Climate change vulnerability assessment for West Eugene Wetland species
Local climate is one important factor that controls species distributions,range, phenology, and ability to compete with non-native species, among many effects. To preserve rare grassland species, manage and restore grassland habitat,
Local climate is one important factor that controls species distributions,range, phenology, and ability to compete with non-native species, among many effects. To preserve rare grassland species, manage and restore grassland habitat, and maintain communities that are resilient to climate change in the Pacific Northwest (PNW), land managers and restoration practitioners in the Willamette Valley (WV) need to proactively incorporate climate change considerations into both short- and long- term planning and management actions.
This project is one of the first to assess climate vulnerability of individual grassland plant and animal species in the WV, and will directly support development of a Resource Management Plan for the West Eugene Wetlands (WEW) on Bureau of Land Management (BLM) lands.
For this assessment of species’ vulnerabilities to climate change, we utilized NatureServe’s Climate Change Vulnerability Index (CCVI). Developed by Young et al. (2011), the CCVI is an evaluation tool that combines downscaled local and regional physical climate change data with species biological information to generate two principal outputs: 1) a categorical rank assigning relative risk to each species that climate change will cause a species to decline or increase and 2) identification of the factors causing risk.
The goal of this project is to investigate the climate change vulnerabilities of native grassland species, of which six are federally listed, four are species of conservation concern and one is semi-aquatic; as well as key invasive species that pose a significant threat to native species of grasslands. We model vulnerabilities at multiple geographic scales and under three increasing climate change scenarios to understand the full range of potential future effects of climate change for each species.
This project has three primary objectives:
- Assess the relative climate change vulnerabilities of 31 Willamette Valley native species and 5 invasive species;
- Determine the extent of climate change vulnerability at local (WEW) and ecoregional (WV) scales for all species, and range-wide within the United States for all listed/conservation concern species; and
- Assess climate change vulnerabilities across a range of climate change scenarios predicting little change to significant change.
The vulnerability to climate change of a diverse group of species found in the West Eugene Wetlands assessment area varied substantially among species, regions, and climate change scenarios. Below are several general conclusions that can be drawn from this project:
- Butterflies may be especially vulnerable to moderate or severe climate change at all spatial scales we examined.
- Native Willamette Valley rare, nectar, and core prairie plant species are moderately to highly vulnerable to moderate and severe climate change.
- The Western pond turtle does not appear to be vulnerable to climate change using this assessment tool, but the species is currently suffering from low reproductive success and juvenile survival. If predation pressure increases under future climates and if that process were included in the assessment, this species’ ranking could worsen.
- Most invasive plant species we examined are likely to be unaffected by climate change or will increase in abundance.
- The CCVI method incorporates many factors that potentially affect species’ vulnerability, but for plants in particular negative effects to pollinators, competitive exclusion, and changes to the frequency or intensity of disturbance regimes also driven by climate change were not considered and will likely have mostly negative effects.
- CCVI is just one approach to assessing species vulnerability to climate change. Other methods are available, including bioclimatic envelope mapping and sophisticated demographic modeling approaches, and these are being applied to some of the rare species in our region. However, these methods require use of large amounts of data and intensive analysis. CCVI makes many assumptions but it is relatively fast and efficient for a large number of taxa, with broad applicability for land managers.