We assessed the ‘vulnerability’ of roughly 10% of California’s rare plant species (156 of 1625 total rare plants) representing a range of species characteristics. The project used species distribution modeling to assess the risk to habitat change under various climate change scenarios for rare plants. To predict the response of rare plant species to climate change, the project modeled the current distribution of the species using climate and environmental data (e.g., soils, disturbance, land-use), use these models to predict the species distribution given climate change, calculate current and future range size, calculate the amount of overlap of predicted future distribution with current distribution, and assess where barriers and protected areas are located with reference to the change in species distribution. Given the results of the distribution modeling, each species was be scored with regard to predicted vulnerability to climate change. In addition, the modeling results will be used to identify areas of high rare plant diversity and to predict areas that will serve as climatic refugia in the future for rare plant diversity.alifornia’s rare plant species (156 of 1625 total rare plants) representing a range of species characteristics.
We used the Climate Change Vulnerability Index (CCVI) developed by NatureServe, a national conservation science organization. As input for the CCVI, we collected three types ofinformation:
- Information about how much climate change will occur where the species grows;
- Data showing how sensitive each species will be to future climate change based on itsbiological and geographical characteristics;
- Predictions of whether future temperature and precipitation conditions are expected to havea positive or negative effect on the available habitat for each species using a techniquecalled ‘species distribution modeling’.
These three sources of information were put into the CCVI. The CCVI combines thisinformation and calculates a vulnerability score for each species. The score indicates howvulnerable the populations or range of the species will be to effects of climate change.Ninety-nine of our 156 species (63%) were vulnerable to climate change (scored as moderatelyvulnerable or worse). The vulnerability scores and the number of plant species receiving thatCCVI score were:
• extremely vulnerable (substantial decline or extinction expected by 2050; n = 2),• highly vulnerable (significant decline expected by 2050; n = 40),• moderately vulnerable (decline expected by 2050; n = 57),• presumed stable (no change expected; n = 32),• increase likely (increase of populations or range expected by 2050; n = 16),• insufficient information (n = 9).
The two most vulnerable species in our subset, scored as extremely vulnerable, were Yadon’srein orchid (Piperia yadonii) and purple monkeyflower (Mimulus purpureus).
All the information used to make the determinations is accessible at http://www.dfg.ca.gov/biogeodata/projects/climate.asp
