Post on 03-Jun-2018
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Kepentingan biodiversiti
Biodiversiti adalah pentingdan perlu di
pulihara
tetapi
kefahaman terhadapnya adalah rendah
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1. Prinsip asas:
biodiversiti mempunyai nilai intrinsik
setiap organisma mempunyai hak untuk hidup
Manusia mempunyai tanggungjawab moral
and etika untuk memuliharanya
these arguments often considered the mostimportant, but sofar, have had the least impact
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2. Manfaat ekonomi:
biodiversiti menyediaka sumber komoditi yang
boleh dipasarkan
Makanan
Bahan perubatan
agen kawalan biologi
Bahan industri
Rekreasi
tidak mengaitkan kebanyakan spesies
Menekan eksploitasi lebih daripada pemuliharaan
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3. Kemandirian :
biodiversiti menyediakan bahan tidak komersil &perkhidmatan
Fungsi ekosistem - interaksi antara organisma
with their, and our, environments
Peranan ekologi - interaksi organisma antara
satu sama lain
Pengetahuan - biologi/ekologi organisma
Nilai estetikkeseronokan pengalaman denganorganisma liar
Existence values - the values people place on
organisms although they may never encounter them
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ecosystem servicesare natural functions of anecosystem that can be, secondarily, used for
human benefit and ecological sustainabilityis thecapacity to maintain vital ecosystem processes
ecosystem services include
water and gas regulationnutrient cycling
pollination
biological control
genetic resources
landscape amenity (ecotourism)
this is why
we need to
maintain
highbiodiversity !
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a matter of survival:
an example ofecosystem servicesprovided by
riverside (riparian) vegetation
regulation of water flow
regulation of water quality - sinksfor P and N
regulation of water temperatureinput of organic food for aquatic community (fishneed trees!)
stabilization of banks - reduced erosion
creation of in-stream habitat for aquatic wildlife
enhanced fish productiontimber production
habitat for terrestrial wildlife
enhanced landscape quality
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ecosystem services
pollination services
about 90% of angiospermspecies depend on animals
esp. insectsfor pollination
human & domesticated animalsdepend (directly or
indirectly)on pollination for approx. 1/3 of their food
pollination services in agriculturalsystems in the
USA are worth 20-40 billiondollars
pollination services on a global scaleare worth 200
billiondollars
Costanza et al. (1997) Nature387, 253-260.
Kearns et al. (1998) Annual Review of Ecology and Systematics29, 83-112.
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but
agricultural pollination is carried out by European
honey-bees and some native beesnot a very
diverse group but successful ??
natural biodiversityis still important - in coffeeplantations close to forest fragments(fragments =
other species, bio-control, nest sites, food resources
when the coffee is not flowering etc.) pollination
and crop yield was 20% greaterthan in isolatedplantations (an increase of $US1500per ha per
year)
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a matter of survival...
ecosystem services
the value of these ecosystem services is usually
grossly undervalued by policy decision
nutrient cyclingservices estimated to be inthe order of US $17 x 1012 annually !!!
$17,000,000,000,000!
1997 estimates of the worth of all services
provided by the ecosystem were
33 trillion dollars per year!!!
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What does biodiversity actually do?
biological diversity allows the different ecosystem
functions to be carried out
the primary ecosystem functions are to
Capture
Store
Transfer
Energy
Carbon dioxide
NutrientsWater
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ECOSYSTEMS
ecosystems are a network of
interactions, beginning with
the PRIMARY PRODUCERS
(the PLANTS) and
connecting to herbivores,carnivores, parasites,
decomposers
...energy, nutrients & water
are cycled through thenetwork by these different
groups
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butmany different species are involved in theseecosystem activities
for example
thousands of different species of plant are able to
photosynthesize and capture carbon dioxide,
produce carbohydrates, store them etc.
for example
many species are able to fix nitrogen from the
atmosphere and store it
acacias (wattles), peas, blue-green algae, bacteria
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for example:
many species are involved in decomposition of plantand animal parts and the re-cyclingof nutrients,
carbon dioxide and water
microfauna, fungi, bacteria, larger herbivores &carnivores consumption defaecation
decomposition nutrients
do we really need all these different species
(biodiversity) ?
arent some species more important than
others?
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Are some species more important than others?
species differ in their ecological role
species differ in capacity to adapt to environmental
change
species differ in some aspects of their importance
in their community
in conservation, several categories of importance
are used
indicator species
keystone species
umbrella species
flagship species
New (2000) pages
83-89
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Keystone Species
keystone-nesswas only originally proposed as a
metaphorfor characterizing predators which havea large impact on other (vaguely specified) species
the key stonewas the
single stone which held
the arch-stones in place
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Keystone Species
= species which affect the organization of thecommunity to a far greater degree than one would
predict from the number of individuals or biomass
= most obvious keystone species are top order
predators often important in controllingherbivore populations
eg. grey wolves decline deer populations
explode habitat overgrazed herbaceous
species lost loss detrimental to deer, otherherbivores, insects reduced plant cover soil
erosion further plant loss
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it is simplisticas it views ecosystem interactions
as hierarchicalrather than a webof interrelations
it ignores the role of redundant or
substitutable or back-up speciesin ecosystem
reliability
it has an image problemas keystone species are
often the large top order carnivores (where is the
lowly keystone fungus ??)
it takes little account of the right of individual
species to exist
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what happens to the rest of the ecosystem
if we concentrate our conservation efforts
only on keystone species ???conservation
success ?
an implication of the keystone concept is
that species are either keystone or they are
not a dichotomy not supported in nature
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Umbrella Species
species which can provide
shelter for many others
need not be common or
dominanteg. Eucalyptus camaldulensis
River Red Gum - provides
habitat for numerous
inconspicuous invertebratespecies, birds, other plants etc.
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Flagship Species
species which have
general public appeal -attention grabbing
species
strong emotional
appeal
eg. Eltham Copper Butterfly
Paralucia pyrodiscus lucida or the
Helmeted Honeyeater- used to
gather urgent public support for
immediate identified needs
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Indicator Species
eg. Sooty OwlTyto tenebricosusconsistently
recorded from Mountain Ash forests in Victoria
dependent on arboreal marsupialsand nesting and
roosting sites in maturetrees managementindicator species of forestry practices (which lead
to an abundance of younger regenerating stands of
Mountain Ash, unsuitable for a range of other
species)
species which can be used to
measure, monitor or indicate
some aspect of environmental
change
changes in abundance
loss from local areas
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species grouped according to their
ecological function
one way of examining biodiversity, and what the
range of organisims does, is to put them into
functional groups
functional groups contain species which carry out
similar activities functionally similar taxa or
functional analogues
for example:kangaroo, wombat, sheep, cow, deer, alpacca,
rabbit - are all functionally similar
all consumers of plant material all graze
all herbivores
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ECOSYSTEMS
ecosystems are a network of
interactions, beginning with
the PRIMARY PRODUCERS
(the PLANTS) and
connecting to herbivores,
carnivores, parasites,
decomposers
...energy, nutrients & waterare cycled through the
network by these different
groups
different functional groups
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an example of similar function
nitrogen is the only nutrient which does not
derive from the weathering of rock a
biologicalnutrient
nitrogen gas from the atmosphere must be
fixedinto a form available to plants
170 megatons fixedby biological organisms
20 megatons fixedby lightening
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in ecosystems with high species diversity,
ecosystem processes are much less
sensitiveto variations in that diversity
variations in diversity can arise fromnatural , cyclic processes seasonal,
diurnal, disturbances such as fire
or from extinctionsof species
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Fire
nitrogen lost as vapour (gas)
germination & growth of nitrogen-
fixing species eg. Acacia, Allocasuarina,
the Fabaceae(peas)
nitrogen fixation high
nitrate levels rise and post-fire species
(Acacia, Allocasuarina, peas) eventuallydie
nitrogen persistence now depends on
species which conserve and re-cycle it
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nitrate levels in the soil fall and fixation isresumed by symbiotic or free-living bacteria
nitrogen can be transported in water or
eroded by wind or consumed by herbivores or
by predators
net result is a pool of nitrogen held within
plants, fungi, soil organisms, invertebrate
animals(a highly diverse set of species)
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high species redundancy(= high biodiversity) should
be valued as a critical featureof ecosystems
high diversity must be conservedif ecosystems are to
function reliably
high biodiversity = high reliability of
ecosystem services
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