@article{6434a115892c4d81a1a52c42215f6514,
title = "Tussocks Enduring or Shrubs Greening: Alternate Responses to Changing Fire Regimes in the Noatak River Valley, Alaska",
abstract = "As the Arctic warms, tundra wildfires are expected to become more frequent and severe. Assessing how the most flammable regions of the tundra respond to burning can inform us about how the rest of the Arctic may be affected by climate change. Here we describe ecosystem responses to tundra fires in the Noatak River watershed of northwestern Alaska using shrub dendrochronology, active-layer depth monitoring, and remotely sensed vegetation productivity. Results show that relatively productive tundra is more likely to experience fires and to burn more severely, suggesting that fuel loads currently limit tundra fire distribution in the Noatak Valley. Within three years of burning, most alder shrubs sampled had either germinated or resprouted, and vegetation productivity inside 60 burn perimeters had recovered to prefire values. Tundra fires resulted in two phases of increased primary productivity as manifested by increased landscape greening. Phase one occurred in most burned areas 3–10 years after fires, and phase two occurred 16–44 years after fire at sites where tundra fires triggered near-surface permafrost thaw resulting in shrub proliferation. A fire-shrub-greening positive feedback is currently operating in the Noatak Valley and this feedback could expand northward as air temperatures, fire frequencies, and permafrost degradation increase. This feedback will not occur at all locations. In the Noatak Valley, the fire-shrub-greening process is relatively limited in tussock tundra communities, where low-severity fires and shallow active layers exclude shrub proliferation. Climate warming and enhanced fire occurrence will likely shift fire-poor landscapes into either the tussock tundra or erect-shrub-tundra ecological attractor states that now dominate the fire-rich Noatak Valley.",
keywords = "Alaska, Arctic greening, fire ecology, permafrost, tundra fires",
author = "Gaglioti, {B. V.} and Berner, {L. T.} and Jones, {B. M.} and Orndahl, {K. M.} and Williams, {A. P.} and L. Andreu-Hayles and D'Arrigo, {R. D.} and Goetz, {S. J.} and Mann, {D. H.}",
note = "Funding Information: This project was funded by the Joint Fire Science Program (Project 16-1-01-8 awarded to D. H. Mann and B. V. Gaglioti), and the National Science Foundation Arctic Natural Sciences program (16-61723 awarded to L. Andreu-Hayles, R. D. D'Arrigo, and S. J. Goetz). B. V. Gaglioti was partially funded by the Lamont-Doherty Earth Observatory's Postdoctoral Fellowship Program. L. Andreu-Hayles was partially funded by National Science Foundation grant PLR-1504134. S. J. Goetz, L. T. Berner, and K. Orndahl were supported by the NASA Arctic Boreal Vulnerability Experiment (grants NNX17AE44G and 80NSSC19M0112 to S. J. Goetz). B. M. Jones was supported by the National Science Foundation Office of Integrative Activities (OIA-1929170) programs. The authors thank Louise Farquharson for providing permafrost modeling results presented in Figure 1. We also thank Virgil E. Purchase for fieldwork, Golden Eagle Flight Service for expert piloting, and Kyle Hansen for measuring and cross-dating Alder ramets. Our thinking about this subject benefitted from discussions with Eric Miller and Jennifer Barnes. This is LDEO contribution #8480. Funding Information: This project was funded by the Joint Fire Science Program (Project 16‐1‐01‐8 awarded to D. H. Mann and B. V. Gaglioti), and the National Science Foundation Arctic Natural Sciences program (16‐61723 awarded to L. Andreu‐Hayles, R. D. D'Arrigo, and S. J. Goetz). B. V. Gaglioti was partially funded by the Lamont‐Doherty Earth Observatory's Postdoctoral Fellowship Program. L. Andreu‐Hayles was partially funded by National Science Foundation grant PLR‐1504134. S. J. Goetz, L. T. Berner, and K. Orndahl were supported by the NASA Arctic Boreal Vulnerability Experiment (grants NNX17AE44G and 80NSSC19M0112 to S. J. Goetz). B. M. Jones was supported by the National Science Foundation Office of Integrative Activities (OIA‐1929170) programs. The authors thank Louise Farquharson for providing permafrost modeling results presented in Figure 1 . We also thank Virgil E. Purchase for fieldwork, Golden Eagle Flight Service for expert piloting, and Kyle Hansen for measuring and cross‐dating Alder ramets. Our thinking about this subject benefitted from discussions with Eric Miller and Jennifer Barnes. This is LDEO contribution #8480. Publisher Copyright: {\textcopyright} 2021. American Geophysical Union. All Rights Reserved.",
year = "2021",
month = apr,
doi = "10.1029/2020JG006009",
language = "English (US)",
volume = "126",
journal = "Journal of Geophysical Research: Biogeosciences",
issn = "2169-8953",
number = "4",
}