Phenological responsiveness to climate differs among four species of Quercus in North America

Abstract

Summary The timing of the seasonal activity of organisms is a tractable indicator of climate change. Many studies in North America have investigated the role of temperature on the onset date of phenological transitions in temperate deciduous trees and found that the onset of leafing and flowering in numerous species has occurred earlier in recent years, apparently in response to higher temperatures in winter and spring. Few studies have examined the climatic and biogeographic drivers of phenological responses in water‐limited ecosystems or explored interspecific variation in responses of phenological metrics other than the timing of onset, such as the periodicity or duration of phenological activity. This study used phenological observations of four species of Quercus contributed to the USA National Phenology Network database from 2009 to 2014 to investigate how responses to climate (temperature and precipitation) and geographic location (latitude, longitude and elevation) varied among two western North American species (Q. agrifolia and Q. lobata) and two eastern and central North American species (Q. alba and Q. rubra). Within years, in species in the western, water‐limited ecosystems, the phenological phases observed here (bud break, flowers or flower buds) tend to occur intermittently throughout the growing season, and each event is of longer duration than the same phenophases of the temperate‐zone species, rendering a single onset date an incomplete metric with which to track responsiveness or to compare species. By contrast, the eastern/central U.S. species were phenologically more responsive than the western species to spatial and temporal variation in winter, spring, and fall precipitation and maximum temperature. Synthesis. Within and between regions these congeners exhibited a diversity of responses to seasonal temperature and precipitation. This indicates that for predictive model development it is critical to understand how each underlying driver influences species that are adapted to different climatic regimes. These results underscore the value of studying a range of phenological metrics and species from a variety of ecosystems to better predict phenological responses to short‐term variation and to long‐term change in climate.

Phenology as a process rather than an event: from individual reaction norms to community metrics

“…First event dates are also a poor metric for phenophases that do not have a single uninterrupted period, but stop and restart, such as plants that flower sporadically (Gerst et al. ). Peak event times (e.g., mating displays for mammals, calling times for frogs, peak flowering times for plants) should be more comparable than disparate metrics such as first flowering for plants vs peak spawning activity for fish, although even peaks will not always be comparable across phenologies at different levels of biological organization.…”

Warming delays the phenological sequences of an autumn‐flowering invader

“…Plant phenology is strongly driven by climate, and temperature is the most important driver of plant phenology (Lieth, 1974). Climate warming profoundly influences plant phenology (Cleland, Chiariello, Loarie, Mooney, & Field, 2006;Gerst, Rossington, & Mazer, 2017;Godoy et al, 2009;Hovenden, Wills, Schoor, Williams, & Newton, 2008;Novy et al, 2013), and invasive plants track climate warming more closely than native plants (Wolkovich et al, 2013). Aside from climate warming, atmospheric nitrogen (N) deposition is also among the key components of global change (Galloway et al, 2004).…”

Evidence of an extreme weather‐induced phenological mismatch and a local extirpation of the endangered Karner blue butterfly

“…However, earlier leaf out or flowering is not consistent across plant classes, related sub-species, or within a single species. For example, trees have not advanced their phenology as much as other plant groups and some flowering forbs vary within genus (Gerst, Rossington, & Mazer, 2017;Root et al, 2003). Flowering among related species of plants may respond differently, with one subspecies blooming earlier and another remaining unchanged as demonstrated in Mertensia and Solidago (Hafdahl & Craig, 2014;Miller-Rushing & Inouye, 2009).…”