Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 22
Filter
1.
J Am Water Resour Assoc ; 59(5): 1099-1114, 2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37941964

ABSTRACT

Channel dimensions (width and depth) at varying flows influence a host of instream ecological processes, as well as habitat and biotic features; they are a major consideration in stream habitat restoration and instream flow assessments. Models of widths and depths are often used to assess climate change vulnerability, develop endangered species recovery plans, and model water quality. However, development and application of such models require specific skillsets and resources. To facilitate acquisition of such estimates, we created a dataset of modeled channel dimensions for perennial stream segments across the conterminous U.S. We used random forest models to predict wetted width, thalweg depth, bankfull width, and bankfull depth from several thousand field measurements of the National Rivers and Streams Assessment. Observed channel widths varied from <5 m to >2000 m and depths varied from <2 m to >125 m. Metrics of watershed area, runoff, slope, land use, and more were used as model predictors. The models had high pseudo R-squared values (0.70 to 0.91) and median absolute errors within ±6% to ±21% of the interquartile range of measured values across ten stream orders. Predicted channel dimensions can be joined to 1.1 million stream segments of the 1:100K resolution National Hydrography Dataset Plus (version 2.1). These predictions, combined with a rapidly growing body of nationally available data, will further enhance our ability to study and protect aquatic resources.

2.
Glob Chang Biol ; 29(19): 5482-5508, 2023 10.
Article in English | MEDLINE | ID: mdl-37466251

ABSTRACT

Human activities and climate change threaten coldwater organisms in freshwater ecosystems by causing rivers and streams to warm, increasing the intensity and frequency of warm temperature events, and reducing thermal heterogeneity. Cold-water refuges are discrete patches of relatively cool water that are used by coldwater organisms for thermal relief and short-term survival. Globally, cohesive management approaches are needed that consider interlinked physical, biological, and social factors of cold-water refuges. We review current understanding of cold-water refuges, identify gaps between science and management, and evaluate policies aimed at protecting thermally sensitive species. Existing policies include designating cold-water habitats, restricting fishing during warm periods, and implementing threshold temperature standards or guidelines. However, these policies are rare and uncoordinated across spatial scales and often do not consider input from Indigenous peoples. We propose that cold-water refuges be managed as distinct operational landscape units, which provide a social and ecological context that is relevant at the watershed scale. These operational landscape units provide the foundation for an integrated framework that links science and management by (1) mapping and characterizing cold-water refuges to prioritize management and conservation actions, (2) leveraging existing and new policies, (3) improving coordination across jurisdictions, and (4) implementing adaptive management practices across scales. Our findings show that while there are many opportunities for scientific advancement, the current state of the sciences is sufficient to inform policy and management. Our proposed framework provides a path forward for managing and protecting cold-water refuges using existing and new policies to protect coldwater organisms in the face of global change.


Subject(s)
Ecosystem , Rivers , Humans , Fresh Water , Cold Temperature , Climate Change , Water
3.
Proc Annu Hawaii Int Conf Syst Sci ; 2023: 3141-3145, 2023.
Article in English | MEDLINE | ID: mdl-36650889

ABSTRACT

The diagnosis and treatment of common toxicologic disorders is an area of core content that emergency medicine (EM) resident physicians and physician assistants (PA) are required to demonstrate competence in order to become proficient practicing clinicians. Even when EM programs have a required toxicology elective, learners do not encounter all core toxicologic presentations. To supplement these knowledge gaps, many toxicology curriculums rely on internet learning modules which have variable uptake in practice. With remote learning and education becoming more common, we aim to perform a need-based assessment of EM resident and PA toxicology education and use the results to develop and deploy a text message-based, interactive toxicology supplemental program for EM residents and PAs and measure its acceptability and preliminary effectiveness to teach core toxicology principles.

4.
Ecosphere ; 13(11)2022 Nov 09.
Article in English | MEDLINE | ID: mdl-36505090

ABSTRACT

The importance of thermal refuges in a rapidly warming world is particularly evident for migratory species, where individuals encounter a wide range of conditions throughout their lives. In this study, we used a spatially explicit, individual-based simulation model to evaluate the buffering potential of cold-water thermal refuges for anadromous salmon and trout (Oncorhynchus spp.) migrating upstream through a warm river corridor that can expose individuals to physiologically stressful temperatures. We considered upstream migration in relation to migratory phenotypes that were defined in terms of migration timing, spawn timing, swim speed, and use of cold-water thermal refuges. Individuals with different migratory phenotypes migrated upstream through riverine corridors with variable availability of cold-water thermal refuges and mainstem temperatures. Use of cold-water refuges (CWRs) decreased accumulated sublethal exposures to physiologically stressful temperatures when measured in degree-days above 20, 21, and 22°C. The availability of CWRs was an order of magnitude more effective in lowering accumulated sublethal exposures under current and future mainstem temperatures for summer steelhead than fall Chinook Salmon. We considered two emergent model outcomes, survival and percent of available energy used, in relation to thermal heterogeneity and migratory phenotype. Mean percent energy loss attributed to future warmer mainstem temperatures was at least two times larger than the difference in energy used in simulations without CWRs for steelhead and salmon. We also found that loss of CWRs reduced the diversity of energy-conserving migratory phenotypes when we examined the variability in entry timing and travel time outside of CWRs in relation to energy loss. Energy-conserving phenotypic space contracted by 7%-23% when CWRs were unavailable under the current thermal regime. Our simulations suggest that, while CWRs do not entirely mitigate for stressful thermal exposures in mainstem rivers, these features are important for maintaining a diversity of migration phenotypes. Our study suggests that the maintenance of diverse portfolios of migratory phenotypes and cool- and cold-water refuges might be added to the suite of policies and management actions presently being deployed to improve the likelihood of Pacific salmonid persistence into a future characterized by climate change.

5.
Sci Adv ; 8(26): eabn0929, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35776798

ABSTRACT

Mining provides resources for people but can pose risks to ecosystems that support cultural keystone species. Our synthesis reviews relevant aspects of mining operations, describes the ecology of salmonid-bearing watersheds in northwestern North America, and compiles the impacts of metal and coal extraction on salmonids and their habitat. We conservatively estimate that this region encompasses nearly 4000 past producing mines, with present-day operations ranging from small placer sites to massive open-pit projects that annually mine more than 118 million metric tons of earth. Despite impact assessments that are intended to evaluate risk and inform mitigation, mines continue to harm salmonid-bearing watersheds via pathways such as toxic contaminants, stream channel burial, and flow regime alteration. To better maintain watershed processes that benefit salmonids, we highlight key windows during the mining governance life cycle for science to guide policy by more accurately accounting for stressor complexity, cumulative effects, and future environmental change.

6.
PLoS One ; 17(7): e0268452, 2022.
Article in English | MEDLINE | ID: mdl-35857741

ABSTRACT

Recent increases in the burn area and severity of wildfires in the western US have raised concerns about the impact on stream water temperature-a key determinant of cold-water fish habitats. However, the effect on seasonal water temperatures of concern, including winter and summer, are not fully understood. In this study, we assessed the impact of wildfire burns at Boulder Creek (Oregon), Elk Creek (Oregon), and Gibbon River (Wyoming) watersheds on the downstream winter and summer water temperatures for the first three post-fire years. To obtain results independent of the choice of the analytical method, we evaluated the consequence of each burn using three different statistical approaches that utilize local water temperature data. Our results from the three approaches indicated that the response of water temperatures to wildfire burns varied across seasons and sites. Wildfire burns were associated with a median increase of up to 0.56°C (Standard Error; S.E. < 0.23°C) in the summer mean water temperatures (MWT) and 62 degree-day Celsius (DDC; S.E. < 20.7 DDC) in the summer accumulated degree days (ADD) for the three subsequent years across studied stream sites. Interestingly, these burns also corresponded to a median decrease of up to 0.49°C (S.E. < 0.45°C) in the winter MWT and 39 DDC (S.E. < 40.5 DDC) in the winter ADD for the same period across sites. Wildfire effects on the downstream water temperatures diminished with increasing site distance from the burn perimeter. Our analyses demonstrated that analytical methods that utilize local watershed data could be applied to evaluate fire effects on downstream water temperatures.


Subject(s)
Burns , Wildfires , Animals , Retrospective Studies , Seasons , Temperature , Water
7.
Ecol Evol ; 11(18): 12259-12284, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34594498

ABSTRACT

Wildfires in many western North American forests are becoming more frequent, larger, and severe, with changed seasonal patterns. In response, coniferous forest ecosystems will transition toward dominance by fire-adapted hardwoods, shrubs, meadows, and grasslands, which may benefit some faunal communities, but not others. We describe factors that limit and promote faunal resilience to shifting wildfire regimes for terrestrial and aquatic ecosystems. We highlight the potential value of interspersed nonforest patches to terrestrial wildlife. Similarly, we review watershed thresholds and factors that control the resilience of aquatic ecosystems to wildfire, mediated by thermal changes and chemical, debris, and sediment loadings. We present a 2-dimensional life history framework to describe temporal and spatial life history traits that species use to resist wildfire effects or to recover after wildfire disturbance at a metapopulation scale. The role of fire refuge is explored for metapopulations of species. In aquatic systems, recovery of assemblages postfire may be faster for smaller fires where unburned tributary basins or instream structures provide refuge from debris and sediment flows. We envision that more-frequent, lower-severity fires will favor opportunistic species and that less-frequent high-severity fires will favor better competitors. Along the spatial dimension, we hypothesize that fire regimes that are predictable and generate burned patches in close proximity to refuge will favor species that move to refuges and later recolonize, whereas fire regimes that tend to generate less-severely burned patches may favor species that shelter in place. Looking beyond the trees to forest fauna, we consider mitigation options to enhance resilience and buy time for species facing a no-analog future.

8.
J Therm Biol ; 100: 103028, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34503775

ABSTRACT

Under a warmer future climate, thermal refuges could facilitate the persistence of species relying on cold-water habitat. Often these refuges are small and easily missed or smoothed out by averaging in models. Thermal infrared (TIR) imagery can provide empirical water surface temperatures that capture these features at a high spatial resolution (<1 m) and over tens of kilometers. Our study examined how TIR data could be used along with spatial stream network (SSN) models to characterize thermal regimes spatially in the Middle Fork John Day (MFJD) River mainstem (Oregon, USA). We characterized thermal variation in seven TIR longitudinal temperature profiles along the MFJD mainstem and compared them with SSN model predictions of stream temperature (for the same time periods as the TIR profiles). TIR profiles identified reaches of the MFJD mainstem with consistently cooler temperatures across years that were not consistently captured by the SSN prediction models. SSN predictions along the mainstem identified ~80% of the 1-km reach scale temperature warming or cooling trends observed in the TIR profiles. We assessed whether landscape features (e.g., tributary junctions, valley confinement, geomorphic reach classifications) could explain the fine-scale thermal heterogeneity in the TIR profiles (after accounting for the reach-scale temperature variability predicted by the SSN model) by fitting SSN models using the TIR profile observation points. Only the distance to the nearest upstream tributary was identified as a statistically significant landscape feature for explaining some of the thermal variability in the TIR profile data. When combined, TIR data and SSN models provide a data-rich evaluation of stream temperature captured in TIR imagery and a spatially extensive prediction of the network thermal diversity from the outlet to the headwaters.


Subject(s)
Infrared Rays , Remote Sensing Technology/methods , Rivers , Thermography/methods , Oregon , Temperature
9.
Nat Clim Chang ; 11: 354-361, 2021 Mar 25.
Article in English | MEDLINE | ID: mdl-35475125

ABSTRACT

A common goal of biological adaptation planning is to identify and prioritize locations that remain suitably cool during summer. This implicitly devalues areas that are ephemerally warm, even if they are suitable most of the year for mobile animals. Here we develop an alternative conceptual framework, the growth regime, which considers seasonal and landscape variation in physiological performance, focusing on riverine fish. Using temperature models for 14 river basins, we show that growth opportunities propagate up and down river networks on a seasonal basis, and that downstream habitats that are suboptimally warm in summer may actually provide the majority of growth potential expressed annually. We demonstrate with an agent-based simulation that shoulder-season use of warmer downstream habitats can fuel annual fish production. Our work reveals a synergy between cold and warm habitats that could be fundamental for supporting coldwater fisheries, highlighting the risk in conservation strategies that underappreciate warm habitats.

10.
J Surg Res ; 259: 217-223, 2021 03.
Article in English | MEDLINE | ID: mdl-33229015

ABSTRACT

BACKGROUND: Defining the work performed by emergency general surgery (EGS) surgeons has relied on quantifying surgical interventions, failing to include nonsurgical management performed. The purpose of this study was to identify the extent of operative and nonoperative patient management provided by an EGS service line in response to consults from other hospital providers. METHODS: This is a retrospective descriptive study of all adult patients with an EGS consult request placed from July 1, 2014 to June 30, 2016 at a 1000-bed tertiary referral center. Consult requests were classified by suspected diagnosis and linked to patient demographic and clinical information. Operative and nonoperative cases were compared. RESULTS: About 4998 EGS consults were requested during the 2-y period, of which 69.6% were placed on the first day of the patient encounter. Disposition outcomes after consultation included admission to the EGS service (27.6%) and discharge from the emergency department (25.3%). Small bowel obstruction, appendicitis, and cholecystitis decisively comprised the top three diagnoses for overall consults and those requiring admission to the EGS service. For every consult requiring an operation (n = 1400), 2.6 consults were managed without an operation (n = 3598). CONCLUSIONS: EGS surgeons are asked to evaluate and manage a variety of potentially surgical diagnoses. As most consults do not require surgical intervention, operative volume is a poor surrogate for quantifying EGS productivity. The role of this service is vital to patient triage and disposition, particularly in the emergency department setting. Institutions should consider the volume of their nonoperative consultations when evaluating EGS service line workload and in guiding staffing needs.


Subject(s)
Emergency Service, Hospital/statistics & numerical data , Referral and Consultation , Surgical Procedures, Operative/statistics & numerical data , Adult , Aged , Appendicitis/surgery , Cholecystitis/surgery , Female , Humans , Intestinal Obstruction/surgery , Male , Middle Aged , Retrospective Studies
11.
Front Ecol Environ ; 18(5): 271-280, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32944010

ABSTRACT

Within the context of climate adaptation, the concept of climate refugia has emerged as a framework for addressing future threats to freshwater fish populations. We evaluated recent climate-refugia management associated with water use and landscape modification by comparing efforts in the US states of Oregon and Massachusetts, for which there are contrasting resource use patterns. Using these examples, we discuss tools and principles that can be applied more broadly. Although many early efforts to identify climate refugia have focused on water temperature, substantial gains in evaluating other factors and processes regulating climate refugia (eg stream flow, groundwater availability) are facilitating refined mapping of refugia and assessment of their ecological value. Major challenges remain for incorporating climate refugia into water-quality standards, evaluating trade-offs among policy options, addressing multiple species' needs, and planning for uncertainty. However, with a procedurally transparent and conceptually sound framework to build upon, recent efforts have revealed a promising path forward.

12.
J Trauma Acute Care Surg ; 88(6): 770-775, 2020 06.
Article in English | MEDLINE | ID: mdl-32118825

ABSTRACT

BACKGROUND: The American Association for the Surgery of Trauma (AAST) developed a severity scale for surgical conditions, including diverticulitis. The Hinchey classification requires operative intervention yet remains the established scoring system for acute diverticulitis. This is a pilot study to compare the AAST grading scale for acute colonic diverticulitis with the traditional Hinchey classification. We hypothesize that the AAST classification scale is equivalent to the Hinchey in predicting outcomes. METHODS: This is a retrospective cohort study at an academic medical center. A consecutive sample of patients with acute diverticulitis and computed tomography imaging was reviewed. Chart review identified demographic and physiologic data with interventional and clinical outcomes. Each computed tomography scan was assigned AAST and modified Hinchey classification scores by a radiologist. Multivariate regression and receiver operating characteristic curve analysis compared six outcomes: need for procedure, complication, intensive care unit (ICU) admission, length of stay, 30-day readmission, and mortality. RESULTS: One hundred twenty-nine patients were included. Of the total patients, 42.6% required procedural intervention, 21.7% required ICU admission, 18.6% were readmitted, and 6.2% died. Both AAST and Hinchey predicted the need for operation (AAST odds ratios, 1.55, 12.7, 18.09, and 77.24 for stages 2-5; Hinchey odds ratios, 8.85, 11.49, and 22.9 for stages 1b-3, stage 4 predicted perfectly). The need for operation c-statistics (area under the curve) for AAST and Hinchey was 0.80 and 0.83 for Hinchey and AAST, respectively (p = 0.35). The complication c-statistics curve for AAST and Hinchey was 0.83 and 0.80, respectively (p = 0.33). The AAST and Hinchey scores were less predictive for ICU admission, readmission, and mortality with c-statistics of less than 0.80. CONCLUSION: The AAST grading of acute diverticulitis is equivalent to the modified Hinchey classification in predicting procedural intervention and complications. The AAST system may be preferable to Hinchey because it can be applied preoperatively. Although this pilot study demonstrated that the AAST score predicts surgical need, a larger study is required to evaluate the AAST score for other outcomes. LEVEL OF EVIDENCE: Prognostic and epidemiological study, level III.


Subject(s)
Diverticulitis, Colonic/diagnosis , Severity of Illness Index , Surgical Procedures, Operative/statistics & numerical data , Academic Medical Centers/statistics & numerical data , Acute Disease/mortality , Acute Disease/therapy , Adult , Colon/diagnostic imaging , Diverticulitis, Colonic/mortality , Diverticulitis, Colonic/surgery , Female , Hospital Mortality , Humans , Intensive Care Units/statistics & numerical data , Length of Stay/statistics & numerical data , Male , Middle Aged , Patient Admission/statistics & numerical data , Patient Readmission/statistics & numerical data , Prognosis , Retrospective Studies , Societies, Medical , Tomography, X-Ray Computed , Traumatology , United States , Young Adult
13.
Front Ecol Environ ; 18(5): 228-234, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-33424494

ABSTRACT

Climate-change adaptation focuses on conducting and translating research to minimize the dire impacts of anthropogenic climate change, including threats to biodiversity and human welfare. One adaptation strategy is to focus conservation on climate-change refugia (that is, areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and sociocultural resources). In this Special Issue, recent methodological and conceptual advances in refugia science will be highlighted. Advances in this emerging subdiscipline are improving scientific understanding and conservation in the face of climate change by considering scale and ecosystem dynamics, and looking beyond climate exposure to sensitivity and adaptive capacity. We propose considering refugia in the context of a multifaceted, long-term, network-based approach, as temporal and spatial gradients of ecological persistence that can act as "slow lanes" rather than areas of stasis. After years of discussion confined primarily to the scientific literature, researchers and resource managers are now working together to put refugia conservation into practice.

14.
J Ecohydraul ; 1: 1-13, 2020 Dec 17.
Article in English | MEDLINE | ID: mdl-33898904

ABSTRACT

Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon (Oncorhynchus tshawytscha) and summer-run steelhead trout (O. mykiss) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.

15.
Am J Emerg Med ; 38(1): 114-117, 2020 01.
Article in English | MEDLINE | ID: mdl-31349907

ABSTRACT

INTRODUCTION: Emergency department (ED) providers and clinicians find that feedback on acute stroke patients is rewarding, valuable to professional development, and helpful for practice improvement. However, feedback is rarely provided, particularly for patients with stroke. Here we describe the implementation of an electronic stroke outcome reporting tool for providing feedback to ED providers. METHODS: We sought to evaluate the implementation of an electronic stroke outcome reporting tool at 3 Nashville hospitals. ED staff and providers voluntarily enrolled to receive de-identified reports of clinical (e.g., survival) and operational (e.g., timeliness) outcomes of patients with acute ischemic stroke and were offered free continuing education (CE) credits for following up on patients. We evaluated the implementation of this system through a descriptive evaluation of the feasibility, use of the system and CE, and perceived usefulness of the reports. RESULTS: We enrolled 232 ED providers, including 107 (46%) nurses and 57 (25%) attending physicians and transmitted 55 stroke outcome reports. Reports took 30-60 min to compile and were viewed by a mean of 2.6 (SD 1.5) registered providers; 97.1% found the reports useful and 36.2% reported likelihood to change practice. Continuing education credits were initiated or claimed by 22 providers. CONCLUSIONS: An electronic stroke outcome reporting tool was used and liked by ED staff and providers but the time to compile the reports is the major challenge to scalability. Future research should address the effectiveness of this reporting tool as a source of provider education and its impact on clinical and operational outcomes.


Subject(s)
Emergency Service, Hospital/organization & administration , Outcome Assessment, Health Care/organization & administration , Stroke/therapy , Emergency Service, Hospital/standards , Feedback , Humans , Internet , Medical Staff, Hospital , Outcome Assessment, Health Care/methods , Pilot Projects , Quality Improvement
16.
Landsc Ecol ; 34(4): 737-754, 2019 Apr 01.
Article in English | MEDLINE | ID: mdl-33424124

ABSTRACT

CONTEXT: Diadromous fish populations in the Pacific Northwest face challenges along their migratory routes from declining habitat quality, harvest, and barriers to longitudinal connectivity. These stressors complicate the prioritization of proposed management actions intended to improve conditions for migratory fishes including anadromous salmon and trout. OBJECTIVES: We describe a multi-scale hybrid mechanistic-probabilistic simulation model linking migration corridor conditions to fish fitness outcomes. We demonstrate the model's utility using a case study of salmon and steelhead adults in the Columbia River migration corridor exposed to spatially- and temporally-varying stressors. METHODS: The migration corridor simulation model is based on a behavioral decision tree that governs individual interactions with the environment, and an energetic submodel that estimates the hourly costs of migration. Emergent properties of the migration corridor simulation model include passage time, energy use, and survival. RESULTS: We observed that the simulated fishes' initial energy density, the migration corridor temperatures they experienced, and their history of behavioral thermoregulation were the primary determinants of their fitness outcomes. Insights gained from use of the model might be exploited to identify management interventions that increase successful migration outcomes. CONCLUSIONS: This paper describes new methods that extend the suite of tools available to aquatic biologists and conservation practitioners. We have developed a 2-dimensional spatially-explicit behavioral and physiological model and illustrated how it can be used to simulate fish migration within a river system. Our model can be used to evaluate trade-offs between behavioral thermoregulation and fish fitness at population scales.

17.
Water (Basel) ; 10(5): 1-604, 2018 May 05.
Article in English | MEDLINE | ID: mdl-30079254

ABSTRACT

Watershed integrity, the capacity of a watershed to support and maintain ecological processes essential to the sustainability of services provided to society, can be influenced by a range of landscape and in-stream factors. Ecological response data from four intensively monitored case study watersheds exhibiting a range of environmental conditions and landscape characteristics across the United States were used to evaluate the performance of a national level Index of Watershed Integrity (IWI) at regional and local watershed scales. Using Pearson's correlation coefficient (r), and Spearman's rank correlation coefficient (rs ), response variables displayed highly significant relationships and were significantly correlated with IWI and ICI (Index of Catchment Integrity) values at all watersheds. Nitrogen concentration and flux-related watershed response metrics exhibited significantly strong negative correlations across case study watersheds, with absolute correlations (|r|) ranging from 0.48 to 0.97 for IWI values, and 0.31 to 0.96 for ICI values. Nitrogen-stable isotope ratios measured in chironomids and periphyton from streams and benthic organic matter from lake sediments also demonstrated strong negative correlations with IWI values, with |r| ranging from 0.47 to 0.92, and 0.35 to 0.89 for correlations with ICI values. This evaluation of the performance of national watershed and catchment integrity metrics and their strong relationship with site level responses provides weight-of-evidence support for their use in state, local and regionally focused applications.

19.
Ecosphere ; 8(12): 1-23, 2017 Dec 22.
Article in English | MEDLINE | ID: mdl-29552374

ABSTRACT

It is generally accepted that climate change will stress coldwater species like Pacific salmon. However, it is unclear what aspect of altered thermal regimes (e.g., warmer winters, springs, summers, or increased variability) will have the greatest effect, and what role the spatial properties of river networks play. Thermally diverse habitats may afford protection from climate change by providing opportunities for aquatic organisms to find and use habitats with optimal conditions for growth. We hypothesized that climate-altered thermal regimes will change growth and timing of life history events such as emergence or migration but that changes will be moderated in topologically complex stream networks where opportunities to thermoregulate are more readily available to mobile animals. Because climate change effects on populations are spatially variable and contingent upon physiological optima, assessments of risk must take a spatially explicit approach. We developed a spatially-structured individual based model for Chinook Salmon (Oncorhynchus tshawytscha) in which movement decisions and growth were governed by water temperature and conspecific density. We evaluated growth and phenology (timing of egg emergence and smolting) under a variety of thermal regimes (each having a different minimum, rate of warming, maximum, and variability) and in three network shapes of increasing spatial complexity. Across networks, fish generally grew faster and were capable of smolting earlier in warmer scenarios where water temperatures experienced by fish were closer to optimal; however, growth decreased for some fish. We found that salmon size and smolt date responded more strongly to warmer springs and summers than to warmer winters or increased variability. Fish in the least complex network grew faster and were ready to smolt earlier than fish in the more spatially complex network shapes in the contemporary thermal regime; patterns were similar but less clear in warmer thermal regimes. Our results demonstrate that network topology may influence how fish respond to thermal landscapes, and this information will be useful for incorporating a spatiotemporal context into conservation decisions that promote long-term viability of salmon in a changing climate.

20.
PLoS One ; 11(8): e0159909, 2016.
Article in English | MEDLINE | ID: mdl-27509088

ABSTRACT

Refugia have long been studied from paleontological and biogeographical perspectives to understand how populations persisted during past periods of unfavorable climate. Recently, researchers have applied the idea to contemporary landscapes to identify climate change refugia, here defined as areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and socio-cultural resources. We differentiate historical and contemporary views, and characterize physical and ecological processes that create and maintain climate change refugia. We then delineate how refugia can fit into existing decision support frameworks for climate adaptation and describe seven steps for managing them. Finally, we identify challenges and opportunities for operationalizing the concept of climate change refugia. Managing climate change refugia can be an important option for conservation in the face of ongoing climate change.


Subject(s)
Adaptation, Physiological , Climate Change , Refugium , Animals , Ecosystem , Rabbits
SELECTION OF CITATIONS
SEARCH DETAIL
...