@article{388d00732506477aa3cf1e7b2fe6ef14,
title = "Leaf phenology as an indicator of ecological integrity",
abstract = "Climate change leads to an increased frequency of severe weather events as well as stressful growing conditions. Together these changes may impact the resilience of ecosystems. To keep track of such effects, conservation managers monitor the “ecological integrity” or coherence of ecosystem processes, such as the cycling of carbon and water. Networked phenocams can produce near-continuous observations of leaf function in the context of climate change, capturing declines due to disturbance or stress. Here we explore the application of phenocams to detect responses to disturbance and stress using 14 examples from the PhenoCam Network. We selected these previously published and new examples to include a variety of disturbances in the form of hurricanes, a windstorm, frost, insect defoliation, and stress due to drought. Frost and herbivory disturbances led to both reductions and extensions in the duration of the rising section of the greenness curve, while hurricanes generally led to reductions in the duration of the plateau section and entire leaf-on period. We found that changes of at least ±20% in the duration of the rising section in the seasonal greenness curve, ±20% in the duration of the plateau section following the seasonal greenness peak, and ±10% in the duration of the entire leaf-on period were a reliable signal of leaf functional declines due to disturbance or stress. If such declines become increasingly frequent and severe as a consequence of climate change, this could impact ecological integrity through interruptions to ecosystem processes. Comparing the duration of these periods in a given year to the average for other years with these thresholds resulted in average true detection rates of 86% and false-positive detection rates of 11% when sampling from probability density functions of 344 broadleaf and needleleaf PhenoCam site-years. Here we show that phenocams are powerful ecological integrity monitoring tools, which can be efficiently applied to quantify dynamic responses to disturbance or stress.",
keywords = "climate change, defoliation, drought, ecological integrity, hurricanes, leaf phenology, phenocams, spring frost",
author = "Lynsay Spafford and MacDougall, {Andrew H.} and Yann Vitasse and Gianluca Filippa and Andrew Richardson and James Steenberg and Lever, {J. Jelle}",
note = "Funding Information: The authors would like to acknowledge the valuable in-kind contributions made by Parks Canada, including permission to conduct research within Kejimkujik National Park and National Historic Site, Cape Breton Highlands National Park, Prince Edward Island National Park, and Fundy National Park, as well as field support provided by Donna Crossland, Gavin Carpenter, Friedrich Meyer, Kyle Rowter, Troy Pretzlaw, Jared Tomie, Clayton D'Orsay, Megan Blaxley, Alain Caissie, Neil Vinson, Garrett Mombourquette, Louis Charron, and Travis James. The Nova Scotia Department of Natural Resources and Renewables provided assistance in locating some of the Nova Scotia Acadian Phenocam Network phenocam locations based on analysis of local climate and forest conditions and assisted in the 2019 installation of these phenocams. This research was supported by the National Science and Engineering Research Council of Canada (NSERC) Discovery Grant Program. Lynsay Spafford is grateful for support from NSERC Canada Graduate Scholarships—Doctoral Program Scholarship. This research was enabled in part by support provided by Compute Canada (www.computecanada.ca). Advanced computing resources are provided by the Digital Research Alliance of Canada, the organization responsible for digital research infrastructure in Canada, and ACENET. We thank the collaborators, including site PIs and technicians, for their efforts in support of PhenoCam. The development of PhenoCam has been funded by the Northeastern States Research Cooperative and NSF's Macrosystems Biology program (awards EF-1065029 and EF-1702697). Acknowledgments for each PhenoCam site are provided in Appendix S1: Table S1. Funding Information: The authors would like to acknowledge the valuable in‐kind contributions made by Parks Canada, including permission to conduct research within Kejimkujik National Park and National Historic Site, Cape Breton Highlands National Park, Prince Edward Island National Park, and Fundy National Park, as well as field support provided by Donna Crossland, Gavin Carpenter, Friedrich Meyer, Kyle Rowter, Troy Pretzlaw, Jared Tomie, Clayton D'Orsay, Megan Blaxley, Alain Caissie, Neil Vinson, Garrett Mombourquette, Louis Charron, and Travis James. The Nova Scotia Department of Natural Resources and Renewables provided assistance in locating some of the Nova Scotia Acadian Phenocam Network phenocam locations based on analysis of local climate and forest conditions and assisted in the 2019 installation of these phenocams. This research was supported by the National Science and Engineering Research Council of Canada (NSERC) Discovery Grant Program. Lynsay Spafford is grateful for support from NSERC Canada Graduate Scholarships—Doctoral Program Scholarship. This research was enabled in part by support provided by Compute Canada ( www.computecanada.ca ). Advanced computing resources are provided by the Digital Research Alliance of Canada, the organization responsible for digital research infrastructure in Canada, and ACENET. We thank the collaborators, including site PIs and technicians, for their efforts in support of PhenoCam. The development of PhenoCam has been funded by the Northeastern States Research Cooperative and NSF's Macrosystems Biology program (awards EF‐1065029 and EF‐1702697). Acknowledgments for each PhenoCam site are provided in Appendix S1 : Table S1 . Publisher Copyright: {\textcopyright} 2023 The Authors. Ecosphere published by Wiley Periodicals LLC on behalf of The Ecological Society of America.",
year = "2023",
month = may,
doi = "10.1002/ecs2.4487",
language = "English (US)",
volume = "14",
journal = "Ecosphere",
issn = "2150-8925",
publisher = "Ecological Society of America",
number = "5",
}