Chapter 38 Conservation Biology
1. Biodiversity crisis
a. rapid decrease in Earth’s variety of life
b. Key deer
i. found only in Florida keys
ii. unique gene pool
1. cut off from whitetail deer on mainland when seas rose after last
ice age (allopatric population)
2. naturally selected (adapted) to a tropical island habitat
a. eat native plants
b. tolerate drinking brackish (salty) water
iii. hunted almost to extinction in the early 1900’s
1. hunting banned in 1939
2. only 50 remained (bottleneck)
3. 1957 - National Key Deer Refuge established on Big Pine Key
4. 1967 – placed on endangered species list and still there
5. 600-800 today
iv. human population on Big Pine Key
1. grew from 500 to 5000 since 1967
2. habitat reduced by development
3. motorists are biggest threat to deer
a. >50% of Key deer deaths result on US1
b. plans to buld fences along road and underground tunnels
to allow migration (gene flow)
c. Happening all of the world (Holocene extinction)
i. All because of a big-brained, manually dextrous, environmentmanipulating toolmaker that has named itself Homo sapiens.
d. Biodiversity
i. estimated 30 to 80 million species on Earth
ii. we have identified on 1.5 million
iii. Thus, impossible to measure rate of species loss
e. Conservation Biology
i. an attempt to conserve life
ii. seeks to counter the biodiversity crisis
2. The major threats to biodiversity
a. Habitat destruction
i. Due to:
1. expansion of agriculture to feed growing pop. of humans
2. urban development
3. forestry
4. mining
5. environmental pollution
ii. Human altered land surface reaching 50%
iii. Humans use >50% of accessible fresh water
iv. coastal areas and coral reefs
v. implicated in 73% of extinct, endangered, vulnerable or rare species
b. introduced (exotic) species
i. accidently carry seeds or insects during world travel
ii. intentionally introduce foreign plants or animals
1. agricultural reasons
2. ornamental reasons
iii. Most transplanted species fail to survive outside their range, but many
have
1. Some Introduced species
a. Starling
b. Rock Doves (pigeons)
c. house sparrows
iv. US has 50,000 introduced species
1. cost of 130 billion dollars in damage and control efforts
2. loss of native species
v. Lake Victoria (on planet Earth series)
1. largest rapid-extinction events yet recorded
a. 200 Species of native fish found nowhere else have been
lost
b. Cause:
i. introduction of an exotic predator – the Nile
Perch (Fig. 38.1B)
c. How:
i. on purpose to provide high-protein food to
growing population
c. overexploitation
i. excessive commercial harvest and sport hunting
1. whales, American Bison, Galapagos tortoises, many fish species
2. other species are killed in the crossfire (caught in nets, etc…)
a. dolphins, seabirds, marine turtles, etc…
ii. illegal world trade in wildlife products
1. elephant tusks
2. rhino horns, etc…
3. Biodiversity is vital to human welfare
a. Why should we care about loss of diversity?
i. E. O. Wilson
1. biophilia – sense of connection to nature and other forms of life
(aesthetic and ethical reasons)
ii. depend on many species for food, clothing, shelter, oxygen, soil fertility,
etc…
iii. 25% of all our prescribed medicine in US have ingredients from plants
1. Rosy periwinkle
a. flowering plant native to Madagascar
b. contains 2 chemicals that fight certain cancer types
2. Madagascar
a. 8,000 species of flowering plants (angiosperms)
b. 80% live only there
c. 200,000 species of plants and animals
d. one of top five most biodiverse countries
e. humans have lived here for 2000 years
i. 10 million people now
ii. most desperately poor
iii. unlikely to care about environment if they can’t
even feed themselves.
iv. Result:
1. 80% of forests lost
2. 50% of native species gone
iv. Humans are threatened
1. we like all organisms are dependent on biotic and abiotic factors
2. we evolved in our environment like all life
3. By destroying other species we may destroy ourselves
a. loss of wetlands = more floods
b. increased UV light
c. air and water pollution
d. food pollution
e. pollination
f. and the list goes on?
4. Who is most respondsible?
a. those using the greatest amount of resources
b. those in developed nations
c. we are
4. Technology and the population explosion compound our impact on habitats and other
species
a. technology fuels population explosion
i. feeding, clothing, housing
ii. excessive consumption of resources by certain segments of human
population (United States)
1. we have become mass consumers
2. Average US citizen consumes 9X more resources than average
person in China, 17X more than person in India, 40X more than
person in Bangladesh (Table – page 766)
b. If we continue, the resources like soil, water, fossil fuels will be depleted
c. 1989, March 24th – supertanker in Alaska runs aground
i. 10 million gallons of crude oil spilled into Prince William Sound
ii. All to burn gas in LA, New York, Chicago, etc…
d. Pollution released in Ohio is carried across North East and results in acid rain.
i. acid precipitation (from acid rain) destroys lakes and forests
e. Ozone layer
i. thinning since 1975
ii. protects us from harmful UV light
iii. will lead to increased skin cancer and cataracts
iv. crops and natural communities (phytoplankton) will also likely be
affected
v. caused by CFCs
vi. although we limit their use now, these chemical persist for a hundred
years in the atmosphere
f. chemical pesticides
i. DDT – helped reduce mosquito populations and the diseases they carry
(malaria, yellow fever, etc…)
ii. malaria was common in US – eliminated in 1950 using DDT
iii. However, DDT persists in environment and travels around in the water
1. showed up in fat tissue of birds and mammals in the 1960s
2. found in marine mammals in the Arctic,
a. far from anywhere DDT was used
3. concentrates as it moves through food web
a. called Biological magnification (Fig. 38.3B)
4. 1960s – 70s
a. found high DDT levels in predatory birds correlated to
thinning egg shells
i. weight of parent broke eggs during incubation
ii. populations declined
iii. Silent spring by Rachel Carson (module 34.3)
5. DDT banned in US in 1971
6. companies still sold to other countries until 1984
7. DDT and related chemicals still used in developing nations
8. US has replaced DDT with other chemicals
a. 1999 – areas of NYC sprayed will pyrethroids as
precaution against West Niles virus carried by
mosquitoes.
b. massive die-off of lobsters in Long Island Sound within
months
iv. Bottom line:
1. technology allows us to grow in population and reduces pain
and suffering
2. it is often implemented immediately without testing
3. the biosphere becomes the testing ground
g. How is biological magnification directly relevant to the health of most humans in
developed countries?
5. Rapid global warming could alter the entire ecosphere
a. will affect biodiversity worldwide
b. Fossil fuels power
i. most industries
ii. agricultural equipment
iii. automobiles
iv. Industrial revolution
c. CO2 levels have risen dramatically since industrial revolution (Fig. 38.4A)
i. burning tons of fossil fuel and wood removed by deforestation
1. before 1850 – CO2 was ~274 ppm
2. 1958 – accurate measurements first made (Hawaii) – 316ppm
3. Today – 370 ppm (17% increase from 1958)
d. CO2 is one of several greenhouse gases (molecules that absorb IR – infrared)
i. slows escape of IR from Earth
1. atmosphere warms = greenhouse effect (Fig. 38.4B)
e. Other greenhouse gases
i. methane
ii. nitrous oxide N2O
1. both increasing in atmosphere from fossil fuel combustion,
industry and agriculture
f. Greenhouse effect is essential for life
i. without CO2, average Earth temp would be -18C
g. Climatologist predict at present greenhouse gas emission, average Earth temp in
next 50-100 years will increase 2 to 3 degrees C.
i. As temp increases, soil bacteria will increases and more CO2 and
methane will be released (positive feedback)
ii. Increase of 5C by 2100 is possible (Fig. 38.4C)
h. Consequences of global warming?
i. 2 degree shift would be enough to melt polar ice caps
1. sea level rises
2. end of 21st century – flood coastal areas that are environemental
sensitive or heavily populated (NY, Miami, LA underwater)
ii. may change global weather patterns
1. grain belts of US and Asia may become much drier and unable to
support crops
2. forested areas could become deserts
3. habitats will be altered
i. Some scientists and business leaders:
i. want more data before we do anything (sounds a lot like the detergent
companies)
ii. point out that Earth has a long history of climate change not caused by
humans
iii. other state the increased cloud cover and smoke from burning fossil fuels
will lead to a decrease in Earths temp
j. What is being done?
i. Kyoto protocol
1. 165 countries have signed
a. not US
2. requires industrialized countries to limit and cut emissions
ii. reduce destruction of forest, replant destroyed areas
iii. there needs to be an acceptance of life style change
1. reduce, reuse, recycle
2. conserve energy at home
3. use bikes, walk, etc…
iv. Develop alternative energy
1. solar
2. wind
3. geothermal
6. Some locations n biosphere are especially rich in biodiversity
a. tropical habitats generally support larger numbers of species
i. Fig. 38.5A
ii. climate is seen as the major reason
iii. greatest solar energy and water
1. results in large and diverse plant community
a. which supports a large and diverse animal community
iv. Longer growing season
1. more time for speciation to occur
v. many temperate and polar regions have had to “start over” many times
1. glaciation events
b. biodiversity hot spots
i. relatively small areas with
1. exceptional concentration of species
2. large # of endangered and threatened species
ii. many species are endemic species
1. found nowhere else
iii. cover 1.5% of Earth’s land
iv. home to 1/3 of all species of plants and animals!
v. certain aquatic ecosystems (certain rivers and reefs) are also hot spots
vi. 90% of habitat has been lost in 1/3 of hotspots to humans and it
continues
1. result: predicted that ½ of species will be lost here (10-15 years)
vii. these areas are high on the protection list
1. biggest bang for the buck
2. but we still need to mind everywhere else
viii. It is a challenge to presereve organisms that are concentrated
1. monarch butterfly example
2. Loggerhead turtles
7. There are two approaches to studying endangered populations
a. endangered species
i. defined by the US Endangered Species Act (ESA)
ii. one that is in danger of extinction throughout all or a significant portion
of its range
b. threatened species
i. those that are likely to become endangered in the foreseeable future
c. Very difficult to determine is a species is on brink of distinction
i. look at reproductive success and habitat available
d. fragmented populations
i. those populations isolated by humans
1. generates subpopulations
a. reduces overall size of population
b. reduces gene flow
ii. Fig 38.6A – Mount Hood National Forest (NW Oregon)
1. bare patches were logged
iii. Northern spotted owl
1. inhabits coniferous forests of the US pacific NW (Fig. 38.6B)
2. populations were fragmented and declined when the forests were
logged
e. small-population approach
i. a small population may enter a spiral toward smaller and smaller size and
eventually extinction
1. why? loss of genetic variation due to inbreeding and genetic drift
2. need variation to handle environmental challenges
ii. Treatment
1. bring in individuals from other populations
2. maintain sufficient habitat to support minimum viable population
size
f. declining population approach
i. proactive strategy for detecting, diagnosing, and halting population
decline
ii. must determine causes of decline
iii. steps
1. confirm species is in decline
2. study species natural history to determine environmental
requirements
3. determine all possible causes of decline
4. test causes, most likely one first (remove cause in test population
and see what happens)
5. apply results to management of species
8. Identifying critical habitat factors is a central goal in conservation research
a. Red-cockaded woodpecker – illustrating the declining-population approach
i. endangered, endemic species found in South Eastern US
ii. requires mature pine forests
1. preferably dominated by long-leaf pine (Pinus palustris)
2. drills its holes in these living trees for nests
a. drills other holes around main one which ooze resin
(seems to keep certain predators away)
iii. requires low growth of plants beneath trees (Fig. 38.7B)
1. fires have always swept through pines keeping undergrowth low
2. breeding birds leave nest when surrounding vegetation is too
thick (higher than 15feet)
a. birds need a clear path of flight
iv. recovery of woodpecker to sustainable size required knowing and
providing these factors
1. make sure longlead pines available
2. controlled fires to keep undergrowth low
v. Also found that excavating nest cavities in pines in unoccupied areas
sped up spreading to new territories
9. Increased fragmentation threatens many populations: A case study
a. Habitat fragmentation
b. Bull trous (Salvelinus confluentus) (Fig. 38.8A)
i. endangered
ii. inhabits lakes, rivers, and mountain streams in NW Canada and US
including Alaska
iii. requires
1. cold, fast flowing streams with pebble-covered bottoms and little
or no silt for breeding sites and egg laying (Fig. 38.8B)
iv. Figure 38.8C
1. S3 and S4 – maintained gene flow to S1 and S2
2. S2 most isolated – located above a region where stream tends to
dry up during many summers
a. during wet years some S3 used the S2 area to breed
3. Alterations
a. hydroelectric dams
b. logging
c. road building
d. mining
i. all further fragmented bull trout populations
ii. reduced size and connectedness of
subpopulations
iii. S1 isolated by mining – release toxix chemicals
in stream
iv. S2 even more isolated – logging and roads leave
stream even more dry than before – both have
also increased silt in water and some breeding
grounds were lost
v. S3 reduced by mining, logging, and roads
vi. s4 split to s4 and s5 – hydroelectric dam
vii. S4 can’t easily make it to breeding grounds
viii. S5 cut-off and can’t access historic breeding
grounds
v. Population viability analysis (PVA)
1. computer simulation using all available data
10. Sustaining ecosystems and landscapes is a conservation priority
a. in the past, conservation biologists focused on a single species
b. today, they focus on conserving communities or whole landscapes
c. ecological landscapes
i. interacting ecosystems
1. forest, adjacent fields, wetlands, streams, etc…
d. Landscape ecology
i. application of ecological principles to the study of human land-use
patterns
ii. goal:
1. make biodiversity conservation a part of land-use
2. must understand community and ecosystem ecology as well as
human population dynamics and economics
e. Gap analysis
i. Figure 38.9A
ii. overlay of many maps showing range of species, protected areas, etc…
iii. Areas that are vital for a species may not be protected
1. these maps show this clearly
iv. need to determine areas that humans can occupy such that they are
compatible with local species
11. Edges and corridors can strongly influence landscape biodiversity
a. edges (boundaries) between ecosystems (Fir. 38.10A)
i. Ex. Australia – dry forest meets rocky area with grassy lands and a flatgrass covered lakeshore
ii. edges have their own sets of conditions
1. ex. forest edge more susceptible to wind damage
2. therefore they usually have their own communities of organisms
3. some organisms need the resources from both areas (so they live
at edge)
b. Movement corridor – Narrow strips or series of small clumps of quality habitat
connecting isolated patches
i. Fig. 38.10 Underpass serving as a movement corridor for Florida
panthers
ii. Key deer underpasses
iii. promote dispersal and reduce inbreeding
iv. can also be harmful
1. spread of disease
12. Restoring degraded habitats is a developing science
a. some areas we alter or degrade are eventually abandoned by us
b. oil spills
c. restoration ecology
i. use ecological principles to return degraded ecosystems to conditions as
similar as possible to original
ii. bioremediation
1. key strategy in restoration ecology
2. use organisms (usually prokaryotes, fungi, plants) to detoxify
polluted ecosystems
a. pseudomonas bacteria has been used to clean up oil
spills on beaches
b. lichens and plants to concentrate mining wastes
i. Trapelia involuta – grows on soil polluted with
Uranium dust from mining (Fig. 38.11A)
ii. concentrates uranium in dark brown structures
c. plants to extract toxic zinc, nickel, lead and cadmium
from soil
iii. augmentation of ecosystem processes – second key strategy
1. must find out if a chemical nutrient that has been removed from
area is limiting recovery
a. soils in tropical rainforests become nutrient-deficient in
less than 5 years of farming
b. plants legumes that thrive in nitrogen-poor soil
(nitrogen-fixing bacteria).
i. provides organic material (nitrogen) for native
species (Fig. 38.11B – Albizzia)
iv. It is easy to take apart an ecosystem or automobile engine. Putting it back
together is not straight forward though.
v. As complementary strategies for restoration ecology, contrast the use of
organisms in bioremediation versus augmentation for altering the
chemical composition of a degraded ecosystem.
13. Sustainable development is an ultimate goal
a. in numbers, geographic range, and capacity to alter biosphere – humans are one
of the most successful species
b. “With great power comes great responsibility”
i. stewardship of the environment
1. all species are our great cousins
c. Problems
i. increasing degradation of ecosystems
ii. fragmentation of habitats
iii. loss of biodiversity
d. Questions
i. What is the best way to manage Earth’s resources?
ii. Which habitat areas to we focus our energy on and are most practical to
protect and manage?
e. Sustainable development
i. the long-term prosperity of human societies and the ecosystems that
support them
ii. we need to work towards changing our values
1. reduce our orientation toward short term personal gain
f. grey-headed flying fox (cover of book)
i. symbolized the biodiversity crisis
ii. habitat destruction
iii. human killing (they eat fruit crops)
iv. population declined 75% in past 25 years
v. may soon be endangered
vi. important pollinator and for seed dispersal in forest
g. Humans must work toward long-term sustainability
h. we are most likely to save what we appreciate and to appreciate what we
understand…biology