Julian D. Olden

Julian D. Olden
University of Washington Seattle | UW · School of Aquatic and Fisheries Sciences

M. Sc., Ph. D.

About

430
Publications
243,670
Reads
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39,285
Citations
Citations since 2016
192 Research Items
25564 Citations
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Introduction
Julian Olden is a Professor in the School of Aquatic and Fishery Sciences at the University of Washington whose research explores the ecology and conservation of freshwater ecosystems. Twitter: @oldenfish
Additional affiliations
September 2008 - present
Griffith University
Position
  • Adjunct Research Scientist
September 2006 - September 2011
University of Washington Seattle
Position
  • Professor (Assistant)
September 2004 - September 2006
University of Wisconsin–Madison
Position
  • PostDoc Position
Education
September 2002 - September 2006
Colorado State University
Field of study
  • Ecology
September 2000 - September 2002
University of Toronto
Field of study
  • Zoology

Publications

Publications (430)
Article
Intermittent and ephemeral streams in dryland environments support diverse assemblages of aquatic and terrestrial life. Understanding when and where water flows provide insights into the availability of water, its response to external controlling factors, and potential sensitivity to climate change and a host of human activities. Knowledge regardin...
Article
While decision-making can benefit from considering positive and negative outcomes of change, over the past half-century, research on non-native species has focused predominately on their negative impacts. Here we provide a framework for considering the positive consequences of non-native species relative to relational, instrumental, and intrinsic v...
Article
Full-text available
Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many case...
Article
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Littoral zones − referring to benthic areas above the light compensation depth − provide numerous ecosystem functions, including mediating light, temperature, and nutrient dynamics, and supporting important foraging and refuge areas for macroinvertebrates, fishes and water birds. Habitat assessments of littoral zones remain fundamental to lake and...
Article
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Knowing where and when rivers flow is paramount to managing freshwater ecosystems. Yet stream gauging stations are dis- tributed sparsely across rivers globally and may not capture the diversity of fluvial network properties and anthropogenic influences. Here we evaluate the placement bias of a global stream gauge dataset on its representation of s...
Article
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Trait‐based models of ecological communities and ecosystem functioning often fail to account for intraspecific variation in functional traits, assuming that intraspecific variability is negligible compared with interspecific variability. However, this assumption remains poorly tested across vertebrate animals where past studies routinely describe s...
Article
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Dams and diversions are a primary threat to freshwater fish biodiversity, including the loss of species and restructuring of communities, often resulting in taxonomic homogenization (increased similarity) over time. Mitigating these impacts requires a strong scientific understanding of both patterns and drivers of fish diversity. Here, we test whet...
Article
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Unselective fishing involves activities that target the entire assemblage rather than specific fish species, size classes, or trophic levels. This common fishing approach has been in practice for decades in inland waters in China but its implications for biodiversity remain unclear. We addressed this issue by studying fish assemblages in freshwater...
Preprint
The temporal stability of ecological properties increases with spatial scale and levels of biological organization, but how does it propagate across trophic levels? We compiled 35 metacommunity time-series datasets spanning basal resources (e.g., phytoplankton) to top predators (e.g., piscivorous fish) from 384 freshwater sites across three contine...
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How scientists communicate can influence public viewpoints on invasive species. In the scientific literature , some invasion biologists adopt neutral language, while others use more loaded language, for example by emphasizing the devastating impacts of invasive species and outlining consequences for policy and practice. An evaluation of the use of...
Article
Capturing the ecological effects of climate-induced shifts in hydrologic and thermal regimes in regulated river systems remains a challenge in regional-scale studies. In this study, we used a well-established species distribution model to analyze the results of a process-based hydrologic modeling approach that accounts explicitly for regulation imp...
Article
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Freshwater ecosystems are facing a deepening biodiversity crisis. Developing robust indicators to assess ecological integrity across large spatial scales and identifying the specific threats and pathways of impairment are thus critically needed if we are to inform freshwater conservation strategies. Here we present the first comprehensive threat as...
Article
Every year, field excursions engage students of ecology in experiential learning that results in wide‐ranging and well‐documented pedagogical benefits. Much less appreciated, however, is the potential for these excursions to contribute long‐term data that advance scientific knowledge and natural resource management. Here we explore this potential b...
Article
The Olympic mudminnow (Novumbra hubbsi) is a small freshwater fish, endemic to western Washington State. Although the species is listed as a Washington sensitive species, the lack of routine monitoring has resulted in poor understanding of population dynamics over time needed to support management and conservation actions. Olympic mudminnow commonl...
Article
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Altering the natural flow regime, an essential component of healthy fluvial systems, through hydropower operations has the potential to negatively impact freshwater fish populations. Establishing improved management of flow regimes requires better understanding of how fish respond to altered flow components, such as flow magnitude. Based on the res...
Article
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Efficient management of invasive species benefits from understanding patterns of persistence and change over time. In this study, we compare distribution and abundance of the invasive macrophyte parrotfeather (Myriophyllum aquaticum) in an unregulated river system between the time near its presumed introduction and 20 years later. Initial surveys w...
Article
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Understanding the effects of hydrology on fish populations is essential to managing for native fish conservation. However, despite decades of research illustrating streamflow influences on fish habitat, reproduction, and survival, biologists remain challenged when tasked with predicting how fish populations will respond to changes in flow regimes....
Article
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Headwater streams are critical for freshwater ecosystems. Global and continental studies consistently show major dams as dominant sources of hydrological stress threatening biodiversity in the world’s major rivers, but cumulative impacts from small artificial impoundments (SAIs) concentrated in headwater streams have rarely been acknowledged. Using...
Preprint
Headwater streams are critical for freshwater ecosystems. Global and continental studies consistently show major dams as dominant sources of hydrological stress threatening biodiversity in the world’s major rivers, but cumulative impacts from small artificial impoundments concentrated in headwater streams have rarely been acknowledged. Using the Mu...
Article
• Olympic mudminnow (Novumbra hubbsi) is the only endemic freshwater fish species in Washington State and is limited to south-western and northern coastal wetlands there. Population decline has led to its listing as state ‘Sensitive’, while recent genetic analysis has identified north coast populations as a sub-group of potential concern because of...
Article
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ContextUntangling relationships between landscape patterns shaped by human stressors and related response of fish communities is important for identifying biodiversity patterns and conservation targets, yet in large rivers this knowledge is extremely limited.Objectives Our study focuses on how human stressors within a riparian landscape zone, inclu...
Article
Growing ecological and economic impacts of invasive species have heightened the need for new science to inform management that prevents and counteracts their impacts. A persistent challenge is to identify whether removal programs, which range widely in their approach, are successful. Given the variability in dynamic environmental conditions and com...
Article
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Abstract Management strategies to address the challenges associated with invasive species are critical for effective conservation. An increasing variety of mathematical models offer insight into invasive populations, and can help managers identify cost effective prevention, control, and eradication actions. Despite this, as model complexity grows,...
Article
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Adaptive capacity (AC)—the ability of a species to cope with or accommodate climate change—is a critical determinant of species vulnerability, along with exposure and sensitivity. Using information on species’ adaptive capacity in conservation planning is critical for ensuring successful outcomes. Here, we make connections between a list of species...
Article
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Mining activities have significantly affected the Neotropical freshwater ichthyofauna, the most diverse in the world. However, no study has systematized knowledge on the subject. In this review, we assembled information on the main impacts of mining of crude oil, gold, iron, copper, and bauxite on aquatic ecosystems, emphasizing Neotropical freshwa...
Article
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Climate change is a global persistent threat to fish and fish habitats throughout North America. Climate‐induced modification of environmental regimes, including changes in streamflow, water temperature, salinity, storm surges, and habitat connectivity can change fish physiology, disrupt spawning cues, cause fish extinctions and invasions, and alte...
Article
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Non-perennial streams are widespread, critical to ecosystems and society, and the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based on long-term averages, generally using annually aggregated data to characterize a highly variable process. As a result, it is not well understood if, how, or why the hy...
Article
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• Freshwater biodiversity is declining at an unprecedented rate. Freshwater conservationists and environmental managers have enough evidence to demonstrate that action must not be delayed but have insufficient evidence to identify those actions that will be most effective in reversing the current trend. • Here, the focus is on identifying essential...
Article
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Significance Understanding the mechanisms by which biological communities are reorganized by environmental change is a key question facing ecologists. Using a global database of fish abundance time series spanning recent decades, together with community-level indices describing species temperature and flow affinities, we show that two important asp...
Article
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Abstract Resource managers face mounting challenges when it comes to the implementation of climate change adaptation strategies. Novel adaptation strategies, such as managed relocation, frequently entail embracing substantial risk of unintended harm to the focal ecosystems, in an effort to alleviate serious threats to biological diversity (e.g. ext...
Article
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The ornamental aquarium pet trade is a leading pathway for the introduction of aquatic invasive species. In addition to purchasing live organisms in stores, hobbyists are engaging more with alternative informal online marketplaces that enable peer-to-peer selling of aquarium organisms via auctions. Although growing in popularity, little is known re...
Article
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Small hydropower plants (SHPs) are proliferating globally, but their cumulative threat to blocking migratory fish and the fisheries that these fish sustain has been underappreciated when compared with large hydropower plants (LHPs). Here, we quantified the trade-offs between hydroelectric generation capacity and the impacts on river connectivity fo...
Article
Overcoming challenges of water scarcity necessitates creative flow management approaches that account for multiple, potentially competing water needs of plants and animals in river ecosystems. Mechanistic multispecies models can guide decision making by evaluating trade‐offs associated with flow regimes designed for specific ecosystem outcomes befo...
Article
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Dendritic habitats, such as river ecosystems, promote the persistence of species by favouring spatial asynchronous dynamics among branches. Yet, our understanding of how network topology influences metapopulation synchrony in these ecosystems remains limited. Here, we introduce the concept of fluvial synchrogram to formulate and test expectations r...
Technical Report
Full-text available
Nota técnica: A crescente expansão das hidrelétricas na Amazônia representa uma das principais ameaças à rica biodiversidade e aos modos de vida de populações humanas na região, tanto em áreas urbanas como rurais. Grandes obras, como por exemplo as usinas de Santo Antônio e Jirau, em Rondônia, ou Belo Monte, no Pará, já se impuseram na paisagem dos...
Article
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Executive Summary Changing climate and introduced species are placing an increasing number of species at risk of extinction. Increasing extinction risk is increasing calls to protect species by relocating, or translocating, them to locations with more favorable biotic or climatic conditions. Managed relocation, or assisted migration, of species ent...
Article
• In 1949, Aldo Leopold formalized the concept of the ‘land ethic’, in what emerged as a foundational and transformational way of thinking about natural resource management, biodiversity conservation, and stewardship in terrestrial systems. Yet, the land ethic has inherent linkages to aquatic ecosystems; Leopold himself conducted research on rivers...
Article
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Over half of global rivers and streams lack perennial flow, and understanding the distribution and drivers of their flow regimes is critical for understanding their hydrologic, biogeochemical, and ecological functions. We analyzed nonperennial flow regimes using 540 U.S. Geological Survey watersheds across the contiguous United States from 1979 to...
Article
Arsenic (As) causes cancer and non-cancer health effects in humans. Previous research revealed As concentrations over 200 μg g⁻¹ in lake sediments in the south-central Puget Sound region affected by the former ASARCO copper smelter in Ruston, WA, and significant bioaccumulation of As in plankton in shallow lakes. Enhanced uptake occurs during summe...
Article
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Classifying rivers into homogeneous categories based on hydrological and/or environmental attributes supports the implementation of environmental flows to sustain aquatic ecosystems and support the resource needs of society. Hydrological classifications provide decision‐makers with a pragmatic number of water management units by grouping individual...
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Motivation: We compiled a global database of long-term riverine fish surveys from 46 regional and national monitoring programmes and from individual academic research efforts, with which numerous basic and applied questions in ecology and global change research can be explored. Such spatially and temporally extensive datasets have been lacking for...
Chapter
Aim: To provide an overview of ecology and management of invasive species in riverine ecosystems. Key findings: ●Aquatic invasive species are a primary threat to streams and rivers across the globe, impacting biodiversity, disrupting key ecological functions, and compromising ecosystem services. ●Invasive species are those that are transported out...
Article
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Background There is growing evidence of the potential negative consequences of altered flow regimes, in terms of magnitude, frequency, timing, duration or season pattern, on fluvial ecosystems and the fisheries they support. The scientific and policy communities have acknowledged the need for a better understanding of the effects of flow alteration...
Article
The COVID-19 global pandemic and resulting effects on the economy and society (e.g., sheltering-in-place, alterations in transportation, changes in consumer behaviour, loss of employment) have yielded some benefits and risks to biodiversity. Here, we considered the ways the COVID-19 pandemic has influenced (or may influence) freshwater fish biodive...
Article
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1. Around the globe, instream infrastructures such as dams, weirs, and culverts associated with roads are wide‐spread and continue to be constructed. There is limited documentation of smaller infrastructure because of mixed regulation and laws related to instream construction, as well as difficulty in documentation because of their size and frequen...
Article
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The conservation challenges facing freshwater ecosystems necessitate broadening our science from understanding individual species loss to anticipating multi-faceted changes to biodiversity. In recent decades, the process of biotic homogenization by which regional biotas become more similar through time has attracted considerable attention. Here, we...
Article
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Establishment of nonnative fishes and extirpations of native fishes have homogenized freshwater fish faunas, yet our understanding of the drivers of this process remain limited. We addressed this knowledge gap by testing three hypotheses about introductions and homogenization of fish communities is the eastern United States: First, whether nonnativ...
Article
In addition to accidental aquaculture escapees, an increasing number of freshwater fish expressing different domestication levels are voluntarily released into the wild primarily as stocking supplement for fisheries and for conservation programmes. Because domestication modifies individual traits and because subtle changes in intraspecific variabil...
Article
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Shifts in wildflower phenology in response to climate change are well documented in the scientific literature. The majority of studies have revealed phenological shifts using in-situ observations, some aided by citizen science efforts (e.g., National Phenology Network). Such investigations have been instrumental in quantifying phenological shifts b...
Article
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Prevention of aquatic invasive species is a fundamental management challenge. With hundreds of millions of people participating in fishing trips each year, understanding angler movements that transmit invasive species can provide critical insight into the most effective locations and scales at which to apply preventative measures. Recent evidence s...
Article
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Conceptual models underpin river ecosystem research. However, current models focus on continuously flowing rivers and few explicitly address characteristics such as flow cessation and drying. The applicability of existing conceptual models to nonperennial rivers that cease to flow (intermittent rivers and ephemeral streams, IRES) has not been evalu...
Article
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Assessing the vulnerability of species to climate change serves as the basis for climate-adaptation planning and climate-smart conservation , and typically involves an evaluation of exposure, sensitivity, and adaptive capacity (AC). AC is a species' ability to cope with or adjust to changing climatic conditions, and is the least understood and most...
Article
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We examined changes in density, distribution, and size of migratory sculpins (Coastrange Sculpin [Cottus aleuticus] and Prickly Sculpin [C. asper]) in 4 small lowland urban tributaries following the removal of instream barriers. In 3 of the streams, a complete or partial barrier to upstream movements of migratory sculpins was removed. In the 4th st...
Article
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Rivers that cease to flow are globally prevalent. Although many epithets have been used for these rivers, a consensus on terminology has not yet been reached. Doing so would facilitate a marked increase in interdisciplinary interest as well as critical need for clear regulations. Here we reviewed literature from Web of Science database searches of...
Article
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Environmental DNA (eDNA) analysis offers a promising tool for rapid and early detection of aquatic plant invasive species, but currently suffers from substantial unknowns that limit its widespread use in monitoring programs. We conducted the first study to test the factors related to eDNA-based detectability of 2 invasive aquatic plants, Egeria den...