Michelle McClure | Northwest Fisheries Science Center, NOAA (original) (raw)

Papers by Michelle McClure

Transactions of the American Fisheries Society, Jul 19, 2012

ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout... more ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout their freshwater habitat, but the cumulative effect of these disturbances is often not known or not easily quantifiable. One such disturbance is water diversions, which can entrain fish and alter streamflow regimes. Threatened Lemhi River (Idaho) Chinook salmon O. tshawytscha smolts encounter 41–71 water diversions during their out-migration. We used passive integrated transponder tag data to model the entrainment rate of Chinook salmon smolts as a function of the proportion of water removed by an irrigation diversion. Under median-streamflow conditions with unscreened diversions, the estimated cumulative effect of the diversions was a loss of 71.1% of out-migrating smolts due to entrainment. This is a large potential source of mortality, but screening is an effective mitigation strategy, as estimated mortality was reduced to 1.9% when all diversions were screened. If resources are limited, targeting the diversions that remove a large amount of water and diversions in locations with high fish encounter rates is most effective. Our modeling approach could be used to quantify the entrainment effects of water diversions and set screening priorities for other watersheds.Received October 28, 2011; accepted March 19, 2012

Science

... Ecology Division, Northwest Fisheries Science Center, NMFS, 2725 Montlake Boulevard East, Sea... more ... Ecology Division, Northwest Fisheries Science Center, NMFS, 2725 Montlake Boulevard East, Seattle, WA 98118, USA. Michelle M. McClure. ... Perhaps George Frampton, acting chair of the White House Council on Environmental Quality, summarized the scientific debate best ...

Background/Question/Methods The influence of invasive species can be widespread with direct impac... more Background/Question/Methods The influence of invasive species can be widespread with direct impacts to competitors and prey species, and indirect impacts that can extend through the food web. In the western US, the invasion of brook trout into streams historically dominated by other salmonid species has become an issue of particular concern. Most of the work on brook trout invasion has focused on their impact to native salmonids, particularly those that are threatened or endangered. Surprisingly few studies have evaluated the broader impacts of brook trout on streams food webs as a whole. In this research, we use a mass balance ecosystem/foodweb model (Ecopath with Ecosim - EwE) to evaluate potential impacts of brook trout invasion not only on native salmonids, but on the broader biotic community in two Chinook salmon rearing streams in the Snake River basin of Idaho. Parameter estimates for each of the 17 groups in the EwE models were derived from direct field data collected in mid...

Evolutionary Applications

Most hatchery programs for anadromous salmonids have been initiated to increase the numbers of fi... more Most hatchery programs for anadromous salmonids have been initiated to increase the numbers of fish for harvest, to mitigate for habitat losses, or to increase abundance in populations at low abundance. However, the manner in which these programs are implemented can have significant impacts on the evolutionary trajectory and long-term viability of populations. In this paper, we review the potential benefits and risks of hatchery programs relative to the conservation of species listed under the US Endangered Species Act. To illustrate, we present the range of potential effects within a population as well as among populations of Chinook salmon (Oncorhynchus tshawytscha) where changes to major hatchery programs are being considered. We apply evolutionary considerations emerging from these examples to suggest broader principles for hatchery uses that are consistent with conservation goals. We conclude that because of the evolutionary risks posed by artificial propagation programs, they should not be viewed as a substitute for addressing other limiting factors that prevent achieving viability. At the population level, artificial propagation programs that are implemented as a short-term approach to avoid imminent extinction are more likely to achieve long-term population viability than approaches that rely on long-term supplementation. In addition, artificial propagation programs can have out-of-population impacts that should be considered in conservation planning.

North American Journal of Fisheries Management, 2014

ABSTRACT Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northw... more ABSTRACT Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northwest is an issue of great concern ecologically, culturally, and economically. Growth during the first summer is vitally important for juvenile Chinook Salmon, as it influences not only life history decisions (to smolt or not to smolt) but also subsequent river and ocean survival. Using Ecopath with Ecosim, we developed a food web model for a representative stream in the Salmon River basin, Idaho, to evaluate potential species-specific and food web effects of three management strategies: (1) adding salmon carcasses or carcass analogs to promote primary production and detrital availability that were lost due to declining salmon returns; (2) removal of nonnative Brook Trout Salvelinus fontinalis, which are competitors with and predators on juvenile Chinook Salmon; and (3) stocking hatchery Chinook Salmon into streams to supplement wild production. Overall, juvenile Chinook Salmon responded strongly to increases in basal resources. Removal of Brook Trout had little effect on potential production for juvenile Chinook Salmon, but the responses of sculpins Cottus spp. were strong, primarily due to the sculpins’ high degree of dietary overlap with and predation by Brook Trout. Supplementation with hatchery-origin juveniles depressed the production of wild juvenile Chinook Salmon, especially at the densities commonly applied to streams in this region. Our results suggest that efforts to enhance basal resources are likely to be the most effective in promoting the production of juvenile Chinook Salmon and nearly all food web groups considered in our model system. Removal of nonnative Brook Trout is unlikely to substantially affect salmon but could have a disproportionately large effect on nongame species, which are generally overlooked in single-species management approaches.Received October 2, 2013; accepted March 24, 2014

Salmon populations suffer from anthropogenic impacts throughout their life history. Accordingly, ... more Salmon populations suffer from anthropogenic impacts throughout their life history. Accordingly, recovery plans for threatened and endangered populations typically involve mitigation actions in several life stages. This presents the challenge of assessing how multiple mitigation actions will integrate into cumulative benefits for a population. Incorporating predicted survival improvements into life-cycle models is a useful approach for translating multiple improvements into changes in population viability metrics such as probability of extinction or long-term abundance. We developed stochastic, stage-based life-cycle models of salmon and steelhead populations throughout the interior Columbia River basin. We included climate effects in the freshwater rearing and in early ocean survival and density dependent recruitment of juveniles. We used the models to predict how mitigation actions in freshwater rearing habitats and in the estuary and improvements in the hydropower system will enh...

Managing fish populations in the face of escalating human water demand and climate change is a ma... more Managing fish populations in the face of escalating human water demand and climate change is a major challenge for the 21st century. Water diversion is causing shifts in the quantity and timing of streamflow, and climate change may further impact temperature and flow regimes. Historically, the Lemhi River subbasin in Idaho had a large Chinook salmon population, but the population has experienced substantial declines and is currently listed as threatened. The Lemhi River experiences large-scale water diversion for irrigation and the impacts of this for spring Chinook salmon are not fully understood. We used 15 years of data to model the relationship of flow, temperature, and density on juvenile salmon survival. Spring flow and summer temperature were found to be good predictors of juvenile survival with higher flow and lower temperatures associated with increased survival. We used these models to compare survival between diverted and undiverted scenarios for both current and predicte...

Background/Question/Methods Our improved ability to model climate allows us to better estimate ho... more Background/Question/Methods Our improved ability to model climate allows us to better estimate how climate change will alter freshwater habitat quality and availability. However, significant challenges remain, particularly in combining the effects of climate change and human habitat alteration. We examined these impacts on shallow water beach habitat (SWH) in the lower Willamette River, Oregon (U.S.A.). A proposed project to stabilize ~450 m (1500 ft) of shoreline with riprap would alter SWH and is subject to Endangered Species Act (ESA) Section 7 consultation. The lower river has been highly altered by urban and industrial development. Mainstem beach SWH is important to subyearling ESA-listed Upper Willamette River Chinook salmon (Oncorhynchus tshawytscha), and the amount of SWH fluctuates with river stage levels. Historically, the lower river was connected to its floodplain and river stages in the spring often significantly exceeded modern flood stages, providing additional but no...

Transactions of the American Fisheries Society

Background/Question/Methods A changing climate makes the conservation of marine, estuarine, and f... more Background/Question/Methods A changing climate makes the conservation of marine, estuarine, and freshwater organisms even more challenging than these efforts would normally be due to the strong links between climatic and aquatic processes, the dynamism of aquatic systems, the large migrations of many aquatic organisms, and the relative uncertainty of the pace and magnitude of climate-related changes in some areas. Changing environmental conditions (including ocean acidification) have the potential not only to worsen the conditions for imperiled species, but also to pose new scientific and societal challenges to their conservation especially within the context of statutory mandates such as the U.S. Endangered Species Act (ESA). Recent court decisions have affirmed the importance of considering climate change in determinations under the ESA. Recognizing the need to address this issue, the U.S. National Marine Fisheries Service (NMFS) conducted eight case studies to explore approaches ...

Many conservation and recovery efforts are contemplating the reintroduction of anadromous salmoni... more Many conservation and recovery efforts are contemplating the reintroduction of anadromous salmonids to areas from which they have been extirpated. Given the wide range of settings under which these reintroductions might take place, and the variety of goals for these efforts, appropriate approaches for reintroductions are likely to vary. We reviewed scientific considerations for reintroduction efforts, and identified conditions particularly conducive to successful reintroductions. Areas considered include the effect of the reintroduction on overall population and ESU viability, past and current limiting factors, condition of the habitat in the area to be open, the presence of native and introduce species, contingency planning, alternative approaches to recolonization, source stocks, and passage issues. We also treated emerging issues such as evolutionary responses to habitat blockage and opening, and considerations for reintroductions in a changing climate. Finally, we applied the pr...

Ecological Applications, 2013

Climate change is likely to lead to increasing population variability and extinction risk. Theore... more Climate change is likely to lead to increasing population variability and extinction risk. Theoretically, greater population diversity should buffer against rising climate variability, and this theory is often invoked as a reason for greater conservation. However, this has rarely been quantified. Here we show how a portfolio approach to managing population diversity can inform metapopulation conservation priorities in a changing world. We develop a salmon metapopulation model in which productivity is driven by spatially distributed thermal tolerance and patterns of short- and long-term climate change. We then implement spatial conservation scenarios that control population carrying capacities and evaluate the metapopulation portfolios as a financial manager might: along axes of conservation risk and return. We show that preserving a diversity of thermal tolerances minimizes risk, given environmental stochasticity, and ensures persistence, given long-term environmental change. When the thermal tolerances of populations are unknown, doubling the number of populations conserved may nearly halve expected metapopulation variability. However, this reduction in variability can come at the expense of long-term persistence if climate change increasingly restricts available habitat, forcing ecological managers to balance society's desire for short-term stability and long-term viability. Our findings suggest the importance of conserving the processes that promote thermal-tolerance diversity, such as genetic diversity, habitat heterogeneity, and natural disturbance regimes, and demonstrate that diverse natural portfolios may be critical for metapopulation conservation in the face of increasing climate variability and change.

Transactions of the American Fisheries Society, 2012

Transactions of the American Fisheries Society, 2012

ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout... more ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout their freshwater habitat, but the cumulative effect of these disturbances is often not known or not easily quantifiable. One such disturbance is water diversions, which can entrain fish and alter streamflow regimes. Threatened Lemhi River (Idaho) Chinook salmon O. tshawytscha smolts encounter 41–71 water diversions during their out-migration. We used passive integrated transponder tag data to model the entrainment rate of Chinook salmon smolts as a function of the proportion of water removed by an irrigation diversion. Under median-streamflow conditions with unscreened diversions, the estimated cumulative effect of the diversions was a loss of 71.1% of out-migrating smolts due to entrainment. This is a large potential source of mortality, but screening is an effective mitigation strategy, as estimated mortality was reduced to 1.9% when all diversions were screened. If resources are limited, targeting the diversions that remove a large amount of water and diversions in locations with high fish encounter rates is most effective. Our modeling approach could be used to quantify the entrainment effects of water diversions and set screening priorities for other watersheds.Received October 28, 2011; accepted March 19, 2012

Journal of Evolutionary Biology, 1995

It has been suggested that the biogeographic and clade-level characteristics of marine invertebra... more It has been suggested that the biogeographic and clade-level characteristics of marine invertebrate groups important in survival through mass extinctions are different from those important in survival during normal times. The role played by ecologically important characters in survival across mass extinctions, however, has not been well-studied.

Conservation Biology, 2013

Significant challenges remain in the ability to estimate habitat change under the combined effect... more Significant challenges remain in the ability to estimate habitat change under the combined effects of natural variability, climate change, and human activity. We examined anticipated effects on shallow water over low-sloped beaches to these combined effects in the lower Willamette River, Oregon, an area highly altered by development. A proposal to stabilize some shoreline with large rocks (riprap) would alter shallow water areas, an important habitat for threatened Chinook salmon (Oncorhynchus tshawytscha), and would be subject to U.S. Endangered Species Act-mandated oversight. In the mainstem, subyearling Chinook salmon appear to preferentially occupy these areas, which fluctuate with river stages. We estimated effects with a geospatial model and projections of future river flows. Recent (1999Recent ( -2009 median river stages during peak subyearling occupancy (April-June) maximized beach shallow water area in the lower mainstem. Upstream shallow water area was maximized at lower river stages than have occurred recently. Higher river stages in April-June, resulting from increased flows predicted for the 2080s, decreased beach shallow water area 17-32%. On the basis of projected 2080s flows, more than 15% of beach shallow water area was displaced by the riprap. Beach shallow water area lost to riprap represented up to 1.6% of the total from the mouth to 12.9 km upstream. Reductions in shallow water area could restrict salmon feeding, resting, and refuge from predators and potentially reduce opportunities for the expression of the full range of life-history strategies. Although climate change analyses provided useful information, detailed analyses are prohibitive at the project scale for the multitude of small projects reviewed annually. The benefits of our approach to resource managers include a wider geographic context for reviewing similar small projects in concert with climate change, an approach to analyze cumulative effects of similar actions, and estimation of the actions' long-term effects.

Conservation Biology, 2013

Climate change is expected to be a top driver of global biodiversity loss in the 21st century. It... more Climate change is expected to be a top driver of global biodiversity loss in the 21st century. It poses new challenges to conserving and managing imperiled species, particularly in marine and estuarine ecosystems. The use of climate-related science in statutorily driven species management, such as under the U.S. Endangered Species Act (ESA), is in its early stages. This article provides an overview of ESA processes, with emphasis on the mandate to the National Marine Fisheries Service (NMFS) to manage listed marine, estuarine, and anadromous species. Although the ESA is specific to the United States, its requirements are broadly relevant to conservation planning. Under the ESA, species, subspecies, and "distinct population segments" may be listed as either endangered or threatened, and taking of most listed species (harassing, harming, pursuing, wounding, killing, or capturing) is prohibited unless specifically authorized via a case-by-case permit process. Government agencies, in addition to avoiding take, must ensure that actions they fund, authorize, or conduct are not likely to jeopardize a listed species' continued existence or adversely affect designated critical habitat. Decisions for which climate change is likely to be a key factor include: determining whether a species should be listed under the ESA, designating critical habitat areas, developing species recovery plans, and predicting whether effects of proposed human activities will be compatible with ESA-listed species' survival and recovery. Scientific analyses that underlie these critical conservation decisions include risk assessment, longterm recovery planning, defining environmental baselines, predicting distribution, and defining appropriate temporal and spatial scales. Although specific guidance is still evolving, it is clear that the unprecedented changes in global ecosystems brought about by climate change necessitate new information and approaches to conservation of imperiled species.

Conservation Biology, 2013

Increased concern over climate change is demonstrated by the many efforts to assess climate effec... more Increased concern over climate change is demonstrated by the many efforts to assess climate effects and develop adaptation strategies. Scientists, resource managers, and decision makers are increasingly expected to use climate information, but they struggle with its uncertainty. With the current proliferation of climate simulations and downscaling methods, scientifically credible strategies for selecting a subset for analysis and decision making are needed. Drawing on a rich literature in climate science and impact assessment and on experience working with natural resource scientists and decision makers, we devised guidelines for choosing climate-change scenarios for ecological impact assessment that recognize irreducible uncertainty in climate projections and address common misconceptions about this uncertainty. This approach involves identifying primary local climate drivers by climate sensitivity of the biological system of interest; determining appropriate sources of information for future changes in those drivers; considering how well processes controlling local climate are spatially resolved; and selecting scenarios based on considering observed emission trends, relative importance of natural climate variability, and risk tolerance and time horizon of the associated decision. The most appropriate scenarios for a particular analysis will not necessarily be the most appropriate for another due to differences in local climate drivers, biophysical linkages to climate, decision characteristics, and how well a model simulates the climate parameters and processes of interest. Given these complexities, we recommend interaction among climate scientists, natural and physical scientists, and decision makers throughout the process of choosing and using climate-change scenarios for ecological impact assessment.

Transactions of the American Fisheries Society, Jul 19, 2012

ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout... more ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout their freshwater habitat, but the cumulative effect of these disturbances is often not known or not easily quantifiable. One such disturbance is water diversions, which can entrain fish and alter streamflow regimes. Threatened Lemhi River (Idaho) Chinook salmon O. tshawytscha smolts encounter 41–71 water diversions during their out-migration. We used passive integrated transponder tag data to model the entrainment rate of Chinook salmon smolts as a function of the proportion of water removed by an irrigation diversion. Under median-streamflow conditions with unscreened diversions, the estimated cumulative effect of the diversions was a loss of 71.1% of out-migrating smolts due to entrainment. This is a large potential source of mortality, but screening is an effective mitigation strategy, as estimated mortality was reduced to 1.9% when all diversions were screened. If resources are limited, targeting the diversions that remove a large amount of water and diversions in locations with high fish encounter rates is most effective. Our modeling approach could be used to quantify the entrainment effects of water diversions and set screening priorities for other watersheds.Received October 28, 2011; accepted March 19, 2012

Science

... Ecology Division, Northwest Fisheries Science Center, NMFS, 2725 Montlake Boulevard East, Sea... more ... Ecology Division, Northwest Fisheries Science Center, NMFS, 2725 Montlake Boulevard East, Seattle, WA 98118, USA. Michelle M. McClure. ... Perhaps George Frampton, acting chair of the White House Council on Environmental Quality, summarized the scientific debate best ...

Background/Question/Methods The influence of invasive species can be widespread with direct impac... more Background/Question/Methods The influence of invasive species can be widespread with direct impacts to competitors and prey species, and indirect impacts that can extend through the food web. In the western US, the invasion of brook trout into streams historically dominated by other salmonid species has become an issue of particular concern. Most of the work on brook trout invasion has focused on their impact to native salmonids, particularly those that are threatened or endangered. Surprisingly few studies have evaluated the broader impacts of brook trout on streams food webs as a whole. In this research, we use a mass balance ecosystem/foodweb model (Ecopath with Ecosim - EwE) to evaluate potential impacts of brook trout invasion not only on native salmonids, but on the broader biotic community in two Chinook salmon rearing streams in the Snake River basin of Idaho. Parameter estimates for each of the 17 groups in the EwE models were derived from direct field data collected in mid...

Evolutionary Applications

Most hatchery programs for anadromous salmonids have been initiated to increase the numbers of fi... more Most hatchery programs for anadromous salmonids have been initiated to increase the numbers of fish for harvest, to mitigate for habitat losses, or to increase abundance in populations at low abundance. However, the manner in which these programs are implemented can have significant impacts on the evolutionary trajectory and long-term viability of populations. In this paper, we review the potential benefits and risks of hatchery programs relative to the conservation of species listed under the US Endangered Species Act. To illustrate, we present the range of potential effects within a population as well as among populations of Chinook salmon (Oncorhynchus tshawytscha) where changes to major hatchery programs are being considered. We apply evolutionary considerations emerging from these examples to suggest broader principles for hatchery uses that are consistent with conservation goals. We conclude that because of the evolutionary risks posed by artificial propagation programs, they should not be viewed as a substitute for addressing other limiting factors that prevent achieving viability. At the population level, artificial propagation programs that are implemented as a short-term approach to avoid imminent extinction are more likely to achieve long-term population viability than approaches that rely on long-term supplementation. In addition, artificial propagation programs can have out-of-population impacts that should be considered in conservation planning.

North American Journal of Fisheries Management, 2014

ABSTRACT Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northw... more ABSTRACT Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northwest is an issue of great concern ecologically, culturally, and economically. Growth during the first summer is vitally important for juvenile Chinook Salmon, as it influences not only life history decisions (to smolt or not to smolt) but also subsequent river and ocean survival. Using Ecopath with Ecosim, we developed a food web model for a representative stream in the Salmon River basin, Idaho, to evaluate potential species-specific and food web effects of three management strategies: (1) adding salmon carcasses or carcass analogs to promote primary production and detrital availability that were lost due to declining salmon returns; (2) removal of nonnative Brook Trout Salvelinus fontinalis, which are competitors with and predators on juvenile Chinook Salmon; and (3) stocking hatchery Chinook Salmon into streams to supplement wild production. Overall, juvenile Chinook Salmon responded strongly to increases in basal resources. Removal of Brook Trout had little effect on potential production for juvenile Chinook Salmon, but the responses of sculpins Cottus spp. were strong, primarily due to the sculpins’ high degree of dietary overlap with and predation by Brook Trout. Supplementation with hatchery-origin juveniles depressed the production of wild juvenile Chinook Salmon, especially at the densities commonly applied to streams in this region. Our results suggest that efforts to enhance basal resources are likely to be the most effective in promoting the production of juvenile Chinook Salmon and nearly all food web groups considered in our model system. Removal of nonnative Brook Trout is unlikely to substantially affect salmon but could have a disproportionately large effect on nongame species, which are generally overlooked in single-species management approaches.Received October 2, 2013; accepted March 24, 2014

Salmon populations suffer from anthropogenic impacts throughout their life history. Accordingly, ... more Salmon populations suffer from anthropogenic impacts throughout their life history. Accordingly, recovery plans for threatened and endangered populations typically involve mitigation actions in several life stages. This presents the challenge of assessing how multiple mitigation actions will integrate into cumulative benefits for a population. Incorporating predicted survival improvements into life-cycle models is a useful approach for translating multiple improvements into changes in population viability metrics such as probability of extinction or long-term abundance. We developed stochastic, stage-based life-cycle models of salmon and steelhead populations throughout the interior Columbia River basin. We included climate effects in the freshwater rearing and in early ocean survival and density dependent recruitment of juveniles. We used the models to predict how mitigation actions in freshwater rearing habitats and in the estuary and improvements in the hydropower system will enh...

Managing fish populations in the face of escalating human water demand and climate change is a ma... more Managing fish populations in the face of escalating human water demand and climate change is a major challenge for the 21st century. Water diversion is causing shifts in the quantity and timing of streamflow, and climate change may further impact temperature and flow regimes. Historically, the Lemhi River subbasin in Idaho had a large Chinook salmon population, but the population has experienced substantial declines and is currently listed as threatened. The Lemhi River experiences large-scale water diversion for irrigation and the impacts of this for spring Chinook salmon are not fully understood. We used 15 years of data to model the relationship of flow, temperature, and density on juvenile salmon survival. Spring flow and summer temperature were found to be good predictors of juvenile survival with higher flow and lower temperatures associated with increased survival. We used these models to compare survival between diverted and undiverted scenarios for both current and predicte...

Background/Question/Methods Our improved ability to model climate allows us to better estimate ho... more Background/Question/Methods Our improved ability to model climate allows us to better estimate how climate change will alter freshwater habitat quality and availability. However, significant challenges remain, particularly in combining the effects of climate change and human habitat alteration. We examined these impacts on shallow water beach habitat (SWH) in the lower Willamette River, Oregon (U.S.A.). A proposed project to stabilize ~450 m (1500 ft) of shoreline with riprap would alter SWH and is subject to Endangered Species Act (ESA) Section 7 consultation. The lower river has been highly altered by urban and industrial development. Mainstem beach SWH is important to subyearling ESA-listed Upper Willamette River Chinook salmon (Oncorhynchus tshawytscha), and the amount of SWH fluctuates with river stage levels. Historically, the lower river was connected to its floodplain and river stages in the spring often significantly exceeded modern flood stages, providing additional but no...

Transactions of the American Fisheries Society

Background/Question/Methods A changing climate makes the conservation of marine, estuarine, and f... more Background/Question/Methods A changing climate makes the conservation of marine, estuarine, and freshwater organisms even more challenging than these efforts would normally be due to the strong links between climatic and aquatic processes, the dynamism of aquatic systems, the large migrations of many aquatic organisms, and the relative uncertainty of the pace and magnitude of climate-related changes in some areas. Changing environmental conditions (including ocean acidification) have the potential not only to worsen the conditions for imperiled species, but also to pose new scientific and societal challenges to their conservation especially within the context of statutory mandates such as the U.S. Endangered Species Act (ESA). Recent court decisions have affirmed the importance of considering climate change in determinations under the ESA. Recognizing the need to address this issue, the U.S. National Marine Fisheries Service (NMFS) conducted eight case studies to explore approaches ...

Many conservation and recovery efforts are contemplating the reintroduction of anadromous salmoni... more Many conservation and recovery efforts are contemplating the reintroduction of anadromous salmonids to areas from which they have been extirpated. Given the wide range of settings under which these reintroductions might take place, and the variety of goals for these efforts, appropriate approaches for reintroductions are likely to vary. We reviewed scientific considerations for reintroduction efforts, and identified conditions particularly conducive to successful reintroductions. Areas considered include the effect of the reintroduction on overall population and ESU viability, past and current limiting factors, condition of the habitat in the area to be open, the presence of native and introduce species, contingency planning, alternative approaches to recolonization, source stocks, and passage issues. We also treated emerging issues such as evolutionary responses to habitat blockage and opening, and considerations for reintroductions in a changing climate. Finally, we applied the pr...

Ecological Applications, 2013

Climate change is likely to lead to increasing population variability and extinction risk. Theore... more Climate change is likely to lead to increasing population variability and extinction risk. Theoretically, greater population diversity should buffer against rising climate variability, and this theory is often invoked as a reason for greater conservation. However, this has rarely been quantified. Here we show how a portfolio approach to managing population diversity can inform metapopulation conservation priorities in a changing world. We develop a salmon metapopulation model in which productivity is driven by spatially distributed thermal tolerance and patterns of short- and long-term climate change. We then implement spatial conservation scenarios that control population carrying capacities and evaluate the metapopulation portfolios as a financial manager might: along axes of conservation risk and return. We show that preserving a diversity of thermal tolerances minimizes risk, given environmental stochasticity, and ensures persistence, given long-term environmental change. When the thermal tolerances of populations are unknown, doubling the number of populations conserved may nearly halve expected metapopulation variability. However, this reduction in variability can come at the expense of long-term persistence if climate change increasingly restricts available habitat, forcing ecological managers to balance society's desire for short-term stability and long-term viability. Our findings suggest the importance of conserving the processes that promote thermal-tolerance diversity, such as genetic diversity, habitat heterogeneity, and natural disturbance regimes, and demonstrate that diverse natural portfolios may be critical for metapopulation conservation in the face of increasing climate variability and change.

Transactions of the American Fisheries Society, 2012

Transactions of the American Fisheries Society, 2012

ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout... more ABSTRACT Pacific salmon Oncorhynchus spp. experience multiple small-scale disturbances throughout their freshwater habitat, but the cumulative effect of these disturbances is often not known or not easily quantifiable. One such disturbance is water diversions, which can entrain fish and alter streamflow regimes. Threatened Lemhi River (Idaho) Chinook salmon O. tshawytscha smolts encounter 41–71 water diversions during their out-migration. We used passive integrated transponder tag data to model the entrainment rate of Chinook salmon smolts as a function of the proportion of water removed by an irrigation diversion. Under median-streamflow conditions with unscreened diversions, the estimated cumulative effect of the diversions was a loss of 71.1% of out-migrating smolts due to entrainment. This is a large potential source of mortality, but screening is an effective mitigation strategy, as estimated mortality was reduced to 1.9% when all diversions were screened. If resources are limited, targeting the diversions that remove a large amount of water and diversions in locations with high fish encounter rates is most effective. Our modeling approach could be used to quantify the entrainment effects of water diversions and set screening priorities for other watersheds.Received October 28, 2011; accepted March 19, 2012

Journal of Evolutionary Biology, 1995

It has been suggested that the biogeographic and clade-level characteristics of marine invertebra... more It has been suggested that the biogeographic and clade-level characteristics of marine invertebrate groups important in survival through mass extinctions are different from those important in survival during normal times. The role played by ecologically important characters in survival across mass extinctions, however, has not been well-studied.

Conservation Biology, 2013

Significant challenges remain in the ability to estimate habitat change under the combined effect... more Significant challenges remain in the ability to estimate habitat change under the combined effects of natural variability, climate change, and human activity. We examined anticipated effects on shallow water over low-sloped beaches to these combined effects in the lower Willamette River, Oregon, an area highly altered by development. A proposal to stabilize some shoreline with large rocks (riprap) would alter shallow water areas, an important habitat for threatened Chinook salmon (Oncorhynchus tshawytscha), and would be subject to U.S. Endangered Species Act-mandated oversight. In the mainstem, subyearling Chinook salmon appear to preferentially occupy these areas, which fluctuate with river stages. We estimated effects with a geospatial model and projections of future river flows. Recent (1999Recent ( -2009 median river stages during peak subyearling occupancy (April-June) maximized beach shallow water area in the lower mainstem. Upstream shallow water area was maximized at lower river stages than have occurred recently. Higher river stages in April-June, resulting from increased flows predicted for the 2080s, decreased beach shallow water area 17-32%. On the basis of projected 2080s flows, more than 15% of beach shallow water area was displaced by the riprap. Beach shallow water area lost to riprap represented up to 1.6% of the total from the mouth to 12.9 km upstream. Reductions in shallow water area could restrict salmon feeding, resting, and refuge from predators and potentially reduce opportunities for the expression of the full range of life-history strategies. Although climate change analyses provided useful information, detailed analyses are prohibitive at the project scale for the multitude of small projects reviewed annually. The benefits of our approach to resource managers include a wider geographic context for reviewing similar small projects in concert with climate change, an approach to analyze cumulative effects of similar actions, and estimation of the actions' long-term effects.

Conservation Biology, 2013

Climate change is expected to be a top driver of global biodiversity loss in the 21st century. It... more Climate change is expected to be a top driver of global biodiversity loss in the 21st century. It poses new challenges to conserving and managing imperiled species, particularly in marine and estuarine ecosystems. The use of climate-related science in statutorily driven species management, such as under the U.S. Endangered Species Act (ESA), is in its early stages. This article provides an overview of ESA processes, with emphasis on the mandate to the National Marine Fisheries Service (NMFS) to manage listed marine, estuarine, and anadromous species. Although the ESA is specific to the United States, its requirements are broadly relevant to conservation planning. Under the ESA, species, subspecies, and "distinct population segments" may be listed as either endangered or threatened, and taking of most listed species (harassing, harming, pursuing, wounding, killing, or capturing) is prohibited unless specifically authorized via a case-by-case permit process. Government agencies, in addition to avoiding take, must ensure that actions they fund, authorize, or conduct are not likely to jeopardize a listed species' continued existence or adversely affect designated critical habitat. Decisions for which climate change is likely to be a key factor include: determining whether a species should be listed under the ESA, designating critical habitat areas, developing species recovery plans, and predicting whether effects of proposed human activities will be compatible with ESA-listed species' survival and recovery. Scientific analyses that underlie these critical conservation decisions include risk assessment, longterm recovery planning, defining environmental baselines, predicting distribution, and defining appropriate temporal and spatial scales. Although specific guidance is still evolving, it is clear that the unprecedented changes in global ecosystems brought about by climate change necessitate new information and approaches to conservation of imperiled species.

Conservation Biology, 2013

Increased concern over climate change is demonstrated by the many efforts to assess climate effec... more Increased concern over climate change is demonstrated by the many efforts to assess climate effects and develop adaptation strategies. Scientists, resource managers, and decision makers are increasingly expected to use climate information, but they struggle with its uncertainty. With the current proliferation of climate simulations and downscaling methods, scientifically credible strategies for selecting a subset for analysis and decision making are needed. Drawing on a rich literature in climate science and impact assessment and on experience working with natural resource scientists and decision makers, we devised guidelines for choosing climate-change scenarios for ecological impact assessment that recognize irreducible uncertainty in climate projections and address common misconceptions about this uncertainty. This approach involves identifying primary local climate drivers by climate sensitivity of the biological system of interest; determining appropriate sources of information for future changes in those drivers; considering how well processes controlling local climate are spatially resolved; and selecting scenarios based on considering observed emission trends, relative importance of natural climate variability, and risk tolerance and time horizon of the associated decision. The most appropriate scenarios for a particular analysis will not necessarily be the most appropriate for another due to differences in local climate drivers, biophysical linkages to climate, decision characteristics, and how well a model simulates the climate parameters and processes of interest. Given these complexities, we recommend interaction among climate scientists, natural and physical scientists, and decision makers throughout the process of choosing and using climate-change scenarios for ecological impact assessment.