OPS 1-7
Phenological patterns along biogeographic gradients: A case study from the California Phenology Project
Phenology is the study of seasonal biological events such as flowering, leaf-out, insect emergence, and animal migration. Long-term observational studies have found that the timing of phenological events responds to environmental, inter-annual, and long-term variation in climate. To assess these sources of variation on California’s flora, the National Park Service (NPS), the University of California, Santa Barbara (UCSB), and the USA National Phenology Network (USA-NPN) established The California Phenology Project (CPP) in 2010 with funding support from the NPS Climate Change Response Program. The primary goals of the CPP are to develop and test protocols and to create tools and infrastructure to support long-term phenological monitoring and public education in California national parks. The CPP has identified scientific questions to guide monitoring efforts across all NPS units in California, selected focal plant species, and established monitoring infrastructure in seven pilot parks that represent a range of bioclimatic regions. The CPP has adapted and tested standardized phenological monitoring protocols developed in collaboration with the USA-NPN for tracking the phenological status of 25 plant species across key environmental gradients (e.g., latitude, elevation, and precipitation). To date, over 500K phenological records have been collected by the CPP and entered in the National Phenology Database. Here, we highlight results from three species that occur within the Santa Monica National Recreation Area.
Results/Conclusions
Across California, warmer winter temperatures delayed flowering and fruiting for Baccharis pilularis. Paradoxically, within Santa Monica Mountains National Recreation Area, among sites distributed across an elevation gradient, warmer temperatures advance the onset of fruiting. Thus, the scale of observation can influence the effects of climate on phenology. Sites distributed across an elevation gradient reveal that warmer temperatures advance flowering in Adenostoma fasciculatum and sites with warmer temperatures exhibit delayed phenology for Quercus lobata. We found that data recorded during the first 28 months of the pilot phase are of sufficiently high resolution to detect the effects of local climate on the onset of targeted phenophases. Phenological monitoring at a frequency of two times per week was sufficient to detect phenological differences associated with climate among species, between sites, and between years. These comparisons between sites and between years allow us to generate preliminary predictions regarding how different species will respond to future climate change. Species differed qualitatively with respect to the effects of a warmer climate on the onset dates of targeted phenophases.