| February 2002 |
The
Weight of a Petal: The Value of Botanical
Gardens
By H. Bruce Rinker
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Plants influenced the
evolution of life on land.
Plants predate
human origins.
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Gardens, as landscapes with scattered
trees and copses interspersed with open spaces or
bodies of water, widely appeal to our aesthetic
sense and our need to perceive an organized
natural world. Such settings may even appeal to a
genetic memory of humanity's remote origins on the
African savanna. Undoubtedly, flowers and the
near-infinite diversity of their fruits influenced
the survival of early hominids and the skill of
modern humans to inhabit every corner of the
planet.7 Flowering plants originated
during the Cretaceous Period, nearly 100 million
years ago when Africa and South America were still
connected to each other. The dramatic co-evolution
of flowering plants and their insect pollinators
colored the face of the planet and set the stage
for the emergence of our vision-dominated
ancestors millions of years later. Loren Eiseley,
late anthropologist from the University of
Pennsylvania, exclaimed, "the weight of a petal
changed the face of the world and made it
ours."4 |
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Gardens are more than
places to visit; they are centers of research and
conservation. |
What are botanical
gardens?
Some people have the mistaken impression
that botanical gardens are parks devoid of play,
something like 19th century museums where plants
bear labels with unpronounceable names. Modern
botanical gardens, however, are global treasures
in an age of ecological crisis. Today numbering
more than 2000 gardens worldwide, they are places
devoted to the culture, study, and exhibition of
documented collections of living
plants.12,13 Further, they:
- are committed to developing, documenting,
verifying, maintaining, sharing, propagating,
and disseminating their plant collections -- a
description offered by the American Association
of Botanical Gardens and Arboreta
(AABGA)11
- serve as reference centers for plant
identification, cultivar registration,
nomenclature, and plant exploration
- and, for some threatened species, have
become the last hope for their precarious
survival
Simply put, modern botanical gardens are
scholarly places for the research and conservation
of plants. |
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The first gardens in
Europe were medicinal. |
The western tradition of botanical
gardens
Botanical gardens can be traced to human
beginnings and are found in all cultures, past and
present. In the western world, gardens went
through a metamorphosis:
Medicinal Gardens: 16th and 17th
centuries
The early European institutions were
medicinal gardens, also called physics gardens or
gardens of simples (such as Florence's Giardino
dei Semplici), whose principle role was to provide
material for medical faculties in Italy, France,
and other western countries. The earliest
medicinal gardens in Europe were all established
in the 16th and 17th centuries: Pisa (1543),
Zurich (1560), Paris (1597), Oxford (1621), Berlin
(1679), and others.9,11
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Colonial Gardens: 17th and 18th
centuries
Later on, governments created
tropical botanical gardens as instruments of
colonial expansion and commercial
development.2 The celebrated 18th
century Calcutta Botanical Garden and Royal
Botanic Gardens Pamplemousses in Mauritius come to
mind. |
| The scientist Linnaeus
inspired gardens to conduct plant
research. |
Linnaean Gardens: 18th and 19th
centuries
Gradually, a strict utilitarian
display gave way to a comprehensive study of
plants. Based on the work of Carolus Linnaeus
(1707-1778),15 the father of modern
taxonomy, gardens were laid out to show plant
relationships. Live and preserved material poured
into the botanical gardens of Europe, especially
from the New World, to be exhibited, studied, and
identified. As taxonomy gained in prominence,
botanical gardens emphasized their herbaria,
laboratories, and libraries over their living
collections, on which little research was then
undertaken. |
|
Civic Gardens: 19th and 20th
centuries
Municipal gardens were founded in the
19th and 20th centuries (e.g., Missouri Botanical
Garden in 1859) that advanced the horticultural
aspects of their living collections. |
|
Specialist Gardens: 20th and
21st centuries
Specialist gardens, such as
experimental stations and orchid gardens, emerged
in the 20th century that highlighted research on
particular plant groups. Floristic explorations
and taxonomic studies, especially in remote
tropical locations, allowed botanical gardens to
expand their living and preserved collections. It
also allowed them to advance as leading research
centers for plant conservation. |
| Gardens today are
havens for species that are extinct in the
wild.
|
Sanctuary Gardens: 20th and 21st
centuries
Today, much of the responsibility for
the genetic protection of threatened species,
along with ex situ protection of plants
with economic and ecological importance, rests
with botanical gardens. For instance, the Marie
Selby Botanical Gardens in Sarasota, Florida
propagates a handful of species that are listed as
no longer existing in the wild: Anthurium
leuconeurum (Araceae) from Chiapas, Mexico;
Epidendrum ilense (Orchidaceae) from the
Pinchincha Province in Ecuador; Platycerium
grande (Polypodiaceae) from Mt. Banahau in the
Philippines; and others. These species may depend
upon the horticultural and scientific support of
trained staff members at the Gardens for their
survival. Botanical gardens have become flagships
of our international botanical efforts in the
service of science and humanity during an age of
unparalleled ecological crisis.2
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We may lose
2/3 of
plant species by the end of the
century. |
Stewardship in an age of
crisis
Botanists have identified more than 400,000
species of plants worldwide.5
However,
- approximately 34,000 are threatened at
present6
- two-thirds of the world's plant species
are in danger of extinction during the course of
the 21st century3
- of the 20,000 known plant species in the
United States, more than 200 had already
vanished by the end of the 20th century; and
another 600 to 700 are in imminent
jeopardy10
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| Humans are the main
cause of plant extinctions. |
These plant species are in jeopardy because
of a burgeoning human population that then affects
proximate causes such as deforestation, habitat
loss, the spread of invasive species, and
agricultural expansion.3,6 Given the
deplorable rates of deforestation throughout the
tropics, where most of the planet's biodiversity
is located, we stand to lose thousands of plant
species worldwide in the next few decades unless
we make a concerted and collaborative effort to
conserve them. |
| Conservation is
accomplished by wise management.
|
Conservation is not always synonymous
with preservation. Conservation implies wise
management. Preservation means to put aside.
Preservation can be a conservation strategy,
however, for a natural resource that is rare,
nonrenewable, or irreplaceable. For example,
authorities for a national forest may decide to
protect an old-growth stand from hunting, logging,
and other extractive uses because of its overall
value for posterity. Conservation, then, is an
umbrella term that widely encompasses use and
nonuse of natural resources, depending upon our
management strategy. Ideally, that strategy should
be based on four
considerations:1
- What ecosystem service is provided
by the resource?
- What is the economic benefit of
the resource?
- What is the aesthetic value of the
resource?
- What is the ethical value of the
resource?
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Services provided by
nature are superior to human
invention. |
Ecosystem service
Easily
overlooked are free services provided by nature,
such as:
- clean air and water
- nitrogen cycling
- decomposition
- erosion control
- climate stability
It is near-to-impossible to place a dollar
value on these benefits, and attempts to replace
them with human technologies have fallen short.
Mangroves are superior to seawalls, protecting our
shorelines from wave erosion and acting as a
resilient living barrier during hurricanes.
Bacteria return nitrogen gas from our atmosphere
to all other living things, where it is essential
for the construction of proteins. No invention has
been able to imitate that ancient global function.
These services have immeasurable value for all
living things on the planet. |
| Many of our resources
come from plants.
|
Economic benefit
Many plants
provide us with food, shelter, fuel, clothing, and
medicines. Indigenous peoples face this reality on
a daily basis. People in the United States and
other affluent countries may think they live
removed from local ecosystems, but no one escapes
from nature entirely. As a global species, we gain
our sustenance from our surroundings. For
example:
- fully 50% of our medicines are derived
from plants
- 25% of all prescription drugs have their
origins in tropical forests
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| Medicine, paper, and
fuel are products derived from
plants.
|
The cinchona tree of the eastern Andean
tropical forest yields the anti-malarial drug,
quinine. The rosy periwinkle from Madagascar
produces scores of different alkaloids, two of
which led to major breakthroughs in cancer
treatment. In addition to their medicinal value,
plants provide us with numerous other economic
benefits: food products, building materials,
paper, ornamentation, fuelwood, green gas, even
pest control (e.g., the use of the carnivorous
plant, Utricularia, to trap aquatic insect
pests in ponds). Life on the planet, much of it
unexplored, represents a cornucopia of natural
resources for humanity. |
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Aesthetic value
In addition
to deriving our livelihood directly and indirectly
from the planet's rich biodiversity, we also value
species richness for
- recreation
- scientific research
- wonder
- and primal companionship
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| Plants add to our
enjoyment of nature. |
Early exploration of the tropical
rainforest canopy yielded new kinds of organisms
and new ecological processes unknown to us.
Fishermen, hunters, skiers, golfers, pet owners,
and boatmen all value the outdoors for their
sports and livelihoods. And who can say how the
faithful of major world religions have been
affected by the natural world in which their
credos emerged? |
| It is our moral
obligation to protect all living
things. |
Ethical value
What is the
moral basis for conserving our natural resources,
especially the more diminutive, not-so-glamorous
species such as bacteria, mosses, and worms? Some
scientists argue that morality is the most valid
reason for our management strategies, obligating
us to do everything possible to prevent
human-caused extinction everywhere on the planet.
For many scientists, in situ preservation
of species is the first commandment of
conservation. As Aldo Leopold wrote in his A
Sand County Almanac, "To keep every cog and
wheel is the first precaution of intelligent
tinkering."8 |
| The degree of
extinction is greater than first
imagined.
|
Education and environmental
ethics
Education and ethics are components of a
vital formula for our survival on an ancient, but
latterly threatened, planet. Already botanists
have documented relentless threats facing the
tropics and their plant stocks. Recent data from
the latest IUCN Red List of Threatened
Species, released in September 2000 by the
International Union for the Conservation of
Nature, indicate that the global extinction crisis
is worse than previously
believed:14
- Not only has the magnitude of risk
increased with forest areas shrinking around the
world, but the capacity of remaining forests to
maintain biodiversity also appears to be
diminishing significantly.
- Plant species are declining most rapidly
in Central and South America, historically
important areas for many botanical gardens, as
well as in Central and West Africa, and
Southeast Asia.
- Some plants are no longer found in the
wild. Botanists have catalogued and preserved
many species of orchids and bromeliads that,
because of tropical habitat destruction, may now
exist only in greenhouses.
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In short, the plants forming the basis of
botanical gardens' core mission and ethics are
under serious threat around the globe. A solid
commitment to education and ethics could stem this
appalling trend, launching botanical gardens as
leaders in ecological stewardship. |
|
Botanical gardens are
crucial in this age of biodiversity
crisis. |
Conclusion: the weight of a
petal
Many modern botanical gardens started in
far different times. Twenty-five years ago the
threats to tropical systems were not as widely
documented as they are now. Then we had barely
begun our explorations in the world's treetops.
Today we sense the imminent collapse of entire
ecosystems, including many vital habitats for
threatened plant species. The early mission of
botanical gardens prioritized the exploration and
cataloguing of the wealth of tropical rainforest
flora that formed the basis of their plant
collections. Today exploration and collection of
species are increasingly limited by international
regulations and botanical gardens are expanding
the scope of their mission to be relevant in the
next 25 years. |
| Conclusion: Without
plant conservation, the balance in nature may be
irreparably damaged. |
Botanists now recognize unequivocally
the temporal/spatial ecological connections
operating within plant communities. We no longer
simply focus on collections of rare and unusual
species but also include in situ and ex
situ conservation of their ecological
associates. Thanks to pioneering efforts during
the last 25 years in many remote regions,
especially the canopies of tropical rainforests,
we now realize how little is known about the
diversity and ecological richness of the world's
plants -- and how much effort is needed to
conserve them. Botanical gardens can change the
world as flagship institutions for research and
education about the plant kingdom. Plants
represent the basis of most life on the planet.
Like the weight of a petal, a handful of botanical
gardens across the globe can help us steward
earth's green mantle and, thereby, insure our own
survival in an age of ecological crisis.
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