Biodiversity and conservation

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Biodiversity and conservation

• Genetic diversity within species variation (e.g
  corn Zea mays in North vs. Central America)
• Species diversity species richness
• Ecosystem diversity variety of habitats

2
Basic questions in biodiversity researchfor any
plot of land (or patch of sea)

• Why does it contain this many plant and animal
  species, and not more, or less?
• Why is species Y common and species X rare?

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The standard answer

• it depends on the of available niches, OR
  it depends on.
• Availability of resources / intensity of
  competition, predation, infection, etc.

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The neutral answer

• It depends on chance!
• Diversity f(immigration, extinction, evolution)
• Consider the example of a patch of tropical
  forest in Panama - how many tree species will it
  contain?

Hubbell, S.P. 2001. The unified neutral theory
of biodiversity and biogeography, Princeton U.P.
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Tree diversity of a Panamanian forest
How many treescan island sustain?
Immigrationrate?
How diverse is the forest reservoir?
How fast are newtree species evolving?
Satellite image of Barro Colorado Island, Panama
(Image NASA)Map source www.geographic.org,
used with permission
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Testing Hubbells model on Barro Colorado
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Patterns of biodiversity
1. Latitudinal gradient in species richness
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Global species richness(composite index)
Hotspots
diversity gradient
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Biodiversity as a function of latitude(North and
Central America)
Birds Beetles
Ants
Labrador 81 Labrador 169
Alaska 7 New York 195 Massachusetts
2000 Iowa 73 Guatemala 469
Florida 4000 Trinidad 134
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North America
S. Florida
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Diversity of North American tree species
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Biodiversity gradients (tree species) in
temperate coastal evergreen forests
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Biodiversity gradients in the temperate coastal
evergreen forest of North America
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Ranges of newts andsalamandersin
thetemperateevergreenforests of western North
America
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Patterns of biodiversity
2. Altitudinal gradient
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Altitudinal gradientsin bird species diversity
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Species richness andtemperature range
Birds
Mammals
Snails
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Biodiversity and moisture availability
Ants
Rodents
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Species richness and productivity
N. American data
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Habitat complexity(e.g. of forest strata)
Low complexity (single stratum)
High complexity (multi-strata)
approx. equivalent tree species richness
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Species diversity and habitat complexity
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Conservation of biodiversity

• Are we engaged in a biotic holocaust?
• How many species are currently being lost?
• Why is biodiversity important?
• How can species conservation be best achieved?

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Conservation of biodiversity
Extinction - the demise (locally or globally) of
a species Endangered species - a species or
subspecies that is at risk of extinction
throughout all or part of its range Threatened
(or vulnerable) species - possibly at risk of
extinction in the near future
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Species under threat endemics(e.g. Hawaiian
honeycreepers)

• Generally very small populations
• At risk from habitat loss and introduction of
  aliens (particularly predators)

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Island endemics under threat

• 4 000 endemic or native plant and animal species
  live in the archipelago (cf. 100 in British
  Isles).

e.g. Canary Islands
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Canary Islands endemics

• On average a new species invades every 17 days a
  new serious pest invades on average every 6
  months.
• Most problematical pests are the Barbary ground
  squirrel, the Corsican mouflon, and most
  recently, a beetle (picudo rojo), that feeds on
  native palms.
• 20 endemics are considered endangered several
  have lt100 individuals left.

Source New York Times, Aug. 29, 2006, p. A4
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Species under threat widespread species and
range collapse
Population collapse is generally accompanied by
(or caused by) range collapse (e.g. American
bison giant panda black-footed ferret). In
most cases marginal populations, which may have
distinctive genomes, are the only survivors.
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What is the current extinction rate?
Very difficult to demonstrate that a species is
truly extinct (e.g. the ivory-billed woodpecker
of the SE USA) so estimates of modern extinction
rates vary widely. Colinvaux notes that the
rate is incalculable Myers (1979) says we
have no way of knowing let alone an
approximate guess.
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Biotic holocaust?
Extreme estimates of current annual species
loss 40,000 (Myers, 1979) widely cited in
1980-90s (e.g. by Al Gore) 27,000 - 100,000
(Wilson, 1992) 20 of all species gone by
2020! 250,000 (Ehrlich, cited in Stork,
1997) all species gone by
2010-2025!
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Sources for previous estimates

• Myers, N. 1979. The Sinking Ark. Pergamon Press.
• Wilson, E.O. 1992. The Diversity of Life.
• Stork, N.E. in Wilson, E.O. et al., 1997.
  Biodiversity, pp. 41-68.

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Alternative estimates

• A much lower estimate of 1400 extinctions per yr
  (0.7 in 50 years) was derived by Lomborg
  (1998). This is still 1500 times greater than
  estimated background rates from geological data

Lomborg (1998) The Skeptical Environmentalist
Measuring the Real State of the World. Cambridge
U.P.
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Modern extinctions a fishy example
In the Nearctic realm 1033 species of fish are
known to have inhabited streams and lakes in
recent historic times. Of these, 27 (3) are
thought to be extinct, and 277 (28) are
endangered or vulnerable. The factors that
caused these declines are habitat destruction,
introduction of alien species, pollution,
hybridization and over-harvesting.
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Forest fragmentationWisconsin (1830-1950).
Area 100 km2
1830
1882
shaded forest white agriculture(prairie in
1830)
1950
1902
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Forest fragmentation Bahia (coastal S. Brazil)
dark forest light agriculture
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Habitat loss and extinction model predictions
Galapagos
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How many species have gone extinct as a result of
diminished habitat area?

• 99 of primary forest of eastern US lost from
  1800-2000 only one bird species extinct
  (Simberloff)
• 88 of forest along Atlantic coast of Brazil
  cleared in same period none of the 171 animals
  have gone extinct (Brazilian Soc. Zoologists).
• See Lombock (1998) for discussion of these and
  other examples

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Slow relaxation to a new equilibrium with
changing island area
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Forest fragmentation Rondonia, Brazil
1975
1992
100 km2
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Forest fragmentation experiment, Amazonas
Thomas Lovejoy, Smithsonian Institute
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Mammals in rain forest fragments
These results are from trapping experiments and
do not include bats and nocturnal canopy species.
In intact forest 9 spp. were common in 10 ha
fragments, only one in 1 ha fragments, all
mammals were uncommon.
Data from Lovejoy et al. (1984) in Nitecki,
M.H. Extinctions. Univ. Chicago Press
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Why conserve?

• Intrinsic and aesthetic value of species
  (mosquitoes?)
• Economic value (gene pools, untapped riches)

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The rewards of conservation

Global data Source New York Times Aug. 29,
2006 p. D3
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Some of the saved
California condor
Mauritius parakeet
Mauritius kestrel
Chatham Island taiko Lears macaw
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Species conservation the task ahead
The threat ahead is massive. Its like weve
ridden our first wave on a surfboard and feel
good about it, but look back and theres a
tsunami coming in. Dr. Stuart Pimm, a
conservation ecologist at Duke University, quoted
in the New York Times, Aug 29, 2006, p. D3.
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How conserve?

• Zoos and captive breeding (e.g. condors)
• Predator control (e.g. Chatham Is. taiko)
• Habitat preservation / restoration(e.g.
  Mauritius parakeet) for its own sake, or combined
  with sustainable economic diversification (e.g.
  turtle harvesting vs. cattle farming on the
  Amazon floodplain the former retains the galeria
  forest).
• Compensatione.g. ranchers in Wyoming for cattle
  killed by wolves farmers in Bahia, Brazil
  for corn eaten by Lears parrot

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Predator control
Pre

• Eradication scorecard ( island removals)
• e.g. mammals (all alien) have been eradicated on
  68 of the 168 islands in New Zealand 41
  introduced mammal populations have been
  eradicated on 27 islands off the Pacific coast of
  Mexico. Native plant and animal species have
  rebounded following eradications.
• Source Krajick. K. 2005. Science 310, p.
  1410-1413.

Post
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Predator control -gt habitat restoration
goat exclosure
Pre

• e.g. removal of goats on Santiago Island
  (Galapagos) leads to recovery of native
  vegetation.
• Source Krajick. K. 2005. Science 310, p.
  1410-1413.

Post
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Species need space!How big a fragment would
conserve 95 of the species over a 50-yr
period?Ans. 100,000 ha. 100 km x 100km!
Based on surveys of avifauna in Amazonas
New Scientist 8-14 November, 2003, p.15
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Applications of island biogeography theory to
habitat conservation
Good choice Poor choice
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Corridors and conservation

• Experiment to determine effects of corridors
  between open patches on plant biodiversity in
  longleaf pine (Pinus palustris) forest in South
  Carolina. Patches created in 2000.

Source Dametsch, E. et al., 2006. Science 313,
1284 - 1286
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Corridor experiment results
Connected patches have 20 more plant spp. than
unconnected patches few weedy exotics
Source Dametsch, E. et al., 2006. Science 313,
1284 - 1286
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Do the ecological reserves in BC display these
principles?
Goosegrass Creek (Kootenays) E.R. 55
Haynes Lease (Okanagan) E.R. 100
1 km
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Future challenges climate change
In alpine areas timberline is creeping upwards by
a few meters per decade alpine species are
therefore occupying smaller and smaller refuges.
In NZ, for example, it is predicted that 80 of
alpine islands will be wiped out in this century,
and 200-300 alpine plant species will go
extinct. How do we develop conservation
strategies that are nimble enough to deal with
climate change? Halloy, S.R.P., and Mark, A.F.
2003. Arctic, Antarctic, and Alpine Research,
35, 248-254.
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A more local example of this problem.
1930
Subalpine rodents, (e.g. Zapus spp.) are now
found 700m higher than they were a century ago
the altitudinal ranges of Alpine chipmunks and
pikas have shrunk correspondingly
Pika (Ochotona princeps)
Pacific jumping mouse (Zapus trinotatus)
2006
Lassen Peak, northern California
Graphics NY Times (Nov. 7, 2006) Wikipedia