Who won the root races?

Newsletter

Volume 6, Number 4
July - August 1989

Director’s Note

Summer at the Institute, as in nature,
brings rapid growth in new directions.
Scientists from around the world come
to do field studies and to collaborate with
lES ecologists. Students arrive to do
independent study or to work as summer
project assistants. This is also the time
when lES ecologists are busy doing much
of their field work — sampling, measuring,
counting, observing, and analyzing data
from their research projects.

Summer 1989 brought over 50 visiting
scientists and students, and found some of
our staff extending their ranges as well.
The July- August and September-October
issues of the newsletter will highlight
some of the past summer’s work.

The lES Newsletter is published by
the Institute of Ecosystem Studies
at the Mary Flagler Cary Arboretum.
Located in Millb^rook, New Y ork,
the Institute is a division of The
New York Botanical Garden. All
newsletter correspondence should
be addressed to the Editor.

Gene E. Likens, Director
Joseph S. Warner, Administrator
Alan R. Berkowitz,

Head of Education

Editor: Jill Cad wallader
Design and Printing: Central Press

INSTITUTE OF
ECOSYSTEM STUDIES
The New Y ork Botanical Garden
Mary Flagler Cary Arboretum
BoxAB

Millbrook, NY 12545
(914)677-5343

“The Root Race Experiment” is the
creation of Dr. Francis Putz. As the 1989
Cary Fellow, Dr. Putz spent the summer
at lES, working with lES plant ecologist
Dr. Charles Canham on the right-of-way
study L His research grew from the
observation that in abandoned fields, on
roadsides and along utility rights-of-way,
dense stands of shrubs apparently slow the
rate of tree encroachment. Are shrubs
more effective competitors than trees, and
if so, why? Dr. Putz’s root race experiment
was one of two ways in which the ecologist
set about studying the interactions
between trees and shrubs.

Dr. Putz hypothesized that shrubs are
more effective than trees in below-ground
competition for nutrients. To test this
hypothesis, he designed large wooden
boxes with Plexiglas sides and a number
of “root race courses”. He planted
seedlings of 4 tree species and 4 shrub
species, one seedling per section. By
adding slow release fertilizer pellets —
lower concentrations near the seedlings
and higher concentrations at the Plexiglas
end of the course — he provided a nutrient
gradient. As soon as a seedling’s roots
could be seen through the Plexiglas, that
seedling was harvested to measure its total
root weight.

1 . lES ecologists are studying plant-plant,
plant-animal and plant-resource relation-
ships along utility rights-of-way, in an effort
to develop natural ways to control plant
growth (see lES NEWSLETTER Volume 5
Numbers.

There were two ways to “win” the race.
One, perhaps the most obvious, was for a
root to reach the Plexiglas first. Dr. Putz,
however, was more interested in the
second, which was for a root to go the
farthest with the least expenditure of
energy. In typical soil, nutrients tend to
occur in patches due to the way that those
nutrients are deposited — from a dead
animal, rotting leaves, etc. — and a root
that can seek out nutrient patches faster or
more efficiently is likely to be a more
serious competitor. Therefore, the data
from the root races should provide an
indication of whether shrub roots are more
effective foragers than those of trees. The
winner of the race was, indeed, a shrub,
smooth sumac, but in second and third
places were the gray birch and red maple
trees. Obviously the story of root foraging
is more complicated than originally
anticipated.

The root race experiment was done in the
lES Greenhouse, but Dr. Putz did the
other part of his summer research in three
fields — wet, dry and mesic (moderate
moisture) — on the Arboretum. Selecting
clumps of shrubs in each of these three
field types, he planted tree seedlings in the
centers: red maple seedlings were planted
in smooth sumac and gray dogwood
clumps, and white ash in other patches of
gray dogwood.

In these experiments, he measured
competition for nutrients and water, and

continued on page 3

When Shrimp Stir Up the Sand

Throughout tropical and subtropical
waters, species of shrimp feed on particles
of organic matter in the sand surrounding
their deep burrows. As they do so, their
back legs move constantly to keep sand
from clogging the tunnels. This
excavation causes sediment particles to be
propelled from the mouths of the burrows.
How does this process affect the cycling of
organic materials through food chains, and
how does it contribute to a healthy marine
environment?

When animals living in sediments stir up
these sediments through their normal
feeding and shelter-building behavior, the
process is known as bioturbation.
Bioturbation can enhance microbial
activity, increase the release of nutrients
from sediments, and increase the
circulation of oxygen. Callianassa is a
genus of shrimp that comprises some of
the most effective invertebrate
bioturbators of sediments in marine
waters. These 5 centimeter-long (2 inch)
shrimp dig burrows that may reach depths
of 3 meters (almost 10 feet). At the top of
each burrow is a mound of excavated sand
often 30 cm (1 ft.) high. The shrimp are
deposit feeders, which means that they
collect food particles from the sediments.
As they do so, they sort out the finer
grained deposits that are richest in organic
matter. This sorted material is what gets
pushed out of the burrows, where it settles
on the sediment surface and may even
filter back down into the burrows.

Dr. Thomas S. Bianchi, a post doctoral
aquatic ecologist at lES, recently received
a special grant from the Bermuda
Biological Station for Research (BBSR) to
observe and measure bioturbation in an
area where Callianassa shrimp are
plentiful and easily studied. The purpose
of this field study was to learn more about
the source materials in a marine food chain
and the decomposition of organic matter.

Dr. Bianchi’s interest in bioturbation
began while he worked as a graduate
student with Dr. Donald L. Rice, a
geochemist at the University of Maryland.
Together they examined how Callianassa
bioturbation affects the chemistry of
sediments in the Bahamas. Since his
arrival at the Institute a year ago. Dr.
Bianchi has been looking at food resources
for the Hudson River food chain, but has
maintained his interest in food web
processes of marine environments as well.

In June Dr. Bianchi spent a week in
Bermuda, dividing his time between the
BBSR laboratories and Coot Pond, a
sheltered bay at the northeast end of the
Island where there is a particularly high
density of Callianassa. The ecologist was

Dr. Bianchi used a pvc coring tube to collect sediments from Coot Pond, Bermuda. Thin sections of the
cores were later examined for plant pigments, to learn which plants were important in the local food chain.

especially interested in knowing the
importance of land-derived food material
relative to marine-derived food material
in the nearshore marine food chain.
Specifically, did the mangrove leaves that
fell off trees on Coot Pond’s shores
contribute significantly to the marine
animals’ diets? To help answer the
question, he used plant pigments
(primarily the chlorophylls and
carotenoids that plants require for
photosynthesis) as tracers, or clues to the
types of plant material that were moving
into the food chain in Coot Pond.

Each day, at low tide, he cored into the
sediments and carried the full pvc coring
tubes back to the laboratory in a cooler
strapped to his motorbike. He extruded
and sliced the cores at 1 cm (0.39in.)
intervals and at the end of his field work
brought the slices, frozen and protected
from light to prevent pigment degradation,
back to his lES laboratory for pigment
analysis by a technique known as high
pressure liquid chromatography.

Evidence provided by the plant pigments
suggests that diatoms — single-celled
algae — rather than dead mangrove leaves
are the chosen food of Callianassa. As the
shrimp eat the plant material and stir up
the sediments, fragments of the plants and
their pigments are deposited. It was the
pigment from diatoms that was found
distributed, by bioturbation, throughout
the cores, indicating the importance of
these microscopic plants in the food chain.

But where does the detritus from
surrounding mangrove trees go, if not to

the Coot Pond sediments? Dr. Bianchi
hypothesizes that this material may travel
out to the sediments of the Bermuda
Platform and may therefore benefit
benthic (sea-bed) communities. The
eventual products of the breakdown of
mangrove leaves may even be beneficial to
Bermuda’s reef communities, and might
help to compensate for the scarcity of
phytoplankton in the surrounding ocean
waters.

Dr. Bianchi is using data from his work at
the BBSR in a preliminary proposal for a
research grant to study the transport and
utilization of organic matter in Bermuda
Platform sediments. This proposed
research could provide an important
contribution to coastal studies and to the
growing body of knowledge of land margin
ecosystems.

At the Perennial Garden
This Fall...

Chrysanthemum nipponicum (Nippon
Daisy)

Sedum telephium ‘Autumn Joy’ (Live-
Forever)

Epimedium sp. (Barronwort)
Belamcanda chinensis (Blackberry Lily)
Aconitum arendsii (Monkshood)
Asarum sp. (Wild Ginger)

Ceratostigma plumbaginoides (Plum-
bago)

Boltonia asteroides ‘Snowbank’
Ornamental Grass Bed

Races, from page 1

On May 1, Gregory R. Long began his duties as the eighth president of The New York
Botanical Garden, succeeding Dr. James H Hester who had been president since 1980.
Coming to the Garden from The New York Public Library where he was vice president for
public affairs and development, Mr. Long brings experience as a leader in the develop-
ment of effective administration, resourceful financing and innovative programs for major
non-profit institutions. He shows great interest in the research and public education
programs of lES, and in August visited the Institute to meet the staff. Here, Mr. Long (r.)
discusses Plant Science Building roof renovations with lES director Dr. Gene E. Likens.

New Staff

BERTRAND BOEKEN will be at the
Institute for two years as a postdoctoral
fellow. Working with Dr. Charles
Canham, Dr. Boeken is studying the
invasion of the shrub Cornus racemosa
(gray dogwood) into herbaceous
communities along utilities rights-of-way
and the expansion of clones after
successful colonization. Dr. Boeken has an
M.Sc. from Amsterdam University, The
Netherlands, and a Ph.D. from Ben-
Gurion University of the Negev in Israel.

SANDRA S. HILL, research assistant,
assists Dr. Clive Jones on his cottonwood
study (see lES NEWSLETTER 6:3). She
is currently working to develop a method
to analyze cottonwood leaves for naturally
occurring chemicals called phenol
glycosides. Decreases in these chemicals
are believed to be one reason why ozone
exposure makes cottonwood leaves more
palatable to an insect pest. Ms. Hill has
bachelor’s degrees in chemistry and
medical technology from Hartwick
College in Oneonta, New York.

MARK J. MATTSON was appointed
postdoctoral associate with Dr. Gene
Likens. A graduate student at Cornell
University and lES, he did his Ph.D. thesis
work on decomposition processes in
Mirror Lake (Hubbard Brook

Experimental Forest, New Hampshire).
During the summer he worked at
Hubbard Brook, overseeing the field
laboratory, assisting with computer
facilities and continuing studies of Mirror
Lake.

ANDREW J. TOBIAS, research
assistant, works with manager of
laboratory facilities Kathleen Weathers
and maintains the lES environmental
monitoring program. This program, linked
to many of the Institute’s long-term
research projects, includes an air quality
meteorology/station and a stream flow
station. After earning a B.S. at SUNY
College of Environmental Science and
Forestry, Mr. Tobias served four years in
the U.S. Coast Guard on board oceano-
graphic/meteorological research vessels.

VOLUNTEERS NEEDED

to help in the Gift and Plant Shop.

Requirements? Interest in people,
plants and the environment...

Please call Marcia Davis, assistant to the
education staff, at 677-5358 if you would
like to help out.

for sunlight. Four treatments, with
replicates, were done in each field. In the
first treatment, a trench was dug around
the tree seedling and a root barrier was
installed; here, then, the tree seedling had
unlimited access to water and nutrients, as
shrub roots could not invade its root space.
In the second treatment, where guy wires
were used to hold shrub branches out of
the way, the tree seedling was given
unlimited sunlight. Treatment #3
consisted of the trenching/root barrier
and guy wires, so the tree seedling had no
below-ground competition, and unlimited
sunlight. The fourth treatment, as in all
good scientific experiments, was no
treatment; the tree seedling and its
surrounding shrubs were left alone, as an
experimental control.

Growth of the research plants has been
good, and results at the end of Dr. Putz’s
three-month stay at lES suggested that
both below-ground and above-ground
competition reduce the growth of tree
seedlings. The tree seedlings will be
remeasured in October but the final results
will not be in until after another growing
season.

The results of Dr. Putz’s research here
will have implications to the management
of plant communities along utility rights-
of-way and elsewhere. The study is one
more example of the importance of
addressing fundamental ecological
questions to reach answers of interest
to managers.

» » » « « «

The Cary Summer Fellowship is an annual
award enabling one or more scientists to do
research at the Institute. Funds for the
award are provided by the Mary Flagler
Cary Charitable Trust. Results from the
Cary Fellows ’ short-term projects at lES
contribute to the scientists’ long-term
teaching and research programs at their
home institutions.

Dr. Francis E. Putz is an associate professor
of botany and forestry at the University of
Florida, Gainesville. In his teaching and
research he works to bridge the gap between
forest ecology and forest management. Most
of his field work is done in the tropical
rainforests of Southeast Asia and in South
and Central America, where he studies the
natural factors that limit tree growth. One of
his next research expeditions will be to
Ecuador, to look at the potential for
rejuvenating the button palm as an economic
resource for Ecuadorians. Also known as the
ivory nu t palm or vegetable ivory palm, its
extremely hard, white seeds were once used to
make high quality buttons.

CONTINUING EDUCATION PROGRAM

Classes in Landscape Design, Gardening, Botany,
Biological Illustration and Nature Photography
begin throughout the fall.

Ecological Excursions and Workshops are
also scheduled for fall. Stop by the Gifford House or
call the number below for a Continuing Education
Program catalogue.

Workshops ... Call to preregister for:

N ov. 4 Planting the Seeds for Y our New

Business

Nov. 11 Ecological Landscape Assessment

Holiday Workshops, taught by members of the
Nine Partners Garden Club, are offered in October,
November and December. Call for information.

SUNDAY ECOLOGY PROGRAMS

Free public programs are offered on the first and
third Sunday of each month, except over holiday
weekends. Tentative schedule (please call (914) 677-
5359 to confirm the day’s topic):

Oct. 15 — Norway: Fjords, fish ... and acid rain, a
talk by Dr. Helge Leivestad
Nov. 5 — Life in the Hudson River, a talk by Dr.
Michael Pace

Nov. 19 — A Visit to the Bottom of the Ocean:
Research Experience with the ALVIN, a talk by Dr.
Jonathan Cole

Dec. 3 — The Hubbard Brook Ecosystem Study, a
talk by Dr. Gene E. Likens

These slide presentations begin at 2 p.m. at the
Gifford House on Route 44A.

In case of inclement weather, call (914) 677-5358
after 1 p.m. to learn the status of the day’s program.

Fall Calendar

lES SEMINARS

The Institute’s weekly program of scientific
seminars features presentations by visiting scientists
or Institute staff. All seminars are held in the Plant
Science Building on Fridays at 3:30 p.m. Admission
is free. Scheduled for this fall are:

Oct. 13 — The mode of Toxic Action of Acid/
Aluminum on Fish, by Dr. Helge Leivestad (Univ. of
Bergen, Norway)

Oct, 20 — Topic: Long-term studies on herbivory
and plant demography, by Dr. John Thompson
(Washington State Univ.)

Oct. 27 — Photosynthesis in Fluctuating Light
Regimes, by Dr. Robin Chazdon (Univ. of
Connecticut)

Nov. 3 — Topic: Lead biogeochemistry, by Dr.

Russ Flegal (Univ. of California at Santa Cruz)

Nov. 10 — Topic: Sulfur biogeochemistry, by Dr.
Bob Cook (Oak Ridge National Laboratory,
Tennessee)

Nov. 17 — Organic Diagenesis and the Nutrition of
Deposit-Feeders, by Dr. Donald L. Rice (Chesapeake
Biological Laboratory, Univ. of Maryland)

Dec. 1 — Biological Control of Bracken, by Dr. John
H. Lawton (Univ. of York, United Kingdom)

Dec. 8 — Nitrogen Saturation in Forest
Ecosystems, by Dr. John Aber (Univ. of New
Hampshire)

Dec. 15 — Topic: Global warming, by Dr. George
Wood well (Woods Hole Research Center)

Please call (914) 677-5343 to confirm the week’s
seminar topic.

ART EXHIBIT

Selected color and black-and-white photographs by
Michael J. Doolittle are on display at the Plant
Science Building through December 1st.

Hours: 9 a.m. - 4 p.m. weekdays (closed on public
holidays). Free.

GREENHOUSE

The lES greenhouse is a year-round tropical plant
paradise as well as a site for controlled
environmental research. The public is invited to visit
the greenhouse during Arboretum hours. There is
no admission fee, but visitors should first stop at the
Gifford House for a free permit.

GIFT SHOP

Senior Citizens Days: On Wednesdays senior
citizens receive a 10% discount on all purchases
(except sale items).

Fall bulbs are available.

Look for early Christmas specials in October
and November, and mark this year’s Christmas
Sale. December 9th and 10th, on your calendar.

ARBORETUM HOURS

(Winter Hours: October 1 - April 30)

The Arboretum is open Monday through
Saturday, 9 a.m. to 4 p.m.; Sunday 1 - 4 p.m.

The Gift and Plant Shop is open Tuesday
through Saturday 11 a.m. to 4 p.m. and Sunday 1 - 4
p.m. (closed weekdays from 1-1:30 p.m.).

(The Arboretum and Shop are closed on public
holidays.)

All visitors must obtain a free permit at the Gifford
House for access to the Arboretum. Permits are
available up to one hour before closing time.

MEMBERSHIP

Become a member of the Mary Flagler Cary
Arboretum. Benefits include a special member’s rate
for lES courses and excursions, a 10% discount on
purchases from the Gift Shop, free subscriptions to
the lES Newsletter and “Garden” magazine, and
parking privileges and free admission to the Enid A.
Haupt Conservatory at The New York Botanical
Garden in the Bronx. Individual membership is $30;
family membership is $40. For information on
memberships, contact Janice Claiborne at (914) 677-
5343.

For more information, call (914) 677-5359 weekdays from 8:30 - 4:30

INSTITUTE OF
ECOSYSTEM STUDIES
The New York Botanical Garden
Mary Flagler Cary Arboretum
Box AB, Millbrook, New York 12545

Newsletter

Volume 6, Number 4
July - August 1989

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