Tracking Fine-Grain Phenological Dynamics at a Landscape Extent Using a Network of Near-Surface Digital Repeat Photography Stations in West Greenland

Abstract:

The phenology of vegetation emergence in the Arctic is highly sensitive to climatic fluctuations. Spring phenology drives ecological processes across local, population, and ecosystem scales. Traditional approaches to capturing spatio-temporal variation in the annual timing and pace of Arctic green-up, like satellite-derived and plot-level records, are limited by trade-offs in the grain and extent of monitoring through both space and time. Recent studies demonstrate the utility of tracking canopy phenology using near-surface digital repeat photography (phenocams) to overcome spatial and temporal grain limitations at the extent of individual plants or vegetation stands. However, our understanding of how fine-grain phenological dynamics scale to landscape extents is incomplete. Here we report on the fine-grain green-up dynamics of a low-Arctic tundra system in West Greenland at the extent of a caribou calving range (40 km²) using three years (2012-2014) of phenological records derived from a network of 50 phenocams, field observations, and high-resolution satellite imagery. Using geostatistics and multiple-regression models, we characterize spatiotemporal patterns of plant phenology, landscape controls on the timing of emergence of common shrub and graminoid species, and assess scale-dependency in patterns of vegetation green-up. We link these results with coarse-grained satellite records of plant phenology to clarify how fine-grained dynamics contribute to the widely reported broad-scale patterns of phenological and ecological change in the Arctic.