Diabstraksikan oleh:
soemarno, psdl ppsub, desember 2012
INDEKS KELESTARIAN
LINGKUNGAN
=
Environmental
Sustainability Index
BIODIVERSITAS
Bahan Kajian pada MK. PSDAL
BIODIVERSITY = KEANEKA RAGAMAN HAYATI
1.
Keragaman hayati (biodiversity atau biological diversity) merupakan istilah yang
digunakan untuk menggambarkan kekayaan berbagai bentuk kehidupan di bumi ini
mulai dari organisme bersel tunggal sampai organisme tingkat tinggi. Keragaman
hayati mencakup keragaman habitat, keragaman spesies (jenis) dan keragaman
genetik (variasi sifat dalam spesies)
2. Keanekaragaman Hayati adalah tingkat variasi bentuk kehidupan dalam suatu
ekosistem tertentu, bioma, atau seluruh planet. Keanekaragaman Hayati adalah
ukuran dari kesehatan ekosistem. Keanekaragaman Hayati adalah sebagian fungsi
dari iklim. Pada habitat darat, daerah tropis biasanya kaya sedangkan daerah-daerah
kutub dukungan spesies yang lebih sedikit. Perubahan lingkungan yang cepat
biasanya menyebabkan kepunahan massa. Salah satu perkiraan adalah bahwa kurang
dari 1% dari spesies yang telah ada di Bumi yang masih ada.
3. Keanekaragaman Hayati adalah keseluruhan variasi berupa bentuk, penampilan,
jumlah, dan sifat yang dapat ditemukan pada makhluk hidup.Keanekaragaman hayati
merupakan lahan penelitian dan pengembangan ilmu yang sangat berguna untuk
kehidupan manusia.
Diunduh dari:
http://woentari-monica.blogspot.com/2012/05/pengertian-keanekaragaman-hayati-dari.html………………
KEANEKARAGAMAN HAYATI
Keanekaragaman hayati menekankan pada semua jenis spesies
tumbuhan, hewan dan mikroorganisme juga dengan ekosistimnya
dimana mereka merupakan bagian yang tak terpisahkan, termasuk
jumlah dan frekuensi ekosistem, spesies dan gen yang saling berkaitan.
Ada tiga macam keanekaragaman hayati, yaitu :
a. Keanekaragaman spesies (Species Diversity)
b. Keanekaragaman ekosistem (Ecosystem Diversity)
c. Keanekaragaman genetika (Genetic Diversity)
Diunduh dari: http://staff.blog.ui.ac.id/andreas.pramudianto/2009/02/27/keanekaragaman-hayati-dalam-hukum-lingkunganinternasional/ ……………… 4/12/2012
Keanekaragaman spesies / jenis (Species Diversity)
Keanekaragaman
spesies terbentuk oleh
adanya kesesuaian
kandungan genetika
yang mengatur sifat dari
kebakaan dengan
lingkungan terhadap
anggota jenis yang sama
yang dalam hal ini
memiliki kerangka
dasar, komponen
genetika khususnya
kromosom yang sama.
Species Richness Index: Simpson’s
Index
Simpson gave the probability of any two individuals drawn
at random from an infinitely large community belonging to
different species.
The Simpson index is therefore expressed as 1-D or 1/D.
Simpson’s index is heavily weighed towards the most
abundant species in the sample while being less sensitive to
species richness. It has been shown that once the number of
species exceeds 10 the underlying species abundance
distribution is important in determining whether the index
has a high or low value.
The D value which is standing for the dominance index is
used in pollution monitoring studies. As D increases,
diversity decreases.
(diunduh dari:
http://webcache.googleusercontent.com/search?q=cache:CN372gBQkCwJ:ocw.unu.edu/)
Diunduh dari: http://staff.blog.ui.ac.id/andreas.pramudianto/2009/02/27/keanekaragaman-hayati-dalam-hukum-lingkunganinternasional/ ……………… 4/12/2012
Species Diversity Indices: Shannon-Wiener Index
Shannon and Wiener independently derived the function which has become known as
Shannon index of diversity. This indeed assumes that individuals are randomly
sampled from an independently large population.
The index also assumes that all the species are represented in the sample. Log2 is
often used for calculating this diversity index but any log base may be used. It is of
course essential to be consistent in the choice of log base when comparing diversity
between samples or estimating evenness.
The value of Shannon diversity is usually found to fall between 1.5 and 3.5 and only
rarely it surpasses 4.5. It has been reported that under log normal distribution, 105
specieswillbe needed to produce a value of Shannon diversity more than 5. Expected
Shannon diversity is also used (Exp H’) as an alternative to H’. Exp H’ is equivalent to
the number of equally common species required to produce the value of H’ given by
the sample.
The observed diversity (H’) is always compared with maximum Shannon diversity
(Hmax) which could possibly occur in a situation where all species were equally
Abundant.
Diunduh dari: http://staff.blog.ui.ac.id/andreas.pramudianto/2009/02/27/keanekaragaman-hayati-dalam-hukum-lingkunganinternasional/ ……………… 4/12/2012
Keanekaragaman ekosistem (Ecosystem Diversity)
Merupakan suatu kesatuan
lingkungan yang
melibatkan unsur-unsur
biotik, faktor fisik (iklim,
tanah dan air) dan faktor
kimia (keasaman) yang
saling berinteraksi.
An ecosystem is a community plus the physical environment
that it occupies at a given time. An ecosystem can exist at any
scale, for example, from the size of a small tide pool up to the
size of the entire biosphere. However, lakes, marshes, and
forest stands represent more typical examples of the areas
that are compared in discussions of ecosystem diversity.
Beberapa tipe (kelompok)
keanekaragaman ekosistem
antara lain :
1. Ekosistem bahari:
Terdiri dari ekosistem
laut dan ekosistem
pantai
2. Ekosistem darat”:
Terdiri dari vegetasi
dataran rendah,
vegetasi pegunungan
dan vegetasi munson.
The diversity of an ecosystem is dependent on the physical
characteristics of the environment, the diversity of species
present, and the interactions that the species have with each
other and with the environment. Therefore, the functional
complexity of an ecosystem can be expected to increase with
the number and taxonomic diversity of the species present,
and the vertical and horizontal complexity of the physical
environment.
(Sumber: http://cnx.org/content/m12156/latest/#roth)
Diunduh dari: http://staff.blog.ui.ac.id/andreas.pramudianto/2009/02/27/keanekaragaman-hayati-dalam-hukum-lingkunganinternasional/ ……………… 4/12/2012
KEANEKARAGAMAN GENETIKA (GENETIC DIVERSITY)
Keanekaragaman genetik (genetic diversity) adalah
Setiap kerangka dasar
komponen genetika
tersusun ribuan faktor
kebakaan keturunan.
suatu tingkatan biodiversitas yang merujuk pada jumlah total
variasi genetik dalam keseluruhan spesies yang mendiami
sebagian atau seluruh permukaan bumi yang dapat didiami. Ia
berbeda dari variabilitas genetik, yang menjelaskan
kecenderungan kemampuan suatu karakter/sifat untuk
bervariasi yang dikendalikan secara genetik.
Satu faktor pengatur
kebakaan disebut gen,
suatu lingkungan yang
memuat tumbuhan
yang liar/sudah
didomestikasi.
Pengukuran keanekaragaman genetik
Keanekaragaman genetika suatu populasi dapat diperkirakan
dengan menggunakan beberapa pengukuran sederhana.
1. Keanekaragaman gen, adalah proporsi lokus polimorfik
diseluruh genom.
2. Heterozigositas, adalah jumlah rata-rata individu dengan
lokus polimorfik.
3. Alel per lokus, juga digunakan untuk mendemonstrasikan
variabilitas.
(sumber: http://id.wikipedia.org/wiki/Keanekaragaman_genetik)
Diunduh dari: http://staff.blog.ui.ac.id/andreas.pramudianto/2009/02/27/keanekaragaman-hayati-dalam-hukum-lingkunganinternasional/ ……………… 4/12/2012
Biodiversity
Variety of living things, number
of kinds
Ecological diversity
different habitats, niches, species
interactions
Species diversity
different kinds of organisms,
relationships among species
Genetic diversity
different genes & combinations
of genes within populations
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Manfaat Biodiversitas
• Fungsi ekosistem
• Jasa-jasa Ekosistem
• Membersihkan air,
• Cleaning air,
• Habitat & breeding areas for wildlife, …
• Manfaat estetika dan budaya
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Sumberdaya Alam
• Vital economic natural resources
– Renewable
•
•
•
•
•
Forests (plants, wildlife)
Soils
Fresh water (lakes, rivers)
Wildlife and fisheries
Rangeland
– Nonrenewable
• Minerals
• Fossil Fuels
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Sumberdaya Alam
• Management of natural
resources
– Assure availability of
resources for the future
– Three “philosophies”
• Maximum sustained yield
• Ecosystem-based
management
• Adaptive management
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Manfaat Biodiversitas
• New food sources
– Grains, fruits, vegetables, meat, fish
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Manfaat Biodiversitas
Pengobatan:
• Plants
• Jellyfish & sea
anemones
• Nudibranchs
• Marine slugs
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Biodiversitas
Berapa besar biodiversitas
 1.7—2.0 million species
 Estimates to 100 million
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Biodiversitas
Dimana biodiversitas?
– Everywhere
• Every continent and
habitat has unique life
forms
– Concentrated in the
tropics
• Panama: > 500 species
of breeding birds
• Arctic: 50-100 species
– Dense concentrations
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Ancaman Biodiversitas
Kepunahan & Reduksi
Populasi
– Perburuan & Panen
berlebihan
•
•
•
•
Tiger
Dodo
Whales
Sharks
– Kehilangan Habitat
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Ancaman Biodiversitas
• Extinction and
population reductions
– Pollution
– Climate change
– Invasive species
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
• How can we protect
biodiversity
– Stop overharvesting
• Sustainable yield
• Hunting & fishing laws
(every state ?)
– in developing nations ?
– Protect habitat
• Refuges, parks, preserves
– Endangered Species Act
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
• Refuges, parks, preserves
– How big should refuges be?
– Where should they be?
– McArthur & Wilson “Theory of Island
Biogeography”
• colonization rate
• extinction rate (local)
• predicts number of species
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
• Effect of island size
• Effect of island distance
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
McArthur & Wilson:
“Teori Biogeografi
Pulau”
– Laju Kolonisasi
– Laju Kepunahan (lokal)
– predicts number of
species
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
Biogeografi Pulau:
Ukuran Pulau memprediksi jumlah spesies
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
Proteksi Biodiversitas
Biogeografi Pulau
– Everyplace is an island
– Fragmentasi Habitat
• Smaller fragments hold
fewer species
Diunduh dari: facstaff.gpc.edu/~apennima/ENVS/Biodiversity.ppt
BIODIVERSITAS EKOSISTEM
ECOSYSTEM BIODIVERSITY implies the existence of
different species within an ecosystem. It can also be defined
as the degree of variations among the life forms in an
ecosystem or planet.
ECOSYSTEM DIVERSITY is the variety of different
natural systems or ecosystems in a particular area.
Examples of ecosystem diversity are deserts, forests,
wetlands, rain-forests, marine ecosystems etc.
Diunduh dari: http://www.environmentabout.com/820/ecosystem-biodiversity-and-types-of-biodiversity ……………… 4/12/2012
What is biodiversity?
• OED: “biodiversity Ecol., diversity of plant and animal life,
as represented by the number of extant species”
• Ricklefs & Miller: Biodiversity includes a number of
different levels of variation in the natural world: genetic,
species, ecosystem
• Begon et al. “The term may be used to describe the
number of species, the amount of genetic variation or the
number of community types present in an area”.
Tetapi .......… sebagian terbesar penelitian fokus pada
diversitas spesies
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Apakah Biodiversitas
mempengaruhi fungsi-fungsi
ekosistem ?
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Konsekwensi fungsional dari Biodiversitas:
Numbers and
Kinds of
Species
Organismal
traits
Ecosystem
Processes
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Traits & Fungsi Ekosistem
1. Traits may mediate energy and material flow
directly
2. Traits may alter abiotic conditions (limiting
resources, disturbance, microclimate)
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Ekspresi Trait ditentukan oleh:
1.
2.
3.
4.
5.
Species richness
Species evenness
Species composition
Species interaction
Temporal and spatial variation
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
2
-2
Total foliar N (g m ground area)
3.2
r =0.93
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
0.0
0.4
0.8
1.2
1.6
2.0
2.4
LAI
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
The Ecosystem/Ecology Divide
1. Key ecosystem types in Arctic tundra show clear
differences in key species and functional types
2. But at the ecosystem level there are clear patterns in
the landscape irrespective of species composition
3. Bulk measures like LAI and foliar N are good
descriptors of process rates
4. Dengan demikian, Apakah species sangat penting?
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Kekayaan Species & Fungsi Ekosistem : Theory
1. If niches are complementary, adding species
could increase process rates linearly
2. As niches overlap the response should saturate
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Niche differentiation and productivity.
a. A simple model — the 'snowballs on
the barn' model — of niche differentiation
and coexistence. The range of conditions
in which each species can exist is shown
with a circle, the position of which is
defined by its centre. By randomly
choosing locations for various numbers of
circles (species), it is possible to calculate
the effect of diversity on the 'coverage' of
the heterogeneous habitat. The amount of
such coverage is proportional to
community biomass.
b. Results of simulations (triangles) and
of an analytical solution (solid curve) to
the effects of diversity on community
productivity for the snowballs on the
barn model
From: Tilman (2000), Nature.
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
(A) Dependence of
1996 aboveground plant
biomass (that is, productivity)
(mean and SE) on the number
of plant species seeded into the
289 plots.
(B) Dependence of 1996 aboveground plant biomass on the
number of functional groups
seeded into each plot. Curves
shown are simple asymptotic
functions fitted to treatment
means. More complex curves
did not provide significantly
better fits
From: Tilman et al. (1997) Science
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Hypothesized mechanisms
involved in biodiversity
experiments using synthetic
communities. Sampling effects
are involved in community
assembly, such that communities
that have more species have a
greater probability of containing a
higher phenotypic trait diversity.
Phenotypic diversity then maps
onto ecosystem processes through
two main mechanisms:
dominance of species with
particular traits, and
complementarity among species
with different traits.
Intermediate scenarios involve
complementarity among
particular species or functional
groups or, equivalently,
dominance of particular subsets
of complementary species.
From: Loreau et al (2001) Science
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Kemerataan Species
1. Human effects on species more commonly involve
alteration of relative abundance than extinction
2. Little research on importance of evenness of
function so far
3. Future richness experiments should include
evenness effects
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Komposisi Species
• Species mediate pathways of energy
and material flow
• Examples: Introduced species can alter
patterns of ecosystem processes
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Species introduksi dapat mengubah pola proses-proses
ekosistem
1. Introduction of N-fixing tree Myrica faya to Nlimited Hawaiian forests led to 5-fold increase
in N inputs
2. Dampak signifikan terhadap struktur dan
fungsi hutan
Vitousek et al. (1987) Science
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Species introduksi dapat mengubah pola proses-proses
ekosistem
• Introduction of deep-rooted salt cedar (Tamarix
sp.) to Mojave and Sonaran deserts resulted in:
– Increased water accessed by vegetation
– Increased surface litter and salts
– Inhibited many native species, reduced
biodiversity
Berry (1970)
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Species introduksi dapat mengubah pola proses-proses
ekosistem
• Introduction of Agropyron cristatum, tussock
grass, to US Great Plains
– Reduced allocation to roots compared to
native grasses
– Soil N levels reduced, and 25% less total soil C
compared to native prairie soil
Christian & Wilson (1999)
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Species introduksi dapat mengubah pola proses-proses
ekosistem
• Introduction of Bromus tectorum, cheatgrass, to
western US
– Fire frequency increased by a factor of 10 in the
>40 million ha it now dominates
Whisenant (1990)
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Interaksi Species
• Mutualism
• Trophic interaction
– Predation
– Parasitism
– Herbivory
• Competition
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Mutualism
1. N-fixation in plant-microbe symbiosis
2. Plant-mycorrhizal associations
1. Both increase production and accelerate
succession
3. Decomposition is driven by highly integrated
consortia of microbes
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
STUDI KASUS
Mycorrhizal fungal diversity
determines plant biodiversity,
ecosystem variability and
productivity
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Experiment 2
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
van der Heijden 1998
Komunitas mikroba: Semakin beragam semakin efisien
Soil microbial functional diversity
(Shannon index H') and
metabolic quotient (qCO2 = soil
basal respiration/soil microbial
biomass) correlate inversely.
A higher diversity in the organic
plots is related to a lower qCO2,
indicating greater energy
efficiency of the more diverse
microbial community.
The Shannon index is
significantly different between
both conventional systems
(CONFYM, CONMIN) and the
BIODYN system, the qCO2,
between CONMIN and BIODYN
(P < 0.05).
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Maeder 2002
Interaksi Trophik
• Modify fluxes of energy and materials
• Influence abundance of species that control
these fluxes
– e.g., predator removal can lead to a cascade of
ecological effects
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
(A) Changes in sea otter abundance
over time at several islands in the
Aleutian archipelago and
concurrent changes in (B) sea
urchin biomass, (C) grazing
intensity, and (D) kelp density
measured from kelp forests at Adak
Island. Error bars in (B) and (C)
indicate 1 SE. The proposed
mechanisms of change are
portrayed in the marginal cartoons-the one on the left shows how the
kelp forest ecosystem was
organized before the sea otter's
decline and the one on the right
shows how this ecosystem changed
with the addition of killer whales as
an apex predator. Heavy arrows
represent strong trophic
Estes et
al. (1998)
Science
interactions;
light
arrows
represent
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Interaksi Trophik
1. All types of organisms must be considered in
understanding biodiversity effects
2. Interactions among species must be
considered
3. Changes in interactions can alter traits
expressed by species, so presence/absence of
species is insufficient to predict impact
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Biodiversity & Jasa Ecosystem
1. Ecosystem services are defined as the processes
and conditions of natural ecosystems that support
human activity and sustain human life
2. E.g., maintenance of soil fertility, climate
regulation, natural pest control
3. E.g., flows of ecosystem goods such as food,
timber and freshwater
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Valuasi Biodiversitas
1. Techniques used include direct valuation based
on market prices, and estimates of what
individuals are willing to pay to protect
endangered wildlife
2. Valuation of marginal losses that accompany
specific biodiversity changes are most relevant
to policy decisions
3. Predictions are highly uncertain
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt
Apa pengaruh diversitas tumbuhan thd proses-proses
ekosistem?
Diversitas Tumbuhan:
1. Genetic
2. Population
3. Species
4. Functional group of species
5. Habitat
Plant community composition = IDENTITY
Plant diversity = RICHNESS
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
State Factors
Climate
Time
Ecosystem
structure and
function
Organisms
Relief
(Topography)
Parent material
Ecosystem = (Cl, O, R, P, T)
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Mengapa kita peduli ?
• Understand a state factor control over
ecosystem variation:
• in space
• in time
Memahami dampak aktivitas manusia:
• Habitat destruction and extinction
• Simplification through management
• Biological invasions
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Variation in key plant traits can cause species to differ in their
effects on ecosystem processes
• Biogeochemical cycles
• Biophysical processes
• Trophic structure
• Disturbance regime
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Functional types are a useful simplification
•
Groups of species that have a similar influence on an
ecosystem process
•
Relevant grouping depends on process of interest
•
Life forms often make useful groups
•
Makes it possible to represent aspects of diversity in
models
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Identitas Species :
How does who’s there affect ecosystem processes?
Siklus N ….…
•
•
•
•
•
N fixation
Space and time of N uptake
Species of N used
Turnover time and allocation
Litter quality
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Plant litter traits can reinforce
site nutrient availability
 Growth
+
 Quality litter
 Nutrient mineralization
 Growth
+
 Quality litter
 Nutrient mineralization
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Wedin and Tilman 1990
Diunduh dari: www.biology.ufl.edu/.../Diversity%20and%20ecosystems,%2011-3-10.p...
Kekayaan Spesies = Species richness
How does species number affect ecosystem processes?
Is there an effect of diversity per se that
is independent of identity?
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Production: +, saturating
Changes in diversity
have their largest effects
at low diversity
Tilman et al. 1997
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Mekanisme-mekanisme
1. Complementary resource use:
 Species = more complete resource use
Niche differentiation, niche partitioning
2. Sampling effect:
 Species =  probability of getting spp. with strong
effects on processes
How can we differentiate between these mechanisms?
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Experiment: Menanam spesies secara Monokultur dan
Campuran
1. Complementary resource use:
Production in mixture >> production in monoculture
Synergy: “Overyielding”
2. Sampling effect:
Production in mixture = production in monoculture
Few well-controlled empirical tests have manipulated
richness independent of composition
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1. Functional diversity
explained the greatest
amount of variation in plant
biomass
2. When functional diversity
was included, species
diversity had no effect
Doesn’t matter how many
species, only how many
functional groups
Tilman et al. 1997
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Effects of functional diversity were
caused by presence or absence of
key functional groups
Overyielding was also
observed:
C4 grasses yielded more in
high then in low diversity
treatments
Productivity = C4 grasses, legumes
Plant %N = legumes
Soil NO3- = C4 grasses
Tilman et al. 1997
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References
• Chapin et al (2000) Consequences of changing biodiversity.
Nature 405: 234-242
• Tilman, Wedin and Knops (1996) Productivity and
sustainability influenced by biodiversity in grassland
ecosystems. Nature 379: 718-720
• Naeem & Li (1997) Biodiversity enhances ecosystem
reliability. Nature 390:507-509
• Van der Heijden et al. (1998) Nature 396: 69-72
• Constanza et al (1997) The value of the world's
ecosystem services and natural capital. Nature 387:
253-260
• Maeder et al (2002) Soil fertility and biodiversity in
organic farming. Science 296: 1694-7
Diunduh dari: www.geos.ed.ac.uk/homes/mwilliam/Biodiversity1.ppt