(Table 3) Leaf area and leaf nitrogen for deciduous, evergreen, forb and graminoid species at Barrow, Svalbard and Zackenberg

• Main Authors: Street, Lorna E, Shaver, Gauis R, Rastetter, Edward B, van Wijk, Mark T, Kaye, Brooke A, Williams, Mathew
• Format: Dataset
• Language: English
• Published: PANGAEA 2012
• Subjects: Area/locality; Barrow_plain; Barrow; Alaska; USA; Biological sample; BIOS; International Polar Year (2007-2008); IPY; Latitude of event; Leaf area; specific; per mass dry weight; Longitude of event; MULT; Multiple investigations; Nitrogen; organic; standard deviation; Nitrogen per area; Sample amount; Species; Svalbard; Vegetation type; ZAC; Zackenberg; Northeast Greenland; Arctic; Greenland; International Polar Year; Tundra
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.837943; https://doi.org/10.1594/PANGAEA.837943

Arctic vegetation is characterized by high spatial variability in plant functional type (PFT) composition and gross primary productivity (P). Despite this variability, the two main drivers of P in sub-Arctic tundra are leaf area index (LT) and total foliar nitrogen (NT). LT and NT have been shown to be tightly coupled across PFTs in sub-Arctic tundra vegetation, which simplifies up-scaling by allowing quantification of the main drivers of P from remotely sensed LT. Our objective was to test the LT-NT relationship across multiple Arctic latitudes and to assess LT as a predictor of P for the pan-Arctic. Including PFT-specific parameters in models of LT-NT coupling provided only incremental improvements in model fit, but significant improvements were gained from including site-specific parameters. The degree of curvature in the LT-NT relationship, controlled by a fitted canopy nitrogen extinction co-efficient, was negatively related to average levels of diffuse radiation at a site. This is consistent with theoretical predictions of more uniform vertical canopy N distributions under diffuse light conditions. Higher latitude sites had higher average leaf N content by mass (NM), and we show for the first time that LT-NT coupling is achieved across latitudes via canopy-scale trade-offs between NM and leaf mass per unit leaf area (LM). Site-specific parameters provided small but significant improvements in models of P based on LT and moss cover. Our results suggest that differences in LT-NT coupling between sites could be used to improve pan-Arctic models of P and we provide unique evidence that prevailing radiation conditions can significantly affect N allocation over regional scales.