Justification: Phenology is the study of cyclic and seasonal natural phenomena in relation to climate and plant and animal life. Climate warming and changes in precipitation have already impacted the life cycles of many species (Kimball et al. 2010; Crimmins et al. 2011), such as the timing of plant flowering and the emergence of insects, both of which are strongly correlated with temperature or other climatic cues (Bale et al. 2002; Crimmins et al. 2009, 2011; Strange & Ayres 2010). As a consequence, phenology may be a leading indicator of climate change impacts.
PRISSM’s objective is to understand how plant phenology varies among sites in California Sage Scrub (CSS) habitats, as well as how interannual variation in temperature and precipitation influences the timing of different life history traits. Consequently, our protocols are designed to assess the phenology of multiple individuals for each species at each site, with a focus on floral resources. Our protocol was not designed to comprehensively study the phenology of any one species. A researcher using our protocol can survey multiple species and individuals within a species in approximately 2 hours, depending on the distance among individuals.
Monitoring Protocol: The plant phenology protocol was designed to monitor phenological patterns of common CSS plant species on a weekly basis beginning in November and ending at the end of June every year. While surveys may need to be conducted longer in coastal sites, flowering of all plant species, except White Sage, is completed by June. In addition, human resources are low after June at most participating institutions, limiting the ability to compile complete data sets.
Plant species were chosen because they were commonly found at a large portion of the CSS fragments and they represent important resources for animals, particularly butterflies in the spring season (see Butterfly Monitoring). The five species of plants chosen for phenological monitoring include: California Sagebrush (Artemisia californica), White Sage (Salvia apiana), California Buckwheat (Eriogonum fasciculatum), California Thistle (Cirsium occidentale), and royal penstemon (Penstemon spectabilis). We also recommend that Yerba Santa (Eriodictyon trichocalyx or Eriodictyon crassifolium depending on the site) and Deerweed (Acmispon glaber) be monitored at sites when managers can expand their effort. In the next few years, we will be expanding our efforts to include non-native grasses, mostly Bromus spp. Other species such as Pine-Bush (Ericameria pinifolia) and Scale-Broom (Lepidospartum squamatum) are important in the CSS ecosystem, since are often the only plants flowering in fall. However, allocating resources at many sites later in the summer and into the fall is logistically difficult, especially on a weekly basis for many managers of CSS fragments. Only one of these species (Eriogonum fasciculatum) is monitored by the California Phenology Project. Increasing the number of CSS plants will increase our ability to detect changes.
To monitor the phenology of these plant species, six individuals of each species will be identified and tagged, less if a site does not have a species or fewer than six individuals of a particular species. Individuals should be widely distributed across each CSS fragment to effectively sample phenology in various micro-habitats. When possible, individuals will be tracked for as many years as possible. If an individual dies during or between sampling seasons, a new individual will be chosen and given a new identifying code. As such, loss of an individual should represent mortality of the individual. Starting the first week in November and every week after until the beginning of July, researchers should visit each individual plant and record characteristics identified for each species. While our focus is on timing of flowering and floral resources, occasionally, we record other life-history characteristics: presence/abundance of functioning leaves, buds, and/or seeds/fruit. For more detailed information on what needs to be recorded for each species, please download the PRISSM plant phenology data collection sheet [link coming soon!] and the PRISSM plant phenology category description document [link coming soon!]. For details on data management, please refer to the PRISSM plant phenology data management plan.
[Link to PRISSM Plant Phenology Data 2014-2017 coming soon!]
- Bale, J.S., G.J. Masters, I.D. Hodkinson, C. Awmack, T.M. Bezemer, V.K. Brow, J. Butterfield, A. Buse, J.C. Coulson, J. Farrar, J.E.G. Good, R. Harrington, S. Hartley, T.H. Jones, R.L. Lindroth, M.C. Press, I. Symrniodis, A.D. Watt, & J.B. Whittaker. 2002. Herbivory in global climate change research: direct effects of rising temperature on insect herbivores. Global Change Biology 8: 1–16.
- Crimmins, T.M., M.A. Crimmins, & D. Bertlesen. 2009. Flowering range changes across an elevation gradient in response to warming summer temperatures. Global Change Biology 15: 1141-1152
- Crimmins, T.A., M.A. Crimmins, & D. Bertlesen. 2011. Onset of summer flowering in a ‘Sky Island’ is driven by monsoon moisture. New Phytologist 191: 468-479.
- Kimball, S., Angert, A.L., Huxman, T.E., Venable, D.L. 2010. Contemporary climate change in the Sonoran Desert favors cold-adapted species. Global Change Biology 16: 1555-1565.
- Strange, E.E., & M.P. Ayres 2010. Climate change impacts: insects. In: Encyclopedia of Life Sciences, John Wiley & Sons, Ltd. Chichester, UK.