Impact of Warmer Spring Temperatures on Flowering Times of - - PowerPoint PPT Presentation

Impact of Warmer Spring Temperatures on Flowering Times of Individual Native Wisconsin Prairie Plants

LAKESHORE NATURE PRESERVE COMMITTEE MEETING

Historical Study of Phenology: Aldo Leopold

Background & Biological Rationale

• Study of cyclical natural phenomena

110 120 130 140 150 160 170 4.00 6.00 8.00 10.00 12.00

First Flower Date (Day of the Year) Average Spring Temperature (°C)

Historical First Flower vs. Average Spring Temperature

spiderwort prairie phlox shooting star 110 120 130 140 150 160 170 0.00 10.00 20.00 30.00 40.00 50.00

First Flower Date (Day of the Year) Spring Precipitation (cm)

Historical First Flower vs. Spring Precipitation

spiderwort prairie phlox shooting star

April-|------- May -------|-------June- April-|------- May -------|-------June-

Figure 1: First flowering dates of spiderwort (T. ohiensis, max=162, min=127, mean=148.1), prairie phlox (P. pilosa, max=159, min=118, mean=137.3), and shooting star (P. fassettii, max=147, min=122, mean=134.0). Data were collected in 1935-1945 by Aldo Leopold, his students, and members of his family and in 1977-2012 by Nina Leopold Bradley, Stanley A. Temple, and members of the Aldo Leopold Foundation. A) First flowering date compared to average spring temperature (spiderwort: R2 = 0.4023, F(1, 45) = 30.29, p < 0.001; prairie phlox: R2 = 0.343, F(1, 45) = 23.50, p < 0.001; shooting star: R2 = 0.7029, F(1, 45) = 106.48, p < 0.001). Average spring temperature was calculated using temperatures in March, April, and May. B) First flowering date compared to spring precipitation (spiderwort R2 = 0.0264, F(1, 45) = 1.22, p = 0.275; prairie phlox: R2 = 0.0012, F(1, 45) = 0.054, p = 0.817; shooting star: R2 = 0.0851, F(1, 45) = 4.19, p = 0.047). Spring precipitation includes both rainfall and snowfall for March, April, and May (13). First flowering dates are given as days of the year, where January 1st is day 1.

Methods

1. Identify plants 2. Label with metal stakes 3. Find location coordinates 4. Observe plants 5. Record first flowering date 6. Photograph flower 7. Compare first flowering date to other years (using average spring temperature, spring precipitation, and other variables)

Figure 2: Map of the Biocore Prairie with grid overlay. Each of the six lupine (Lupinus perennis) are indicated by a red pin. Their coordinates correspond to their location within the grid: L20, 7.0m E, 7.1m N; L20, 13.5m E, 16.6m N; M20, 19.3m E, 4.9m N; Q17, 1.0m E, 0.0m N; Q17, 3.4m E, 0.0m N; and R18, 2.7m E, 16.9m N.

Photographs

6/12/2017 6/19/2016 6/6/2016 6/5/2016 6/9/2016 6/27/2017 6/4/2017 6/14/2017

purple prairie clover meadow rue prairie phlox clasping milkweed

6/18/2018 6/4/2018 6/4/2018 6/18/2018

Figure 3: First flowers of plants whose flowering dates were recorded in 2016, 2017, and 2018. Each column includes the images for an individual plant in each year of the study: purple prairie clover (Dalea purpurea), meadow rue (Thalictrum dasycarpum), prairie phlox (Phlox pilosa), and clasping milkweed (Asclepias amplexicaulis).

• No significant relationship between spring temperature and flowering time for individual prairie plants

Results & Analysis

1-Jun 6-Jun 11-Jun 16-Jun 21-Jun 26-Jun 1-Jul 7 7.5 8 8.5 9

First Flower Date Average Spring Temperature (°C)

First Flower vs. Average Spring Temperature

purple prairie clover clasping milkweed prairie phlox meadow rue 1-Jun 6-Jun 11-Jun 16-Jun 21-Jun 26-Jun 1-Jul 40 50 60 70 80

First Flower Date Spring Precipitation (cm)

First Flower vs. Spring Precipitation

purple prairie clover clasping milkweed prairie phlox meadow rue

Figure 4: Graph of data from 2016, 2017, and 2018. Each line represents an individual plant’s first flowering dates in 2016, 2017, and 2018. A) First flowering date compared to average spring temperature. Average spring temperature was calculated using temperatures in March, April, and May (8.93°C in 2016, 8.21°C in 2017, and 7.21°C in 2018). B) First flowering date compared to spring precipitation. Spring precipitation included both rainfall and snowfall for March, April, and May (41.96 cm in 2016, 48.95 cm in 2017, and 75.21 cm in 2018).

2018 2017 2016 2016 2017 2018

Results & Analysis

• Relationship between climatic variables and flowering time is species dependent

1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 2017 2018

First Flower Date Year

First Flower in 2017 and 2018

Yellow Coneflower Butterfly Milkweed Meadow Rue 1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 2017 2018

First Flower Date Year

First Flower in 2017 and 2018

Flowering Spurge Prairie Blazing Star Rosinweed White Prairie Clover

Figure 4: Graph of data from 2017 and 2018. Each line represents an individual plant’s first flowering dates in 2017 and 2018. Lines of the same color are individuals of the same species. In 2017, average spring temperature was 8.21°C, spring rainfall was 27.84 cm, spring snowfall was 21.11 cm, and total spring precipitation was 48.95 cm. In 2018, average spring temperature was 7.21°C, spring rainfall was 32.16 cm, spring snowfall was 43.05 cm, and total spring precipitation was 75.21

• cm. Spring temperatures and precipitation were calculated using values from March, April, and May.

Implications

Temperature & sunlight Precipitation Winter temperature & snow depth Flowering time Genetic constraints

Implications

Water uptake Interactions with pollinators & herbivores Nutrition cycling & carbon sequestration Altered flowering time

Accomplishments

Thank You!