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.
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 of
information:
1. Information about how much climate change will occur where the species grows;
2. Data showing how sensitive each species will be to future climate change based on its
biological and geographical characteristics;
3. Predictions of whether future temperature and precipitation conditions are expected to have
a positive or negative effect on the available habitat for each species using a technique
called ‘species distribution modeling’.
These three sources of information were put into the CCVI. The CCVI combines this
information and calculates a vulnerability score for each species. The score indicates how
vulnerable 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 moderately
vulnerable or worse). The vulnerability scores and the number of plant species receiving that
CCVI 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's
rein 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.
