Abstract Detail

IAPT Early Career Investigator Program: Life at the Edge

Humphreys, Aelys [1], Nuppenau, Jan-Niklas [1], Minadakis, Nikolaos [1], Lancaster, Lesley [2].

Thermal tolerances of plants – geographical patterns at global and local scales.

Temperature is considered one of the strongest determinants of plant distribution patterns globally. Yet, our understanding of what drives the geographic distribution of plant thermal tolerances is poor. In this context, I will present preliminary results of two ongoing projects. In the first, we are analysing the global distribution of plant thermal tolerances. Previous studies of ectothermic animals suggest that thermal tolerance breadth increases toward the poles. Explanations for this pattern include local adaptation to the more variable conditions at high latitudes, phylogenetic (physiological) constraints limiting variation in upper thermal limits and biogeographic history related to species' recent range expansions. Using a newly compiled global dataset of measured upper and lower critical thermal limits (cold and heat tolerance) for land plants, we show that plants exhibit the expected latitudinal patterns but that there is no single explanation for these patterns. Instead we suggest that global variation in thermal tolerances is generated by several processes acting at different temporal and geographical scales. In the second project, we are studying grasses (Poaceae) from geothermally heated and non-heated areas of Iceland. Geothermally heated soils in Iceland never freeze and are on average 10 ºC warmer than surrounding soils throughout the year. Fine temperature gradients over short geographic distances have made this an attractive system for studying the effect of warming on plant phenology. However, the winter season has received less attention and we do not know whether there is a tradeoff between adapting to warm soils and the ability to survive a normal temperate winter. Using common (winter) garden experimentation, we are comparing the winter survival ability and phenology of populations from heated and non-heated soils. We are also studying the population structure and phylogeography to assess the nature of any ongoing gene flow among populations. A previous study of Agrostis in North America found restricted gene flow among populations on heated and non-heated soils because of a shift to earlier flowering on the heated soils. At the time of writing we are only just beginning to see results for Iceland and I will summarise these in my talk.

1 - Department of Ecology, Environment and Plant Sciences, Svante Arrhenius väg 20A, Stockholm, 10691, Sweden
2 - The School of Biological Sciences, King's College, University of Aberdeen, Aberdeen, AB243FX, UK

Keywords:
biogeography
thermal tolerance
cold tolerance
heat tolerance
critical thermal limit.

Presentation Type:
Session: SYM6, IAPT Early Career Investigator Program: Life at the Edge
Location: Tucson E/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 11:30 AM
Number: SYM6007
Abstract ID:239
Candidate for Awards:None