Download Lesson 2 : Deforestation and Loss of Biodiversity

165
Lesson 2 : Deforestation
I.
and Loss of Biodiversity
Deforestation
A. The Importance of Biodiversity
Forests, grasslands, deserts, wetlands, coral reefs,
and other ecosystems throughout the world are coming under
increasing stress from population growth and economic
development.
The three components of the planet’s
biodiversity are (1) genetic diversity - variability in the
genetic makeup among individuals within a single species;
(2) species diversity - the variety of species on earth and
in different habitats of the planet, and (3) ecological
diversity - the variety of forests, deserts, grasslands,
streams, lakes, oceans, and other biological communities
that interact with one another and with their nonliving
environments (Miller, 1994).
Because biodiversity is a vital part of the earth’s
capital that sustains all life, preserving the planet’s
genes, species, and ecosystems should be among our most
important priorities. One way to do this is to protect
species from sharp population declines and premature
extinctions that result from human activities. However,
most wildlife biologist believe that the best way to
protect species diversity is to sustain and protect the
earths ecosystems that serve as habitats. This means
establishing a worldwide network of reserves, parks,
wildlife
sanctuaries,
and
other
protected
areas.
Protecting these vital oases of biodiversity from damage,
using them sustainably by learning how nature does this,
and helping heal those we have damaged are important
challenges (Miller, 1994).
As of 1993, about 7,000 protected areas throughout the
world, occupy 4.9 percent of the earth’s land surface. That
is an important beginning, but environmentalists say that a
minimum of 10 percent of the globe’s land area must be
protected. Moreover, many existing reserves are too small
to provide any real protection for the populations of wild
species that live on them. (Miller, 1994).
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B. Forests
The forest is a focal ecosystem.
Its state affects
almost all other ecosystems.
It plays a very crucial
ecological role in soil and water conservation (Tujan,
1997).
Types of Forests
Old-growth forests are virgin (uncut) forests and old
second-growth forests have not been seriously disturbed for
several hundred years. They contain massive trees that are
hundreds or even thousands of years old.
The understory
and other vegetation zones in old-growth forests provide
ecological niches for a variety of wildlife species. These
forests also have large numbers of standing dead trees
(snags) and fallen logs (boles), which are habitats for a
variety of species. Decay of this dead vegetation returns
nutrients to the soil (Miller, 1994).
Second-growth forests are stands of trees resulting
from secondary ecological succession after cutting. About
40 percent of tropical forests are second-growth forests.
Some old second-growth stands have remained undisturbed
long enough to be classified as old-growth forests, but
many are tree farms - managed tracts of uniformly aged
trees of one species that are harvested as soon as they
become commercially valuable (Miller, 1994).
Commercial and Ecological Importance of Forests
Forests give us lumber for housing, biomass for
fuelwood, pulp for paper, medicines, and many other
valuable products such as turpentine, nuts and fruits, and
charcoal. Many forestlands are also used for mining,
grazing livestock, and recreation (Miller, 1994; Miller,
1994).
Forested watersheds act as giant sponges, slowing down
runoff and absorbing and holding water that recharges
springs, streams, and groundwater. Thus, they regulate the
flow of water from mountain highlands to croplands and
urban areas, and they help control soil erosion, reduce
flooding, and reduce the amount of sediment washing into
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streams,
1994).
lakes,
and
reservoirs
(Miller,
1994;
Miller,
Forests also influence local, regional, and global
climate. For example, 50 – 80 percent of the moisture in
the air above tropical forests comes from trees via
transpiration and evaporation. If large areas of these lush
forests are cleared, average annual precipitation drops,
the regions climate gets hotter and drier, and soils become
depleted of already-scarce nutrients, baked, and washed
away.
Eventually this process can convert a diverse
tropical forest into a sparse grassland or even a desert
(Miller, 1994; Miller, 1994).
Forests also provide habitats for more wildlife
species than any other biome, making them the planet’s
major reservoir of biodiversity. They also buffer us
against noise, absorb air pollutants, and nourish the human
spirit. Since agriculture began about 10,000 years ago,
human activities have reduced the earth’s forest cover by
at least one-third,
to about 34 percent of the world’s
land area (Miller, 1994).
Forest act as carbon sink that traps carbon dioxide
released in the atmosphere. According to studies, a hectare
of vegetated forests can trap a ton of carbon dioxide every
year. Forests, too, can moderate local climate (Tujan,
1997).
Forests serve as efficient watersheds, collecting and
regulating the flow of water supply which can be tapped for
household and industrial use, or agricultural irrigation.
Forests prevent flash floods. They control soil
erosion and water pollution.
Aside from being the source
of wood and water, forests also supply power.
Philippine forests host one of the world’s richest
plant and animal species. They are estimated to harbor
about 8,120 species of flowering plants, 3,500 species of
indigenous trees, 33 species of gymnosperms, 640 species of
mosses, 2,400 species and sub-species of fish, around 240
species and sub-species of mammals. There are 3,000 species
of plants which are endemic (i.e. found nowhere else in the
world) to the Philippines. The Philippine forests also
harbor around 7.1 million indigenous peoples (Tujan, 1997).
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Depleted forests means less sources of food, medicinal
plants and renewable energy, and less capacity to nurture
genetic species. Degraded forests translate to erosion of
otherwise productive lands, siltation and sedimentation of
inland and coastal waters, among others. Cleared forests
could spell the loss of home and livelihood for 18.6
million indigenous peoples and upland dwellers (Tujan,
1997).
The Philippine Forests
The Philippine forests are among the most diverse in
the world and are also the most endangered. The state of
Philippine forests is critical. Latest estimates place the
country’s remaining forest areas at 5.6 million hectares
from 20 million hectares a century ago. (Table 1)
This
forest cover is roughly 18.6 percent of the country’s total
land area, and thus, far below the country’s ideal forest
cover. For the Philippines to be ecologically sound and
able to sustain its ecosystems, its ideal forest cover, or
what is fit for its narrow, mountainous terrain, should be
54 percent of its land area (Tujan, 1997; EMB, DENR, 1994).
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Table
3
further
loses
significance
considering
government definition of forests simply as areas of one
hectare or more and at least 60 meters wide which are at
least 10 percent stocked with forest trees (including
seedlings and saplings), wild palms, bamboo or brush.
Table 3. Change in forest land area, selected years
Year
Forest Cover
(million hectares)
1575
1863
1920
1934
1970
1980
1990
1991
1992
1993
1994
1995
27.5
20.9
18.9
17.8
10.9
7.4
6.2
6.0
5.9
5.8
5.7
5.6
Proportion to Total
Land Area (%)
92.0
70.0
64.0
57.3
36.3
24.7
20.7
20.5
19.6
19.3
18.9
18.6
Deforestation Rate
(hectares/year
22,917
35,088
78,571
191,667
350,000
120,000
120,000
120,000
120,000
120,000
120,000
120,000
Source: Department of Environment and Natural Resources
The Philippine forests have been steadily shrinking at
an average rate of 2 percent per annum, or a relatively
fast deforestation rate of 550,000 hectares per year. This
rate means that every hour, 63 hectares of forests are
cleared. At this rate, all our forests would be gone by the
turn of the century.
Because the country is an archipelago with diverse
terrain, flora species also vary. Thus, the Philippine
forests are further categorized into dipterocarp (66.06%),
mossy (18.9%), sub-marginal (8.7%), pine (4.1%), and
mangrove (2.1%) (Table 4).
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Dipterocarp forests, prevalent all throughout the
archipelago, are the most important type. They are the
major source of timber and other forest products. They
support one of the world’s richest plant and animal life,
and have nurtured innumerable generations of tribal
Filipinos. Philippine dipterocarp forests can either be old
growth - the tropical rainforests without traces of
commercial logging (sometimes known as virgin forests) - or
residual - those with traces of commercial logging.
Table
4 shows that there are now more residual forests than an
old-growth forests, a complete reversal of the situation
early this century (Tujan, 1997; EMB, DENR, 1996).
Table 4 shows that in the past eight years alone,
dipterocarp forests narrowed down by 24 percent, residual
forests by 20 percent, and old growth by the fastest rate
of 34 percent. While Table 4 shows that since 1991, the
area of old growth forests has been maintained (presumably
because of the government log ban policies), deforestation
of old growth forests is irreversible. For every five years
since 1970, the deforestation rate increased (Table 5).
Table 5. Change in old-growth dipterocarp forest area
Source:
Year
Area
(in million has.)
1970
1975
1980
1985
1990
1995
5.217
3.687
2.443
1.539
0.861
0.805
Deforestation
Rate
306,000
249,000
181,000
136,000
11,000
Philippine Forestry Statistics, various years
On the other hand, mossy and sub-marginal forests
protect watershed areas and provide a sustainable supply of
water for irrigation and domestic use in the lowlands.
They also protect the soil and water of wildlife feeding
grounds. They are not commercially exploitable (Tujan,
1997; EMB, DENR, 1996).
Still, majority of the country’s watersheds are
considered bydrologically critical because of their present
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degraded condition. Erosion of watershed areas has already
reached critical proportions (Table 6). Of the 11 million
hectares of critically denuded forest land, at least two
million hectares are in critical watershed areas, like
those of the Agno River, Pampanga River, Cagayan River, the
Maga, and the Pantabangan watersheds (Tujan, 1997; EMB,
DENR, 1996; Sajise, 1992).
Table 6. Extent of degradation of watershed areas extended for agriculture
and non-agriculture uses (in ‘000 Hectares)
AGRICULTURE
Moderate to Proportion
Area
Severe
Eroded
Erosion
Luzon
Vizayas
Mindanao
Philippines
Source:
NON-AGRICULTURE
Moderate to Proportion
Area
Severe
Eroded
Erosion
5,994
1,294
5,480
1,440
501
3,868
24.0%
38.7%
70.6%
8,146
2,174
4,720
4,564
1,320
4,129
56.0%
60.7%
87.5%
12,767
5,809
45.5%
15,039
10,013
66.6%
ALMED -Bureau of Soils and Water Management, 1990
Pine forests are endemic to the higher altitudes of
Luzon while mangroves occur on tidal flats along the sea
coast up to the streams where the water is brackish (Tujan,
1997; EMB, DENR, 1994).
Forest Distribution in the Philippines
No data is available that solely pins down forest
destruction as the cause of soil erosion and sedimentation.
However, it is estimated that deforestation-induced erosion
is 100,000 hectares at one meter depth of one billion cubic
meters every year (Tujan, 1997; Sajise, 1992).
The Environmental Management Bureau reported in 1990
that, because of forest denudation, 22 of the country’s
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provinces were already badly eroded. Aside from soil
erosion,
the
capacity
of
the
soil
to
hold
water
deteriorated with forest destruction. In Cebu, where
forests have been almost totally lost, underground water
coming out of private wells have become brackish.
Siltation problems occur in major rivers and dams
because of the destruction of watersheds. The glaring
example is the Agno River, some areas of which overflow to
surrounding fields due to heavy siltation. Deforestation
also reduces rainfall, as was found in a study in Northern
Luzon in the mid-seventies (Tujan, 1997).
Much of our floods are traceable to forest denudation.
Examples are flooding catastrophes in Cagayan Valley where
entire villages were washed away in Mindanao where flash
floods occur every now and then, in very denuded Negros
which experienced destructive floods which brought down
huge logs from the mountains and eroded thousands of
hectares of productive farm land. In 1991, the tragedy in
Ormoc City, which has only 10 percent forest cover left,
claimed 8,000 lives and millions worth of properties
(Tujan, 1997; Vitug, 1993).
Forest destruction has also threatened the country’s
genetic resources, putting many species on the endangered
list, and bringing some on the verge of extinction (Table
7). Out of 1,657 existing wildlife species in the country,
47 country could be extinct by now, are endangered
(including the tamaraw, crocodile and the famous monkey eating eagle). Seven ornamental plants are endangered and
the gigantic molave trees, “the best that can be found in
the universe”, are practically extinct. Aside from List 1,
as of 1996, there have been 10 identified rare, endemic,
and endangered plants of the Philippines (Tujan, 1997; EMB,
DENR, 1996).
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Table 7: Partial list of priority species
Common Name
Fauna
A. Wild Birds
Spot-billed Pelican/Philippine Pelican
Serpent Eagle
Philippine Eagle/Monkey Eating Eagle
Philippine Hawk Eagle
Philippine Megapode/Incubator Bird
Palawan Peacock Pheasant
Negros Fruit Dove
Luzon Bleeding Heart Pigeon
Nicobar Pigeon
Mt. Apo Lorikeet/Mindanao Lorikeet
Philippine Cockatoo/Red-vented Cockatoo
Philippine Hanging Parakeet
Oriental Hawk Owl/Philippine Horned Owl
Mindanao Parrotfinch
Peregrine Falcon
Spotted Green Shank
Mindoro Imperial Pigeon
Koch’s Pitta
Giant Scops Owl
Parrots (all species)
Falcons
Pygmy Curlew
Rufous Hornbill
B. Mammals
Tamaraw
Calamian Deer
Mouse Deer/Luzon Sambar Deer
Status
Threatened
CITES II
Endangered - CITES II
CITES II
CITES II
Vulnerable - CITES II
Threatened
Threatened - CITES II
CITES II
CITES II
Insufficiently known CITES II
CITES II
CITES II
Threatened
CITES I
CITES I
CITES I
CITES I
CITES I
CITES II
CITES II
CITES II
CITES II
CITES II
Vulnerable - CITES II
Vulnerable
CITES III
CITES III
Palawan Bear-Cat
Indeterminate
Luzon Forest Rat
CITES II
Philippine Monkey/Long-Tailed Macaque
Endangered
Philippine Tarsier
Philippine Tree Shrew/Mindanao Slender- CITES II
CITES II
tailed Shrew
CITES II
Palawan Scaly Anteater
Dugong
Pangolin
CITES II
Rare - CITES II
C. Reptilla
Indeterminate
Philippine or Freshwater crocodile
CITES I
Gray Monitor Lizard
CITES I
Leyte Freshwater Turtle
CITES I
Hawksbill Turtle
Olive-backed/Pacific
Ridley’s
Logger CITES I
CITES II
Head
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Table 5. Con’t…
Green Sea Turtle
Saltwater or Estuarine Crocodile
Phyton
CITES
CITES
CITES
CITES
CITES
CITES
CITES
CITES
CITES
CITES
CITES
CITES
Flora
Sander’s Alocasia
Striped Alocasia
Pither Plant
Orchids
Bungang Ipot
Voyavoi
Calakab/Dalubi
Tagbak
Cycas/Pitogo
Ferns
Aloe/Sabila
Cactus
I
I
I
II
II
II
II
II
II
II
II
II
CITES
I
–
Trade
of
species
and
subspecies
of
wildlife
is
strictly
prohibited
except
for
education,
scientific
or
research
and
study
purposes.
CITE II – Populations of species and
subspecies of wildlife highly need local
protection set under national policies
as determined by the country’s CITES
Management Authority
CITES – Convention
Trade of Endangered
Flora and Fauna
Source:
Protected
Bureau, 1996
on International
Species of Wild
Areas
and
Wildlife
Lastly, the destruction of our forests spells the
displacement and dislocation of the indigenous peoples and
upland dwellers whose virtual environments are the forests.
Causes of Deforestation in the Philippines
According
to
the
survey
of
the
Department
of
Environment and Natural Resources, the activities of the
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common man or woman, most probably the indigenous peoples
and
upland
dwellers
are
the
principal
causes
of
deforestation (Table 8).
Table 8. DEFORESTATION BY REGION, 1995 (in hectares)
REGION
CAUSES
Kaingin
Illegal
Logging
CAR
1
2
3
4
5
6
7
8
9
10
11
12
ARMM
355.00
24.73
0.00
0.80
3.31
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
7.86
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1,479.07
1,678.96
4,296.65
1,808.94
14.15
0.00
183.54
432.80
43.00
204.00
153.54
36.07
0.00
0.00
0.00
720.40
0.00
12.00
2,238.40
10,993.00
0.00
70.55
0.00
0.00
40.00
0.00
0.00
0.00
1,841.93
2,424.09
4,321.76
1,820.94
2,254.35
10,996.31
183.54
503.35
43.00
204.00
193.54
36.07
0.00
0.00
PHILS
408.95
8.86
10,330.72
14,074.35
24,822.88
Source:
Forest
Fire
Others
Total
Department of Environment and Natural Resources
Table 8 gives several misconceptions about the major
causes of deforestation. One, forest fires rank as the most
destructive cause which, according to the DENR, worsened
“during the El Niño phenomenon which recurs every ten
years.” Two, mining operations which are man-made are
lumped together with volcanic eruptions which are natural
calamities as “other” causes. Three, kaingin is destructive
while the DENR recognizes that upland settlers and peasants
are “very knowledgeable on the concepts of stewardship and
possess a vast knowledge of local environment conservation
measures.” Therefore, kaingineros, marginalized, dislodged
and escaping from a pattern of land ownership, are victims
of a more systematic cause of deforestation. Lastly, the
DENR recognizes that there is no clear line drawn between
legal and illegal logging.
Precisely so, because of the
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much abused license held by big loggers who do not possess
concepts of reforestation and responsibility. The small
loggers, now deemed as illegal, are just victims of a
large-scale exploitation (Tujan, 1997; EMB, DENR, 1996).
Loss of Tropical Forests
Tropical forests, which cover about 6 percent of the
earth’s land area, grow near the equator in Latin America,
Africa, and Asia. About 56 percent of the worlds tropical
forests have already been cleared or damaged. Satellite
scans and ground-level surveys indicate that the remaining
forests are vanishing rapidly, at a rate of at least
154,000 square kilometers (59,000 square miles) per year equivalent to about 34 city blocks per minute, or almost
two football fields per second.
Its estimated that an
equivalent area of these forests is damaged every year
(Miller, 1994).
Reforestation in the tropics scarcely deserves the
name, with only one tree planted for every 10 trees cut. In
Africa, the rate is 1 to 29. If the current rate of loss
continues, all remaining tropical forests (except for a few
preserved but still vulnerable patches) will be gone within
30 to 50 years, and much sooner in some areas (Miller,
1994).
Why should we care about Tropical Forests
Environmentalists consider the plight of tropical
forests to be one of the world’s most serious environmental
problems. These forests are home to at least 50 percent
(some estimate 90 percent) of the earth’s total stock of
species, most of which are still unknown and unnamed
(Miller, 1994).
Tropical forests touch the daily lives of everyone on
Earth through the products and ecological services they
provide.
These forests supply half of the world’s annual
harvest of hardwood, hundreds of food products (including
coffee, tea, cocoa, spices, nuts, chocolate, and tropical
fruits) This include many materials (including natural
latex rubber, resins, dyes, and essential oils) than can be
harvested sustainably and generate twice as much revenue
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per hectare as timber production and three times as much as
cattle ranching (Miller, 1994).
The active ingredients for 25 percent of the world’s
prescription drugs are substances derived from plants, most
of which grow in tropical rain forests. Such drugs are used
in birth control pills, tranquilizers, muscle relaxes, and
life-saving drugs for treating malaria, leukemia and
Hodgkin’s disease, testicular and lung cancer, heart
disease, high blood pressure, multiple sclerosis, venereal
warts, and many other diseases. Seventy percent of the
3,000 plants identified by the National Cancer Institute as
sources of cancer-fighting chemicals come from tropical
forests. While you are reading this page, a plant species
that could cure a type of cancer, AIDS, or some other
deadly disease might be wiped out forever (Miller, 1994).
Botanists also believe that tens of thousands of
strains of plants with potential food value await discovery
in tropical forests. Despite their immense potential, less
than one percent of the estimated flowering plant species
in the world’s tropical forests have been examined closely
for their possible use as human resources (Miller, 1994).
Biologist E.O. Wilson warns that destroying these
forest and the species they support for short-term economic
gain is like throwing away a wrapped present or burning
down an ancient library before you read the books. In
addition, the Environmental Policy Institute estimates that
unless destruction of tropical forests stops, the resulting
flooding and loss of topsoil could cause as many as a
billion people to starve during the next 30 years (Miller,
1994).
C. Global Causes of Tropical Deforestation
The two major underlying causes of the current massive
destruction and degradation of tropical forest are (Miller,
1994):

Population growth and poverty, which combine to drive
subsistence farmers and the landless poor to tropical
forests to try to grow enough food to survive, often
using unsustainable methods.
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
Massive foreign debt and policies of governments and
international development and lending agencies that
encourage rapid depletion of resources to stimulate
short-term economic growth. Less developed countries
(LDCs) are encouraged to borrow huge sums of money from
more developed countries (MDCs) to finance economic
growth.
To pay interest on their debts, these countries
often sell their forest, mineral, oil, and other
resources - mostly to MDCs - at low prices dictated by
the international marketplace.
The process of degrading a tropical forest begins with
a road.
Once the forest becomes accessible, it is usually
cut or degraded and fragmented into vulnerable patches by
the following activities:

Unsustainable
small-scale
farming.
Colonist
follow
logging roads into the forest to plant crops on small
cleared plots, to build homes, and to try to survive.
With little experience in potentially sustainable slashand-burn and shifting cultivation, many newcomers cut and
burn much forest to grow crops and don’t allow depleted
soils to recover, ultimately degrading large tracts of
forest.

Cattle ranching. Cattle ranches are often established on
exhausted
and
abandoned
cropland,
often
aided
by
government
subsidies
to
make
ranching
profitable.
Overgrazing further degrades the land.

Commercial logging. Since 1950, the consumption of
tropical lumber has risen 14-fold, with Japan now
accounting for 60 percent of annual exports (followed by
the United States and Great Britain).
The World Bank
estimates that by 2000, only 10 of the 33 countries now
exporting tropical timber will have any left to export.
Although timber exports to MDCs contribute to tropical
forest depletion and degradation, over 80 percent of the
trees cut in LDCs are used at home

Raising cash crops. Tropical forests are cut and
converted to immense plantations used to grow crops such
as sugarcane, banana, tea, and coffee, mostly for export
to MDCs.
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
Mining operations. Most of the extracted minerals, such
as iron ore and bauxite (aluminum ore) are exported to
MDCs.

Oil drilling and extraction.

Damming rivers and flooding large areas of forest.
D. Solution: Reducing Tropical Deforestation
Environmentalists have suggested the following ways to
reduce tropical deforestation (Miller, 1994):

Use remote-sensing satellites to find out how much of the
world is covered with forest and how much has been
deforested. This could be done for about what the world
spends for military purposes every three minutes.

Establish
a
mandatory
international
system
for
identifying tropical (and other) timber grown and
harvested sustainably. So far, only 0.1 percent of the
world’s tropical forests are managed sustainably.

Reform tropical timber-cutting regulations and practices.
New logging contracts would charge more for timbercutting concessions and require companies to post
adequate bonds for restoration and reforestation.

Fully fund the Rapid Assessment Program (RAP), which
sends biologists to assess the biodiversity of “hot spot”
- forests and other habitats that are both rich in unique
species and in imminent danger - with the goal of
channeling funds and efforts toward immediate protection
of these endangered ecosystems.

Use debt-for-nature swaps and conservation easements to
encourage countries to protect tropical forests or other
valuable natural systems. In a debt-for-nature swap,
participating tropical countries act as custodians for
protected forest reserves in return for foreign aid or
debt relief. With conservation easements, a country, a
private organization, or a group of countries compensates
individual countries for protecting selected forest
areas.
181

Help
settlers
learn
how
sustainable agriculture.

Stop funding tree and crop plantations, ranches, roads,
and destructive types of tourism on any land now covered
by old-growth tropical forests.

Concentrate farming tree and crop plantations, and
ranching on cleared or degraded tropical forest areas
that are in various stages of secondary ecological
succession.

Set aside large protected areas for indigenous tribal
peoples. Indigenous peoples are the primary guardians and
sustainable users of vast, mostly undisturbed habitats.
These peoples are being driven from their homelands in
tropical forests and other biomes by commercial resource
extractors and the landless poor.

Pressure
banks
and
international
lending
agencies
(controlled
by
MDCs)
not
to
lend
money
for
environmentally destructive projects especially road
building involving old-growth tropical forests.

Reduce poverty and the flow of the landless
tropical forests by slowing population growth.

Reforest and rehabilitate degraded tropical forests and
watersheds.

Work with local people to protect forest.
to
practice
small-scale
poor
to
II. Biodiversity
Biodiversity is the totality of genes, species, and
ecosystems in a region.
The wealth of life on earth today
is the product of hundreds of millions of years of
evolutionary history. Over the course of time, human
cultures have emerged and adapted to the local environment,
discovering, using, and altering local biotic resources.
Many areas that now seem “natural” bear the marks of
millennia of human habitation, crop cultivation, and
resource harvesting. The domestication and breeding of
local varieties of crops and livestock have further shaped
biodiversity (Reid et. al., 1992).
182
Biodiversity
categories-genes,
quite different
scientists measure
can be divided into three hierarchical
species, and ecosystems that describe
aspects of living systems and that
in different ways.
Genetic diversity refers to the variation of genes
within species. This covers distinct populations of the
same species (such as the thousands of traditional rice
varieties
in
India)
or
genetic
variation
within
a
population (which is very high among Indian rhinos, for
example, and very low among cheetahs). Until recently,
measurements of genetic diversity were applied mainly to
domesticated species and populations held in zoos or
botanic gardens. Increasingly the techniques are being
applied to wild species (Reid et. al., 1992).
Species diversity refers to the variety of species
within a region. Such diversity can be measured in many
ways, and scientists have not settled on a single best
method. The number of species in a region-its species
“riches” is one often-used measure, but a more precise
measurement, “taxonomic diversity,” also considers the
relationship of species to each other. For example, an
island with two species of birds and one species of lizard
has greater taxonomic diversity than an island with three
species of birds but no lizards. Thus, even though there
may be more species of beetles on earth than all other
species combined, they do not account for the greater part
of species diversity because they are so closely related.
Similarly, many more species live on land than in the sea,
but terrestrial species are more closely related to each
other than ocean species are, so diversity is higher in
marine ecosystems than a strict count of species would
suggest (Reid et. al., 1992).
Ecosystem diversity is harder to measure than species
or
genetic
diversity
because
the
“boundaries”
of
communities - associations of species and ecosystems are
elusive. Nevertheless, as long as a consistent set of
criteria is used to define communities and ecosystems their
number and distribution can be measured. Until now, such
schemes have been applied mainly at national and subnational levels, though some coarse global classification
have been made (Reid et. al., 1992).
183
Besides ecosystem diversity, many other expressions of
biodiversity can be important. These include the relative
abundance of species, the age structure of populations, the
pattern of communities in a region, changes in community
composition and structure over time, and even such
ecological
processes
as
perdition,
parasitism,
and
mutualism. More generally, to meet specific management or
policy goals, it is often important to examine not only
compositional diversity but also genes, species, and
ecosystems (Reid et. al., 1992).
Importance of Biodiversity
The conservation of biodiversity is important in both
economic and ethical terms. There is no shortage of example
of wild animals and plants being put to service for the
benefit and economic development of mankind: new drugs, new
fibers, new foods, new genetic capabilities. All these
things are derived from often unexpected sources in nature,
sources that have survived more by chance than by human
design or management.
Beyond this, however, lies a nonmaterial valuation of biodiversity, less often expounded
and still less often grasped, but in many ways more
powerful (FPE & PBC, 1994).
While in the economic sense, biodiversty represents
unimaginable wealth. In the ethical sense it is simply
priceless.
The Ethical Importance
Ethics provide the basis for deciding what is good or
bad or right or wrong. The importance of ethics in helping
to make good choices concerning nature is well recognized.
The world Charter for Nature, adopted by the United Nations
General Assembly in 1982, states:
“Every form of life is
unique, warranting respect regardless of its worth to man,
and to accord other organisms such recognition, man must be
guided by a moral code of action” (FPE & PBC, 1994).
Importance of Biodiversity to Food (FPE & PBC, 1994)

Only seven species provide 75 percent of human nutrition,
namely: wheat, rice, maize, potato, barley, sweet potato
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and cassava. The first three provide more than 50 percent
of human nutrition.
Roughly 20 percent of protein requirements of humans in
developing countries is provided by animals.
Fifty five percent of protein requirements of humans in
developed countries is provided by animals.
Only 5,000 out of 75,000 edible plant species on earth
have been used for food by humans.
Humans depend on only three plant species for 60 percent
of their calorie requirement and 56 percent of their
protein requirement.
Temperate zone plants provide about 10 fruit species
while the tropical rainforests supply almost 200 and over
3,000 species are available.
Importance of Biodiversity to Health (FPE & PBC, 1994)

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Less than 1 percent of tropical plants has been screened
for medical uses.
Only 5,000 species of higher plants have been studied as
potential medicinal sources.
Some 119 pure chemical substances are extracted from
higher plants which are used in medicines worldwide.
These are obtained from less than 90 species of plants.
Forty percent of all prescription drugs used in
industrialized countries are derived from plant and
animal species.
Amazonian Indians use 1,300 plant species as medicines.
Traditional healers in Southeast Asia use 6,500 plant
species as medicines.
At least 68 common plants in the Philippines are being
used as medicines.
A
total
of
3,000
plants
are
found
in
tropical
rainforests, 70 percent of which have been identified by
the US National Cancer Institute as having anti - cancer
properties.
One out of 10 plant species is believed by scientists to
contain compounds with ingredients that are active
against cancer.
All prescription and non-prescription drugs containing
active ingredients derived from plants are worth $40
billion each year.
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Tubocurarine, a muscle relaxant used in surgery is
derived from plant - based curare, a substance used by
South American Indians to poison-tip blowpipe darts.
China has over 5,000 medicinal plants, 1,700 of which are
used commonly.
Some of the most toxic natural substances known come from
marine organisms.
More than 500 marine organisms yield chemicals with anticancer potential, e.g., serum from horseshoe crabs serves
to isolate tumor cells from the blood of cancer
patients, and it is also a source of substances used to
detect bacterial toxins in human blood;
shark livers
contain lipids that enhance human resistance to cancer;
and clams yield extracts which delay cancer development
in mice.
Some animals which possess medicinal values include:
blister beetles provide contharidin used to treat
urinogenital disorders; leeches produce hirudin, a
valuable anti-coagulant; bee venom is used in the
treatment of arthritis; and venom from a Brazilian snake
is used to produce captopril which helps control
hypertension.
Plants are extraordinary chemical factories and some of
their chemicals have revolutionized certain procedures,
e.g., steroid from a Mexican yam enable “the Pill” to be
developed as a mass birth-control agent; the rosy
periwinkle, a pretty little plant from Madagascar,
yielded vincristine and vinblastine which, when used with
other treatments, increased the long-term complete
remission chances of children stricken with leukemia from
20 percent to 80 percent.
Some other plant compounds have served as natural
chemistry lessons, the essential items ultimately being
manufactured synthetically. The aspirin story is a
classic example. Dioscorides described as the white
willow (Salix alba) is a pain killer in Materia Medica.
The active ingredient was identified in the 19th century
and named salicin. A similar compound was also isolated
from meadowsweet (Spirea ulmaria) and named salicylic
acid.
In 1899, it was found that a mixture of this with
acetic acid was more effective, and the new compound
(acetylsalicylic acid) was named aspirin (after Spirea).
It is now manufactured synthetically, and is the most
widely-taken medicine in the world.
Quinine, an alkaloid from the bark of the Cinchona tree,
was first isolated in 1820.
It was successful in the
186
treatment of malaria. A demand for the drug almost wiped
out the producer trees until mass production was made
possible through a high yielding strain which lent itself
to cultivation.
Importance of Biodiversity to Industry (FPE & PBC, 1994)

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Due to rapid depletion, Philippine forests now contribute
only 1.7 percent to the gross national product.
Forty million tons of bananas are consumed by humans each
year.
Humans consume 1.3 million tons of mangoes and 1.5
million tons of papayas each year.
“Minor forest products”, such as rattan, bamboo, fruits,
nuts, and spices are worth $10 billion each year.
At least 2,100 plants are reported to have pestcontrolling property powerful enough to be commercially
developed.
Natural starches are used in fabrics, glue, soaps,
cosmetics,
medicines,
numerous
prepared
foods,
photographic film, explosives, colourings, car tires,
plastics, several industrial processes and even the
preservation of human blood plasma.
Rubber ranks among the world’s top crops.
Timber is the biggest wild plant contributor to industry
with a world trade value of US$ 40 billion per year.
The world currently consumes 10,000 years worth of solar
energy in one year’s supply of coal alone.
Over time, the greatest value of the variety of life
may be found in the opportunities it provides humanity for
adapting to local and global change. The unknown potential
of genes, species, and ecosystems represents a never-ending
biological frontier of inestimable but certainly high
value. Genetic diversity will enable breeders to tailor
crops to new climatic conditions. Earth’s biota - a
biochemical laboratory unmatched for size and innovation hold the still-secret cures for emerging diseases. A
diverse array of genes, species, and ecosystems is a
resource that can be tapped as human needs and demands
change (Reid et. al., 1992).
Because biodiversity is so closely intertwined with
human
needs,
its
conservation
should
rightfully
be
187
considered an element of national security. It has become
increasingly apparent that national security means much
more than military might. Ecological dimensions of national
security cannot be ignored when countries fight over access
to water or when environmental repugees strain national
budgets and public infrastructure. A secure nation means
not only a strong nation, but also one with a healthy and
educated populace, and a healthy and productive environment
as well. National security will be strongest in countries
that care for their biodiversity and the services it
provides.
The many values of biodiversity and its importance for
development suggest why biodiversity conservation differs
from
traditional
nature
conservation.
Biodiversity
conservation entails a shift from a defensive posture protecting nature from the impacts of development - to an
offensive effort seeking to meet peoples needs from
biological
resources
while
ensuring
the
long-term
sustainability of Earth’s biotic wealth. It thus involves
not
only
the
protection
of
species
but
also
the
safeguarding of the genetic diversity of cultivated and
domesticated species and their wild relatives.
This goal
speaks to modified and intensively managed ecosystems as
well as natural ones, and it is pursued in the human
interest and for human benefit. In sum, biodiversity
conservation seeks to maintain the human life support
system provided by nature, and the living resources
essential for development (Reid et. al., 1992).
Losses of Biodiversity and their Causes
We aren’t quite sure who is cutting our forests and
who is going to flood our land but we know they live in
town, where rich people are getting richer, and we poor
people are losing what little we have (Statement of the
Iban People, Sarawak, Malaysia).
Biological diversity is being eroded as fast today as
at any time since the dinosaurs died out some 65 million
years ago. The crucible of extinction is believed to be in
tropical forests. Around 10 million species live on earth,
according to the best estimates and tropical forests house
between 50 and 90 percent of this total.
about 17 million
hectares of tropical forests - an area four times the size
of Switzerland - are now being cleared annually and
188
scientists estimate that at these rates roughly 5 to 10
percent of tropical forest species may face extinction
within the next 30 years. This estimate may prove
conservative, however.
Rates of tropical forest loss are
accelerating, and some particularly species-rich forests
are likely to be largely destroyed in out lifetime.
Some
scientists believe that about 60,000 of the world’s 240,000
plant species, and perhaps even higher proportion of
vertebrate and insect species, could lose their lease on
life over the next three decades unless deforestation is
slowed immediately (Reid et. al., 1992).
Tropical forests are by no means the only sites with
endangered
biodiversity.
Worldwide,
nearly
as
much
temperate rain forest - once covering an area nearly the
size of Malaysia - has also been lost.
Although the total
extent of forest in the northern temperate and boreal
regions has not changed much in recent years, in many areas
the species rich, old-growth forest have been steadily
replaced
by
second-growth
forests
and
plantations.
Evidence of accelerating clearance of temperate forests is
also appearing: between 1977 and 1987, 1.6 million hectares
of forest was lost in the United States alone (Reid, et.
al., 1992).
In several spots in Europe, fungal species diversity
has dropped by 50 percent or more over the past 60 years.
In such “Mediterranean” climes as California, South Africa,
central Chile, and Southwest Australia, at least 10 percent
of all plant and animal species are imperiled. The largest
number of recent extinctions have been on oceanic islands:
some 60 percent of plant species endemic to the Galapagos
Islands are endangered, as are 42 percent of the Azores
endemic species and 75 percent of the endemic plant species
of the Canary Islands Reid et. al., 1992).
The biodiversity of marine and freshwater systems
faces serious loss and degradation. Perhaps hardest hit of
all are freshwater ecosystems, battling long term pollution
and the introduction of many alien species. Marine
ecosystems too are suffering from the loss of unique
populations of many species and are undergoing major
ecological changes (Reid et. al., 1992).
The number of documented species extinctions over the
past century is small compared to those predicted for the
coming decades. This difference is due, in part, to the
189
acceleration of rates of habitat loss over decades but also
to the difficulty of documenting extinctions. The vast
majority of species has not yet even been described, and
many may disappear before they are even known to science
(Reid, et. al., 1992).
Habitat
loss
not
only
precipitates
species
extinctions, it also represents a loss of biodiversity in
its own right. In many countries, relatively little natural
vegetation remains untouched by human hands. In Bangladesh,
only 6 percent of the original vegetation remains. Forests
around the Mediterranean Sea probably once covered 10 times
their current area, and in the Netherlands and Britain,
less than 4 percent of lowland raised bogs remain undamaged
(Reid et. al., 1992).
The dramatic losses of species and ecosystems obscure
equally large and important threats to genetic diversity.
Worldwide, some 492 genetically distinct populations of
tree species (including some full species) are endangered.
In the northwestern United States, 159 genetically distinct
populations of ocean-migrating fish are at high or moderate
risk of extinction, if they have not already slipped into
oblivion (Reid et. al., 1992).
Loss of genetic diversity could imperil agriculture.
How much the genetic base has already eroded is hard to
say, but since the 1950s, the spread of modern “Green
Revolution” varieties of corn, wheat, rice, and other crops
has rapidly squeezed out native landraces. Modern varieties
were adopted on 40 percent of Asia’s rice farms within 15
years of their release, and in the Philippines, Indonesia,
and some other countries, more than 80 percent of all
farmers now plant the new varieties.
In Indonesia, 1500
local rice varieties have become extinct in the last 15
years. A recent survey of sites in Kenya with wild coffee
relatives found that the coffee plants in two of the sites
had disappeared, three sites were highly threatened, and
six were possibly threatened. Only two were secure (Reid
et. al., 1992).