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• 1. [Article] Oregon Lake Watch, 2014 Annual Report

  The Oregon Lake Watch (OLW) volunteer monitoring program is now in its second year of operation, continuing its focus on early detection of aquatic invasive species (AIS), with a secondary focus on lake ...

  Citation × Citation Citation Abstract Copy Title: Oregon Lake Watch, 2014 Annual Report Author: Jordan, Meredith, Miller, Rich, Strecker, Angela L. Year: 2015 The Oregon Lake Watch (OLW) volunteer monitoring program is now in its second year of operation, continuing its focus on early detection of aquatic invasive species (AIS), with a secondary focus on lake water quality. The aquatic invasive species chosen as Watch List priorities for the OLW are based on the Oregon Department of Agriculture’s Noxious Weed List (Oregon Department of Agriculture Noxious Weed Control Program 2014) as well as professional judgement (more information can be found in Oregon Lake Watch Final Report 2014). This report summarizes the data collected by 15 of 24 OLW volunteers over 2014, across 110 sampling events and 20 Oregon lakes. Data collected by trained volunteers includes sightings of both native and aquatic invasive plants and animals, as well as recordings of lake temperature profiles, and Secchi depth, a measure of clarity. Of the 16 original water bodies surveyed in OLW’s first year (2013), 12 were surveyed again in 2014, and 8 are new waterbodies. Long-term monitoring of these lakes provides valuable information over time, and expanding the number of lakes monitored, especially in the case of monitoring for invasive species, means that more potentially harmful invasions can be stopped sooner. Ideally, the OLW will continue to monitor these current lakes, and expand their volunteer network to cover more waterbodies across Oregon as this program continues to grow. Title: Oregon Lake Watch, 2014 Annual Report Author: Jordan, Meredith, Miller, Rich, Strecker, Angela L. Year: 2015 The Oregon Lake Watch (OLW) volunteer monitoring program is now in its second year of operation, continuing its focus on early detection of aquatic invasive species (AIS), with a secondary focus on lake water quality. The aquatic invasive species chosen as Watch List priorities for the OLW are based on the Oregon Department of Agriculture’s Noxious Weed List (Oregon Department of Agriculture Noxious Weed Control Program 2014) as well as professional judgement (more information can be found in Oregon Lake Watch Final Report 2014). This report summarizes the data collected by 15 of 24 OLW volunteers over 2014, across 110 sampling events and 20 Oregon lakes. Data collected by trained volunteers includes sightings of both native and aquatic invasive plants and animals, as well as recordings of lake temperature profiles, and Secchi depth, a measure of clarity. Of the 16 original water bodies surveyed in OLW’s first year (2013), 12 were surveyed again in 2014, and 8 are new waterbodies. Long-term monitoring of these lakes provides valuable information over time, and expanding the number of lakes monitored, especially in the case of monitoring for invasive species, means that more potentially harmful invasions can be stopped sooner. Ideally, the OLW will continue to monitor these current lakes, and expand their volunteer network to cover more waterbodies across Oregon as this program continues to grow. Close

• 2. [Article] Oregon Lake Watch, 2015 Annual Report

  The Oregon Lake Watch (OLW) volunteer monitoring program completed its third year of operation during 2015 with a focus on early detection of aquatic invasive species (AIS) and water quality status and ...

  Citation × Citation Citation Abstract Copy Title: Oregon Lake Watch, 2015 Annual Report Author: Cimino, Samuel, Miller, Rich, Strecker, Angela L. Year: 2015 The Oregon Lake Watch (OLW) volunteer monitoring program completed its third year of operation during 2015 with a focus on early detection of aquatic invasive species (AIS) and water quality status and trend assessments for the better management of Oregon’s lakes and reservoirs. AIS surveys emphasized the detection of Watch List aquatic plant and species that can have a negative impacts on the beneficial uses of our waterbodies. Water transparency and temperature measurements were used to track the condition of volunteers' lakes. Thirty-one Oregon lakes have been surveyed during the OLW’s three years, 16 of which were surveyed during 2015. Seven lakes have been surveyed all three years and seven more have been surveyed two of the three years. Four Watch List plant and one animal species were found during 2015. Eurasian watermilfoil (Myriophyllum spicatum) was found in three lakes, Brazilian elodea (Egeria densa) and curly leaf pondweed (Potamogeton crispus) were each found in two lakes, and yellow flag iris (Iris pseudacorus) was found in one lake. Asian clams (Corbicula fluminea) were found in one lake. A diverse array of native plants were found along with native signal crayfish (Pacifasticus leniusculus). Water quality ranged from eutrophic to oligotrophic conditions based on water transparency and water temperatures ranged as high as 28°C (82°F). More years of data collection are necessary to track water quality trends. Title: Oregon Lake Watch, 2015 Annual Report Author: Cimino, Samuel, Miller, Rich, Strecker, Angela L. Year: 2015 The Oregon Lake Watch (OLW) volunteer monitoring program completed its third year of operation during 2015 with a focus on early detection of aquatic invasive species (AIS) and water quality status and trend assessments for the better management of Oregon’s lakes and reservoirs. AIS surveys emphasized the detection of Watch List aquatic plant and species that can have a negative impacts on the beneficial uses of our waterbodies. Water transparency and temperature measurements were used to track the condition of volunteers' lakes. Thirty-one Oregon lakes have been surveyed during the OLW’s three years, 16 of which were surveyed during 2015. Seven lakes have been surveyed all three years and seven more have been surveyed two of the three years. Four Watch List plant and one animal species were found during 2015. Eurasian watermilfoil (Myriophyllum spicatum) was found in three lakes, Brazilian elodea (Egeria densa) and curly leaf pondweed (Potamogeton crispus) were each found in two lakes, and yellow flag iris (Iris pseudacorus) was found in one lake. Asian clams (Corbicula fluminea) were found in one lake. A diverse array of native plants were found along with native signal crayfish (Pacifasticus leniusculus). Water quality ranged from eutrophic to oligotrophic conditions based on water transparency and water temperatures ranged as high as 28°C (82°F). More years of data collection are necessary to track water quality trends. Close

• 3. [Article] OSMB Final Report, Task 4: Oregon Lake Watch

  The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species ...

  Citation × Citation Citation Abstract Copy Title: OSMB Final Report, Task 4: Oregon Lake Watch Author: Strecker, Angela L., Miller, Rich, Morgan, Vanessa Year: 2014 The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species (AIS), provide early detection of AIS invasions, and provide long term water quality data for the better management of Oregon’s lakes and reservoirs. Protocols were created for citizen scientists to survey for AIS, collect temperature and water clarity data, and record the data through an online data entry portal. An OLW website was developed to educate about AIS and provide survey protocols and identification materials to volunteers. AIS surveys were focused on Watch List Species which are selected AIS that have a negative impact on the beneficial uses of our waterbodies. Eighteen volunteers were trained during five sessions conducted in western and central Oregon. Fourteen of the trained volunteers collected data from sixteen waterbodies. Six Watch List species and one other AIS species were observed in four of the waterbodies. The three Watch List Species observed in Salish Pond and one in Olallie Lake were new observations. Temperature measurements indicated a wide range of thermal profiles and Secchi transparency measurement indicated a range of trophic status from oligotrophic to eutrophic. Title: OSMB Final Report, Task 4: Oregon Lake Watch Author: Strecker, Angela L., Miller, Rich, Morgan, Vanessa Year: 2014 The Oregon Lake Watch (OLW) volunteer monitoring program was resurrected after over a decade in hibernation. The new program was designed to educate the public about threats of aquatic invasive species (AIS), provide early detection of AIS invasions, and provide long term water quality data for the better management of Oregon’s lakes and reservoirs. Protocols were created for citizen scientists to survey for AIS, collect temperature and water clarity data, and record the data through an online data entry portal. An OLW website was developed to educate about AIS and provide survey protocols and identification materials to volunteers. AIS surveys were focused on Watch List Species which are selected AIS that have a negative impact on the beneficial uses of our waterbodies. Eighteen volunteers were trained during five sessions conducted in western and central Oregon. Fourteen of the trained volunteers collected data from sixteen waterbodies. Six Watch List species and one other AIS species were observed in four of the waterbodies. The three Watch List Species observed in Salish Pond and one in Olallie Lake were new observations. Temperature measurements indicated a wide range of thermal profiles and Secchi transparency measurement indicated a range of trophic status from oligotrophic to eutrophic. Close

• 4. [Article] OSMB Final Report: Task 6. Tenmile Lake Boat Wash Effectiveness Monitoring

  Public awareness of aquatic invasive species and proper boat cleaning procedures may prove to be beneficial in reducing the transport and establishment of aquatic invasive species like New Zealand mud ...

  Citation × Citation Citation Abstract Copy Title: OSMB Final Report: Task 6. Tenmile Lake Boat Wash Effectiveness Monitoring Author: Cimino, Samuel, Strecker, Angela L. Year: 2014 Public awareness of aquatic invasive species and proper boat cleaning procedures may prove to be beneficial in reducing the transport and establishment of aquatic invasive species like New Zealand mud snails and zebra and quagga mussels as well as hydrilla and Eurasian watermilfoil. The primary objectives of this research project were to observe the use and determine the efficacy of a public boat wash station as well as increase the public’s awareness of proper boat cleaning procedures and aquatic invasive species. The Tenmile Lakes Basin Partnership, Oregon State Marine Board, and the United States Forest Service (USFS) have undertaken an initiative to increase public awareness of invasive species and proper cleaning procedures by building a boat wash station at the Tenmile Lake public boat launch. In the summer of 2012, 199 qualitative human subject surveys were administered at Tenmile Lake in Lakeside, Oregon to boaters on their boating habits and knowledge of invasive species prior to building the boat wash (“pre-boat wash”). An extension of the 2012 study was conducted in the summer of 2013 on 200 boaters after the completion of the Tenmile Lake boat wash station (“post-boat wash”). Comparisons were made on the observations and answers of boaters prior to and after the boat wash installation. Of the boaters surveyed in the pre-boat wash field season, 75.9% of boaters claimed they would use a boat wash station at Tenmile Lake. The actual use of the boat wash station based on observations made by the field researcher during the post-boat wash field season indicated only 38.5% of surveyed boaters used the station. Furthermore, more than 20% of boaters could not verbally identify an invasive species in either field season when asked their awareness of aquatic invasive species. However, the majority of boaters surveyed at Tenmile Lake in the pre-boat wash field season (63.3%) and post-boat wash field season (66%) were aware of the phrase “Clean, Drain, Dry”. These results identify a disconnect in what boaters say and what boaters do and the knowledge gaps boaters have on aquatic invasive species, but these results also identify a growing awareness of proper boat cleaning procedures. Title: OSMB Final Report: Task 6. Tenmile Lake Boat Wash Effectiveness Monitoring Author: Cimino, Samuel, Strecker, Angela L. Year: 2014 Public awareness of aquatic invasive species and proper boat cleaning procedures may prove to be beneficial in reducing the transport and establishment of aquatic invasive species like New Zealand mud snails and zebra and quagga mussels as well as hydrilla and Eurasian watermilfoil. The primary objectives of this research project were to observe the use and determine the efficacy of a public boat wash station as well as increase the public’s awareness of proper boat cleaning procedures and aquatic invasive species. The Tenmile Lakes Basin Partnership, Oregon State Marine Board, and the United States Forest Service (USFS) have undertaken an initiative to increase public awareness of invasive species and proper cleaning procedures by building a boat wash station at the Tenmile Lake public boat launch. In the summer of 2012, 199 qualitative human subject surveys were administered at Tenmile Lake in Lakeside, Oregon to boaters on their boating habits and knowledge of invasive species prior to building the boat wash (“pre-boat wash”). An extension of the 2012 study was conducted in the summer of 2013 on 200 boaters after the completion of the Tenmile Lake boat wash station (“post-boat wash”). Comparisons were made on the observations and answers of boaters prior to and after the boat wash installation. Of the boaters surveyed in the pre-boat wash field season, 75.9% of boaters claimed they would use a boat wash station at Tenmile Lake. The actual use of the boat wash station based on observations made by the field researcher during the post-boat wash field season indicated only 38.5% of surveyed boaters used the station. Furthermore, more than 20% of boaters could not verbally identify an invasive species in either field season when asked their awareness of aquatic invasive species. However, the majority of boaters surveyed at Tenmile Lake in the pre-boat wash field season (63.3%) and post-boat wash field season (66%) were aware of the phrase “Clean, Drain, Dry”. These results identify a disconnect in what boaters say and what boaters do and the knowledge gaps boaters have on aquatic invasive species, but these results also identify a growing awareness of proper boat cleaning procedures. Close

• 5. [Article] The Interplay Between Landscape Structure and Biotic Interactions

  Landscape structure and biotic interactions are closely linked. We identify five aspects of landscape structure that contribute to the co-occurrence of species and restrict or enable different types of ...

  Citation × Citation Citation Abstract Copy Title: The Interplay Between Landscape Structure and Biotic Interactions Author: Zarnetske, Phoebe, Baiser, Benjamin, Strecker, Angela L., Record, Sydne, Belmaker, Jonathan, Tuanmu, Mao-Ning Year: 2017 Landscape structure and biotic interactions are closely linked. We identify five aspects of landscape structure that contribute to the co-occurrence of species and restrict or enable different types of biotic interactions: patch size and habitat amount, isolation of patches, barriers to dispersal and movement, persistence of landscape structure, and landscape complexity. In addition, these aspects of landscape structure influence the strength and outcome of biotic interactions. Whereas most research focuses on the effects of the abiotic environment on species and their biotic interactions, research on foundation species and ecosystem engineers demonstrates the important influence of biotic interactions on landscape structure itself, including effects on landscape complexity, extent of habitat, and the structure of landscape features. In this review, we describe ecological theories that lay the foundation for interplay between landscape structure and biotic interactions, and summarize these connections across an array of interacting species in freshwater, marine, and terrestrial systems. We end with suggestions for integrating the fields of landscape ecology and community ecology to better understand the connections between landscape structure and biotic interactions and better predict their dynamics in light of global change. Title: The Interplay Between Landscape Structure and Biotic Interactions Author: Zarnetske, Phoebe, Baiser, Benjamin, Strecker, Angela L., Record, Sydne, Belmaker, Jonathan, Tuanmu, Mao-Ning Year: 2017 Landscape structure and biotic interactions are closely linked. We identify five aspects of landscape structure that contribute to the co-occurrence of species and restrict or enable different types of biotic interactions: patch size and habitat amount, isolation of patches, barriers to dispersal and movement, persistence of landscape structure, and landscape complexity. In addition, these aspects of landscape structure influence the strength and outcome of biotic interactions. Whereas most research focuses on the effects of the abiotic environment on species and their biotic interactions, research on foundation species and ecosystem engineers demonstrates the important influence of biotic interactions on landscape structure itself, including effects on landscape complexity, extent of habitat, and the structure of landscape features. In this review, we describe ecological theories that lay the foundation for interplay between landscape structure and biotic interactions, and summarize these connections across an array of interacting species in freshwater, marine, and terrestrial systems. We end with suggestions for integrating the fields of landscape ecology and community ecology to better understand the connections between landscape structure and biotic interactions and better predict their dynamics in light of global change. Close

• 6. [Article] Physical, Chemical and Biological Assessment of Yoncalla Log Ponds

  The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and ...

  Citation × Citation Citation Abstract Copy Title: Physical, Chemical and Biological Assessment of Yoncalla Log Ponds Author: Miller, Rich, Sytsma, Mark D., Strecker, Angela L. Year: 2014 The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and the 1950s and used for log storage through the 1970s (North Douglas Betterment 2014). North Douglas Betterment purchased the land surrounding the ponds and contracted with the Center for Lakes and Reservoirs at Portland State University to assess the current morphometry, vegetation and water quality status of the ponds and provide recommendations for management of the aquatic vegetation. The scope of this document covers the current status assessment of the ponds using data collected from June 2013 through May 2014. Title: Physical, Chemical and Biological Assessment of Yoncalla Log Ponds Author: Miller, Rich, Sytsma, Mark D., Strecker, Angela L. Year: 2014 The Yoncalla Log Ponds are a series of four ponds located in within the city limits of the town in Yoncalla in northern Douglas County, Oregon. The ponds were created in stages between the late 1930s and the 1950s and used for log storage through the 1970s (North Douglas Betterment 2014). North Douglas Betterment purchased the land surrounding the ponds and contracted with the Center for Lakes and Reservoirs at Portland State University to assess the current morphometry, vegetation and water quality status of the ponds and provide recommendations for management of the aquatic vegetation. The scope of this document covers the current status assessment of the ponds using data collected from June 2013 through May 2014. Close

• 7. [Article] Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters

  Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. ...

  Citation × Citation Citation Abstract Copy Title: Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters Author: Strecker, Angela L., Olden, Julian D. Year: 2014 Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. Title: Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters Author: Strecker, Angela L., Olden, Julian D. Year: 2014 Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. Close

• 8. [Article] Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives

  Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in ...

  Citation × Citation Citation Abstract Copy Title: Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives Author: Strecker, Angela L., Brittain, Jeffrey Thomas Year: 2017 Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown. Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables. Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies. We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes. Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species. Title: Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives Author: Strecker, Angela L., Brittain, Jeffrey Thomas Year: 2017 Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown. Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables. Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies. We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes. Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species. Close

• 9. [Article] Factors Influencing the Survival of Outmigrating Juvenile Salmonids Through Multiple Dam Passages: An Individual-Based Approach

  Substantial declines of Pacific salmon populations have occurred over the past several decades related to large-scale anthropogenic and climatic changes in freshwater and marine environments. In the Columbia ...

  Citation × Citation Citation Abstract Copy Title: Factors Influencing the Survival of Outmigrating Juvenile Salmonids Through Multiple Dam Passages: An Individual-Based Approach Author: Elder, Timothy, Woodley, Christa M., Weiland, Mark A., Strecker, Angela L. Year: 2016 Substantial declines of Pacific salmon populations have occurred over the past several decades related to large-scale anthropogenic and climatic changes in freshwater and marine environments. In the Columbia River Basin, migrating juvenile salmonids may pass as many as eight large-scale hydropower projects before reaching the ocean; however, the cumulative effects of multiple dam passages are largely unknown. Using acoustic transmitters and an extensive system of hydrophone arrays in the Lower Columbia River, we calculated the survival of yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) passing one, two, or three dams. We applied a unique index of biological characteristics and environmental exposures, experienced by each fish individually as it migrated downstream, in order to examine which factors most influence salmonid survival. High outflow volumes led to involuntary spill in 2011 and created an environment of supersaturated dissolved gas concentrations. In this environment, migrating smolt survival was strongly influenced by barometric pressure, fish velocity, and water temperature. The effect of these variables on survival was compounded by multiple dam passages compared to fish passing a single dam. Despite spatial isolation between dams in the Lower Columbia River hydrosystem, migrating smolt appear to experience cumulative effects akin to a press disturbance. In general, Chinook salmon and steelhead respond similarly in terms of survival rates and responses to altered environmental conditions. Management actions that limit dissolved gas concentrations in years of high flow will benefit migrating salmonids at this life stage. Title: Factors Influencing the Survival of Outmigrating Juvenile Salmonids Through Multiple Dam Passages: An Individual-Based Approach Author: Elder, Timothy, Woodley, Christa M., Weiland, Mark A., Strecker, Angela L. Year: 2016 Substantial declines of Pacific salmon populations have occurred over the past several decades related to large-scale anthropogenic and climatic changes in freshwater and marine environments. In the Columbia River Basin, migrating juvenile salmonids may pass as many as eight large-scale hydropower projects before reaching the ocean; however, the cumulative effects of multiple dam passages are largely unknown. Using acoustic transmitters and an extensive system of hydrophone arrays in the Lower Columbia River, we calculated the survival of yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) passing one, two, or three dams. We applied a unique index of biological characteristics and environmental exposures, experienced by each fish individually as it migrated downstream, in order to examine which factors most influence salmonid survival. High outflow volumes led to involuntary spill in 2011 and created an environment of supersaturated dissolved gas concentrations. In this environment, migrating smolt survival was strongly influenced by barometric pressure, fish velocity, and water temperature. The effect of these variables on survival was compounded by multiple dam passages compared to fish passing a single dam. Despite spatial isolation between dams in the Lower Columbia River hydrosystem, migrating smolt appear to experience cumulative effects akin to a press disturbance. In general, Chinook salmon and steelhead respond similarly in terms of survival rates and responses to altered environmental conditions. Management actions that limit dissolved gas concentrations in years of high flow will benefit migrating salmonids at this life stage. Close

• 10. [Article] Empirical Evidence for the Scale Dependence of Biotic Interactions

  Aim: Although it is recognized that ecological patterns are scale dependent, the exact scales over which specific ecological processes operate are still a matter of controversy. In particular, understanding ...

  Citation × Citation Citation Abstract Copy Title: Empirical Evidence for the Scale Dependence of Biotic Interactions Author: Belmaker, Jonathan, Zarnetske, Phoebe, Zonneveld, Sara, Record, Sydne, Strecker, Angela L., Beaudrot, Lydia Year: 2015 Aim: Although it is recognized that ecological patterns are scale dependent, the exact scales over which specific ecological processes operate are still a matter of controversy. In particular, understanding the scales over which biotic interactions operate is critical for predicting changes in species distributions in the face of the ongoing biodiversity crisis. It has been hypothesized that biotic interactions operate predominately at fine grains, yet this conjecture has received relatively little empirical scrutiny. We use US woodpeckers as a model system to assess the relative importance of biotic interactions, environmental suitability and geographic proximity to other intraspecific occurrence sites, across scales. Methods: We combined species occurrence data from the North American Breeding Bird Survey (BBS) with a large pair-wise interaction matrix describing known interactions among woodpeckers and other bird species. Using a logistic mixed modelling framework we then established the relative importance of biotic interactions as predictors of woodpecker occurrences in relation to environment and geographic proximity to intraspecific occurrence sites. Results: We found that geographic proximity becomes a stronger predictor of woodpecker occurrence as grain becomes coarser, while environment is grain-invariant. As opposed to environment and geographic proximity, we found that when the focal species experienced positive biotic interactions, the importance of interactions decreased with increased grain. However, positive interactions remained important up to a grain size of entire BBS routes (c. 40 km), which is much coarser than the grain size used by most species distribution models. In contrast, when the focal species experienced negative interactions we did not find clear grain dependence. Main conclusions: Biotic interactions (both positive and negative) are important predictors of species occurrences. While these interactions are strongest at fine grains, they can remain important even at coarse grains, and are thus critical for predicting distributional changes in the face of the ongoing biodiversity crisis. Title: Empirical Evidence for the Scale Dependence of Biotic Interactions Author: Belmaker, Jonathan, Zarnetske, Phoebe, Zonneveld, Sara, Record, Sydne, Strecker, Angela L., Beaudrot, Lydia Year: 2015 Aim: Although it is recognized that ecological patterns are scale dependent, the exact scales over which specific ecological processes operate are still a matter of controversy. In particular, understanding the scales over which biotic interactions operate is critical for predicting changes in species distributions in the face of the ongoing biodiversity crisis. It has been hypothesized that biotic interactions operate predominately at fine grains, yet this conjecture has received relatively little empirical scrutiny. We use US woodpeckers as a model system to assess the relative importance of biotic interactions, environmental suitability and geographic proximity to other intraspecific occurrence sites, across scales. Methods: We combined species occurrence data from the North American Breeding Bird Survey (BBS) with a large pair-wise interaction matrix describing known interactions among woodpeckers and other bird species. Using a logistic mixed modelling framework we then established the relative importance of biotic interactions as predictors of woodpecker occurrences in relation to environment and geographic proximity to intraspecific occurrence sites. Results: We found that geographic proximity becomes a stronger predictor of woodpecker occurrence as grain becomes coarser, while environment is grain-invariant. As opposed to environment and geographic proximity, we found that when the focal species experienced positive biotic interactions, the importance of interactions decreased with increased grain. However, positive interactions remained important up to a grain size of entire BBS routes (c. 40 km), which is much coarser than the grain size used by most species distribution models. In contrast, when the focal species experienced negative interactions we did not find clear grain dependence. Main conclusions: Biotic interactions (both positive and negative) are important predictors of species occurrences. While these interactions are strongest at fine grains, they can remain important even at coarse grains, and are thus critical for predicting distributional changes in the face of the ongoing biodiversity crisis. Close