B54A-01 INVITED
An Update on the Emerging USA National Phenology Network: Status, Goals and Objectives, and Collaborative Opportunities
Although phenology is a far-reaching component of environmental science, it is poorly understood relative to other ecological patterns and processes. For example, it is unclear how environmental factors affect the phenology of different organisms, and how those factors vary in importance on different spatial and temporal scales. Futher, it is likely that phenology affects the abundance and diversity of organisms, and their function and interactions in the environment, especially their effects on fluxes in water, energy, and chemical elements at various scales. With sufficient observations and understanding, phenology can be used as a predictor for other processes and variables of importance at local to global scales, and could drive a variety of ecological forecast models with both scientific and practical applications. The USA National Phenology Network (USA-NPN) is a new data resource – a national network of integrated phenological observations essential to evaluate ongoing environmental changes (www.usanpn.org). The NPN will integrate with other observation networks and remote sensing products, emerging technologies and data management capabilities, and will capitalize on myriad educational opportunities and a new readiness of the public to participate in investigations of nature on a national scale. This presentation will provide an update on the implementation of the USA-NPN in terms of network development, cyberinfrastructure, research challenges and opportunities, education and outreach, and opportunities for collaboration with governmental and non-governmental agencies and organizations. http://www.usanpn.org
B54A-02
Project BudBurst: Citizen Science for All Seasons
Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events that raise awareness of climate change, and create a cadre of informed citizen scientists. Citizen science programs such as Project BudBurst provide the opportunity for students and interested laypersons to actively participate in scientific research. Such programs are important not only from an educational perspective, but because they also enable scientists to broaden the geographic and temporal scale of their observations. Project BudBurst launched a pilot program in the Spring of 2007. The goals of Project BudBurst were to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants; and 3) increase science literacy by engaging participants in the scientific process. From April through mid-June 2007, this on-line educational and data-entry program, engaged participants of all ages and walks of life in recording the timing of the leafing and flowering of ~60 easily identifiable, broadly distributed wild and cultivated species found across the continent. We will report on the results of the pilot project and discuss plans to expand Project BudBurst as it becomes a year round event beginning in 2008. A broad consortium of collaborators, representing the Chicago Botanic Garden, Plant Conservation Alliance, ESRI, the USA-National Phenology Network, University Corporation for Atmospheric Research, University of Arizona, University of Montana, University of California-Santa Barbara, University of Wisconsin-Milwaukee and the University of Wisconsin-Madison, came together to design and implement Project BudBurst with seed funding from the U.S. Bureau of Land Management, the National Phenology Network (through a RCN grant from the NSF), and the Plant Conservation Alliance.
B54A-03 INVITED
Monitoring regional patterns of canopy-scale phenology with a network of digitial webcams
Understanding relationships between canopy structure and the seasonal dynamics of photosynthetic uptake of CO2 by forest canopies requires improved knowledge of canopy phenology at eddy covariance flux tower sites. We investigated whether digital webcam images could be used to monitor the trajectories of spring green-up and autumn senescence in a deciduous northern hardwood forest. A standard, commercially available webcam was mounted at the top of the eddy covariance tower at the Bartlett AmeriFlux site. Images were collected each day around mid-day. Red, green and blue color channel brightness data for a 640 x 100 pixel region-of-interest were extracted from each image. We evaluated the green-up signal extracted from webcam images against changes in fAPAR (the fraction of incident photosynthetically active radiation that is absorbed by the canopy), broadband NDVI, and Amax (the light-saturated rate of canopy photosynthesis, inferred from eddy flux measurements). The relative brightness of the green channel (green %) was relatively stable through the winter months. A steady rising trend in green % began around day 120 and continued through day 160, at which point a stable plateau was reached. The relative brightness of the blue channel (blue %) also responded to spring green-up, although there was more day-to-day variation in the signal because blue % was more sensitive to changes in the quality (spectral distribution) of incident radiation. Seasonal changes in blue % were most similar to those in fAPAR and broadband NDVI, whereas changes in green % proceeded more slowly, and were drawn out over a longer period of time. Changes in Amax lagged green-up by at least a week. The onset of autumn senescence was marked by a decrease in green %, which preceded a spike in red % when autumn coloration peaked at day 270. A decrease in red % was observed over the next 30 days (through day 300) as senescence progressed and the deciduous canopy was shed. We conclude that webcams offer an inexpensive means by which phenological changes in canopy state could be quantified using instrument-based "near" remote sensing. We describe a recently-established camera network (13 sites in the northeastern US and Canada, of which 5 sites are instrumented for eddy flux measurements) which will provide a regional perspective on both spatial and temporal variation in patterns of canopy phenology.
B54A-04
Monitoring Phenology by use of Digital Photography
In recent decades phenology has become recognized as an important integrative method for assessing the impact of climate variability and climate change on ecosystems. Time series analysis of selected variables such as green-up, maturity, senescence and dormancy, yield valuable information about ecosystem responses to climate and are widely used in phenological, climatological and ecological models. Phenological ground observations are often observer-biased. Additionally, there is a significant decline in long- term observation sites that continue monitoring plant development due to missing volunteers for phenological field work. For two decades satellite remote sensing has been providing a global integrated view of vegetation phenological states. However this method still heavily depends on ground-based measurements for validation. Moreover, satellite images often have limited temporal and spatial coverage due to clouds, aerosols and other sensor-/platform-specific characteristics. Our project investigates the application of ground-based commercially available digital cameras in observational procedures and quality assurance of phenological monitoring. A standard digital camera (NIKON Coolpix 5400) was mounted on a flux tower at the Lägeren FLUXNET site (Switzerland), providing hourly digital images of a mixed forest. Parameter estimation of phenological stages is based on image statistics and red, green and blue channel colour brightness. Image analysis is conducted on regions of interest (ROI) of single tree species. Camera colour channel values are extracted and averaged across the ROI using daily time step. CO2-fluxes measured by eddy covariance and the phenological data from camera and satellite imagery are jointly analyzed. We anticipate that a network of digital cameras could provide inexpensive, spatially accurate and objective information with the required temporal resolution for phenological monitoring applications and ecosystem research. However, first it needs to be demonstrated that such automatic phenological algorithms are universally applicable and do not suffer from site-specific implicit assumptions.
B54A-05
Reevaluation of the spring onset/fire association in the western U.S. using Phenological vs. Hydrological Models
An important aspect of climate variability and change is the exact timing of the transition from winter to spring, generally defined here as spring onset. Spring onset can have important hydrological and ecological consequences, including changes in the timing of snowmelt and snowmelt runoff, in timing of plant and animal phenologies and their interactions, in ecosystem fluxes, and in the probabilities of ecological disturbances such as fire and insect outbreaks. Spring onset can be variably defined, which can affect its use as a predictor. To evaluate changing fire probabilities in the western U.S., Westerling et al. (2006) used center of mass of annual streamflow (CT, after Stewart et al 2005) for snowmelt-dominated gauge records as a proxy for spring onset, and compared it with the number of forest wildfires greater than 400 ha annually around the western U.S. This study indicated a strong association between large wildfire occurrence across the West and CT, and a particular sensitivity to the timing of snowmelt in the Northern Rockies. Though the timing of snowmelt can affect fire occurrence in several ways, the use of CT as a proxy for spring onset biased the analysis towards higher elevations and latitudes. To skirt this bias, we undertook a similar analysis using Spring Indices (SI) developed from cloned lilac and honeysuckle phenological data and representing seasonally integrated changes in temperature (Schwartz et al. 2006). The SI models can be generated at any location that has daily maximum–minimum temperature time series, and allowed comparison of large fire occurrence in defined regions with a network of select weather stations across the West for which we computed SI. The SI/fire comparison showed strong associations between SI at weather stations, particularly those in the Central Rockies/Colorado Plateau and large fire frequency in the northern, central and southern Rockies, as well as in the Sierra Nevada, but less so in southern California and the Black Hills. Given large differences in fire seasonality, vegetation type, and the importance of snowpack, explanations for the spring onset/fire association could be inherently complex. Though they also have biases and shortcomings, phenological models such as SI may be particularly useful in predicting climate change impacts on fire and other phenomena, and could offer more precision and better lead time in fire forecasting. Schwartz, M.D., R. Ahas, A. Aasa 2006: "Onset of spring starting earlier across the Northern Hemisphere" Global Change Biology, 12: 343-351. Stewart, I.T., D.R. Cayan and M.D. Dettinger, 2005: Changes toward earlier streamflow timing across Western North America. Journal of Climate, 18, 1136-1155. Westerling, A.L., H.G. Hidalgo, D.R. Cayan, T.W. Swetnam 2006: "Warming and Earlier Spring Increases Western U.S. Forest Wildfire Activity" Science, 313: 940-943. http://tenaya.ucsd.edu/~westerli/
B54A-06
Population-level Consequences of Breeding Phenology in Response to Climate Variability in Seabirds and Landbirds: Two Long-term Studies From California
Long-term studies conducted on breeding populations on the Farallon Islands (1971 to 2007) and in the Point Reyes National Seashore (1980 to 2007), provide the means to characterize breeding phenology of seabird and landbird species and determine how that has changed over multiple temporal scales (variation among years, among decades, shifts in ocean regimes, etc.). However, to interpret phenological patterns and shifts requires information on the demography and ecological context of these species. Here we describe studies on three seabird species (Common Murre Uria aalge, Cassin's Auklet Ptychoramphus aleuticus, Brandt's Cormorant, Phalacrocorax penicillatus) where we have tied changes in breeding phenology, within a year, and among years, to demographic consequences (reproductive success, proportion of the population that breeds, adult survival, etc.). In addition, for these species we have information on diet choice of parents feeding chicks and how that has varied within and among years, as well as oceanographic correlates (sea surface temperature, upwelling indices, etc). Results reveal marked variation among the species in their response to oceanographic and climate variability, reflecting their different ecologies. We describe how these results can be used to forecast response to future climate change, as well as to interpret year by response to climate variability. We also summarize results from a long-term study of Song Sparrows (Melospiza melodia), where we have investigated onset and termination of breeding and the climate factors that may influence it, while identifying the population-level responses associated with phenological shifts. We close by making recommendations for large-scale monitoring of phenology based on these more localized studies.
B54A-07 [WITHDRAWN]
How much will evolution buffer changes in climate?
Current climate change is altering the phenology, or seasonal timing of reproduction and other life-history events, of many species. There is now evidence that at least some of these changes in phenology represent genetically- based evolution. Evolution may thus potentially serve as a buffer, allowing species to adapt to changes in climatic conditions. However, there are many constraints to evolution, including lack of genetic variation, antagonistic trait correlations, and physiological and developmental constraints. Furthermore, if changes in climate are extremely rapid and severe, many species may experience extinction rather than rapid evolution. I present recent empirical evidence for evolution following changes in climate, examine constraints to evolution, and ask if evolution can keep pace with rapid climate change. The empirical work focuses on the species Brassica rapa, which I show evolved earlier flowering time following several years of drought in Southern California.