Tracking vegetation phenology across diverse North American biomes using PhenoCam imagery

Abstract

Vegetation phenology controls the seasonality of many ecosystem processes, as well as numerous biosphere-atmosphere feedbacks. Phenology is also highly sensitive to climate change and variability. Here we present a series of datasets, together consisting of almost 750 years of observations, characterizing vegetation phenology in diverse ecosystems across North America. Our data are derived from conventional, visible-wavelength, automated digital camera imagery collected through the PhenoCam network. For each archived image, we extracted RGB (red, green, blue) colour channel information, with means and other statistics calculated across a region-of-interest (ROI) delineating a specific vegetation type. From the high-frequency (typically, 30 min) imagery, we derived time series characterizing vegetation colour, including “canopy greenness”, processed to 1- and 3-day intervals. For ecosystems with one or more annual cycles of vegetation activity, we provide estimates, with uncertainties, for the start of the “greenness rising” and end of the “greenness falling” stages. The database can be used for phenological model validation and development, evaluation of satellite remote sensing data products, benchmarking earth system models, and studies of climate change impacts on terrestrial ecosystems.

An integrated phenology modelling framework in r

“…For this study, we combined spring phenology dates based on PhenoCam 3‐day summary data from the standardized PhenoCam Dataset (Richardson et al. ) with Daymet data (Thornton et al., ) for three common PFTs, deciduous broadleaf forests, evergreen needleleaf forest and grasslands. A total of 102 sites and 508 site years were included in our calibration/validation dataset, of which 63 were deciduous broadleaf forest sites (358 site years), 18 were evergreen needleleaf forest sites (63 site years) and 21 were grasslands (88 site years).…”

“…The data used in the worked examples are freely available as a curated dataset (Richardson et al. ). Manuscript data and figures can be generated using the r scripts listed in the manuscript repository (https://github.com/khufkens/phenor_manuscript/, https://doi.org/10.5281/zenodo.1136233).…”

Tracking seasonal rhythms of plants in diverse ecosystems with digital camera imagery

“…For definitions of site types, ecoregions, biomes, Koeppen Geiger Classifications and IGBP Landcover types, see Richardson et al . (). asl, above sea level; N/A, not available.…”

Phenocams Bridge the Gap between Field and Satellite Observations in an Arid Grassland Ecosystem

“…This offers the opportunity to link organism-level phenology to other measures of ecosystem function. Phenological profiles for diverse plant communities can be developed into an empirical tool to aid natural resource management and identify plant to landscape phenological trends and spatiotemporal variability, when the historical bounds of variability have been reached, and ecosystem components likely tied to such phenomena [21,57]. For management, we need to know what constitutes the "normal" growing season dynamics to most effectively implement real-time monitoring to identify when the bounds of "normal" have been exceeded.…”