John D Reynolds

John D Reynolds
Simon Fraser University · Department of Biological Sciences

@SalmonEco

About

277
Publications
155,671
Reads
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21,198
Citations
Additional affiliations
August 2005 - present
Simon Fraser University
February 1993 - July 2005
University of East Anglia
January 1991 - February 1993
University of Oxford
Position
  • Postdoctoral Fellowship

Publications

Publications (277)
Article
Full-text available
Although marine subsidies often enrich terrestrial ecosystems, their influence is known to be context-dependent. Additionally, the multitrophic impact of marine subsidies has not been traced through food webs across physically diverse islands. Here, we test predictions about how island characteristics can affect marine enrichment of food web consti...
Article
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Pacific salmon (Oncorhynchus spp.) support coastal and freshwater ecosystems, economies and cultures, but many populations have declined. We used priority threat management (PTM), a decision‐support framework for prioritizing conservation investments, to identify management strategies that could support thriving populations of wild salmon over 25 y...
Article
Full-text available
In their native range, Pacific salmon (Oncorhynchus spp.) have strong interactions with a multitude of species due to the annual pulse of marine‐derived nutrients that they deliver to streams and forests when they spawn and die. Over the past few decades, Chinook salmon (Oncorhynchus tshawytscha) has established non‐native populations throughout th...
Article
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Marine‐derived resource subsidies can generate intrapopulation variation in the behaviors and diets of terrestrial consumers. How omnivores respond, given their multiple trophic interactions, is not well understood. We sampled mice (Peromyscus keeni) and their food sources at five sites on three islands of the Central Coast of British Columbia, Can...
Article
Full-text available
Pacific salmon (Oncorhynchus spp.) carcasses can fertilize riparian forests with marine-derived nutrients when populations make their annual return to natal streams to spawn; however, the strength of this cross-system linkage likely varies substantially among years due to the interannual fluctuations in abundance that characterize most salmon popul...
Article
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Abstract When Pacific salmon (Oncorhynchus spp.) spawn and die, they deliver marine‐derived nutrient subsidies to freshwater and riparian ecosystems. These subsidies can alter the behavior, productivity, and abundance of recipient species and their habitats. Isotopes, such as nitrogen‐15 (15N), are often used to trace the destination of marine‐deri...
Article
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The annual migration and spawning event of Pacific salmon ( Oncorhynchus spp.) can lead to cross-boundary delivery of marine-derived nutrients from their carcasses into adjacent terrestrial ecosystems. The densities of some passerine species, including Pacific wrens ( Troglodytes pacificus ), have been shown to be positively correlated with salmon...
Article
The cover image is based on the Original Article Non‐native Chinook salmon add nutrient subsidies and functional novelty to Patagonian streams, by Nicolas J. Muñoz et al., https://doi.org/10.1111/fwb.13655.
Article
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Population and life‐history diversity can buffer species from environmental variability and contribute to long‐term stability through differing responses to varying conditions akin to the stabilizing effect of asset diversity on financial portfolios. While it is well known that many salmon populations have declined in abundance over the last centur...
Article
The ectoparasitic copepods, sea lice (Lepeophtheirus salmonis and Caligus spp.), are major pests to salmon aquaculture and can also affect the health and survival of wild salmon. Policies exist to protect wild salmon by delousing farmed fish when louse abundance exceeds a threshold, but their effectiveness under future climate change is uncertain....
Article
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Annual spawning migrations by Pacific salmon can provide substantial subsidies to nutrient‐limited freshwater and riparian ecosystems, which can affect the abundance, diversity, and physical characteristics of plant and animal species in these habitats. Here, we provide the first investigation of how salmon subsidies affect reproductive output in p...
Article
1. The impacts of non-native species are hypothesised to be proportional to the functional distinctiveness of invaders in their invaded ecosystems. Throughout the Patagonia region of southern South America, Chinook salmon (Oncorhynchus tshawytscha) have recently established non-native populations, and their anadromous, semelparous life cycle could...
Article
Many industries are required to monitor themselves in meeting regulatory policies intended to protect the environment. Self-reporting of environmental performance can place the cost of monitoring on companies rather than tax-payers, but there are obvious risks of bias, often addressed through external audits or inspections. Surprisingly, there have...
Article
Full-text available
Current investment in conservation is insufficient to adequately protect and recover all ecosystems and species. The challenge of allocating limited funds is acute for Pacific salmon Oncorhynchus spp. in Canada, which lack a strategic approach to ensure that resources are spent on actions most likely to cost‐effectively recover diminished populatio...
Article
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Pacific salmon influence temperate terrestrial and freshwater ecosystems through the dispersal of marine-derived nutrients and ecosystem engineering of stream beds when spawning. They also support large fisheries, particularly along the west coast of North America. We provide a comprehensive synthesis of relationships between the densities of Pacif...
Article
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Having the longest coastlines in the world and some of the largest freshwater ecosystems, Canada has a rich history of exploitation and stewardship of its marine and freshwater fisheries resources. For thousands of years prior to European settlement, Indigenous peoples across what is now Canada utilized and managed marine and freshwater fisheries t...
Article
Full-text available
The classical theory of island biogeography, which predicts species richness using island area and isolation, has been expanded to include contributions from marine subsidies, i.e. subsidized island biogeography (SIB) theory. We tested the effects of marine subsidies on species diversity and population density on productive temperate islands, evalu...
Preprint
Current investment in conservation is insufficient to adequately protect and recover all ecosystems and species. The challenge of allocating limited funds is acute for Pacific salmon ( Oncorhynchus spp.) in Canada, which lack a strategic approach to ensure that resources are spent on actions that would cost-effectively recover diminished population...
Article
Full-text available
Conservation scientists rarely have the information required to understand changes in abundance over more than a few decades, even for important species like Pacific salmon. Such lack of historical information can underestimate the magnitude of decline for depressed populations. We applied genetic tools to a unique collection of 100‐year‐old salmon...
Article
Full-text available
The disproportionate effects of some species can drive ecosystem processes and shape communities. This study investigates how distributions of spawning Pacific salmon within streams, salmon consumers, and the surrounding landscape mediate the distribution of salmon carcasses to riparian forests and estuaries. This work demonstrates how carcass tran...
Article
Full-text available
British Columbia has the greatest biological diversity of any province or territory in Canada. Yet increasing numbers of species in British Columbia are threatened with extinction. The current patchwork of provincial laws and regulations has not effectively prevented species declines. Recently, the Provincial Government has committed to enacting an...
Technical Report
Full-text available
British Columbia has the greatest biological diversity of any province or territory in Canada. Yet more and more species in British Columbia are threatened with extinction and require active measures for protection and recovery. The current patchwork of provincial laws and regulations managing wildlife and their habitats has not effectively prevent...
Article
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Mawdsley et al. (2018) respond disapprovingly to our 2018 review of 667 wildlife management systems across Canada and the United States, which found that many of these systems lacked the scientific hallmarks of clear objectives, evidence, transparency, and independent review. Although we strongly agree with several of Mawdsley et al.’s points about...
Article
Macroalgae and seagrasses form the base of productive ecosystems in the Northeastern Pacific Ocean. Often, ecological research on macroalgae, seagrasses, and sea wrack requires the conversion of biomass from wet to dry to create consistency across investigations. This process, however, can be destructive, impractical, time consuming, and labour int...
Article
Full-text available
Key life‐cycle transitions, such as metamorphosis or migration, can be altered by a variety of external factors, such as climate variation, strong species interactions, and management intervention, or modulated by density dependence. Given that these life‐history transitions can influence population dynamics, understanding the simultaneous effects...
Article
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Sensitivity to overfishing is often estimated using simple models that depend upon life history parameters, especially for species lacking detailed biological information. Yet, there has been little exploration of how uncertainty in life history parameters can influence demographic parameter estimates and therefore fisheries management options. We...
Article
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Resource management agencies commonly defend controversial policy by claiming adherence to science-based approaches. For example, proponents and practitioners of the “North American Model of Wildlife Conservation,” which guides hunting policy across much of the United States and Canada, assert that science plays a central role in shaping policy. Ho...
Article
Foraging success can be mediated by parasites, but this is poorly understood for marine fish whose aggregations and patchy prey fields create conditions for intense intraspecific competition. We evaluated whether sea louse infection is associated with decreased stomach fullness of wild juvenile sockeye salmon (Oncorhynchus nerka) in Johnstone Strai...
Article
Canada’s Policy for Conservation of Wild Pacific Salmon has been heralded as a transformative approach to the management of wild salmon whereby conservation is the highest priority. Given that changes to the Policy are under consideration, it is timely that we understand whether our state of knowledge and the status of wild salmon in Canada have in...
Article
Full-text available
Effective management of fisheries depends on the selectivity of different fishing methods, control of fishing effort and the life history and mating system of the target species. For sex-changing species, it is unclear how the truncation of age-structure or selection of specific size or age classes (by fishing for specific markets) affects populati...
Preprint
Full-text available
Effective management of fisheries depends on the selectivity of different fishing methods, control of fishing effort, and the life history and mating system of the target species. For sex-changing species, it is unclear how the truncation of age structure or selection of specific size or age classes (by fishing for specific markets) affects populat...
Article
Full-text available
Body size can sometimes change rapidly as an evolutionary response to selection or as a phenotypic response to changes in environmental conditions. Here, we revisit a classic case of rapid change in body size of five species of Pacific salmon (Oncorhynchus spp.) caught in Canadian waters, with a six-decade analysis (1951–2012). Declines in size at...
Article
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Large male body size is typically favored by directional sexual selection through competition for mates. However, alternative male life-history phenotypes, such as "sneakers," should decrease the strength of sexual selection acting on body size of large "fighter" males. We tested this prediction with salmon species; in southern populations, where s...
Article
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The maximum intrinsic rate of population increase (rmax) is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, rmax can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output (b) instead. This is problematic as it effectively as...
Preprint
Full-text available
The maximum intrinsic rate of population increase r max is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, r max can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output b instead. This is problematic as it effectively assu...
Article
Full-text available
Species' life history traits, including maturation age, number of reproductive bouts, offspring size and number, reflect adaptations to diverse biotic and abiotic selection pressures. A striking example of divergent life histories is the evolution of either iteroparity (breeding multiple times) or semelparity (breed once and die). We analysed publi...
Article
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Human-wildlife conflicts impose considerable costs to people and wildlife worldwide. Most research focuses on proximate causes, offering limited generalizable understanding of ultimate drivers. We tested three competing hypotheses (problem individuals, regional population saturation, limited food supply) that relate to underlying processes of human...
Article
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Sustainably managing marine species is crucial for the future health of the human population. Yet there are diverse perspectives concerning which species can be exploited sustainably, and how best to do so. Motivated by recent debates in the published literature over marine conservation challenges, we review ten principles connecting life-history t...
Data
Appendix S2. Calculation of reference points in an age‐ and size‐structured population. Table S2.1. Description of the age‐structured model in the Box 1 Figure and Figure 2, including the biological processes modeled, corresponding equations, and parameter interpretations. Table S2.2. Life history parameters for the analyses in Fig. 2 (main text)...
Data
Appendix S3. Calculating reproductive value. Table S3.1. Data used to calculate relative fitness of each age in Box 2. Fig. S3.1. In (a) we plot V(a) over age using Eq. S3.1 and estimates of age‐specific mortality, maturity and length.
Data
Appendix S1. Classic models of population dynamics in ecology and fisheries science.
Article
Organisms transporting nutrients from highly productive ecosystems can subsidize food webs and alter ecosystem processes. For example, the carcasses and eggs of migratory Pacific salmon (Oncorhynchus spp.) provide a high-quality food source that could potentially benefit other species of salmon rearing in fresh water. We investigated relationships...
Article
A signature of nonrandom phylogenetic community structure has been interpreted as indicating community assembly processes. Significant clustering within the phylogenetic structure of a community can be caused by habitat filtering due to low nutrient availability. Nutrient limitation in temperate Pacific coastal rainforests can be alleviated to some...
Article
Full-text available
Water temperature is a key driver of aquatic processes. Monitoring stream water temperature is key to understanding current species distributions and future climate change impacts on freshwater ecosystems. However, a very small fraction of streams are continuously monitored for water temperature throughout North America, due to prohibitive logis-ti...
Article
Full-text available
Movement of nutrients across ecosystem boundaries can have important effects on food webs and population dynamics. An example from the North Pacific Rim is the connection between productive marine ecosystems and freshwaters driven by annual spawning migrations of Pacific salmon (Oncorhynchus spp). While a growing body of research has highlighted th...
Article
Full-text available
Recognizing the mechanisms by which environmental conditions drive population dynamics can greatly benefit conservation and management. For example, reductions in densities of spawning Pacific salmon (Oncorhynchus spp.) have received considerable attention, but the role of habitat characteristics on population sizes of breeding salmon is not fully...
Article
Full-text available
Estuaries are amongst the world's most productive ecosystems, lying at the intersection between terrestrial and marine environments. They receive substantial inputs from adjacent landscapes but the importance of resource subsidies is not well understood. Here, we test hypotheses for the effects of both terrestrial- and salmon-derived resource subsi...
Article
Pathogens threaten wildlife globally, but these impacts are not restricted to direct mortality from disease. For fish, which experience periods of extremely high mortality during their early life history, infections may primarily influence population dynamics and conservation through indirect effects on ecological processes such as competition and...
Article
Full-text available
Resource flows and disturbance from species migrations can alter the productivity, structure and function of an ecosystem. Annual mass migrations of Pacific salmon (Oncorhynchus spp.) to coastal watersheds import vast quantities of potentially limiting nutrients that have been shown to increase primary and secondary productivity in streams and lake...
Conference Paper
The conservation status of Canada’s 193 native freshwater fish species has been assessed using a variety of methods. COSEWIC has assessed over 100 species, of which 54 species were listed at the level of Special Concern or higher. Of these 54 species, 39 have been subsequently listed under the federal Species at Risk Act. In 2008, the AFS Conservat...
Article
Full-text available
Riverine connectivity is important to the persistence of fish communities, but culverts may impede fish movements to varying degrees and in both directions. Baffles can be installed in culverts to mitigate upstream connectivity loss; however, evaluation of their effectiveness is limited. To examine the potential impacts of culverts and their potent...
Article
Full-text available
Understanding linkages among life history traits, the environment, and population dynamics is a central goal in ecology. We compared 15 populations of sockeye salmon (Oncorhynchus nerka) to test general hypotheses for the relative importance of life history traits and environmental conditions in explaining variation in population dynamics. We used...
Article
Full-text available
Pacific salmon (Oncorhynchus spp.) can subsidize freshwater food webs with marine-derived nutrients from their eggs, juveniles, and carcasses. However, trophic interactions between spawning salmon and freshwater fish across natural gradients in salmon subsidies remain unclear. We tested how salmon affected the diets and condition of two dominant fr...
Article
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In this article we consider the current educational needs for science and policy in marine resource management, and we propose a way to address them. The existing literature on cross-disciplinary education in response to pressing environmental problems is vast, particularly in conservation biology. However, actual changes in doctoral-level marine s...
Article
Full-text available
Cross-boundary nutrient inputs can enhance and sustain populations of organisms in nutrient-poor recipient ecosystems. For example, Pacific salmon (Oncorhynchus spp.) can deliver large amounts of marine-derived nutrients to freshwater ecosystems through their eggs, excretion, or carcasses. This has led to the question of whether nutrients from one...
Article
Full-text available
Freshwater ecosystems and the fisheries they support are increasingly threatened by human activities. To aid in their management and protection, we outline nine key principles for supporting healthy and productive ecosystems based on the best available science, including laws of physics and chemistry apply to ecology; population dynamics are regula...
Article
Full-text available
Externally derived resources often contribute to the structuring of ecological communities. Estuaries are one of the most productive ecosystems in the world and provide an ideal system to test how communities may be shaped by resource subsidies because they occur at the intersection of marine, freshwater and terrestrial habitats. Here we tested the...
Article
Full-text available
In December 2013, the provincial government of British Columbia, Canada, approved the expansion of a controversial trophy hunt of at-risk grizzly bears. This decision raises doubts about the rigor of wildlife management and government policy in the region.
Article
Nutrient subsidies and physical disturbance from migrating species can have strong impacts on primary producers. In the north Pacific, adult salmon (Oncorhynchus spp.) transport marine-derived nutrients back to freshwater streams and can also significantly disrupt the substratum during spawning events. We tested for effects of spawning pink (O. gor...
Article
Full-text available
A general rule in ecology is that the abundance of species or individuals in communities sharing a common energy source decreases with increasing body size. However, external energy inputs in the form of resource subsidies can modify this size spectrum relationship. Here, we provide the first test of how a marine resource subsidy can affect size sp...