September 27th, 2012
UROP Proposal
Phenological Changes in Northern Minnesota in Response to Global Warming
Background and research questions
Phenology is the study of periodic life cycle events of animals and plants throughout
the year and how they are influenced by seasonal climate variations. Phenological events
include fruiting or flowering of plants, bird migration, and animal reproduction. Scientific
studies carried out in several regions of the United States as well as other parts of the world
show convincing evidence that rising global temperatures are affecting plant and animal
phenology. We are experiencing longer growing seasons, earlier bird migration, as well as
earlier budding of trees due to temperatures warming earlier in the spring time.
We know little about the changing phenology of forest plaints in the Great Lakes
Region. This hinders our ability to predict potential changes to forest communities under
climate change. In my UROP, I ask (1) how have plant species common to forests in
northern Minnesota changed their phenology over the past 30 years and (2) what is the
relationship between interannual variation in climate and interannual variation in
phenology. I will use data collected by John Latimer, a citizen scientist from Grand Rapids,
MN. John Latimer is not only an active naturalist and the official Staff Phenologist of KAXE
radio in Brainerd, Minnesota, but he is also a mail carrier in Grand Rapids. Every day for the
past 25-30 years, he has observed the natural world around him and has documented the
timing of phenological events of plants along his mail route. I expect that spring
phenological events such as the leaf-out of trees or fruiting of plants to occur earlier in the
springtime now than 30 years ago because springs are warmer on average. Similarly, I
expect autumn phenological events such as leaves changing colors and dropping from trees
to happen later in the fall due to temperatures staying warmer longer.
Relationship to faculty mentors research
I will be working with Rebecca Montgomery, an Associate Professor in the Forest
Ecology department. Her interests include studying changes in the environment due to
human actions, and understanding the response of natural systems to these alterations.
Some of her current research topics include examining the potential for projected climate
change to alter tree species composition at the southern boreal-temperate forest ecotone, as
well as studying the relative importance of above-versus belowground competition in
structuring interactions between shrubs, herbs, and trees in forest understories.
Methods
To answer my research question, I will first explore the Latimer dataset and identify
target species and phenological events for analysis. These must have sufficient data to
construct a time series (>15 years with data) and to analyze for correlations between
phenological events and spring/fall temperatures. I will start by making graphs for each
target species and phenological event (e.g. bud break or blooming) showing the dates of
event over the time span of the data (approximately 30 years). I will analyze each time
series for temporal trends using correlation analysis with particular interest in how much
earlier specific phenological events are occurring in the present compared to the beginning
of data collection. To examine the relationship between climate and phenology, I will use
publically available climate data for Grand Rapids (NOAA or other weather station) for each
year of phenology data in the Latimer dataset. I will correlate the date of the specified
phenological events in relation to carious climate metrics such as the mean February –
March temperature. Significant temporal trends and correlations linking warming
temperatures to earlier (e.g. blooming or leafing) or later events (e.g. leaf fall) would
indicate that climate change is, in fact, having an effect on plant phenology in Minnesota.
Significance
Observations made by local naturalists like John Latimer can fill gaps and expand
the knowledge of effects of global warming on ecological communities in our region. Such
results could have serious implications for the state of Minnesota. As conditions become
warmer, many rare species may no longer be able to survive at their present locations due
to altered temperatures (4). If temperatures are warming too quickly for plants to adapt, we
could experience a loss in biodiversity in Minnesota forests as species migrate or become
extinct. In addition to advancing earlier, plants are holding their leaves longer into autumn
as well, lengthening the growing season, which could have positive effects on Minnesota
agriculture.
This research project represents a unique opportunity. Typically people simply record what
they see around their homes or on their daily walks in an informal way on calendars or on
journals. We rarely come across formal phenological data sets taken so frequently over such
a long period of time, and recorded in electronic form. Knowledge gained will enhance
understanding about forest vegetation response to climate change in the Lake States. This is
important because forests support significant economic activities from timber harvesting to
recreation.
When my research is complete, the results will be reported and presented on a
poster at the Undergraduate Symposium in order to educate others about the study. This
project is the first step in pursuing my dream of becoming a climatologist. I hope to gain
valuable experience and knowledge during my research, as well as make connections with
other professionals in the field who have similar interests to mine.
References:
1. Anna, Ledneva, Primack Richard, Miller-Rushing Abraham, and Imbres Carolyn.
"Climate Change as Reflected in a Naturalist's Diary, Middleborough,
Massachusettes." BioOne. (2004): n. page. Web.
2. Bradley, Nina, Carl Leopold, John Ross, and Wellington Huffaker. "Phenological
Changes Reflect Climate Change in Wisconsin." Proceedings of the National
Academy of Sciences. (2007): n. page. Web. 2 Oct. 2012.
3. Inouye, David, Billy Barr, Kenneth Armitage, and Brian Inouye. "Climate Change is
Effecting Altitudinal Migrants and Hibernating Species." Proceedings of the National
Academy of Sciences. (1999): n. page. Web. 2 Oct. 2012.
4. Miller-Rushing, Abraham, Primack Richard, Primack Daniel, and Mukunda Sharda.
"Photographs and Herbarium Specimens as Tools to Document Phenological
Changes in Response to Global Warming." American Journal of Botany. (2006): n.
page. Web. 2 Oct. 2012.
5. Polgar, Caroline, and Richard Primack. "Leaf-Out Phenology of Temperate Woody
Plants: From Trees to Ecosystems." Tansley Review. (2011): 926-937. Web.