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• 1. [Article] A Behavior-Based Framework for Assessing Barrier Effects to Wildlife from Vehicle Traffic Volume

  Roads, while central to the function of human society, create barriers to animal movement through collisions and habitat fragmentation. Barriers to animal movement affect the evolution and trajectory of ...

  Citation × Citation Citation Abstract Copy Title: A Behavior-Based Framework for Assessing Barrier Effects to Wildlife from Vehicle Traffic Volume Author: Jacobson, Sandra L., Bliss-Ketchum, Leslie L., de Rivera, Catherine E., Smith, Winston P. Year: 2016 Roads, while central to the function of human society, create barriers to animal movement through collisions and habitat fragmentation. Barriers to animal movement affect the evolution and trajectory of populations. Investigators have attempted to use traffic volume, the number of vehicles passing a point on a road segment, to predict effects to wildlife populations approximately linearly and along taxonomic lines; however, taxonomic groupings cannot provide sound predictions because closely related species often respond differently. We assess the role of wildlife behavioral responses to traffic volume as a tool to predict barrier effects from vehicle-caused mortality and avoidance, to provide an early warning system that recognizes traffic volume as a trigger for mitigation, and to better interpret roadkill data. We propose four categories of behavioral response based on the perceived danger to traffic: Nonresponders, Pausers, Speeders, and Avoiders. Nonresponders attempt to cross highways regardless of traffic volume. Pausers stop in the face of danger so have a low probability of successful crossing when traffic volume increases. Hence, highway barrier effects are primarily due to mortality for Nonresponders and Pausers at high traffic volumes. Speeders run away from danger but are unable to do so successfully as traffic volume increases. At moderate to high volume, Speeders are repelled by traffic danger. Avoiders face lower mortality than other categories because they begin to avoid traffic at relatively low traffic volumes. Hence, avoidance causes barrier effects more than mortality for Speeders and Avoiders even at relatively moderate traffic volumes. By considering a species’ risk-avoidance response to traffic, managers can make more appropriate and timely decisions to mitigate effects before populations decline or become locally extinct. Title: A Behavior-Based Framework for Assessing Barrier Effects to Wildlife from Vehicle Traffic Volume Author: Jacobson, Sandra L., Bliss-Ketchum, Leslie L., de Rivera, Catherine E., Smith, Winston P. Year: 2016 Roads, while central to the function of human society, create barriers to animal movement through collisions and habitat fragmentation. Barriers to animal movement affect the evolution and trajectory of populations. Investigators have attempted to use traffic volume, the number of vehicles passing a point on a road segment, to predict effects to wildlife populations approximately linearly and along taxonomic lines; however, taxonomic groupings cannot provide sound predictions because closely related species often respond differently. We assess the role of wildlife behavioral responses to traffic volume as a tool to predict barrier effects from vehicle-caused mortality and avoidance, to provide an early warning system that recognizes traffic volume as a trigger for mitigation, and to better interpret roadkill data. We propose four categories of behavioral response based on the perceived danger to traffic: Nonresponders, Pausers, Speeders, and Avoiders. Nonresponders attempt to cross highways regardless of traffic volume. Pausers stop in the face of danger so have a low probability of successful crossing when traffic volume increases. Hence, highway barrier effects are primarily due to mortality for Nonresponders and Pausers at high traffic volumes. Speeders run away from danger but are unable to do so successfully as traffic volume increases. At moderate to high volume, Speeders are repelled by traffic danger. Avoiders face lower mortality than other categories because they begin to avoid traffic at relatively low traffic volumes. Hence, avoidance causes barrier effects more than mortality for Speeders and Avoiders even at relatively moderate traffic volumes. By considering a species’ risk-avoidance response to traffic, managers can make more appropriate and timely decisions to mitigate effects before populations decline or become locally extinct. Close

• 2. [Article] The Limitation of Spread of Non-native Marine Invertebrates from Artificial Structures to Natural Habitats

  Artificial structures created for aquatic anthropogenic activities are often colonized and fouled by many non-native species, few of which have invaded natural areas. Some research has indicated predation ...

  Citation × Citation Citation Abstract Copy Title: The Limitation of Spread of Non-native Marine Invertebrates from Artificial Structures to Natural Habitats Author: McClees, Whitney, de Rivera, Catherine E. Year: 2017 Artificial structures created for aquatic anthropogenic activities are often colonized and fouled by many non-native species, few of which have invaded natural areas. Some research has indicated predation is limiting the spread of non-native species, while other research has indicated that it is dispersal-driven. To determine the effects of dispersal limitation and predation on the risk to surrounding habitats of being invaded by non-native species established on marina docks, we used a three-factor design, deploying seven unglazed ceramic panels per each treatment combination of 1) inside versus outside a marina in Yaquina Bay, Oregon; 2) cage keeping out predators >mesh size, no cage, or partial cage; 3) fixed near the substrata (benthic) versus floating 1m below the surface. We also moved panels of either adults or recruits from floating in the marina to any of the treatment combinations to test if they would have lower survival outside by the substrate. The community on panels suspended in the marina only minimally overlapped with panels outside of the marina near the bottom. However, there was no difference between the cage treatments, which suggests that predators excluded by the cages are not responsible for the observed differences in species richness or composition. Title: The Limitation of Spread of Non-native Marine Invertebrates from Artificial Structures to Natural Habitats Author: McClees, Whitney, de Rivera, Catherine E. Year: 2017 Artificial structures created for aquatic anthropogenic activities are often colonized and fouled by many non-native species, few of which have invaded natural areas. Some research has indicated predation is limiting the spread of non-native species, while other research has indicated that it is dispersal-driven. To determine the effects of dispersal limitation and predation on the risk to surrounding habitats of being invaded by non-native species established on marina docks, we used a three-factor design, deploying seven unglazed ceramic panels per each treatment combination of 1) inside versus outside a marina in Yaquina Bay, Oregon; 2) cage keeping out predators >mesh size, no cage, or partial cage; 3) fixed near the substrata (benthic) versus floating 1m below the surface. We also moved panels of either adults or recruits from floating in the marina to any of the treatment combinations to test if they would have lower survival outside by the substrate. The community on panels suspended in the marina only minimally overlapped with panels outside of the marina near the bottom. However, there was no difference between the cage treatments, which suggests that predators excluded by the cages are not responsible for the observed differences in species richness or composition. Close