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• 1. [Article] Report on Nutria Management and Research in the Pacific Northwest

  The nutria (Myocastor coypus) is a large semi-aquatic mammal native to South America that has been introduced to numerous countries around the world, primarily for fur farming. Nutria were introduced in ...

  Citation × Citation Citation Abstract Copy Title: Report on Nutria Management and Research in the Pacific Northwest Author: Sheffels, Trevor Robert, Sytsma, Mark Year: 2007 The nutria (Myocastor coypus) is a large semi-aquatic mammal native to South America that has been introduced to numerous countries around the world, primarily for fur farming. Nutria were introduced in Oregon and Washington in the 1930s, and feral populations were documented in 1943. Populations are known to be expanding in both Oregon and Washington, and regional nutria damage and nuisance complaints have increased in recent years. Most of the extensive damage caused by nutria is a direct result of feeding and burrowing, but nutria are also capable of transporting parasites and pathogens transmittable to humans, livestock, and pets. Although several past regional and local nutria research and management projects have been identified, there is a shortage of nutria information from the Pacific Northwest considering that the species has been present in the region for approximately seventy years. The Center for Lakes and Reservoirs (CLR) at Portland State University (PSU), in partnership with several local, state, and federal agencies, has taken the lead in addressing the regional nutria problem. Activities completed to date include a regional nutria management workshop, the ongoing development of a regional nutria distribution/density map, and a research project to analyze the impact of nutria herbivory on regional riparian wetland habitat restoration projects. In addition, the CLR at PSU is participating in the development of the national Aquatic Nuisance Species Task Force nutria management plan. This initial assessment of the current nutria situation in the Pacific Northwest conducted by the CLR at PSU has revealed that regional nutria problems are more extensive than previously realized. Nutria sightings have now been confirmed from the Canadian border to near the southern border of Oregon, confirming a larger range than was previously known. It was also found that the main nutria issues in the Pacific Northwest differ from the main nutria issues in Louisiana and Maryland. For example, the most significant category of regional nutria damage appears to be the destruction of water control structures and associated erosion caused by nutria burrowing, as opposed to nutria herbivory damage in Louisiana and Maryland. Another unique situation in the Pacific Northwest is the high density of nutria populations in urban areas, increasing the potential for conflicts between nutria and humans. Nutria attacks have been reported in isolated cases, and nutria are rodents that carry a variety of transmittable parasites and pathogens. It has also been confirmed that significant regional nutria herbivory damage does occur at some locations. Fortunately, it has become evident through the course of this assessment that a strong regional interest to address the nutria problem exists. A wide variety of agencies and organizations across the region are being negatively impacted by nutria, and these entities are ready to move forward to develop a feasible solution. To date, small-scale nutria management and eradication efforts have been somewhat effective temporarily, but a more permanent solution requires that the situation be addressed on a much larger scale. Due to the long period of time since the initial nutria introduction, the extent of current regional nutria populations, and the changing climate patterns, a long-term effort will likely be required to effectively address the regional nutria issue. The most immediate management need is to develop an official regional nutria management plan with the focus of greatly reducing the amount of damage being caused by this invasive rodent and preventing further population growth and expansion. The effectiveness of initial management efforts will shed light on how to adapt management strategies in the future and whether or not regional eradication is a feasible option. Continued nutria research and the development of coordinated management efforts at the regional scale are vital in order to bring the current regional nutria problem under control. The CLR at PSU has developed initial recommendations to help guide the process of determining how to most effectively manage nutria in the Pacific Northwest. First and foremost, funding sources for continued work on the regional nutria problem must be found. Once funding is secured, the development of an official nutria regional management plan is crucial. Priorities connected with the management plan would include creating an early detection rapid response plan, identifying best management practices, initiating a pilot eradication program, and identifying priority research needs. Potential research studies include a long-term pilot eradication project at the watershed level, relationships between climate change and regional nutria dispersal, and the dynamics of nutria-muskrat interactions. It is also evident that further coordination between local, state, and federal agencies is necessary to delegate responsibilities and keep all parties updated. The creation of a central regional database and appropriate agency protocols could be used to collect information about nutria damage and associated economic impacts. Current laws and regulations pertaining to nutria should be enforced and possibly updated so that Oregon and Washington laws are uniform. Finally, it is important to inform the public about current nutria issues and utilize resources the general public can potentially provide. Title: Report on Nutria Management and Research in the Pacific Northwest Author: Sheffels, Trevor Robert, Sytsma, Mark Year: 2007 The nutria (Myocastor coypus) is a large semi-aquatic mammal native to South America that has been introduced to numerous countries around the world, primarily for fur farming. Nutria were introduced in Oregon and Washington in the 1930s, and feral populations were documented in 1943. Populations are known to be expanding in both Oregon and Washington, and regional nutria damage and nuisance complaints have increased in recent years. Most of the extensive damage caused by nutria is a direct result of feeding and burrowing, but nutria are also capable of transporting parasites and pathogens transmittable to humans, livestock, and pets. Although several past regional and local nutria research and management projects have been identified, there is a shortage of nutria information from the Pacific Northwest considering that the species has been present in the region for approximately seventy years. The Center for Lakes and Reservoirs (CLR) at Portland State University (PSU), in partnership with several local, state, and federal agencies, has taken the lead in addressing the regional nutria problem. Activities completed to date include a regional nutria management workshop, the ongoing development of a regional nutria distribution/density map, and a research project to analyze the impact of nutria herbivory on regional riparian wetland habitat restoration projects. In addition, the CLR at PSU is participating in the development of the national Aquatic Nuisance Species Task Force nutria management plan. This initial assessment of the current nutria situation in the Pacific Northwest conducted by the CLR at PSU has revealed that regional nutria problems are more extensive than previously realized. Nutria sightings have now been confirmed from the Canadian border to near the southern border of Oregon, confirming a larger range than was previously known. It was also found that the main nutria issues in the Pacific Northwest differ from the main nutria issues in Louisiana and Maryland. For example, the most significant category of regional nutria damage appears to be the destruction of water control structures and associated erosion caused by nutria burrowing, as opposed to nutria herbivory damage in Louisiana and Maryland. Another unique situation in the Pacific Northwest is the high density of nutria populations in urban areas, increasing the potential for conflicts between nutria and humans. Nutria attacks have been reported in isolated cases, and nutria are rodents that carry a variety of transmittable parasites and pathogens. It has also been confirmed that significant regional nutria herbivory damage does occur at some locations. Fortunately, it has become evident through the course of this assessment that a strong regional interest to address the nutria problem exists. A wide variety of agencies and organizations across the region are being negatively impacted by nutria, and these entities are ready to move forward to develop a feasible solution. To date, small-scale nutria management and eradication efforts have been somewhat effective temporarily, but a more permanent solution requires that the situation be addressed on a much larger scale. Due to the long period of time since the initial nutria introduction, the extent of current regional nutria populations, and the changing climate patterns, a long-term effort will likely be required to effectively address the regional nutria issue. The most immediate management need is to develop an official regional nutria management plan with the focus of greatly reducing the amount of damage being caused by this invasive rodent and preventing further population growth and expansion. The effectiveness of initial management efforts will shed light on how to adapt management strategies in the future and whether or not regional eradication is a feasible option. Continued nutria research and the development of coordinated management efforts at the regional scale are vital in order to bring the current regional nutria problem under control. The CLR at PSU has developed initial recommendations to help guide the process of determining how to most effectively manage nutria in the Pacific Northwest. First and foremost, funding sources for continued work on the regional nutria problem must be found. Once funding is secured, the development of an official nutria regional management plan is crucial. Priorities connected with the management plan would include creating an early detection rapid response plan, identifying best management practices, initiating a pilot eradication program, and identifying priority research needs. Potential research studies include a long-term pilot eradication project at the watershed level, relationships between climate change and regional nutria dispersal, and the dynamics of nutria-muskrat interactions. It is also evident that further coordination between local, state, and federal agencies is necessary to delegate responsibilities and keep all parties updated. The creation of a central regional database and appropriate agency protocols could be used to collect information about nutria damage and associated economic impacts. Current laws and regulations pertaining to nutria should be enforced and possibly updated so that Oregon and Washington laws are uniform. Finally, it is important to inform the public about current nutria issues and utilize resources the general public can potentially provide. Close

• 2. [Article] Status of Nutria (Myocastor coypus) Populations in the Pacific Northwest and Development of Associated Control and Management Strategies, with an Emphasis on Metropolitan Habitats

  The nutria (Myocastor coypus) is a semi-aquatic rodent native to South America that was introduced to the Pacific Northwest, USA, in the 1930s. Primary damage categories from this invasive species include ...

  Citation × Citation Citation Abstract Copy Title: Status of Nutria (Myocastor coypus) Populations in the Pacific Northwest and Development of Associated Control and Management Strategies, with an Emphasis on Metropolitan Habitats Author: Sheffels, Trevor Robert Year: 2013 The nutria (Myocastor coypus) is a semi-aquatic rodent native to South America that was introduced to the Pacific Northwest, USA, in the 1930s. Primary damage categories from this invasive species include burrowing and herbivory, resulting in habitat degradation. Nutria have become well-established in metropolitan habitats, and anecdotal information suggests the problem has increased in recent years. However, little regional research on the species has been conducted. The scope of this research, which emphasizes metropolitan habitats, includes three primary foci in relation to nutria populations in the Pacific Northwest: modeling habitat suitability, assessing activity and movement patterns, and identifying and managing negative impacts. Large-scale management of any invasive species requires understanding of the current and potential future population distribution. Cold temperatures have been assumed to be a limiting factor for the geographic distribution of nutria populations, but this assumption had not been explicitly tested. A mechanistic habitat suitability model based on winter temperatures performed well in predicting nutria distribution in the Pacific Northwest and nationally. Regional results suggest nutria currently occupy most accessible suitable habitat. However, coupling the model with future climate change data suggests a much larger suitable habitat zone regionally and nationally in the near future. Management of an invasive species on a local scale requires region-specific information about behavior patterns. Radio-telemetry tracking of local nutria populations in metropolitan habitats suggested higher diurnal activity levels than reported elsewhere. Activity areas were also on the lower end of reported nutria home ranges, suggesting the studied metropolitan wetland sites represent core habitat for nutria in the region. Comparison of two transmitter attachment methods, a neck collar and a tail mount, did not identify a clearly superior attachment method for short-term nutria behavior studies. The presence of nutria in metropolitan habitats in the Pacific Northwest necessitates the need to expand the limited management techniques available for these habitats. Standard Vexar® plastic mesh tubes very effectively mitigated nutria herbivory damage to woody vegetation live stakes planted in a metropolitan habitat restoration site. A recently developed nutria multiple-capture cage trap captured larger nutria and reduced non-target captures compared to a standard cage trap. The design of the multiple-capture trap, however, prevented multiple-capture events because small nutria escaped the trap. This research contributes substantially to previously limited information about nutria in the Pacific Northwest and resulted in several new findings. Climate change modeling provides the first evidence that nutria ranges could expand in the near future. Evaluation of new radio-telemetry methods will benefit future behavior studies. The assessment of new damage prevention tools provides more options for the management of nutria in urban habitats. Management recommendations include creating regional nutria management plans, identifying and targeting priority monitoring regions, finding key stakeholders, focusing on public education, and initiating a pilot control program. Recommendations for research include evaluating effects on native fauna, conducting disease surveys, assessing the extent of damage, continuing habitat suitability analysis, and developing population indices. Title: Status of Nutria (Myocastor coypus) Populations in the Pacific Northwest and Development of Associated Control and Management Strategies, with an Emphasis on Metropolitan Habitats Author: Sheffels, Trevor Robert Year: 2013 The nutria (Myocastor coypus) is a semi-aquatic rodent native to South America that was introduced to the Pacific Northwest, USA, in the 1930s. Primary damage categories from this invasive species include burrowing and herbivory, resulting in habitat degradation. Nutria have become well-established in metropolitan habitats, and anecdotal information suggests the problem has increased in recent years. However, little regional research on the species has been conducted. The scope of this research, which emphasizes metropolitan habitats, includes three primary foci in relation to nutria populations in the Pacific Northwest: modeling habitat suitability, assessing activity and movement patterns, and identifying and managing negative impacts. Large-scale management of any invasive species requires understanding of the current and potential future population distribution. Cold temperatures have been assumed to be a limiting factor for the geographic distribution of nutria populations, but this assumption had not been explicitly tested. A mechanistic habitat suitability model based on winter temperatures performed well in predicting nutria distribution in the Pacific Northwest and nationally. Regional results suggest nutria currently occupy most accessible suitable habitat. However, coupling the model with future climate change data suggests a much larger suitable habitat zone regionally and nationally in the near future. Management of an invasive species on a local scale requires region-specific information about behavior patterns. Radio-telemetry tracking of local nutria populations in metropolitan habitats suggested higher diurnal activity levels than reported elsewhere. Activity areas were also on the lower end of reported nutria home ranges, suggesting the studied metropolitan wetland sites represent core habitat for nutria in the region. Comparison of two transmitter attachment methods, a neck collar and a tail mount, did not identify a clearly superior attachment method for short-term nutria behavior studies. The presence of nutria in metropolitan habitats in the Pacific Northwest necessitates the need to expand the limited management techniques available for these habitats. Standard Vexar® plastic mesh tubes very effectively mitigated nutria herbivory damage to woody vegetation live stakes planted in a metropolitan habitat restoration site. A recently developed nutria multiple-capture cage trap captured larger nutria and reduced non-target captures compared to a standard cage trap. The design of the multiple-capture trap, however, prevented multiple-capture events because small nutria escaped the trap. This research contributes substantially to previously limited information about nutria in the Pacific Northwest and resulted in several new findings. Climate change modeling provides the first evidence that nutria ranges could expand in the near future. Evaluation of new radio-telemetry methods will benefit future behavior studies. The assessment of new damage prevention tools provides more options for the management of nutria in urban habitats. Management recommendations include creating regional nutria management plans, identifying and targeting priority monitoring regions, finding key stakeholders, focusing on public education, and initiating a pilot control program. Recommendations for research include evaluating effects on native fauna, conducting disease surveys, assessing the extent of damage, continuing habitat suitability analysis, and developing population indices. Close