Submitted to: Scientific Data
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2016
Publication Date: 10/11/2016
Citation: Reyes-Fox, M.A., Steltzer, H., Lecain, D.R., McMaster, G.S. 2016. Five years of phenology observations from a mixed-grass prairie exposed to warming and elevated CO2. Scientific Data. doi:10.1038/sdata.2016.88.

Interpretive Summary: The data referenced in this paper were collected over a five year period from 2007-2011 in a climate warming and elevated CO2 experiment and have been placed in one of the Nature recommended data repositories. Four life history events were monitored for six abundant species in a temperate semi-arid grassland ecosystem for four treatments. We followed species-level phenology in control, warmed, CO2 enriched, and warmed x CO2 enriched plots. Although warmer temperatures alone and in combination with elevated CO2 often led to earlier leaf expansion, later senesce due to elevated CO2 had a greater effect on extending season length in the warmed ecosystem. Longer growing seasons are likely due to climate warming and concomitant CO2 enrichment, which enable some plant species to live longer.

Technical Abstract: Atmospheric CO2 concentrations have been steadily increasing since the Industrial Era and contribute to concurrent increases in global temperatures. Many observational studies suggest climate warming alone contributes to a longer growing season. To determine the relative effect of warming on plant phenology, we investigated the individual and joint effects of warming and CO2 enrichment on a mixed-grass prairie plant community by following the development of six common grassland species and recording four major life history events. Our data support that, in a semi-arid system, while warming advances leaf emergence and flower production, it also expedites seed maturation and senescence at the species level. However, the additive effect can be an overall lengthening of the growing and reproductive seasons since CO2 enrichment, particularly when combined with warming, contributed to an even longer growing season by delaying senescence. We purport this is due to plant water savings, resulting from exposure to elevated CO2, allowing plants to persist later into the season. The effect of CO2 on the reproductive season was less clear.