Zealand Streams Research Articles

Exploring freshwater stream bacterial communities as indicators of land use intensity

BackgroundStream ecosystems comprise complex interactions among biological communities and their physicochemical surroundings, contributing to their overall ecological health. Despite this, many monitoring programs ignore changes in the bacterial communities that are the base of food webs in streams, often focusing on stream physicochemical assessments or macroinvertebrate community diversity instead. We used 16S rRNA gene sequencing to assess bacterial community compositions within 600 New Zealand stream biofilm samples from 204 sites within a 6-week period (February–March 2010). Sites were either dominated by indigenous forests, exotic plantation forests, horticulture, or pastoral grasslands in the upstream catchment. We sought to predict each site’s catchment land use and environmental conditions based on the composition of the stream bacterial communities.ResultsRandom forest modelling allowed us to use bacterial community composition to predict upstream catchment land use with 65% accuracy; urban sites were correctly assigned 90% of the time. Despite the variation inherent when sampling across a ~ 1000-km distance, bacterial community data could correctly differentiate undisturbed sites, grouped by their dominant environmental properties, with 75% accuracy. The positive correlations between actual values and those predicted by the models built using the stream biofilm bacterial data ranged from weak (average log N concentration in the stream water, R2 = 0.02) to strong (annual mean air temperature, R2 = 0.69).ConclusionsFreshwater bacterial community data provide useful insights into land use impacts on stream ecosystems; they may be used as an additional measure to screen stream catchment attributes.

Reproductive phenology and the influence of temperature in two sympatric New Zealand freshwater mussel species

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. Aims We investigated intra- and interspecific reproductive timing variations in sympatric Echyridella aucklandica and E. menziesii, and identified thermal cues (accumulated degree days, ADD) associated with brooding and glochidia maturation. Methods Brooding activity and glochidia maturation were assessed fortnightly–monthly over 1 year within four New Zealand streams. Results The previously unknown phenology of E. aucklandica showed earlier brooding (May–July) and longer gravidity (9–11 months) than for E. menziesii (August; 6–7 months). Both species exhibited peak brooding in late austral spring–summer (November–December). ADD played a key role in regulating the timing of brooding onset in both species, as evidenced by the narrow ADD range observed across sites, and the relationship between ADD and brooding onset in both species. Conclusion The demonstrated link between ADD and reproductive phenology has broad implications in the context of climate change. Specifically, it raises concerns about potential timing mismatches in glochidia release and host-fish availability, which could affect the survival and reproductive success of freshwater mussels.

Growth response to nitrate enrichment helps facilitate success of an alien Potamogeton in New Zealand streams

Motivated by stream ecosystem degradation by eutrophication, we mimicked slow flowing lowland stream conditions with a novel experimental setup to further our understanding of aquatic plant responses to increases in nitrate and light. We conducted a mesocosm growth experiment of two species from the genus Potamogeton: P. crispus (alien) and P. ochreatus (native), grown at four nitrate and four light levels. We hypothesised that (i) internal nutrient status of the plants would scale with water column nutrient concentration, and that (ii) plant performance would reflect the nutrient status of the plant. Furthermore, we hypothesised that (iii) a low irradiance level would negate the effects of an increased nitrate level. In relation to (ii) we hypothesised that (iv) the traits of the alien species would enable it to outperform the native species where both the availability of light and nutrient resources was high. Internal tissue N content was broadly similar in the two higher (>250 μg NO3− L−1) and the two lower nutrient treatments (<20 μg NO3− L−1) in both species and plants were therefore collapsed into high and low N-groups. High-N individuals had higher growth rates than low-N ones regardless of species or light treatment and plants had reduced growth rates at the lowest light treatment, however this response was less evident for P. crispus. The highest growth rate was found at the high-N individuals of P. crispus at the highest light treatment, and correspondingly, in this treatment this species exhibited an increase in branching degree and lateral spread from the low-N plants. As P. crispus spreads by fragmentation, our results show it to be a highly effective competitor in anthropogenically impacted areas compared to its native counterpart. Our study exemplifies how light can influence eutrophication responses of plants and how both need to be accounted for in management decisions.

Substrate size modifies stream grazer-biofilm interactions in the presence of invertivorous fish.

When herbivore abundance is controlled by predators there may be an indirect positive effect on primary producers due to reduced grazing pressure, but the potential of predation refuges to modify such trophic cascades has rarely been studied. By experimentally manipulating substrate particle size and fish predation regime, we assessed the outcome of invertebrate grazer-biofilm interactions in streams. Locations at the center of larger substrate particles were predicted to pose a higher predation risk, and therefore be subjected to a lower grazing pressure. In our 52-day experiment in a New Zealand stream, small-sized substrates (terracotta tiles) remained virtually free of periphyton across their entire upper surface, whereas a thick periphyton mat was formed across large tiles with only edges remaining free. In channels containing fish (either native Galaxias vulgaris or exotic Salmo trutta), grazing on tiles was lower than in the absence of fish. A preference for grazing near to the edge of tiles was clearest in fish channels but was also evident even in the absence of fish, probably reflecting fish presence and/or fish kairomones in the stream from where the colonizing invertebrates had been derived. Total grazer density was similar across treatments with or without fish, suggesting that our results can be explained mostly by changes in the behavior of grazers. We suggest that refuge availability, interacting with grazer predator-avoidance behavior, may produce a context-dependent patchwork of trophic cascades in streams and other ecosystems.

Assessing population genetic structure of three New Zealand stream insects using mitochondrial and nuclear DNA markers.

Assessing genetic differentiation among natural populations can aid understanding of dispersal patterns and connectivity among habitats. Several molecular markers have become increasingly popular in determining population genetic structure for this purpose. Here, we compared the resolution of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear single nucleotide polymorphism (SNP) markers for detecting population structure among stream insects at small spatial scales. Individuals of three endemic taxa-Coloburiscus humeralis (Ephemeroptera), Zelandobius confusus (Plecoptera), and Hydropsyche fimbriata (Trichoptera)-were collected from forested streams that flow across open pasture in the North Island of New Zealand. Both COI and SNP data indicated limited population structure across the study area, and small differences observed among these species were likely related to their putative dispersal abilities. For example, fine-scale genetic differentiation between and among neighbouring stream populations for H. fimbriata suggests that gene flow, and hence dispersal, may be more limited for this species relative to the others. Based on the generally similar results provided by both types of markers, we suggest that either COI or SNP markers can provide suitable initial estimates of fine-scale population genetic differentiation in stream insects.

The influence of pastoral and native forest land cover, flooding disturbance, and stream size on the trophic ecology of New Zealand streams

AbstractDescribing trophic structure within freshwater food webs can be a useful tool for understanding relationships to make ecological inferences and to inform management action. A complementary analysis examining both stable isotope (SI) and biomass community components may be useful, because these two responses may be influenced differently by habitat factors and perturbations (e.g. flooding disturbance). To test this, stable isotope‐derived trophic height and biomass were characterised, as was coarse allochthonous, periphyton, invertebrate and fish components, for 27 stream communities in Canterbury, New Zealand. Using piecewise structural equation modelling to test relationships between components, it was found that increased catchment agricultural land cover was associated with increased periphyton biomass and δ15N (trophic height) in stream invertebrates and invertivorous fishes, likely due to nitrate runoff, but did not affect piscivorous fishes. Additionally, native forest land cover was associated with increased instream allochthonous biomass. Increased discharge (i.e. larger habitat size) did not affect the trophic height or biomass per‐unit‐area of large‐bodied piscivorous fishes (non‐native trout and native eels), although it did result in decreased biomass of small‐bodied invertivorous fishes (primarily native benthic taxa), likely due to high water velocities in larger habitats rendering habitat less suitable for small‐bodied fishes. Finally, flooding disturbance negatively affected both trophic height and biomass of large‐bodied fishes, but did not affect small‐bodied invertivorous fishes. Overall, describing stream trophic structure with complementary SI and biomass structural equation models appears to be a useful approach for constructing an integrative picture of how abiotic and biotic habitat factors affect freshwater communities. Our findings indicate that land cover, stream size and flooding disturbance should be taken into consideration by stream managers when conducting habitat restoration efforts or setting fish harvest regulations.

Delayed Adaptive Radiation among New Zealand Stream Fishes: Joint Estimation of Divergence Time and Trait Evolution in a Newly Delineated Island Species Flock.

Adaptive radiations are generally thought to occur soon after a lineage invades a region offering high levels of ecological opportunity. However, few adaptive radiations beyond a handful of exceptional examples are known, so a comprehensive understanding of their dynamics is still lacking. Here, we present a novel case of an island species flock of freshwater fishes with a radically different tempo of adaptive history than that found in many popular evolutionary model systems. Using a phylogenomic data set combined with simultaneous Bayesian estimation of divergence times and trait-based speciation and extinction models, we show that the New Zealand Gobiomorphus gudgeons comprise a monophyletic assemblage, but surprisingly, the radiation did not fully occupy freshwater habitats and explosively speciate until more than 10 myr after the lineage invaded the islands. This shift in speciation rate was not accompanied by an acceleration in the rate of morphological evolution in the freshwater crown clade relative to the other species, but is correlated with a reduction in head pores and scales as well as an increase in egg size. Our results challenge the notion that clades always rapidly exploit ecological opportunities in the absence of competing lineages. Instead, we demonstrate that adaptive radiation can experience a slow start before undergoing accelerated diversification and that lineage and phenotypic diversification may be uncoupled in young radiations. [Adaptive radiation; Eleotridae; freshwater; Gobiomorphus; New Zealand.]

Broad and Fine Scale Variability in Bacterial Diversity and Cyanotoxin Quotas in Benthic Cyanobacterial Mats.

Benthic proliferations of Microcoleus autumnalis (basionym Phormidium autumnale) and closely related taxa are being reported with increasing frequency in streams and rivers worldwide. This species commonly produces the potent neurotoxin anatoxin, and exposure to this has resulted in animal fatalities and human health concerns. Bacterial communities within cyanobacterial assemblages can facilitate processes such as nutrient cycling and are posited to influence cyanobacterial growth and function. However, there is limited knowledge on spatial variability of bacterial communities associated with benthic cyanobacteria and anatoxin content and quotas. In this study, M. autumnalis-dominated mat samples were collected from six sites in two New Zealand streams. Associated bacterial communities were characterized using 16S rRNA metabarcoding, anatoxin content by liquid chromatography-mass spectrometry and anaC copies using droplet digital PCR. Bacterial assemblages differed significantly when amplicon sequence variants were compared between streams and most sites within streams. These differences were associated with conductivity, DRP, DIN, temperature, anatoxin concentration, and quota. Despite the differences in bacterial community composition; at phyla, class and order levels there was high similarity across spatial scales, with Bacteroidetes (ca. 67%) and Proteobacteria (ca. 25%) dominant. There was significant variability in total anatoxin concentrations between sites in both streams (p < 0.001). When the data were converted to anatoxin quotas variability was reduced, suggesting that the relative abundance of toxic genotypes is a key driver of total anatoxin concentrations in mats. This study demonstrates the complexity of microbial communities within M. autumnalis-dominated mats and highlights their likely important role in within-mat nutrient cycling processes.

Microplastic pollution in urban streams across New Zealand: concentrations, composition and implications

ABSTRACT Microplastic pollution in aquatic systems has been reported globally at an alarming rate, with an increasing number of documented negative biological consequences. Research on microplastic pollution in freshwaters has barely begun in New Zealand, and few studies from smaller lotic systems such as streams exist globally. We investigated the extent of microplastic pollution within urban streams across New Zealand and determined if microplastic concentrations were related to human population density and urbanisation of streams. Fifty-two streams were surveyed across five urban agglomerations in January 2019. Microplastics were found in samples from all sites at densities ranging from <1 to 44 items/m3. This concentration range was comparable to global data but lower than reported in another recent New Zealand study, probably due to differences in sampling methodology. Microplastic pollution was similar across all urban centres, and neither length of urbanised catchment nor urban proportion of the stream were significant predictors of microplastic concentrations. These findings suggest microplastic pollution in New Zealand streams are comparable to larger aquatic systems globally, and that smaller urban streams are significant transport pathways for microplastics. We also recommend standardising microplastic sampling methods to a greater extent in the future, to improve comparability across studies.

Current-use pesticides in New Zealand streams: Comparing results from grab samples and three types of passive samplers

New Zealand uses more than a ton of pesticides each year; many of these are mobile, relatively persistent, and can make their way into waterways. While considerable effort goes into monitoring nutrients in agricultural streams and programs exist to monitor pesticides in groundwater, very little is known about pesticide detection frequencies, concentrations, or their potential impacts in New Zealand streams. We used the ‘Polar Organic Chemical Integrative Sampler’ (POCIS) approach and grab water sampling to survey pesticide concentrations in 36 agricultural streams in Waikato, Canterbury, Otago and Southland during a period of stable stream flows in Austral summer 2017/18. We employed a new approach for calculating site-specific POCIS sampling rates. We also tested two novel passive samplers designed to reduce the effects of hydrodynamic conditions on sampling rates: the ‘Organic-Diffusive Gradients in Thin Films’ (o-DGT) aquatic passive sampler and microporous polyethylene tubes (MPTs) filled with Strata-X sorbent. Multiple pesticides were found at most sites; two or more were detected at 78% of sites, three or more at 69% of sites, and four or more at 39% of sites. Chlorpyrifos concentrations were the highest, with a maximum concentration of 180 ng/L. Concentrations of the other pesticides were generally below 20 ng/L. Mean concentrations of individual pesticides were not correlated with in-stream nutrient concentrations. The majority of pesticides were detected most frequently in POCIS, presumably due to its higher sampling rate and the relatively low concentrations of these pesticides. In contrast, chlorpyrifos was most frequently detected in grab samples. Chlorpyrifos concentrations at two sites were above the 21-day chronic ‘No Observable Effect Concentration’ (NOEC) values for fish and another two sites had concentrations greater than 50% of the NOEC. Otherwise, concentrations were well-below NOEC values, but close to the New Zealand Environmental Exposure Limits in several cases.

Anthropogenic mining alters macroinvertebrate size spectra in streams

Abstract Food web properties can be used in bioassessment as indicators of ecosystem stress, although logistical constraints restrict their widespread use. Size spectra (body mass–abundance relationships) are easier to produce, still incorporate much of the variation in feeding interactions and indicate the strength of the energy transfer efficiency. Here we examined the effect of acid mine drainage on the size spectra of stream macroinvertebrate communities in 25 New Zealand streams with a comparative survey. We predicted that the largest organisms would be most susceptible to acid mine drainage, leading to a reduction in their abundances and associated decrease in the range of body sizes present across the gradient, as well as a reduction in total community abundance. The largest organisms were more sensitive to inputs of acid mine drainage and were absent at the most affected sites. Surprisingly, the smallest body sizes were also removed by acid mine drainage. This led to a reduction of up to two orders of magnitude in the range of body sizes present in mine impacted sites. Total community abundance decreased along the impact gradient. The changes in size spectra were also associated with changes in the proportion of functional feeding groups, suggesting concomitant changes in food web structure. Specifically, communities became dominated by collector browsers and small bodied predators across the gradient. The simplification of the food web structure suggests that communities may be dominated by a few strong energy pathways, lowering their functionality and stability. However, the loss of large bodied predators also reduces top down pressure, probably increasing community stability. Further research is needed to elucidate the cumulative effects of these interacting processes.

Evaluation of a traditional Māori harvesting method for sampling kōura (freshwater crayfish, Paranephrops planifrons) and toi toi (bully, Gobiomorphus spp.) populations in two New Zealand streams

ABSTRACT Representative sampling of crayfish in streams is often impractical, especially in non-wadable habitats, or in areas with soft substrates. Whakaweku are artificial habitats made from bracken fern (Pteridium esculentum) that can be used successfully in a range of habitats. We compared whakaweku, minnow traps, fyke nets and electrofishing for sampling freshwater crayfish (kōura; Paranephrops planifrons) and bullies (toi toi; Gobiomorphus spp.) in two streams with differing stream characteristics and fish assemblages. Whakaweku captured a full-size range of kōura of both sexes, including small kōura (OCL 7–12 mm) that were not caught by minnow traps or fyke nets. Colonisation by kōura reached 90% of maximum after 2 weeks and CPUE was constant from 2 to 9 weeks. After 9 weeks, CPUE decreased due to decay of the fern fronds. Whakaweku are an effective sampling tool that are inexpensive, simple to set, and do not require expensive equipment or specialised training.

Do latitudinal gradients exist in New Zealand stream invertebrate metacommunities?

That biodiversity declines with latitude is well known, but whether a metacommunity process is behind this gradient has received limited attention. We tested the hypothesis that dispersal limitation is progressively replaced by mass effects with increasing latitude, along with a series of related hypotheses. We explored these hypotheses by examining metacommunity structure in stream invertebrate metacommunities spanning the length of New Zealand’s two largest islands (∼1,300 km), further disentangling the role of dispersal by deconstructing assemblages into strong and weak dispersers. Given the highly dynamic nature of New Zealand streams, our alternative hypothesis was that these systems are so unpredictable (at different stages of post-flood succession) that metacommunity structure is highly context dependent from region to region. We rejected our primary hypotheses, pinning this lack of fit on the strong unpredictability of New Zealand’s dynamic stream ecosystems and fauna that has evolved to cope with these conditions. While local community structure turned over along this latitudinal gradient, metacommunity structure was highly context dependent and dispersal traits did not elucidate patterns. Moreover, the emergent metacommunity types exhibited no trends, nor did the important environmental variables. These results provide a cautionary tale for examining singular metacommunities. The considerable level of unexplained contingency suggests that any inferences drawn from one-off snapshot sampling may be misleading and further points to the need for more studies on temporal dynamics of metacommunity processes.

The effect of forest canopy and flood disturbance on New Zealand stream food web structure and robustness

AbstractThe effects of disturbance on communities have been a focus of both theoretical and empirical inquiries for many years. Food web stability is hypothesized to be affected by disturbance and the nature of the energy pathways (i.e. allochthonous or autochthonous) of a community. In this study, we investigated whether food webs at paired sites, one in forest and the other in grassland, in ten New Zealand streams along a disturbance gradient differ in their topological structure and robustness. Food web robustness (an indicator of web resistance) assesses the ease with which secondary extinctions permeate the food web following an initial random extinction (disturbance). We found that neither the nature of the energy source nor physical disturbance affected structural metrics or web robustness. As stream systems, particularly in New Zealand, are exposed to regular, unpredictable and dramatic physical disturbance from flooding, it may simply be that the floods result in generalist species dominating and increasing robustness irrespective of the energy source.

Stream Ecological Valuation: revisions to the method for assessing the ecological functions of New Zealand streams

ABSTRACTThe Stream Ecological Valuation (SEV) provides water resource managers with a standardised measure of the ecological functions of a stream reach. Reaches are assessed in terms of their hydrological, biogeochemical, habitat and biological functions. SEV has been widely used for resource consent applications and monitoring in the Auckland region since 2006. End-user feedback, expert review, an accumulated database of SEV data and advances in the underlying science of stream functions prompted a review of the method in 2010. The revised SEV is simpler than the original, and based on slightly fewer functions and variables. Definitions of terms and field methods have been clarified, improving interpretability and reducing subjectivity and field time. In a field test of 19 sites, the revised SEV showed a similar mean (0.68 compared to 0.64) but greater range (0.77 compared to 0.40) of scores than the original, indicating little or no information loss but improved ability to discriminate between pristine and degraded streams.

Rotenone treatment has a short-term effect on New Zealand stream macroinvertebrate communities

ABSTRACTInvasive fish eradication is a key management strategy in aquatic ecosystems, and is often accomplished using piscicides such as rotenone. However, the effects of piscicides on aquatic invertebrate communities are poorly understood, particularly over long time scales. We monitored invertebrate communities in two treatment and two reference streams prior to and for one year following the use of rotenone to eradicate trout in Zealandia wildlife sanctuary, Wellington. Immediately following treatment, invertebrate density and taxonomic richness declined significantly, and community composition diverged markedly relative to reference streams, with pollution sensitive taxa declining greater than more tolerant taxa. Treatment streams recovered to pre-treatment conditions within 4–12 months of rotenone application, indicating minor long-term impacts on invertebrate communities. Speed of recovery of individual taxa appeared to be associated with life history variables, e.g. generation times and dispersal ability. Untreated upstream reaches and nearby water bodies likely facilitated successful invertebrate community recovery. Our results demonstrate that rapid recovery of New Zealand stream invertebrate communities is possible within one year of rotenone application.

Community-based monitoring of New Zealand stream macroinvertebrates: agreement between volunteer and professional assessments and performance of volunteer indices

ABSTRACTCommunity-based monitoring of freshwaters (a form of citizen science) is an area of growing interest globally. It could be used to augment professional monitoring in New Zealand, as is done in other countries, if the agreement between volunteer and professional assessments is close enough. We compared volunteer benthic macroinvertebrate data with professional data from parallel monitoring over 18 months at 8 sites across New Zealand. We found strong correlations (r=0.77–0.85) and little bias between volunteer data using volunteer indices and professional data using a professional index. Volunteer classifications in stream ‘quality classes' agreed with professional classifications in 70–85% of cases. Two volunteer-level biotic indices showed slightly different correlation and bias with respect to the professional biotic index. A modified volunteer index could blend the strengths of each. Presence-absence indices correlated as well as, or better than, their quantitative versions. We conclude that, given suitable training and support, volunteer assessments of stream ecological condition agree well with, and are only slightly more variable than, professional assessments.

Acute toxicity of arsenic to larvae of four New Zealand freshwater insect taxa

ABSTRACTArsenic, often found in gold deposits, can enter aquatic systems. The toxicity of arsenate (As(V)), the most common valence state of arsenic in freshwater, was assessed on the larvae of four freshwater insect taxa from naturally acidic (pH 5.9) and circumneutral (pH 7.4) New Zealand streams. Insects from the acidic stream were more sensitive to arsenate-spiked water than those from the circumneutral stream. Early instars (<3 mm) of the mayfly Deleatidium spp. (Leptophlebiidae) were the most sensitive compared to later instars (3–6 mm) (4-d LC50 1.5 and 3.5 mg/L, respectively) or to the stonefly Zelandobius spp. (Gripopterygidae) (4-d LC50 2.5 mg/L). The cased caddisflies Pycnocentria spp. (Conoesucidae) and Helicopsyche spp. (Helicopsychidae) from circumneutral stream were the most tolerant (4-d LC50 45.4 and 113 mg/L, respectively). The 14-day arsenic LC10 and LC50 for Deleatidium spp. late instars exposed to mining-impacted water were 0.12 and 0.36 mg/L, respectively.

Preservatives and sample preparation in stable isotope analysis of New Zealand freshwater invertebrates

ABSTRACTInterpretation of stable isotope data needs to take into account known, but often variable and inconsistent, influences of preservatives and lipids on carbon and nitrogen isotopic values. We tested how short-term (<6 months) preservation (ethanol and freezing) and preparation (lipid extraction) methods influence δ13C and δ15N values of 10 common New Zealand stream invertebrates and assessed whether mathematical lipid corrections (derived overseas) are valid here. The different methods significantly affected δ13C but not δ15N values. Specifically, ethanol-preserved and lipid-extracted samples were enriched in δ13C (by 1–2 ‰) relative to frozen samples. Short-term storage in ethanol (70%) was comparable to lipid removal and similar δ13C values were obtained when frozen samples were corrected mathematically. In contrast, δ15N values differed <0.1‰ across treatments. Together, this suggests that: (i) lipid extraction or mathematical correction may be unnecessary for ethanol-preserved samples, as ethanol appears to behave as a lipid solvent; (ii) existing mathematical corrections can adequately adjust for lipid-related shifts in δ13C in frozen samples; and (iii) δ15N values lend similar insight regardless of preservation/preparation methods. Although these results support the notion that archived (ethanol-preserved) invertebrate samples can inform isotope studies, additional work is needed to determine storage durations to which our findings apply.

Riparian management: A restoration tool for New Zealand streams

SummaryMany New Zealanders are planning and implementing riparian management, and riparian fencing and planting are now standard best practice tools for water quality and habitat restoration. New Zealand has a long history of action, with the first catchment riparian schemes and science dating back to the 1970s. As a result of this, there is now solid scientific evidence that demonstrates the value of a range of management actions including the following: riparian zones and buffers for livestock exclusion (fencing with or without planting), nutrient processing, shading small streams for temperature control, providing leaf and wood input to stream ecosystems, and enhancing fish and invertebrate habitat. In the last decade or so, on‐ground action has accelerated significantly with the introduction of dairy industry and government agreed targets. In 2015, 96% of dairy cows had been excluded from waterways &gt;1 m wide and &gt;30 cm deep on land that cows graze during the milking season providing impetus for on‐ground action to spread into other pastoral industries. Tools for planning, managing and implementing successful riparian restoration have proliferated, informed by on‐ground successes and failures. Despite this, there remain challenges for individuals or communities planning riparian restoration. Careful case‐by‐case assessment is recommended to ensure that plans match design to local landscape constraints and can realistically contribute to improved water quality or habitat outcomes.