively chosen weightings were applied to control the balance of representation across these different features.Consideration was also given to existing patterns of protection, in order to assess the biodiversity representation within areas currently protected and to identify sites that would provide maximum additional benefits if restored or protected.The resulting subcatchment prioritizations have contributed strongly to regional collaborative restoration processes. [ABSTRACT FROM AUTHOR]

Otolith microchemistry was used to identify marine‐ versus freshwater‐derived recruitment of three native freshwater fish species belonging to the southern hemisphere family Galaxiidae, in New Zealand's longest river system, the Waikato River.Water chemistry data for trace elements and 87Sr/86Sr isotope ratios were collected from five lentic and 10 lotic water bodies throughout the lower river floodplain. Potential spawning sites for galaxiids were compared with values obtained by laser ablation inductively coupled mass spectrometry (LA‐ICPMS) depth profiling of young‐of‐the‐year otoliths sampled from fish in nine lower river catchment sites.Otolith chemical signatures from the larval rearing period indicated that catchment‐scale recruitment for two species, Galaxias argenteus (Gmelin, 1789) and Galaxias fasciatus Gray, 1842, was driven predominantly by non‐diadromous recruitment from one lake (Lake Waahi). In contrast, diadromous recruitment appeared to be more common for Galaxias maculatus (Jenyns, 1842); however, non‐diadromous specimens were also identified for the first time from a New Zealand river.Reversing lake outlet flows linked to river stage appears be important in facilitating the dispersal of rheotactic larvae out of lakes, suggesting that lake outflow management at key times could be used to sustain this ecologically important function.This study highlights that some water bodies can supply a disproportionately large number of recruits to support fish populations within the wider riverscape. Identifying these water bodies and managing them to sustain recruitment is key to the conservation of non‐diadromous Galaxiidae in this modified lowland environment [ABSTRACT FROM AUTHOR]

A 16-year series of daily snow-covered area (SCA) for 2000–2016 is derived from MODIS imagery to produce a regional-scale snow cover climatology for New Zealand's largest catchment, the Clutha Catchment. Filling a geographic gap in observations of seasonal snow, this record provides a basis for understanding spatio-temporal variability in seasonal snow cover and, combined with climatic data, provides insight into controls on variability. Seasonal snow cover metrics including daily SCA, mean snow cover duration (SCD), annual SCD anomaly and daily snowline elevation (SLE) were derived and assessed for temporal trends. Modes of spatial variability were characterised, whilst also preserving temporal signals by applying raster principal component analysis (rPCA) to maps of annual SCD anomaly. Sensitivity of SCD to temperature and precipitation variability was assessed in a semi-distributed way for mountain ranges across the catchment. The influence of anomalous winter air flow, as characterised by HYSPLIT back-trajectories, on SCD variability was also assessed. On average, SCA peaks in late June, at around 30 % of the catchment area, with 10 % of the catchment area sustaining snow cover for >120 d yr -1. A persistent mid-winter reduction in SCA, prior to a second peak in August, is attributed to the prevalence of winter blocking highs in the New Zealand region. In contrast to other regions globally, no significant decrease in SCD was observed, but substantial spatial and temporal variability was present. rPCA identified six distinct modes of spatial variability, characterising 77 % of the observed variability in SCD. This analysis of SCD anomalies revealed strong spatio-temporal variability beyond that associated with topographic controls, which can result in snow cover conditions being out of phase across the catchment. Furthermore, it is demonstrated that the sensitivity of SCD to temperature and precipitation variability varies significantly across the catchment. While two large-scale climate modes, the SOI and SAM, fail to explain observed variability, specific spatial modes of SCD are favoured by anomalous airflow from the NE, E and SE. These findings illustrate the complexity of atmospheric controls on SCD within the catchment and support the need to incorporate atmospheric processes that govern variability of the energy balance, as well as the re-distribution of snow by wind in order to improve the modelling of future changes in seasonal snow. [ABSTRACT FROM AUTHOR]

Hydrological models are a mathematical representation of heterogeneous and nonlinear hydrological processes. In the past, a great many simple to complex hydrological models have been developed, but none of these models is superior to the others for all types of practical applications. These hydrological model alternatives have different strengths in representing and capturing complex natural hydrological processes. Yet generally a single hydrological model is used in practice, which may represent certain processes of the catchment well and may be less adequate for others. Moreover, the use of a single hydrological model is restrictive, as the conceptual uncertainty associated with the model structure cannot be identified and quantified. To overcome these issues, the multi-model ensemble approach has recently been applied more commonly to take advantage of the diverse skills of different models. In this study, the multi-model ensemble approach to account for model structure uncertainty is employed to improve hydrological model prediction. While a certain hydrological model may represent particular processes or (extreme) events better than another, two distinct models may represent these processes or events with comparable accuracy. If members of a hydrological ensemble model capture the same process and if they are similar in process representation, then these members will not supply any additional information for prediction and therefore will not improve the accuracy. Hence, by identifying similar models, there is potential to increase the reliability of hydrological ensemble predictions and to reduce computing costs without reducing accuracy. In this study a methodology is presented to identify similar models. The methodology is applied and tested for the Tuapiro catchment in New Zealand. A range of verification statistics are computed to ascertain the validity of the approach. Overall, the multi-model ensemble-based hydrological prediction where non-informative members have been removed is shown to not compromise prediction accuracy. For the case study streamflow prediction an increased flatness of the rank histogram, insignificant changes in the continuous rank probability score, and improved accuracy in terms of Nash-Sutcliffe coefficient, Kling-Gupta efficiency and Root Mean Square Error were found, at lower computing costs. [ABSTRACT FROM AUTHOR]

Background: Many women are affected by anxiety and depression after armed conflict in low-income and middle-income countries, yet few scalable options for their mental health care exist. We aimed to establish the effectiveness of a brief group psychological intervention for women in a conflict-affected setting in rural Swat, Pakistan.Methods: In a single-blind, cluster, randomised, controlled trial, 34 community clusters in two union councils of rural Swat, Pakistan, were randomised using block permutation at a 1:1 ratio to intervention (group intervention with five sessions incorporating behavioural strategies facilitated by non-specialists) or control (enhanced usual care) groups. Researchers responsible for identifying participants, obtaining consent, enrolment, and outcome assessments were masked to allocation. A community cluster was defined as neighbourhood of about 150 households covered by a lady health worker. Women aged 18-60 years who provided written informed consent, resided in the participating cluster catchment areas, scored at least 3 on the General Health Questionnaire-12, and at least 17 on the WHO Disability Assessment Schedule were recruited. The primary outcome, combined anxiety and depression symptoms, was measured 3 months after the intervention with the Hospital Anxiety and Depression Scale (HADS). Modified intention-to-treat analyses were done using mixed models adjusted for covariates and clusters defined a priori. The trial is registered with the Australian New Zealand Clinical Trials Registry, number 12616000037404, and is now closed to new participants.Findings: From 34 eligible community clusters, 306 women in the intervention group and 306 women in the enhanced usual care (EUC) group were enrolled between Jan 11, 2016, and Aug 21, 2016, and the results of 288 (94%) of 306 women in the intervention group and 290 (95%) of 306 women in the EUC group were included in the primary endpoint analysis. At 3 months, women in the intervention group had significantly lower mean total scores on the HADS than women in the control group (10·01 [SD 7·54] vs 14·75 [8·11]; adjusted mean difference [AMD] -4·53, 95% CI -7·13 to -1·92; p=0·0007). Individual HADS anxiety scores were also significantly lower in the intervention group than in the control group (5·43 [SD 4·18] vs 8·02 [4·69]; AMD -2·52, 95% CI -4·04 to -1·01), as were depression scores (4·59 [3·87] vs 6·73 [3·91]; AMD -2·04, -3·19 to -0·88). No adverse events were reported in either group.Interpretation: Our group psychological intervention resulted in clinically significant reductions in anxiety and depressive symptoms at 3 months, and might be a feasible and effective option for women with psychological distress in rural post-conflict settings.Funding: WHO through a grant from the Office for Foreign Disaster Assistance. [ABSTRACT FROM AUTHOR]

Purpose: Stream sediment can control phosphorus (P) in the water column at baseflow. Two common laboratory analyses of sediment P are the equilibrium phosphate concentration at net zero sorption (EPC0) and P fractionation. Good sample handling ensures representative results, but oftentimes, studies rely on air-dried or freeze-dried samples, which alters sediment biogeochemistry. How and to what extent this influences EPC0 and P fractionation remains unclear. We therefore examine pretreatment effects on sediment EPC0 and P fractionation.Materials and methods: We collected fine sediments (< 2 mm) from streams in the Tukituki River and Reporoa Basins in New Zealand (n = 31 sediments). Subsamples were then either kept fresh, frozen then lyophilized (freeze-dried), or dried at 40 °C for 2 weeks (air-dried). Measurements of EPC0 and P fractionation were made in triplicate. The sequential P fractionation scheme determined five different P pools: NH4Cl (labile P), NaOH reactive P (RP; metal oxide-bound P) and unreactive P (URP; organic P), HCl (Ca-mineral P), and residual P. Along with statistical comparisons between fresh results and the two pre-treatments, we explored correlations between pre-treatment effects and sediment physicochemical characteristics.Results and discussion: The sediments had generally low EPC0 (majority < 0.020 mg P L−1), and uncertainty in EPC0 increased with concentration magnitude. While there were sediment-specific changes in EPC0 with pre-treatment, there was no consistent bias caused by pre-treatment. However, the differences between the fresh and air-dried sediment EPC0 were larger and more variable than between fresh and freeze-dried sediment. For P fractionation, the Tukituki sediments were enriched in HCl-P, while Reporoa sediments had more NaOH-RP and NaOH-URP. Despite large sediment-specific changes, the overall effects of freeze- and air-drying sediment were increased NH4Cl-P (estimated average effect, θ̂ = + 0.63 and + 3.7 mg P kg−1), no significant changes for NaOH-RP, contrasting changes in NaOH-URP (− 3.4 and + 3.3 mg P kg−1), and decreased HCl-P (− 40 and − 33 mg P kg−1).Conclusions: We found that drying sediment significantly influenced EPC0 and P fractions (especially the NH4Cl-P fraction). Air-drying was particularly error-prone and should be avoided. The use of freeze-drying to preserve samples for later analyses and improve ease of handling may be used with appropriate consideration of the research objectives and the error introduced by freeze-drying. However, we recommend using fresh sediments for analyses whenever possible, as they best represent natural conditions. [ABSTRACT FROM AUTHOR]

The Clutha River is New Zealand's largest river, both in terms of discharge and catchment size. It has a large seasonal flow variability with large spring and summer flows and very low flows in winter. The river is important for its contribution to energy production from two large hydro dams, irrigation for agriculture and horticulture, and tourist activities. The Clutha River flows are modified by discretionary releases of water from the only storage lake in the catchment, at Hawea. The mountainous South Island topography to the west means that a large part of the catchment is in a rain shadow and is regularly subject to long periods without any significant precipitation, similar to many other rain shadow catchments globally. While floods can be mitigated against, droughts are insidious and generally well established before being identified. A hydrological drought is defined as a lack of water in the hydrological system, identified by abnormally low streamflow in rivers and abnormally low levels in lakes and reservoirs. A drought index is proposed for the upper and mid-Clutha catchment that identifies the onset of hydrological drought conditions, measures the severity of the drought, and signals the end of the drought. This index has the advantage over other hydrological indices in that it uses a daily threshold rather than a monthly or seasonal one and indicates the start of a drought as soon as it occurs. [ABSTRACT FROM AUTHOR]

• Development of aquatic nutrient criteria often rely on relationships with biological indices. • Summarizing taxa to biological indices may drive weak relationships with nutrients. • Nutrient criteria setting should consider relationships between nutrients and individual taxa. Nutrient enrichment is one of the most pervasive impacts on aquatic ecosystems globally. Approaches to establish nutrient criteria that safeguard aquatic ecosystem health are highly variable and, in many instances, criteria are derived from correlations between in-situ nutrient concentrations and biological indices. Summarising entire assemblages with a single index can result in a substantial loss of information and potentially weaker relationships. In this study, we compared the derivation of nutrient criteria using biological indices and those from individual taxa for rivers and streams in New Zealand. Random forest models, including nutrient concentrations, were built to predict two biological indices and individual taxa across New Zealand's river monitoring network. For all acceptable models, the response of the biological indices and individual taxa to increasing Dissolved Inorganic Nitrogen (DIN) and Dissolved Reactive Phosphorus (DRP) were then predicted for every river reach across the nation, and nutrient concentrations that protected 80% of taxa were then identified. Models for the biological indices were poor but were good for most of the taxa, with nutrient concentrations almost always being the most influential factor. To ensure persistence of at least 80% of the taxa within a river reach, we estimated that DIN (Dissolved Inorganic Nitrogen) concentrations would need to be below 0.57–1.32 mg/L, and DRP (Dissolved Reactive Phosphorus) concentrations below 0.019–0.033 mg/L, depending on the river type. In general, high order, low slope rivers and streams required more stringent nutrient criteria than steep, low order streams. The link between nutrient concentrations and biological indices were weak and likely suffer from the loss of information from summarising an entire assemblage into a single numeric. We consider that the derivation of nutrient criteria for waterways should also examine the individual relationships with the taxa in a river system to establish protection for a desired proportion of taxa. [ABSTRACT FROM AUTHOR]

The WATYIELD water balance model is used to demonstrate that increased transpiration and interception associated with mānuka (Leptospermum scoparium) encroachment in the tussock catchment comprising part of the Glendhu experimental catchment study, Otago, New Zealand, is responsible for the flattening and subsequent decline in the difference in water yield between that predicted and observed for the planted (Pinus radiata) catchment from 2005 until 2013. Linear extrapolation based on aerial photographic coverage taken in 1980 and 2015 suggests that mānuka could cover up to three-quarters of the tussock catchment by 2090, which is approximately equivalent to the proportion of forest cover in the planted catchment prior to harvesting. Statistical modelling shows that this could result in an annual reduction in water yield of about 216 mm (25%) in the tussock catchment. [ABSTRACT FROM AUTHOR]