Kevin Collier

Insects are important to ecosystem functioning in freshwater habitats. They have a rich diversity, fill every ecological niche, and as predators and scavengers and the prey of larger species, they play a vital role in nutrient cycling. There is no doubt that aquatic insects are under considerable threat in New Zealand (Grainger et al. 2014, Joy & D...

Context Phenology plays a key role in shaping population dynamics, community structure and evolutionary adaptations. For freshwater mussels that rely on a parasitic larval (glochidia) phase on fish, shifts in reproductive phenology driven by environmental conditions may result in mismatches between glochidia release and host fish availability. Aim...

Globally-threatened freshwater mussels belonging to the order Unionida (Bivalvia) may be adversely affected by dense beds of submerged macrophytes that modify habitat at the sediment-water interface. Such effects can be particularly pronounced in modified lentic ecosystems such as reservoirs which are subject to hydrological regimes (e.g., hydropea...

Globally-threatened freshwater mussels belonging to the order Unionida (Bivalvia) may be adversely affected by dense beds of submerged macrophytes that modify habitat at the sediment-water interface. Such effects can be particularly pronounced in modified lentic ecosystems such as reservoirs which are subject to hydrological regimes (e.g., hydropea...

Floodplain ecosystems are focal points for human settlement, and consequently are often subjected to extensive modification and infrastructure development. Establishment of non-native species in floodscapes presents a range of challenges when they become problematic and drive changes in native aquatic communities and ecosystems. These non-native sp...

Larvae (glochidia) of Unionida mussels form obligate symbiotic associations with host fish to complete their life-cycle. To identify previously unknown host fish associations for the threatened New Zealand Echyridella aucklandica, glochidia infestation on fish by two mussel species was quantified in four Waikato streams. A host for E. aucklandica w...

Larvae (glochidia) of the freshwater mussel order Unionida undergo a brief parasitic phase by attaching to and metamorphosing on suitable host fish. Here, novel observations of complex glochidia release strategies and glochidia morphometry are reported and compared in two sympatric New Zealand hyriid species, Echyridella menziesii (Gray, 1843) and...

We measured δ¹⁵N, δ¹³C, and percent carbon (C) and nitrogen (N) on foot and remaining soft tissue of the two native freshwater mussel species Echyridella aucklandica and E. menziesii (Hyriidae: Unionida) from three Waikato, northern New Zealand, streams to investigate differences among sites, sexes and species. Mean differences in δ¹⁵N and δ¹³C bet...

Ponds are increasingly being constructed to enhance amenity values in human-dominated lowland landscapes, but little is known of design features that influence macroinvertebrates which can provide important food resources for fish and waterbirds. We quantified pond characteristics, sampled benthic and water-column macroinvertebrates in winter, and...

• Ponds can provide important refuges for aquatic biota on developed floodplains and are increasingly being constructed in an effort to enhance native biodiversity and ecosystem services in degraded landscapes. This study examined 34 constructed ponds to investigate the influence of design features on community composition, native biodiversity, and...

Dense macrophyte beds are known to produce extreme diurnal oxygen and temperature conditions in shallow lakes. However their influences in managed hydropeaking reservoirs has received limited attention. We measured dissolved oxygen, pH and water temperature in the Lake Karāpiro hydroreservoir, northern New Zealand, across a gradient of proportional...

The 2018 conservation status assessment of freshwater invertebrate taxa was the most comprehensive to date. Of the Threatened and At Risk taxa in 2018 (177 taxa), 48 were listed as Nationally Critical, 14 as Nationally Endangered, 16 as Nationally Vulnerable, 10 as Declining, and 89 as Naturally Uncommon. Most taxa were listed as either Not Threate...

Interactions between multiple stressors can result in unexpected ecological outcomes, especially in lowland lakes. Degraded shallow lakes typically occur in populated areas and are therefore subject to the combined effects of increased nutrient and sediment loading, and species invasions. This presents challenges for meeting ecological restoration...

Island nations such as New Zealand provide valuable insights into conservation challenges posed by strongly connected and recently developed or exploited freshwater and marine ecosystems. The narrow land mass, high rainfall, and steep terrain of New Zealand, like many other island nations, mean that land‐based stressors are rapidly transferred to f...

Global biodiversity loss is accelerating at an alarming rate. While considerable effort and resources have gone into conservation management for many threatened species in New Zealand (NZ), some species are still ‘losing the battle’ despite much effort, and others have been ignored altogether. Here, we present seven case studies to illustrate the b...

• 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 a...

• Understanding the multiple agents of decline is important for the conservation of globally threatened Unionida (Class Bivalvia), but threats from non‐native species have received limited attention. To address this gap, a global meta‐analysis was conducted aimed at identifying known interactions and mechanisms of impact and informing potential eff...

Unbiased estimates of the current state of target ecosystems and identification of potential causal factors are key to managing stressors over large scales, and for guiding policy and decision makers to set realistic targets and expectations in light of economic pressures. A probability survey design for 176 target wadeable, perennial streams mappe...

Resilience in river ecosystems requires that organisms must persist in the face of highly dynamic hydrological and geomorphological variations. Disturbance events such as floods and droughts are postulated to shape life history traits that support resilience, but river management and conservation would benefit from greater understanding of the emer...

We analysed 344 juvenile Galaxias maculatus (length 35–59 mm) collected from two sites in the lower Waikato River, North Island, New Zealand, to determine diet during the period of upstream migration (August–November). In total, 53% of guts contained invertebrate food items comprising 16 taxa, with Cladocera numerically most abundant overall (32% o...

We characterised the quantity (mass per unit area or volume), quality (cabon:nitrogen ratio) and enrichment (δ¹⁵N) of basal food resources and benthic macroinvertebrates in six shallow lakes in the Waikato region, New Zealand, to elucidate patterns related to lake type (peat, riverine), habitat (littoral, mid-lake) and enrichment status (Trophic Le...

Bank stabilization is increasing along large rivers as urban areas expand, and the need to protect infrastructure increases in the face of changing climate and flow patterns, but the cumulative effects of different stabilization approaches on reach‐scale biodiversity are not well understood. We investigated physical habitat characteristics and macr...

We quantified trophic overlap between the invasive, non‐native catfish brown bullhead (Ameiurus nebulosus) and the New Zealand native shortfin eel (Anguilla australis) in four peat and riverine lakes using stable isotope (δ¹³C and δ¹⁵N) and gut content analyses. Across all lakes and fish sizes over the austral spring–summer period, shortfin eel gut...

Lakes across the globe require help. The Lake Restoration Handbook: A New Zealand Perspective addresses this need through a series of chapters that draw on recent advances in modelling and monitoring tools, citizen science and First Peoples’ roles, catchment and lake-focused restoration techniques, and policy implementation. New Zealand lakes, like...

This document is the final written output from the Ministry for the Environment funded project on benthic macroinvertebrate indicators of ecosystem health (Contract 21630). The project was designed to address a recognised need to include macroinvertebrates in the National Policy Statement for Freshwater Management (NPS-FM) 2014. Benthic macroinvert...

New Zealand's Waikato River has had a short but intense history of development, primarily through land-use change and flow regulation in the upper river, and in the lower river through flood control works, non-native species invasion, and land-use intensification. The river undergoes sharp transitions across montane-flood plain-coastal environments...

Laboratory experiments on the New Zealand freshwater mussel Echyridella menziesii were used to investigate the short-term effects (7–8 days) of food type on rates of biodeposition and benthic substrate respiration. Post-feeding biodeposition rates ranged from 0.34 to 1.52 mg g⁻¹ h⁻¹ (mean = 0.50 mg g⁻¹ h⁻¹) and were unaffected by the addition of to...

We investigated the potential for zooplankton to emerge following inundation of dry soils on the lower Waikato River floodplain, North Island, New Zealand. Soil cores were collected from native forest remnants, scrub (predominantly Salix spp.) and pasture, and from sites inside or outside of stopbanks, to examine the effects of vegetation type and...

Native freshwater mussels (Bivalvia: Unionoida) can represent a large portion of benthic biomass, but their functional role is still poorly understood. We sampled Echyridella menziesii (Hyriidae) in six lakes from two regions of the North Island of New Zealand to develop general allometric relationships for predicting filtration, excretion and biod...

Reference benchmarks are needed to assess the contemporary status of rivers and to establish restoration targets. We developed predictive models to estimate site-specific reference values for a macroinvertebrate community index (MCI), which is used to indicate a range of human impacts on wadeable streams. We compared three statistical modelling app...

We sampled natural and reconstructed side-arms during different stages of hydrological connectivity with a large floodplain river in northern New Zealand, to determine whether re-establishment of connectivity would be an effective strategy for restoring plankton communities in former side-arms. Connectivity between side-arms and the river was moder...

Predictions of invasion risk for seven non‐indigenous fish species, ecological impact scores for individual species, and lake conservation rankings were linked to develop Invasion Risk Impact ( IRI ) and Lake Vulnerability ( LV ) indices that help identify New Zealand lakes most at risk of loss of conservation value from potential multi‐species inv...

Consideration of the need and opportunities for restoration of freshwater lakes in New Zealand requires individualised approaches that account for lake type, invasive species and food web structure.

Invertebrates inhabiting marine and freshwater ecosystems make important contributions to global biodiversity and provide significant services that have cascading effects across ecosystems. However, this group is grossly under‐represented in assessments of conservation status and often neglected in targeted aquatic conservation efforts. In global a...

As part of its Environmental Indicators Programme, the Waikato Regional Council has been conducting annual surveys of aquatic invertebrates and stream habitat to document the state and trend of the ecological condition of streams and rivers in the region since 1994 (Regional Ecological Monitoring of Streams—REMS). This report presents the second co...

The ability to predict invasive species spread is essential for effective biosecurity management and the allocation of scarce monitoring resources. Prevention of invasive fish incursions poses a significant challenge because of the wide physiological tolerances of many species, their mobility and the role that human vectors play in their spread. In...

Heterogeneity of lateral habitats along large rivers can enhance rates of ecological processes such as nutrient transformations and contaminant sequestration. Consequently, construction or reconnection of hydraulic retention zones such as side‐arms is being widely promoted in river restoration projects, although limited information is available to...

The importance of environmental heterogeneity in lotic ecosystems is well recognised in river management, and continues to underpin studies of hierarchical patch dynamics, geomorphology and landscape ecology. We evaluated how physical characteristics and water chemistry measurements at high spatiotemporal resolution defi ne channel units of potenti...

Samples from multiple sites can also be run together by attaching specific identification tags • Detecting multiple species in multiple samples simultaneously (as presence/absence data) makes NGS an ideal method for MCI analysis DNA sequencing of the mitochondrial Cytochrome c Oxidase subunit I (COI) "barcoding" gene can provide an accurate taxonom...

http://www.2014watersymposium.co.nz/asset/library/Parshotam.pdf

Large rivers present major challenges for biomonitoring and the development of biocriteria because of difficulties obtaining samples representative of the range of habitats present and a paucity of information on taxa responses to environmental conditions. We sampled littoral and deepwater benthic habitats to investigate macroinvertebrate community...

http://ernz2014.eresearch.org.nz/conference/eresearch-nz-2014/schedule/lernzdb-freshwater-database

Off-channel habitats play a crucial role in the life-cycles of many riverine fish species, but lateral movements of fish into these habitats are poorly understood. We tested how flow dynamics affects the movement of fish and shrimps between the main river channel and different types of off-channel habitats: a riverine lake and a wetland. Our study...

Mass loss rates of wooden sticks (Betula platyphylla Sukaczev) and macroinvertebrate community composition were measured in the Waikato Region of northern New Zealand at 53 running water sites draining native forest catchments (reference), or characterised by urban, industrial, agroforestry or hydrological stressors. Overall wood substrates retaine...

The ecological responses of large rivers to human pressure can be assessed at multiple scales using a variety of indicators, but little is known about how the responses of ecological indicators vary over small spatial scales. We sampled phytoplankton, zooplankton and macroinvertebrates and measured river metabolism and cotton strip breakdown rates...

Functional indicators are being increasingly used to assess waterway health but their responses to pressure in non-wadeable rivers have not been widely documented or applied in modern survey designs that provide unbiased estimates of extent. This study tests the response of river metabolism and loss in cotton strip tensile strength across a land us...

Contemporary patterns of land development mean that suitable reference sites for low‐gradient stream and non‐wadeable river biomonitoring are difficult to locate, requiring alternative approaches for benchmarking human impacts. We use two strongly harmonised macroinvertebrate data sets for wadeable streams (180 sites) and non‐wadeable rivers (30 si...

Large river–floodplain systems are characterised by seasonal flow variability. High flows lead to hydrological connection between the main channel and inundated off‐channel lakes, wetlands and floodplains, which provide essential habitats for riverine biota. We tested the following hypotheses: (i) that crustacean zooplankton are more abundant in co...

Responses of macroinvertebrate communities to human pressure are poorly known in large rivers compared with wadeable streams, in part because of variable substrate composition and the need to disentangle pressure responses from underlying natural environmental variation. To investigate the interaction between these factors, we sampled macroinverteb...

We investigated outcomes of three monitoring networks for assessing ecological character and condition of wadeable streams, Waikato region, New Zealand. Site selection was based on professional judgment, stratification within categories of watershed characteristics, or on using an unequal-probability survey design. The professional-judgment network...

Quantifying the contributions of carbon sources that support food webs in large rivers is an important and growing field of ecological research with implications for future management and rehabilitation. Here we review theoretical concepts and recent empirical evidence that address carbon flow through aquatic food webs in large rivers. The literatu...

Using natural abundances of stable carbon ( δ13C) and nitrogen (δ15N) isotopes, we quantified spatial and temporal patterns of carbon flow through the main channel food web in the lowland section of New Zealand ’s longest river, the Waikato River. The study was undertaken with the objective of determining whether the Waikato River conforms to conte...

Although disturbance and productivity are clearly strong influences on lotic diversity, rarely have their interactive effects been studied in running water systems. We hypothesised that the presence or absence of canopy cover in streams would alter productivity–disturbance–diversity relationships due to differential effects on the food base, and te...

Tidal streams are ecologically important components of lotic network, and we identify dissolved oxygen (DO) depletion as a potentially important stressor in freshwater tidal streams of northern New Zealand. Other studies have examined temporal DO variability within rivers and we build on this by examining variability between streams as a basis for...

1. Modification of natural landscapes and land‐use intensification are global phenomena that can result in a range of differing pressures on lotic ecosystems. We analysed national‐scale databases to quantify the relationship between three land uses (indigenous vegetation, urbanisation and agriculture) and indicators of stream ecological integrity....

Resolving land cover hierarchy relationships in urban settings is important for defining the scale and type of management required to enhance stream health. We investigated associations between macroinvertebrate assemblages in urban streams of Hamilton, New Zealand, and environmental variables measured at multiple spatial scales comprising (i) loca...

We report the discovery of a single specimen of a live apple snail Pomacea diffusa Blume 1957 (Ampullariidae: Prosobranchia), from the Waikato River, Hamilton city, central North Island, New Zealand. This species, along with the congeneric P. insularum, is imported for the aquarium trade, and its occurrence in the river likely stemmed from an aquar...

The New Zealand fish fauna contains species that are affected not only by river system connectivity, but also by catchment and local-scale changes in landcover, water quality and habitat quality. Consequently, native fish have potential as multi-scale bioindicators of human pressure on stream ecosystems, yet no standardised, repeatable and scientif...

Freshwater environments in New Zealand provide a range of ecosystem services and contain important biodiversity. Managing these environments effectively requires a comprehensive inventory of the resource and cost-effective tools for regular monitoring. The complex and extensive margins of natural water bodies make them difficult to sample comprehen...

The use of mussel spat ropes to enable the passage of banded kokopu (Galaxias fasciatus) past perched culverts was tested under laboratory conditions. A 0.5 m high simulated perched culvert was fitted with one of two UV stabilised polypropylene rope types: “Russet Loop” and “Super Xmas Tree”. Four randomised replicate trials using each rope type we...

1. The value of measuring ecosystem functions in regular monitoring programs is increasingly being recognised as a potent tool for assessing river health. We measured the response of ecosystem metabolism, organic matter decomposition and strength loss, and invertebrate community composition across a gradient of catchment impairment defined by upstr...

1. Management of stream biodiversity is often tightly linked with the restoration and protection of riparian and catchment vegetation. Despite that, there are no established guidelines on how much forest should be retained or replanted in riparian zones and surrounding catchments to maintain or re‐establish instream ecological integrity. In this st...

A method was developed to score the ecological condition of first- to third-order stream reaches in the Auckland region of New Zealand based on the performance of their key ecological functions. Such a method is required by consultants and resource managers to quantify the reduction in ecological condition of a modified stream reach relative to its...

Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, but are increasingly becoming the focus of restoration activities. We investigated habitat quality, ecological function, and fish and macroinvertebrate community composition of gully streams in Hamilton City, New Zealand, and compared these with a...

We compared macroinvertebrate communities colonising multiplate samplers constructed from perspex or tempered hardboard (wood) with an alternative artificial substrate constructed from folded coconut fibre matting (coir) enclosed in nylon netting. Substrates were incubated for 62 days over January to March 2007 at six sites over 240 km along the Wa...

A large river study was conducted as part of the Cross Departmental Research Pool (CDRP) ecological integrity project to (i) provide an overview of the macroinvertebrate faunas of large rivers, including those in deep-water habitats, and (ii) to elucidate links between these faunas, river function and anthropogenic stressors. Eleven sites on 6th-or...

Integrating multiple metrics derived from stream macroinvertebrate communities into single scores that reflect ecological condition can bridge the needs of multiple groups using biomonitoring data. Macroinvertebrate metrics from 511 Waikato, New Zealand, stream samples were standardised by their maximum observed value. Metric redundancy and optimis...

Few attempts have been made to combine multimetric and multivariate analyses for bioassessment despite recognition that an integrated method could yield powerful tools for bioassessment. An approach is described that integrates eight macroinvertebrate community metrics into a Principal Components Analysis to develop a Multivariate Condition Score (...

Identifying the environmental factors influencing biotic patterns in large rivers will assist with extrapolating biological monitoring results to broader scale conclusions about river condition. In the present study, we collected macroinvertebrates and physico-chemical data at 47 shallow-water (<1-m deep) sites, including nine sites at major tribut...

1. A spatially‐extensive data set of stream macroinvertebrate communities from 49 northern New Zealand sites sampled over a 10‐year period was analysed to assess relationships between the environment (catchment land‐cover, landscape position and regional‐scale weather patterns), and (i) community persistence and stability based on the constancy of...

Geographic Information System (GIS) was used to identify potential reference sites for wadeable stream monitoring, and multivariate analyses were applied to test whether invertebrate communities reflected a priori spatial and stream type classifications. We identified potential reference sites in segments with unmodified vegetation cover adjacent t...

This report describes a biogeographic classification for use in identifying water bodies of national importance in New Zealand. The classification aims to identify geographic units likely to have experienced similar physical disturbance regimes, while taking cognisance of potential recolonisation pathways and/or geographic barriers to the dispersal...

We measured water quality, recorded physical habitat characteristics and collected aquatic invertebrates from 17 rockface seeps, five springs and five streams in a geologically diverse region of New Zealand's North Island to investigate factors influencing invertebrate distribution and community composition within and among these habitats. A total...

The interaction of water depth and velocity with size, sex and morphotype of nymphs belonging to the leptophlebiid mayfly genus Deleatidium was investigated in a New Zealand river. Velocity had a significant effect on distribution such that larger nymphs tended to be found more commonly in faster water. Depth also influenced size distribution, but...

1. Water from acid (pH 4.3–5.7), brown water streams was low in alkalinity (0–2.3 g m ⁻³ CaCO 3 ) and conductivity (2.5–4.1 mS m ⁻¹ ) but contained relatively high concentrations of dissolved organic carbon (6.6–16.3 gm ⁻³ ). In contrast, alkaline (pH 6.6–8.0), clearwater streams had high CaCO 3 (12.6–57.6 g m ⁻³ ) and conductivity (3.7–22.3 mS m ⁻...

1. Population dynamics (density, biomass, annual production), gut contents and feeding rates of mayflies (Deleatidium spp.; Leptophlebiidae) were compared in two naturally acid (mean pH≃4.8). brownwater streams and two alkaline (mean pH 7.5), clearwater streams in South Westland, New Zealand. 2. Mean densities of larvae (range 234–2318 m−2) were hi...

Life-history and production of Olinga feredayi in both benthic and hyporheic stream habitats were investigated in a pristine Waikato, New Zealand, forest stream over two years to investigate the contribution of hyporheic habitat to total secondary production. O. feredayi had a univoltine life-history with adult emergence occurring from November to...

Nucleotide sequences of 422 base pairs of the cytochrome c oxidase subunit I (COI) gene were used to assess phylogeographic structure in the New Zealand hydropsychid caddisfly Orthopsyche fimbriata. A hierarchical examination of populations from 16 streams at different spatial scales in the central and northern North Island of New Zealand found 23...

1. Nucleotide sequences of a 280 base pair region of the cytochrome b gene were used to assess genetic diversity and to infer population histories in the New Zealand mayfly Acanthophlebia cruentata. 2. A hierarchial examination of populations from 19 streams at different spatial scales in the central and northern North Island of New Zealand found 3...

A stratified approach based on sample size and level of confidence was applied to Spearman rank correlations to define both ecological and statistical significance of temporal trends in four invertebrate metrics at 49 Waikato, New Zealand, stream sites that had been monitored annually on 8-10 occasions. This approach suggested that ecological condi...

The contribution of invertebrates to weight loss of kamahi leaves incubated in "coarse- mesh" (7 mm) and "fine-mesh" (0.2 mm) bags was investigated in 10 southern New Zealand streams (South Westland and Stewart Island) with a wide range of water pH. Coarse-mesh bags containing plastic strips as leaf analogues were also deployed in the four South We...

We measured water quality, recorded physical habitat characteristics and collected aquatic invertebrates from 17 rockface seeps, five springs and five streams in a geologically diverse region of New Zealand’s North Island to investigate factors influencing invertebrate distribution and community composition within and among these habitats. A total...

Adult survival is thought to be an important factor regulating the size of aquatic insect populations, yet very little is known about the factors that cause mortality during the adult stage. Percentage mortalities over varying time intervals and 96-h lethal temperature values (96-hdmax LT50) were calculated for the adults of the common New Zealand...

The short‐term effects of Pinus radiata forest harvesting to the stream edge followed by stream‐cleaning (removal of woody debris from the stream channel), on instream light levels, stream temperature, dissolved oxygen concentrations, and aquatic invertebrates were assessed in streams draining partly (25% clear‐cut) and totally (100% clear‐cut) har...

We examined changes in stream habitat and benthic invertebrate communities in two contrasting regions of New Zealand’s North Island over a 9–10-year period as pine forest harvesting progressed through the catchments. Increases in streambed cover by sand/silt, wood and macrophytes were recorded as harvesting progressed, but little change was observe...

We investigated factors affecting distribution and abundance of the leptophlebiid mayfly Acanthophlebia cruentata (Hudson) by (1) characterising large-scale environmental features of sites throughout the North Island where Acanthophlebia is known to occur, (2) evaluating relationships between land use and abundance of nymphs in a Waikato catchment,...

The leptophlebiid mayfly Acantho‐phlebia cruentata (Hudson) is restricted to the North Island and some associated offshore islands of northern New Zealand where it commonly occurs in benthic and hyporheic habitats of forested streams. We investigated: (1) life history; (2) secondary production in benthic and hyporheic habitats; and (3) major energy...

1. Perturbation pathways affecting interactions between feeding habitat, food supplies and diet of a lotic avian predator, blue duck (Hymenolaimus malacorhynchos Gemlin), were tracked in a New Zealand river following substantial inputs of sediment from a volcanic eruption. Sediment impacts were separated temporally into two distinct phases: (i) dep...