Juglans californica (California Black Walnut)
Credit: Zhi-Zhong Li
about the species
California walnut (Juglans californica S. Watson, Juglandaceae) is a riparian woodland tree species of Southern California, sometimes within the coast live oak woodlands but also dominating its own woodland ecosystem (Rundel and Gustafson 2005). While naturally fragmented riparian woodlands do not have great area of coverage in Southern California, they play an important ecological role because they occur on the edge of the chaparral dry habitat and mesic woodland habitat, playing a role in stabilizing stream banks, helping water flow, and even acting as fire breaks (Rundel and Gustafson 2005). Moreover, they are also considered a delicacy by California Native Peoples (Anderson 2005).
why species was selected
Under threat due to urbanization and fragmentation, California walnut is classified as nearly threatened on the IUCN Red List of Threatened Species (Stritch and Barstow 2018). Models of current and future land use combined with climatically suitable habitat predict that California walnut will lose about 54% of its habitat by 2080 as a result of human-caused habitat conversion (Riordan et al. 2015). The future of this species will be increasingly isolated population fragments facing warmer climates. Genomic data from this species will reveal indicators of changes in California ecosystems due to climate change or landscape transformation.
