Spring- and fall-flowering species show diverging phenological responses to climate in the Southeast USA

Abstract

Plant phenological shifts (e.g., earlier flowering dates) are known consequences of climate change that may alter ecosystem functioning, productivity, and ecological interactions across trophic levels. Temperate, subalpine, and alpine regions have largely experienced advancement of spring phenology with climate warming, but the effects of climate change in warm, humid regions and on autumn phenology are less well understood. In this study, nearly 10,000 digitized herbarium specimen records were used to examine the phenological sensitivities of fall-and spring-flowering asteraceous plants to temperature and precipitation in the US Southeastern Coastal Plain. Climate data reveal warming trends in this already warm climate, and spring-and fall-flowering species responded differently to this change. Spring-flowering species flowered earlier at a rate of 1.8-2.3 days per 1°C increase in spring temperature, showing remarkable congruence with studies of northern temperate species. Fall-flowering species flowered slightly earlier with warmer spring temperatures, but flowering was significantly later with warmer summer temperatures at a rate of 0.8-1.2 days per 1°C. Spring-flowering species exhibited slightly later flowering times with increased spring precipitation. Fall phenology was less clearly influenced by precipitation. These results suggest that even warm, humid regions may experience phenological shifts and thus be susceptible to potentially detrimental effects such as plant-pollinator asynchrony.

Toward a large‐scale and deep phenological stage annotation of herbarium specimens: Case studies from temperate, tropical, and equatorial floras

“…These specimens were annotated by one co‐author (K.D.P.) for a study of phenological trends in the southeastern United States (Pearson, ). The distinction of this data set from the other three data sets is that (1) it is annotated with fine‐grained phenophase scores rather than presence/absence attributes (see description below), (2) it is annotated by one person only and not a diversity of persons distributed in different herbaria, and (3) all specimens were annotated from images of digitized specimens rather than from physical herbarium specimens or the wild plant.…”

Willow phenological modelling at different altitudes in central Italy

“…Lastly, the phenological derived models will be used to assess the impacts of climate change on the critical development phases in different species, running simulations with the use of climatic data from different forcing scenarios and climate model experiments. Recent simulations of the potential changes in phenological timings may also deliver important information for medium-to-long term planning, suggesting future anticipations of the spring phenophase timings up to about 30 days until the middle of the twenty-first century (Ibanez et al 2010 ; Pearson 2019 ). The growing season length study and forecasting can have important impacts on ecosystem processes, including the uptake of CO 2 , tree growth, microclimate and water movement (White et al 1999 ; Morisette et al 2009 ).…”

Review: Plant Eco-Evolutionary Responses to Climate Change: Emerging Directions

“…The majority of studies of reproductive phenology explore shifts in spring and summer climates and focus on forbs in temperate, boreal, alpine, or subalpine climates [103] (Table 1).…”

“…Few studies: examine the effects of non-growing season temperatures on phenological responses to climate change [10], focus on the tropics [104], or evaluate the duration of reproduction [105][106][107]. Additionally, warming spring and summer temperatures do not affect fall flowering plant phenology at the same rate as spring flowering plants [103,108]. Future studies that incorporate factors beyond spring and summer climates will shed light on phenological shifts, especially in regions where temperatures are relatively consistent yearround [104,109].…”