Summary
Biodiversity COMPLETE SUMMARY
- Institution
- University Of Cape Town (UCT)
Notes covering the biodiversity module of the BIO1004S course.
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Biodiversity and Society (Module 6)• Biodiversity = the variability among living organisms and the ecological complexes of which they
are a part
• De ned by:
• Number of species
• Diversity of types
• Genetic diversity
• Ecological/structural diversity
• Thus —> totality of genes, species in an ecosystem
of a region
• Ecological/evolutionary context of the organisms is
required
• System where the organisms have been
in uenced by the environment or evolved the
environment
• Link between biodiversity and society = mostly at
ecosystem level
• Ecosystem = community of organisms interacting
with each other and their environment such that
energy is exchanged and system level processes
emerge
• Provisors of many goods and services
(ecosystem services)
• Level of biodiversity in uences quality of ecosystem services rendered to society
BIODIVERSITY AND LIVELIHOODS
• Foundation of human well-being and economic activities —> provision of goods and services
• Eg. Livestock grazing, carbon sequestration, ecotourism —> natural capital
1) Conservation related works
1) National parks and reserve management
2) Working for water program
1) Removal of alien invasive plants
3) rehabilitation of wetlands
4) rebreak management
5) rehabilitation of degraded land (restoration and reforestation)
THREE INDICATORS OF BIODIVERSITY
1) Compositional biodiversity
1) What and how many species are present in an area
Ecosystem services Mechanisms that produce the e ect
Species Diversity Stability of biomass Cultivation of more than one species in the same plot
production or landscape maintains production over a broader
range of conditions
Pest and disease control in
agricultural systems High species number can slow down the spread of
pests and pathogens
Enhanced pollination species (variation in owers)
Resistance to invasive Species rich communities are more likely to contain
organisms highly competitive species and to contain less
unused resources — more resistant to invasions
flfi fi fl ff fl
, Keystone species = one which strongly in uences the composition and structure of an ecosystem
• Otters in the sea
• Otters eat sea urchins which eat juvenile kelp. Hunting of otters lead to loss of giant kelp
forests and associated biodiversity
• The populations of the sea urchins increased uncontrollably, and the kelp forest su ered
overgrazing. Ants in fynbos
• Elephants in african savanna
• Strongly in uence composition and structure of both the vegetation and fauna of the
ecosystem
• Feed on shrubs or tree branches
• Can push down trees/strip bark from the trees —> need to be sure not to over populate with
elephants
• Paci c salmon
• Red mangrove trees in tropics
2) Functional biodiversity
1)The component of biodiversity that in uences ecosystem productivity, stability,
dynamics, nutrient balance and other aspects of ecosystems performance
Trait Scale Scope Examples
Ecophysiological individual A ects growth, relative Leaf size, leaf nutrient
tness + survival concentration, body size
Life history Individual Relative tness, lifespan Body size changes, age
to reproduction, lifespan
Demographic Community Change in community Birth and death rate,
over time resprouting and
reseeding
• Inclusive of variation in ower characteristics
• Colour
• Morphology
• Phenology
• Scent that attracts a pollinator
—> increase in species diversity = increase in pollinator diversity
• If a group of plants are linked to one pollinator… problem for conservation because the loss of
the pollinator would likely lead to extinction of the plants
Ecosystem services Mechanisms that produce the e ect
Functional High amount of biomass produced Faster growing, bigger, more locally adapted plants
DIversity across life cycle produce more biomass
Large, slow growing, slow decomposing, long lived
plants retain more carbon
Preservation of the fertility of soils, Fast growing nutrient rich plants = dense root
prevents soil erosion systems
Enhanced pollination success High diversity of pollinators
Genetic improvement and higher number and quality
of fruits
fi ff fi fi fl
fl ff fl fl ff
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