Lecture 1. INTRODUCTION -BIODIVERSITY CONCERVATION MANAGEMENT
Biodiversity
o The variability among living organisms from all sources, including terrestrial, marine and other
aquatic ecosystems and the ecological complexes of which they are part: this includes diversity
within species, between species and of ecosystems.
o Or biological diversity, the sum of area’s organism, considering the diversity of species, their
genes, their populations, and their communities.
Components of Biodiversity
Genetic diversity
Species diversity
Ecosystem diversity
Landscape diversity
Species diversity
o The number or variety of species in a particular region
o Species richness= number of species
o Evenness, or relative abundance= extent which of different species are equal or skewed
o Species= a particular type of organism; a population or group of population whose members
share certain characteristics and can freely breed with one another and produce fertile
offspring.
Shannon-Weiner index, given equation: H’=-∑p log (pi)
Pi= proportion of individuals in the community that belong to species i
H’= 0 = means the community has only 1 single species
The higher the H’ the higher is the species diversity of the community
Roughly 1.75 million species has been formally described by species. But many more exist: estimates
range from 3 million to 100 million. Why are we still so unsure of the number of species on Earth?
o Some areas remain little explored (hydrothermal vents, rainforest canopies, tropical soils).
o Many species are tiny and inconspicuous (microbes, roundworms, protists, fungi…).
o Some species are very similar in appearance (many taxa, even trees, birds, whales).
Genetic diversity
o Includes the difference in DNA composition among individuals with a given species.
o Adaptation to particular environment conditions many weed out genetic variants that are not
successful
o But populations benefit from some genetic diversity, so as to avoid inbreeding or disease
epidemics
, o Genetic variability essential for a healthy breeding population of a species
o If the number of breeding individuals is reduced, the dissimilarity of genetic makeup is reduced
and in-breeding occurs. Eventually this can lead to extinction of species.
o The diversity in wild species forms the ‘gene pool’ from which our crops and domestic animals
have been developed over thousands of years
o Today the variety of nature’s bounty is being further harnessed by using wild relatives of crop
plant to create new varieties of more productive crops and to breed better domestic animals.
Ecosystem diversity
o Includes diversity above the species level
o Biologists have viewed diversity above the species level in various ways. Some alternative ways
to categorize it include:
Community diversity
Habitat diversity
Landscape diversity
Landscape diversity
o Landscape- large area consisting of a mosaic of ecosystems and habitats, including the edges
and the spaces (matrix) surrounding them.
o Landscape components are laid out in various spatial configuration or patterns, providing layers
of information on features, such as vegetation cover, soil type, topography, geological &
ecological events, land use, species distribution and land ownership.
Distribution of biodiversity
o Species are not evenly spread among different groups. Insects comprise than half of all species
in the world. Beetles comprise fully 0% of all insects. Mammals are outnumbered by spiders and
their relatives 16 to 1.
o Some group that have more species may have gone through an adaptive radiation
o This is when an ancestral species give rise to many species that fill different niches, adapting to
them by natural selection.
o Another pattern in uneven distribution of biodiversity is the latitudinal gradient: species
richness increases toward the equator.
Biodiversity loss and species extinction
o Extinction= last member of species dies and the species vanishes forever from earth
o Extirpation= disappearance of a particular population, but not the entire species globally
o These are natural processes
o On average one species goes extinct naturally every 500-1,00 years- this background rate of
extinction
o 99% of all species that ever lived are now extinct.
Mass extinction
, o Earth has experienced five mass extinction events in which over half its species were wiped out
suddenly: Ordovician extinction, devenonian extinction, permo-triassic extinction, end-triassic,
cretaceous-tertiary extinction.
o Today’s mass extinction, currently earth is undergoing its sixth mass extinction- because of
humans
o Humans have increased the extinction rate by a factor of 1,000
o 1,100 species are known to have gone extinct in the past ,00 years
o The Red List, from the IUCN, lists species that today are facing high risks of extinction.
Cause of mass extinction (HIPPO)
Habitat alteration
o Accounts for 85% of population declines of birds and mammals
o Habitat change hurts most organisms because they are adapted to an existing habitat
o Alteration due to: forest clearing, urban development, agriculture, global climate
change, etc.
Invasive species
o Accidental or intentional introduction of exotic species to new areas
o Most do not establish or expand, but some do likely because they are “released” from
limitations imposed by their native predators, parasites, and competitors
o Invasive species have become perhaps the second-worst threat to native biota
Pollution
o Air and water pollution; agricultural runoff, industrial chemicals, etc.
o Pollution does serious and widespread harm, but is not as threatening as the other
elements of HIPPO
Population growth
o Human population growth exacerbates every other environmental problem.
o More people means more habitat change, more invasive species, more pollution, more
overexploitation
o Along with increased resource consumption, it is the ultimate reason behind proximate
threats to biodiversity.
Overexploitation
o Overharvesting of species from wild
o Overconsumption of resource
o Usually overexploitation is not the sole cause of extinction, but it often contributes in
tandem with other causes.
Benefits of biodiversity
Preserving biodiversity preserves ecosystem services, and directly provides things of pragmatic
value to humans.
o Ecological role, o Air and water purification
o Food, fuel and fiber o Waste decomposition
o Shelter and building materials o Climate stabilization and
o Medicine moderation
Biodiversity
o The variability among living organisms from all sources, including terrestrial, marine and other
aquatic ecosystems and the ecological complexes of which they are part: this includes diversity
within species, between species and of ecosystems.
o Or biological diversity, the sum of area’s organism, considering the diversity of species, their
genes, their populations, and their communities.
Components of Biodiversity
Genetic diversity
Species diversity
Ecosystem diversity
Landscape diversity
Species diversity
o The number or variety of species in a particular region
o Species richness= number of species
o Evenness, or relative abundance= extent which of different species are equal or skewed
o Species= a particular type of organism; a population or group of population whose members
share certain characteristics and can freely breed with one another and produce fertile
offspring.
Shannon-Weiner index, given equation: H’=-∑p log (pi)
Pi= proportion of individuals in the community that belong to species i
H’= 0 = means the community has only 1 single species
The higher the H’ the higher is the species diversity of the community
Roughly 1.75 million species has been formally described by species. But many more exist: estimates
range from 3 million to 100 million. Why are we still so unsure of the number of species on Earth?
o Some areas remain little explored (hydrothermal vents, rainforest canopies, tropical soils).
o Many species are tiny and inconspicuous (microbes, roundworms, protists, fungi…).
o Some species are very similar in appearance (many taxa, even trees, birds, whales).
Genetic diversity
o Includes the difference in DNA composition among individuals with a given species.
o Adaptation to particular environment conditions many weed out genetic variants that are not
successful
o But populations benefit from some genetic diversity, so as to avoid inbreeding or disease
epidemics
, o Genetic variability essential for a healthy breeding population of a species
o If the number of breeding individuals is reduced, the dissimilarity of genetic makeup is reduced
and in-breeding occurs. Eventually this can lead to extinction of species.
o The diversity in wild species forms the ‘gene pool’ from which our crops and domestic animals
have been developed over thousands of years
o Today the variety of nature’s bounty is being further harnessed by using wild relatives of crop
plant to create new varieties of more productive crops and to breed better domestic animals.
Ecosystem diversity
o Includes diversity above the species level
o Biologists have viewed diversity above the species level in various ways. Some alternative ways
to categorize it include:
Community diversity
Habitat diversity
Landscape diversity
Landscape diversity
o Landscape- large area consisting of a mosaic of ecosystems and habitats, including the edges
and the spaces (matrix) surrounding them.
o Landscape components are laid out in various spatial configuration or patterns, providing layers
of information on features, such as vegetation cover, soil type, topography, geological &
ecological events, land use, species distribution and land ownership.
Distribution of biodiversity
o Species are not evenly spread among different groups. Insects comprise than half of all species
in the world. Beetles comprise fully 0% of all insects. Mammals are outnumbered by spiders and
their relatives 16 to 1.
o Some group that have more species may have gone through an adaptive radiation
o This is when an ancestral species give rise to many species that fill different niches, adapting to
them by natural selection.
o Another pattern in uneven distribution of biodiversity is the latitudinal gradient: species
richness increases toward the equator.
Biodiversity loss and species extinction
o Extinction= last member of species dies and the species vanishes forever from earth
o Extirpation= disappearance of a particular population, but not the entire species globally
o These are natural processes
o On average one species goes extinct naturally every 500-1,00 years- this background rate of
extinction
o 99% of all species that ever lived are now extinct.
Mass extinction
, o Earth has experienced five mass extinction events in which over half its species were wiped out
suddenly: Ordovician extinction, devenonian extinction, permo-triassic extinction, end-triassic,
cretaceous-tertiary extinction.
o Today’s mass extinction, currently earth is undergoing its sixth mass extinction- because of
humans
o Humans have increased the extinction rate by a factor of 1,000
o 1,100 species are known to have gone extinct in the past ,00 years
o The Red List, from the IUCN, lists species that today are facing high risks of extinction.
Cause of mass extinction (HIPPO)
Habitat alteration
o Accounts for 85% of population declines of birds and mammals
o Habitat change hurts most organisms because they are adapted to an existing habitat
o Alteration due to: forest clearing, urban development, agriculture, global climate
change, etc.
Invasive species
o Accidental or intentional introduction of exotic species to new areas
o Most do not establish or expand, but some do likely because they are “released” from
limitations imposed by their native predators, parasites, and competitors
o Invasive species have become perhaps the second-worst threat to native biota
Pollution
o Air and water pollution; agricultural runoff, industrial chemicals, etc.
o Pollution does serious and widespread harm, but is not as threatening as the other
elements of HIPPO
Population growth
o Human population growth exacerbates every other environmental problem.
o More people means more habitat change, more invasive species, more pollution, more
overexploitation
o Along with increased resource consumption, it is the ultimate reason behind proximate
threats to biodiversity.
Overexploitation
o Overharvesting of species from wild
o Overconsumption of resource
o Usually overexploitation is not the sole cause of extinction, but it often contributes in
tandem with other causes.
Benefits of biodiversity
Preserving biodiversity preserves ecosystem services, and directly provides things of pragmatic
value to humans.
o Ecological role, o Air and water purification
o Food, fuel and fiber o Waste decomposition
o Shelter and building materials o Climate stabilization and
o Medicine moderation
