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• 1. [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

• 2. [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

• 3. [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

• 4. [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

• 5. [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

• 6. [Article] Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities

  Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship ...

  Citation × Citation Citation Abstract Copy Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Title: Increased Taxonomic and Functional Similarity Does Not Increase the Trophic Similarity of Communities Author: Pool, Thomas K., Cucherousset, Julien, Boulêtreau, Stéphanie, Villéger, Sébastien, Strecker, Angela L., Grenouillet, Gaël Year: 2015 Aim: Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Methods: We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results: We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions: Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning. Close

• 7. [Article] The Aquarium Trade as an Invasion Pathway in the Pacific Northwest

  The aquarium trade moves thousands of species around the globe, and unwanted organisms may be released into freshwaters, with adverse ecological and economic effects. We report on the first investigation ...

  Citation × Citation Citation Abstract Copy Title: The Aquarium Trade as an Invasion Pathway in the Pacific Northwest Author: Strecker, Angela L., Campbell, Philip M., Olden, Julian D. Year: 2011 The aquarium trade moves thousands of species around the globe, and unwanted organisms may be released into freshwaters, with adverse ecological and economic effects. We report on the first investigation of the ornamental pet trade as an invasion pathway in the Pacific Northwest region of the United States, where a moderate climate and a large human population present ample opportunities for the introduction and establishment of aquarium trade species. Results from a regional survey of pet stores found that the number of fish (n=400) and plant (n=124) species currently in the aquarium trade is vast. Pet stores import thousands of fish every month, the majority of which (58%) are considered to pose an ecological threat to native ecosystems. Our propagule pressure model suggests that approximately 2,500 fish (maximum 21,000 individuals) are likely released annually to the Puget Sound region by aquarists, and that water temperatures in many parts of Washington are suitable for establishment of populations. In conclusion, the aquarium trade may be a significant source of past and future invasions in the Pacific Northwest, and we recommend enhanced public education programs, greater regulation of the aquarium industry, and improved legislation of nonnative species in the ornamental trade. Title: The Aquarium Trade as an Invasion Pathway in the Pacific Northwest Author: Strecker, Angela L., Campbell, Philip M., Olden, Julian D. Year: 2011 The aquarium trade moves thousands of species around the globe, and unwanted organisms may be released into freshwaters, with adverse ecological and economic effects. We report on the first investigation of the ornamental pet trade as an invasion pathway in the Pacific Northwest region of the United States, where a moderate climate and a large human population present ample opportunities for the introduction and establishment of aquarium trade species. Results from a regional survey of pet stores found that the number of fish (n=400) and plant (n=124) species currently in the aquarium trade is vast. Pet stores import thousands of fish every month, the majority of which (58%) are considered to pose an ecological threat to native ecosystems. Our propagule pressure model suggests that approximately 2,500 fish (maximum 21,000 individuals) are likely released annually to the Puget Sound region by aquarists, and that water temperatures in many parts of Washington are suitable for establishment of populations. In conclusion, the aquarium trade may be a significant source of past and future invasions in the Pacific Northwest, and we recommend enhanced public education programs, greater regulation of the aquarium industry, and improved legislation of nonnative species in the ornamental trade. Close

• 8. [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

• 9. [Article] Dispersal Limitation and Climate-Related Environmental Gradients Structure Microcrustacean Composition in Freshwater Lakes, Ellesmere Island, Canada

  Dramatic environmental change is expected in the Arctic, yet little is known about the occurrence and community composition of microcrustaceans in Arctic lakes and how this will be influenced by future ...

  Citation × Citation Citation Abstract Copy Title: Dispersal Limitation and Climate-Related Environmental Gradients Structure Microcrustacean Composition in Freshwater Lakes, Ellesmere Island, Canada Author: Strecker, Angela L., Milne, Rebecca, Arnott, Shelley E. Year: 2008 Dramatic environmental change is expected in the Arctic, yet little is known about the occurrence and community composition of microcrustaceans in Arctic lakes and how this will be influenced by future environmental change. We sampled and calculated relative abundances of microcrustacean species in 54 lakes on Ellesmere Island, Canada. New species records on Ellesmere Island included Daphnia umbra, Tachidius discipes, and Artemeopsis stefanssoni. Daphnia middendorffiana/tenebrosa was the most common taxon and often dominated microcrustacean assemblages, likely a result of its pigmentation, which offers resistance to ultraviolet radiation. Species richness was positively associated with nutrients, dissolved organic carbon (DOC), temperature, calcium, and conductivity and negatively affected by elevation. In contrast to most findings in temperate systems, we detected a negative relationship between species richness and surface area. Community composition was influenced by DOC, nutrients, and elevation but was also related to spatial variables, suggesting that spatial gradients in environmental conditions and dispersal are important drivers of differences among sites. Arctic ecosystems are expected to change rapidly in the coming years because of climate change and ozone thinning, and we expect that associated changes in DOC, temperature, and nutrients will affect microcrustacean species richness and distribution throughout the landscape. Title: Dispersal Limitation and Climate-Related Environmental Gradients Structure Microcrustacean Composition in Freshwater Lakes, Ellesmere Island, Canada Author: Strecker, Angela L., Milne, Rebecca, Arnott, Shelley E. Year: 2008 Dramatic environmental change is expected in the Arctic, yet little is known about the occurrence and community composition of microcrustaceans in Arctic lakes and how this will be influenced by future environmental change. We sampled and calculated relative abundances of microcrustacean species in 54 lakes on Ellesmere Island, Canada. New species records on Ellesmere Island included Daphnia umbra, Tachidius discipes, and Artemeopsis stefanssoni. Daphnia middendorffiana/tenebrosa was the most common taxon and often dominated microcrustacean assemblages, likely a result of its pigmentation, which offers resistance to ultraviolet radiation. Species richness was positively associated with nutrients, dissolved organic carbon (DOC), temperature, calcium, and conductivity and negatively affected by elevation. In contrast to most findings in temperate systems, we detected a negative relationship between species richness and surface area. Community composition was influenced by DOC, nutrients, and elevation but was also related to spatial variables, suggesting that spatial gradients in environmental conditions and dispersal are important drivers of differences among sites. Arctic ecosystems are expected to change rapidly in the coming years because of climate change and ozone thinning, and we expect that associated changes in DOC, temperature, and nutrients will affect microcrustacean species richness and distribution throughout the landscape. Close

• 10. [Article] OSMB AIS Funds Final Report: Task 1 Boat Ramp Monitoring for New Zealand Mud Snails

  The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is an invasive species found in a variety of ecosystems in Oregon, including brackish estuaries, heavily used recreational rivers, and highly ...

  Citation × Citation Citation Abstract Copy Title: OSMB AIS Funds Final Report: Task 1 Boat Ramp Monitoring for New Zealand Mud Snails Author: Brenneis, Valance, Cimino, Samuel, Strecker, Angela L. Year: 2013 The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is an invasive species found in a variety of ecosystems in Oregon, including brackish estuaries, heavily used recreational rivers, and highly trafficked coastal freshwater lakes. NZMS are an invasive species of concern because once established, they may out-compete native invertebrate grazers, such as native insect larvae that provide important food resources for fish, and NZMS themselves provide little nutritional value. Monitoring for the presence and population density of NZMS was performed at boat ramps located along several water bodies in 2006 – 2007. These water bodies were then re-sampled during the summer of 2012 and winter of 2013 to investigate changes in population densities, as well as the potential spread of NZMS. In addition, six brackish estuaries and six freshwater coastal lakes were sampled in the summer of 2013 once again for population densities but also for stable isotope analysis to better understand the influence NZMS may have on these different ecosystem food webs. This work addresses how NZMS densities differ across invaded sites, how densities vary over time, how community diversity in rivers and estuaries varies between sites and over time, whether there is a correlation between NZMS densities and invertebrate diversity, and whether NZMS density correlates with decreasing dietary specificity for competing benthic invertebrates. Samples were sorted, identified, and counted, and stable isotope analyses from the summer 2013 field season were conducted on macroinvertebrates, zooplankton, and primary producers at the UC Davis Stable Isotope Facility. NZMS densities were found to be dynamic, with population densities increasing and decreasing over time and space. Additionally, two waterbodies (the lower Siuslaw River and the Nestucca River Estuary) previously without reported NZMS presence were identified to have established NZMS populations. Across invaded sites during the 2006 and 2012 sampling periods, there was a strong negative correlation between NZMS density and the diversity of the benthic invertebrate community. Within sites, no significant correlation was detected. High NZMS population densities were found to have a significantly negative relationship with detritivore density populations in the freshwater lake sites sampled in the summer of 2013. There were no significant relationships between NZMS and the density of any particular macroinvertebrate feeding habit group in estuaries. Additionally, stable isotope analyses indicated that NZMS at high population densities in the freshwater lakes share a similar stable isotope signature with macroinvertebrate herbivores, but NZMS had a more specific or narrow dietary range suggesting macroinvertebrate herbivores had more generalized diets than NZMS when at high densities. Conversely, NZMS population densities in the brackish estuary ecosystems showed no discernable patterns from the stable isotope analyses to indicate that their presence, either at high or low density, had an effect on the estuarine food webs. We concluded that continued research on long term population dynamics of invasive species like NZMS and their effects on native food webs remain crucial to future management and mitigation. Title: OSMB AIS Funds Final Report: Task 1 Boat Ramp Monitoring for New Zealand Mud Snails Author: Brenneis, Valance, Cimino, Samuel, Strecker, Angela L. Year: 2013 The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is an invasive species found in a variety of ecosystems in Oregon, including brackish estuaries, heavily used recreational rivers, and highly trafficked coastal freshwater lakes. NZMS are an invasive species of concern because once established, they may out-compete native invertebrate grazers, such as native insect larvae that provide important food resources for fish, and NZMS themselves provide little nutritional value. Monitoring for the presence and population density of NZMS was performed at boat ramps located along several water bodies in 2006 – 2007. These water bodies were then re-sampled during the summer of 2012 and winter of 2013 to investigate changes in population densities, as well as the potential spread of NZMS. In addition, six brackish estuaries and six freshwater coastal lakes were sampled in the summer of 2013 once again for population densities but also for stable isotope analysis to better understand the influence NZMS may have on these different ecosystem food webs. This work addresses how NZMS densities differ across invaded sites, how densities vary over time, how community diversity in rivers and estuaries varies between sites and over time, whether there is a correlation between NZMS densities and invertebrate diversity, and whether NZMS density correlates with decreasing dietary specificity for competing benthic invertebrates. Samples were sorted, identified, and counted, and stable isotope analyses from the summer 2013 field season were conducted on macroinvertebrates, zooplankton, and primary producers at the UC Davis Stable Isotope Facility. NZMS densities were found to be dynamic, with population densities increasing and decreasing over time and space. Additionally, two waterbodies (the lower Siuslaw River and the Nestucca River Estuary) previously without reported NZMS presence were identified to have established NZMS populations. Across invaded sites during the 2006 and 2012 sampling periods, there was a strong negative correlation between NZMS density and the diversity of the benthic invertebrate community. Within sites, no significant correlation was detected. High NZMS population densities were found to have a significantly negative relationship with detritivore density populations in the freshwater lake sites sampled in the summer of 2013. There were no significant relationships between NZMS and the density of any particular macroinvertebrate feeding habit group in estuaries. Additionally, stable isotope analyses indicated that NZMS at high population densities in the freshwater lakes share a similar stable isotope signature with macroinvertebrate herbivores, but NZMS had a more specific or narrow dietary range suggesting macroinvertebrate herbivores had more generalized diets than NZMS when at high densities. Conversely, NZMS population densities in the brackish estuary ecosystems showed no discernable patterns from the stable isotope analyses to indicate that their presence, either at high or low density, had an effect on the estuarine food webs. We concluded that continued research on long term population dynamics of invasive species like NZMS and their effects on native food webs remain crucial to future management and mitigation. Close