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2016 update: Phenology in the remnants

For the past three years, studying phenology in the remnants has been a major focus of our summer field work. The motivation behind this study is to understand how timing of flowering affects the reproductive opportunity and fitness of individuals in natural populations. Stuart began studying phenology in remnant populations between 1996 and 1999 and several students also studied certain populations in following years. From 2014-2016, we tracked phenology in all of our remnant populations. This year there were 1040 flowering plants (1500 flowering heads).

Flowering began on June 18th with one plant at the East Riley roadside remnant. Sadly, this early bloomer was mowed just 6 days after it started flowering. The latest flowering plant shed pollen in the West Unit of Staffanson Prairie Preserve on August 17th. When we consider all populations together, peak flowering was on July 10th. Peak flowering at Staffanson Prairie Preserve was later, on July 18th, likely due to the prescribed burn in the West Unit setting flowering back.

Blue line segments represent the duration of flowering for each remnant population. Click to enlarge!

Line segments represent the duration of flowering for each remnant population. Click to enlarge!

As you can see in the figure above, some populations had much longer duration of flowering than others. Flowering duration at Staffanson Prairie Preserve (‘spp’ in the figure) was longer because the west unit was delayed in flowering. East Riley (‘eri’) has a long duration of flowering, likely due to individuals being mowed early in the season, then resprouting and flowering later. This figure shows the very first and last dates of flowering, but population mean start and end dates of flowering is also informative (see what that flowering schedule looks like here). These figure with generated with R package mateable, which was was developed by Team Echinacea to visualize and analyze phenology data.

Start year: 1996

Location: roadsides, railroad rights of way, and nature preserves in and near Solem Township, MN

Overlaps with: Phenology in experimental plots, demography in the remnants

Physical specimens:

  • We harvested a random sample of 5 heads from most remnant populations (we excluded very small populations) and brought them back to the lab, where student interns will process and assess their seed set (‘regRem’ or ‘regular remnant harvest’).
  • We also harvested the most isolated, least isolated, earliest flowering, and latest flowering individuals from large populations (‘remnant extremes’). Student interns will also process and assess seed set of these heads.

Data collected: We identify each plant with a numbered  tag affixed to the stem and give each head a differently colored twist tie, so that each head has a unique tag/twist-tie combination, or “head ID”, under which we store all phenology data. We monitor the flowering status of all flowering plants in the remnants, visiting at least once every three days until all heads were done flowering to obtain start and end dates of flowering. We managed the data in the R project ‘aiisummer2016′ and will add it to the database of previous years’ remnant phenology records.

GPS points shot: We shot GPS points at all of the plants we monitored except for four, two at SGC and two at ERI, which were mowed (ERI) or dug up (SGC) early in the season. These points were shot under job names following the convention “SURV_2016MMDD_SULU” or “SURV_2016MMDD_CHEK”. The locations of plants this year will be aligned with previously recorded locations, and each will be given an identifier (‘AKA’). We will link this year’s phenology and survey records via the headID to AKA table.

You can find more information about phenology in the remnants and links to previous flog posts regarding this experiment at the background page for the experiment.

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