Phenology and vegetation change measurements from true colour digital photography in high Arctic tundra

Arctic Science

article

Alison L. Beamish¹  Wiebe Nijland²  Marc Edwards¹  Nicholas C. Coops²  Greg H.R. Henry¹ 

[1] Tundra Ecology Laboratory, Department of Geography, University of British Columbia;Faculty of Forestry, University of British Columbia

关键词: phenology;    vegetation;    remote sensing;    digital photography;    high Arctic tundra.;   

DOI  :  10.1139/as-2014-0003

学科分类：地球科学(综合)

来源: NRC Research Press

【 摘 要 】

Manual collection of accurate phenology data is time-consuming and expensive. In this study, we investigate whether repeat colour digital photography can be used (1) to identify phenological patterns, (2) to identify differences in vegetation due to experimental warming and site moisture conditions, and (3) as a proxy for biomass. Pixel values (RGB) were extracted from images taken of permanent plots in long-term warming experiments in three tundra communities at a high Arctic site during one growing season. The Greenness Excess Index (GEI) was calculated from image data at the plot scale (1 × 1 m) as well as for two species, Dryas integrifolia and Salix arctica . GEI values were then compared to corresponding field-based phenology observations. GEI and Normalized Difference Vegetation Index (NDVI) values from a paired set of true colour and infrared images were compared with biomass data. The GEI values followed seasonal phenology at the plot and species scale and correlated well with standardized observations. GEI correlated well with biomass and was able to detect quantitative differences between warmed and control plots and the differences between communities due to site-specific moisture conditions. We conclude that true colour images can be used effectively to monitor phenology and biomass in high Arctic tundra. The simplicity and affordability of the photographic method represents an opportunity to expand observations in tundra ecosystems.

【 授权许可】

CC BY