Conservation Biology MODULE 25: CONSERVATION BIOLOGY UNIT 4: - - PDF document
20Mar17 Conservation Biology MODULE 25: CONSERVATION BIOLOGY UNIT 4: TOPICS AND APPLICATIONS Objectives At the end of this series of lectures, you should be able to: Define terms Describe biodiversity and the types of
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MODULE 25: CONSERVATION BIOLOGY UNIT 4: TOPICS AND APPLICATIONS
At the end of this series of lectures, you should be able to:
Define terms Describe biodiversity and the types of biodiversity that are commonly
described.
Discuss the number of species that have been described and the
problems with this number.
Discuss the number of species on the planet.
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Distinguish between and describe background and current
extinction rates.
Explain the causes of the threats to biodiversity. Describe the threats to biodiversity. Explain climate change. Describe conservation biology as a discipline.
Biological Diversity
Define diversity
Conservation biologists routinely categorize biodiversity into three
levels:
Genetic diversity Species diversity Ecological diversity
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1.4 - 1.8 million species have been described and named.
Why the range?
No one has kept track of the species that have been named.
Species 2000
Unidentified synonyms (one species multiple names) /homonyms (multiple
species one name)
Described/named species is a biased and poor estimator of global
species richness.
Linnean shortfall Centinelean extinctions
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The description of species has not been random.
Spatial – Temperate regions have been well described ~ The tropics
have not.
Size – Larger species tend to be described while smaller species are
Taxonomic – The number of taxonomists working on a group is not
proportional to the number of species within the taxonomic groups.
Terrestrial - know more about terrestrial than aquatic systems
We do not know.
12 million 100 million < 1 billion > 1 trillion
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Background extinction rate -- The natural extinction rate without
human disturbance.
Species last on average 10 million years. Assuming 10-100 million
species on the planet, the background extinction rate should be 0.1-10 species per year.
Combines both natural extinctions and extinctions due to
anthropogenic (human-caused) disturbance.
Two methods are used to estimate the current rate of extinction.
Species area relationship Observed extinction rate
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Current extinction rates are estimated to be 100 to 1000 times
greater than the predicted background extinction rate.
10 – 10,000 species per year
Threats to biodiversity spring from two major causes:
Human population growth Increased standard of living
Distribution of wealth
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The world’s human population is estimated to total ~ 7 billion.
It is increasing by over 100 million annually.
Optimal total human population is ~1.5 to 2 billion
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The human population has increased due to:
High birth rates Declining mortality rates
Reliable food supplies Improved sanitation Medicine
Humans appropriate approximately 40% of all potential terrestrial
net primary productivity.
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We would need 3.5 Earths for the 6.8 people on the planet to live as
we do.
The major threats to biodiversity are the result of human activity.
Habitat destruction, degradation, and fragmentation Introduction of exotic species Overexploitation Increased spread of disease Pollution
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Solar Energy
Some of the light that reaches the Earth’s surface is reflected by snow,
ice, sand, water.
Albedo
Absorbed energy heats surfaces, evaporates water, and creates
energy for photosynthesis.
2nd law of thermodynamics – Entropy
Absorbed energy is reradiated as heat.
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Natural gases
Carbon dioxide (CO2) methane (CH4) water vapor Ozone Nitrous oxides
Other greenhouse gases
chloroflourocarbons
These gases trap heat in the atmosphere
Currently, global warming is occurring as increasing concentrations
This is due to human domestic, industrial & agricultural practices. Carbon sources currently outweigh carbon sinks
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Global mean surface temperature increased 0.5°C in the last 100
years.
20th century was the warmest on record since the15th century 12 warmest years on record occurred in the last 16 years. Rapid rate of increase.
General Circulation Models Expected 1.5 to 6.1◦C increase in next 100 years Warming greatest at poles, weakest at tropics Climates to become more continental (extremes)
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Global precipitation
Changing spatial & temporal patterns Overall increase in volume & intensity In some regions, drought to become more common & severe
Change in ocean currents and atmospheric patterns of circulation Rising ocean levels
Thermal expansion Melting ice
Thomas et al (2004)
2050
Minimum 9-13% species extinctions maximum 21-32% species extinctions
This is based solely on climate predictions, not synergistic,
anthropogenic threat.
Controversial
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Applied branch of biology whose goal is the maintenance of:
Biodiversity
Genes, populations, species, ecosystems
Ecological process
Photosynthesis, natural selection
Synthetic field
Ecology Biogeography Landscape Ecology Population genetics Molecular genetics Economics Political Science Sociology Anthropology Philosophy
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Crisis discipline
Action is taken without complete knowledge Often reactive, ideally proactive Time is critical Working with available information and best intuition and creativity.
Counter to most scientific educations
Management of unprecedented, highly disrupted ecosystems
Inexact Science
Ecological systems are complex and dynamic Small data sets Looks at systems on wide gradient of scales Lots of noise Situations are unique, must be handled case-by-case
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Value-laden
Science is value-free & objective Mission-oriented Advocacy debate
Long time scale
Traditional “Conservation” and “Management”
Maximum sustainable yields Economic feasibility Immediate satisfaction – consumerism
In perpetuity Eternal vigilance
Ex. U.S. Arctic National Wildlife Refuge (oil)