2005 Catalog (PDF: 2.9MB) - Friends School Plant Sale

2005 • Friends School Plant Sale 21
Minding the Monarchs
Citizen scientists document monarch population patterns in gardens, prairies and parks
BY KAREN OBERHAUSER
Did you know that the first monarch
butterfly found in Mexican overwintering
colonies had been tagged by
Minnesota volunteer citizen scientists? Until the
time in 1975 when Chaska’s Jim Gilbert and his
students tagged that first butterfly, the colonies
had been unknown to the scientific community.
This find was the culmination of more than 20
years of tagging efforts, started by Dr. Fred
Urquhart at the University of Minnesota,
intended to track the monarchs’ movements.
Current monarch citizen science projects are
building a treasure trove of long-term data that
will help us better understand monarch and
insect ecology. You can join the hundreds of
Minnesotans who volunteer to help increase our
understanding of potential impacts of global climate
change, pollution, habitat destruction and
other factors on monarchs—and, perhaps, information
to identify habitats of special importance
to monarchs.
Monarch Basics
Minnesota monarchs breed in an area from the
southern U.S. to southern Canada and from the
Atlantic Seaboard to the Rocky Mountains. This
range is limited by the monarch’s milkweed
host plants. Each spring, the monarchs return
to the southern U.S. from overwintering sites
in central Mexico and lay eggs in the southern
U.S. That same spring and summer, more generations
recolonize the rest of the summer
breeding range, with variation each year in their
arrival at different northern locations.
Monarchs appear to vacate the southern U.S.
for much of the summer, probably due to high
temperatures and host plant die-back.
Monarchs have five instars (the caterpillar
stages between molts). At spring temperatures in
the Twin Cities, development can require more
than 60 days, compared to fewer than 30 days in
summer. This timing allows three generations in
the northern part of their range, in addition to
the generation that begins in the southern U.S.
Milkweed Is Key
Volunteer citizen scientists in the Monarch
Larva Monitoring Project (MLMP), part of the
Monarchs in the Classroom program at the
University of Minnesota, collect monarch population
data at a range of times and places. All an
MLMP volunteer needs is access to a site containing
milkweed and willingness to monitor
the site on a weekly basis during the summer!
The number of milkweed plants, site size and
type, and site location vary greatly; sites include
small backyard gardens, railroad right-of-ways,
abandoned fields and pastures, and restored
prairies. Since some volunteers don’t have individual
access to sites or may not want to commit
to weekly monitoring, many nature centers
organize monitoring teams at their centers.
Volunteers thus have ready-made sites and a
larger research team to share their workload.
Once a season, volunteers describe their sites,
recording their location, size, and the milkweed
species that grow on the site. They estimate perplant
monarch densities on a weekly basis, by
either examining all of the milkweed plants for
eggs and larvae (in smaller sites) or sampling a
randomly chosen subset of plants. They record
the number of eggs and each type of larva found
and the number of plants examined.
MLMP Volunteers
More than 500 students, teachers, naturalists,
scientists, retirees, and others have participated
in the MLMP. Together, they have monitored
Above left: a royal visit to a St. Paul garden. Above right: Monarch caterpillars shed their skin five
times between hatching from their egg and becoming a chrysalis, or pupa. The intervals between
shedding this skin are called “instars;” all five instars (and an egg) are shown in this photo.
Below: It takes two generations of monarchs to make the return trip from Mexico to their northern
breeding range each summer.
I’m one of those environmentalists who looks for
opportunities to “walk the talk,” so becoming
involved in citizen science projects just comes
naturally. And since I’m also active in turning
my yard from urban monoculture into a diverse
native habitat, the monarchs add color,
pollination and life to my wild mix.
Neighbors see me going about the data collection
in my yard and sometimes stop to inquire—
a chance to hook them on nature. If I can reach
someone else, maybe just one more person will
make a difference in this fragile planet.
—AN MLMP VOLUNTEER
sites in 29 states and two Canadian provinces.
Whether they work in a classroom or not, many
MLMP volunteers become teachers through
their participation in the project.
Project Findings
MLMP volunteers are helping to answer key
questions about monarch biology:
• How do monarch populations change
throughout the spring, summer and fall in
different parts of North America?
• When does most mortality occur?
• What plant qualities affect female choice of
plants for egg laying?
• What kinds of habitat are best for monarchs?
Together, this team of citizen scientists has
helped to document distinct generations of
monarchs. They’ve learned, in contrast to the
“common wisdom,” that monarchs leave the
northern parts of their summer breeding range
and migrate to overwintering sites in central
Mexico, that many monarchs stop in Texas for
another round of egg production. Scientists at
the University of Minnesota are currently trying
to learn whether this fall behavior represents an
early response to a warming climate.
Citizen scientists have also found that life for
young monarchs is hard; only five to ten percent
survive to become the beautiful orange and
black butterflies that grace our gardens and
prairies.
On an even more alarming note, volunteers
have documented a steady decrease in monarch
numbers over the past three summers. This pattern
will lead to scientific research to point us to
the cause, and thus, hopefully to changes in
human behavior that may help to preserve this
beautiful butterfly.
Be a Citizen Scientist with MLMP
The dedication of over 500 volunteers has been
the foundation of this research. If you would
like to join this intrepid group, visit the MLMP
website at www.mlmp.org to learn more, or
contact Karen Oberhauser at the U of M
(oberh001@umn.edu) or an MLMP trainer at
one of the Minnesota sites below. We promise
that you’ll put your garden to good use!
Karen Oberhauser is a member of the Department of
Fisheries, Wildlife and Conservation Biology,
University of Minnesota. The MLMP is funded by the
National Science Foundation.
Twin Cities-Area MLMP Trainers
Bell Museum Don Luce lucex001@umn.edu
New London Becky West 320-354-5373
Laura Molenaar laura@mlmp.org
Eastman Nature Center Vicky Wachtler
vwachtler@threeriversparkdistrict.org
Friends of Lilydale Park Grit Youngquist
grit.youngquist@co.ramsey.mn.us
Westwood Hills Nature Center Kerry Wilcox
kwilcox@stlouispark.org
Lowry Nature Center Mary Vanderford
mvanderford@threeriversparkdistrict.org
Tamarack Nature Center Anna Newton
anna.newton@co.ramsey.mn.us
Milkweeds at the Plant Sale
Asclepias is the Latin name for the milkweed family.
Members of the family in the plant sale include:
• Natives—A. tuberosa Butterfly Weed, A. incarnata
Swamp Milkweed, A. speciosa Showy Milkweed, and
A. exaltata Poke Milkweed
• Annuals—Asclepias curassivica Butterfly Flower
• Perennials—A. tuberosa and A. incarnata Butterfly
Weed.