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Analysis of Phenological Changes in Coltsfoot (Tussilago farfara L., Asteraceae) Using Data from Herbarium Specimens and Field Observations

Muluneh, Fisseha (2013) BIOM31 20131
Degree Projects in Biology
Abstract
Abstract

Phenological data have recently emerged as effective tools for studying the impact of climate change on demographic and ecosystem processes. In this study, I used records from herbaria and public databases to examine whether the Swedish coltsfoot population has advanced its flowering time, as a response to the increase in mean temperature observed to have taken place over the past centuries in this and other regions. The relationship between flowering date and year of observation depended on the type of data considered and whether comparisons were made between or within datasets. Comparisons between datasets showed long-term advancement of flowering, whereas analyses of individual datasets showed a mixed pattern, ranging from... (More)
Abstract

Phenological data have recently emerged as effective tools for studying the impact of climate change on demographic and ecosystem processes. In this study, I used records from herbaria and public databases to examine whether the Swedish coltsfoot population has advanced its flowering time, as a response to the increase in mean temperature observed to have taken place over the past centuries in this and other regions. The relationship between flowering date and year of observation depended on the type of data considered and whether comparisons were made between or within datasets. Comparisons between datasets showed long-term advancement of flowering, whereas analyses of individual datasets showed a mixed pattern, ranging from no shift at all (herbarium data from 1817-2008) to significant advancement (first flowering dates from 1873-1951) or a period of increasing delay (phenology network data from 2008-2013). Overall, records of first flowering dates showed stronger patterns than records representing the entire flowering curve such as those from herbarium material. Winter and spring temperature were major (but not the only) drivers of observed changes in flowering time. Much of the observed variation in flowering date was explained by latitude and the stage at which a herbarium specimen had been collected during flowering (measured by stem height). My results are consistent with previous observations that date of first flowering is sensitive to climate change but are less conclusive about temporal changes in the overall flowering period. (Less)
Abstract
Popular science summary

Has climate change influenced flowering time of coltsfoot?

Phenological events such as the onset of flowering during the spring are among the most sensitive indicators of climate change. Hence, phenological data have recently emerged as effective tools for studying the impact of climate change on species and ecosystems. In this study, I used records from herbaria and public databases to examine whether the Swedish populaiton of coltsfoot (Tussilago farfara) has advanced its flowering time as a response to the global warming observed in the past century.

Herbarium sheets with specimens of coltsfoot collected at the flowering stage were scored for geographical location and date and year of collection. These... (More)
Popular science summary

Has climate change influenced flowering time of coltsfoot?

Phenological events such as the onset of flowering during the spring are among the most sensitive indicators of climate change. Hence, phenological data have recently emerged as effective tools for studying the impact of climate change on species and ecosystems. In this study, I used records from herbaria and public databases to examine whether the Swedish populaiton of coltsfoot (Tussilago farfara) has advanced its flowering time as a response to the global warming observed in the past century.

Herbarium sheets with specimens of coltsfoot collected at the flowering stage were scored for geographical location and date and year of collection. These records were combined with data on flowering time from plants observed in the field and reported to two public databases (the Swedish species portal, Swedish phenology network) and analyzed statistically to identify temporal and spatial trends in flowering phenology.

The relationship between flowering date and year of observation depended on the type of data considered and whether comparisons were made between or within datasets. Comparisons between data from different periods (e.g. herbarium records vs. recent field data) showed long-term advancement of flowering. Analyses of individual datasets showed a mixed pattern, ranging from no shift at all (herbarium data from 1817-2008) to significant advancement (first flowering dates from 1873-1951) or a period of increasing delay (phenology network data from 1994-2013). Overall, records of first flowering dates showed stronger patterns than records representing the entire flowering curve such as those from herbarium specimens. Winter and spring temperature were major (but not the only) drivers of observed changes in flowering time. My results are consistent with previous observations that date of first flowering is sensitive to climate change but are less conclusive about temporal changes in the overall flowering period.

Advisor: Stefan Andersson
Master´s Degree Project 30 credits in Plant Ecology and Systematics 2013
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Muluneh, Fisseha
supervisor
organization
course
BIOM31 20131
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
4157492
date added to LUP
2013-11-18 15:24:13
date last changed
2013-11-18 15:24:13
@misc{4157492,
  abstract     = {Popular science summary

Has climate change influenced flowering time of coltsfoot? 

Phenological events such as the onset of flowering during the spring are among the most sensitive indicators of climate change. Hence, phenological data have recently emerged as effective tools for studying the impact of climate change on species and ecosystems. In this study, I used records from herbaria and public databases to examine whether the Swedish populaiton of coltsfoot (Tussilago farfara) has advanced its flowering time as a response to the global warming observed in the past century. 

Herbarium sheets with specimens of coltsfoot collected at the flowering stage were scored for geographical location and date and year of collection. These records were combined with data on flowering time from plants observed in the field and reported to two public databases (the Swedish species portal, Swedish phenology network) and analyzed statistically to identify temporal and spatial trends in flowering phenology. 

The relationship between flowering date and year of observation depended on the type of data considered and whether comparisons were made between or within datasets. Comparisons between data from different periods (e.g. herbarium records vs. recent field data) showed long-term advancement of flowering. Analyses of individual datasets showed a mixed pattern, ranging from no shift at all (herbarium data from 1817-2008) to significant advancement (first flowering dates from 1873-1951) or a period of increasing delay (phenology network data from 1994-2013). Overall, records of first flowering dates showed stronger patterns than records representing the entire flowering curve such as those from herbarium specimens. Winter and spring temperature were major (but not the only) drivers of observed changes in flowering time. My results are consistent with previous observations that date of first flowering is sensitive to climate change but are less conclusive about temporal changes in the overall flowering period. 

Advisor: Stefan Andersson 
Master´s Degree Project 30 credits in Plant Ecology and Systematics 2013 
Department of Biology, Lund University},
  author       = {Muluneh, Fisseha},
  language     = {eng},
  note         = {Student Paper},
  title        = {Analysis of Phenological Changes in Coltsfoot (Tussilago farfara L., Asteraceae) Using Data from Herbarium Specimens and Field Observations},
  year         = {2013},
}