Abstract Detail


Heberling, Mason [1], Hughes, Nicole M. [2], George, Christian O. [2], Lee, Ben [3], Neufeld, Howard [4], Webb, Campbell O [5], Lee, David W. [6].

Comparative analysis of autumn leaf coloration across North America.

Autumn leaf color has long fascinated biologists and the public. Though the biochemistry behind the phenomenon is relatively known, the adaptive value of autumn leaf color change remain poorly understood. Within a community, why do some species turn red and others do not? Across regions, why do some floras display more brilliantly colored foliage than others? Many hypotheses have been posited for the adaptive value of autumn leaf coloration, including coevolution with insects and photoprotection. However, these hypotheses are not mutually exclusive and may not be universal. Most comparative studies on autumn leaves use cultivated woody plants in botanical gardens. While useful, these studies have limitations by ignoring non-woody species, community context, and environmental variation. To quantify the species- and community-level patterns of autumn leaf coloration and link to hypotheses, we compiled a dataset from recent and previous fieldwork that includes 611 species and spans 13 sites from Alaska to Florida (768 total species by site observations). At each site, we surveyed vascular plant species with leaves present in autumn, scoring leaf color changing from green to red, yellow, or black. Tissue sections were also observed for the presence and intensity of anthocyanins in different anatomical layers. We also recorded habitat characteristics and life history characteristics for each species at each location. These observations were combined with environmental data for each site (soils, climate, irradiance). Across all sites, 52% of sampled species turned yellow during senescence, 46% turned red, and only 2% turned black (no color change with death by frost). This was highly variable across sites, ranging from 100% of autumn color changing species sampled at one site turning red (Alaska) to the other extreme with only 15% of all surveyed species turning red (Florida). Herbaceous and woody species were similarly likely to produce anthocyanins (44% vs. 46% respectively), indicating that herbaceous species are also be included in comparative studies of autumn leaf color. Long-lived herbs displayed higher levels of anthocyanins than annuals (P<0.001). Anthocyanins were higher in species that fruit during autumn (P<0.01). In support of the hypothesized photoprotective role of anthocyanins, red leaves were significantly associated with colder climates, shorter frost-free growing season, higher elevations, and higher latitude (northern sites). Against expectations, preliminary analysis of each variable individually suggest solar irradiance was negatively associated with red leaves and soil nitrogen was positively associated. However, these variables, along with climate variables, covary across latitude, thereby confounding potnetially causal patterns. This unique dataset provides new insights into understanding patterns and drivers of autumn leaf color.

1 - Carnegie Museum Of Natural, Section Of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, United States
2 - High Point University, Biology, 1 N University Pkwy, High Point, NC, 27268, USA
3 - Carnegie Museum of Natural History, Section of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, USA
4 - Appalachian State University, Biology, 572 Rivers St., Boone, NC, 28608, United States
5 - University of Alaska Fairbanks, Museum of the North, Fairbanks, AK, 99711, USA
6 - Florida International University, Biological Sciences

leaf senescence

Presentation Type: Oral Paper
Number: EPH2004
Abstract ID:429
Candidate for Awards:None

Copyright © 2000-2022, Botanical Society of America. All rights reserved