Dataset DOI: 10.5061/dryad.6q573n6f1

These data are from a long-term study (1998-2024) of a wildflower, tall coneflower, Rudbeckia laciniata L., a herbivore of this plant, the host-specific aphid, Uroleucon rudbeckiae (Fitch), and a complex of predators that feed on the aphid. Investigation of the higher trophic levels are ongoing. Tall coneflower is native to south-eastern North America. Although widespread and sometimes grown as a garden cultivar (Golden Glow), its life history and ecology are little studied. Data from this study were used to test two hypotheses: 1) life history traits of populations at the edge of their range are unstable from year to year; 2) climate change stabilizes such traits at the northern edge of their range:

Lamb, R.J. and MacKay, P.A. (2026). Life history stability under climate change: a wildflower at the northern edge of its range. Nordic Journal of Botany – DOI: 10.1002/njb.05232.

This study included five northern populations of tall coneflower: a garden population (WH) and four wild populations in a national park (CC, BR, BH, BB). (Lamb and MacKay 2026). Four life history traits were monitored annually for the populations, in the third week of August, as the plants finished blooming and began producing seeds.

The WH population was monitored more intensively, to better understand and compare the seasonal development of the species and validate comparisons among life history traits and among populations. The timing of the beginning of the growing season, when shoots first emerge from the soil, and its relationship with the timing of snow melt, were monitored approximately daily in five replicate plant patches (AA, AB, B, C, D) at WH. Subsequently, the WH population was monitored through the growing season, approximately weekly, to define seasonal patterns of development for the life history traits.

Four life history traits were assessed for flowering stems in all populations: stem density, stem height, number of flower/seed heads per stem, and developmental stage. Annual estimates of trait values were used to estimate the year-to-year stability of each trait in each population and test the two hypotheses (Lamb and MacKay 2026).

The data from this study are provided as CSV files, in three appendices. Weather data used in the analyses of effects of climate change on the life history of the plants are from Environment Canada, weather.gc.ca/canada_.e.html. Appendix 1 and 2 present data that quantify seasonal patterns of the life history traits in the WH population.

Description of data

Note: Each Appendix lists the variables contained therein, their descriptions, and units at the top of the spreadsheet.

WH: A garden population of tall coneflower
AA, AB, B, C, D: Replicate plant patches at WH
CC, BR, BH, BB: Wild populations in a national park

Appendix 1 Snow melt and shoot emergence

File: Lamb_and_MacKay_-_Appendix_1_Snow_melts_Shoots_emerge.csv

Dates of snow melt and emergence of first shoots in five plant patches in the WH population. These data were collected to define the starting point of each growing season, which contributed to understanding the level of stability for stem development later in the season.

Cells in the spreadsheet are blank if data were not recorded in a patch in a particular year, because of inclement weather, time constraints, or changes in research priorities. Recording of shoot emergence began in 1998; snow melt records began in 2004.

Appendix 2 Seasonal data for life history traits

25 Files: Appendix_2_WH_2003.csv to Appendix_2_WH_2023.csv

Estimates of three life history traits for individual flowering stems in the five plant patches that constitute the WH population: stem height (Height), number of flower/seed heads per stem (Blooms), developmental stage (Stage). Data were collected through the season, annually from 2003-2023, with sample date (Date) and day of the year (Day) reported for each stem in a patch. In most years, individual stems were tagged and numbered, so that changes in a trait could be followed through the season for each stem, but in 2003, 2007, and 2009 stems were not tagged, and so individual stems could not be followed between sample dates.

Data for each year are presented in 25 separate files, with each filename indicating the year data were collected. Filenames for 2003, 2007, and 2009 have an additional suffix, naming the life history trait in that file, because in those years traits were not necessarily assessed on the same day. In 2009, early in the season before flowering stems were identifiable, canopy height (CHt) and length and width for individual acaulescent leaves (LeafLength, LeafWidth) were recorded in cm.

Cells are blank if data were not recorded in a patch in a particular year. Records ceased if a tagged stem broke in the wind; early records were missing for stems that developed late, or were not initially detected.

Appendix 3 Annual data for four life history traits in five populations

File: Lamb_and_MacKay_-_Appendix_3_Annual_life_history_data.csv

Estimates of annual mean values of life history traits for flowering stems recorded in the third week of August in five populations (1999-2023). The life history traits are stem density (Density), stem height (Height), flowers/seed heads per stem (Blooms), and stem developmental stage (Stage). These data were used to assess the year-to-year stability of each trait and the effect of climate change on the traits.

Cells are blank if data were not recorded in a population in a particular year. Stem density records were initiated first in 1999; monitoring growth and development traits became regular in 2006. At the BH site, very high stem densities made complete counts impractical in most years.

Code/software

Excel or other tabular data software

Access information

Other publicly accessible locations of the data:

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Data was derived from the following sources:

• No other sources than the authors of the publication