Climate-phenology mismatch in human-dominated landscapes

Changing phenology
First-author
Awarded
AGU Advances 2021 (Editor’s Highlight)
Christopher J. Zajic was an undergraduate student at the University of California, Santa Cruz.
Authors

Yiluan Song

Christopher J. Zajic

Taehee Hwang

Christopher R. Hakkenberg

Kai Zhu

Published

December 6, 2021

Keywords

global change biology, environmental data science, phenology, Anthropocene, climate change

Highlights

  • Rapidly shifting vegetation phenology has not kept pace with the recent climate change.
  • Climate-phenology mismatch is more pronounced in human-dominated landscapes with increasing human population density.

Abstract

Plants track changing climate partly by shifting their phenology, the timing of recurring biological events. It is unknown whether these observed phenological shifts are sufficient to keep pace with rapid climate changes. Phenological mismatch, or the desynchronization between the timing of critical phenological events, has long been hypothesized but rarely quantified on a large scale. It is even less clear how human activities have contributed to this emergent phenological mismatch. In this study, we used remote sensing observations to systematically evaluate how plant phenological shifts have kept pace with warming trends at the continental scale. In particular, we developed a metric of spatial mismatch that connects empirical spatiotemporal data to ecological theory using the “velocity of change” approach. In northern mid-to high-latitude regions (between 30–70°N) over the last three decades (1981–2014), we found evidence of a widespread mismatch between land surface phenology and climate where isolines of phenology lag behind or move in the opposite direction to the isolines of climate. These mismatches were more pronounced in human-dominated landscapes, suggesting a relationship between human activities and the desynchronization of phenology dynamics with climate variations. Results were corroborated with independent ground observations that indicate the mismatch of spring phenology increases with human population density for several plant species. This study reveals the possibility that not even some of the foremost responses in vegetation activity match the pace of recent warming. This systematic analysis of climate-phenology mismatch has important implications for the sustainable management of vegetation in human-dominated landscapes under climate change.


Climate and phenology velocity

Schematic diagram showing three scenarios of climate tracking and the corresponding climate-phenology metrics.

Widespread cimate-phenology mismatch

Spatial patterns of four climate-phenology metrics. (a) Velocity of mean annual temperature change. (b) Velocity of growing season length change. (c) Difference in direction. (d) Pace of phenology change relative to climate. Panels on the right show the median and 95% intervals of climate-phenology metrics.

Relationship with human activities

Climate-phenology metrics by land-use types. (a) Map of land-use types in 2000. (b) Distributions of the velocity of mean annual temperature change, the velocity of growing season length change, the difference in direction, and the pacing of phenology relative to climate in five land-use types.

Relationship between population density and climate-phenology metrics. (a) Map of population density in the study area in 2000. (b) Velocity of mean annual temperature change, velocity of growing season length change, the difference in direction, and the pacing of phenology relative to climate in five quantiles of population density.