Download Lecture 8 Conservation

Conservation of BIODIVERSITY
• Biodiversity can be assessed and conserved
at several levels:
– Molecular/Genetic (rare genes and alleles)
– Population
– Species
– Assemblage
– Ecosystem
– Global
BIODIVERSITY
• Molecular/genetic is the level at which natural
selection and evolution occurs
– Loss of genetic diversity impedes “adaptability”
– Loss of populations similarly handicaps a species’
chance of surviving uncertain circumstances in the
future.
Loss of Biodiversity
• Many reasons, often confounded
• Historic extinctions
– p/t extinction (250 mya)
– k/t extinction (65 mya)
• Holocene extinctions: 10,000 years ago to
present
EXTINCTION
• “Given evolutionary turnover, extinction is
inevitable. Like death for the individual, nothing
is more certain in the future of a species than its
ultimate removal.”
P. Martin and R. G.Klein IN
Quarternary Extinctions:
A Prehistoric Revolution
1984
Current Extinctions
• Current biodiversity
crisis
– Human mediated
• Correlated with Homo
sapiens expanding range
and density
• Ever-quickening rate of
extinctions
– Has led to increase of
1000 – 10,000% above
the rate of background
extinctions
Current Extinctions
• Current biodiversity crisis
– Before 1800
• Islands: many unique island assemblages decimated
– Gigantic flightless birds
– Gigantic tortoises
– Dwarf elephants/hippos
• Continents: severe extinctions among megafauna
– North american mammals
– South american marsupials
Current Extinctions
• After 1800:
– Extinctions on islands continue
• Birds, endemic mammals, reptiles
– Extinctions among smaller continental fauna
increase in pace
• Habitat destruction/conversion
• Unregulated trade
• Bounties on “undesirable” species
Conservation of Herpetofauna
• Amphibians and reptiles face many of the same
threats that face other non-human organisms:
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–
–
–
–
–
–
Habitat modification and destruction
Introduction of exotic species
Pollution
Commercial exploitation
Traditional and modern medicine
Pets
Research and teaching
Traffic mortality
Persecution
Habitat modification and
destruction
• The most significant problem
• Absolutely correlated with increasing human population
size
• Extensive and worldwide; all biomes, but tropical
rainforests hit hardest
• “At the current rate of deforestation, within 30 years
there will remain neither extensive tropical forests, nor
their endemic amphibian and reptile fauna”
•
from Pough et al. 2001
1) Habitat destruction
a) Deforestation of
tropical forests
b) Destruction of coral
reef ecosystems
c) Wetland alteration for
development
d) Temperate regions
altered for agriculture
e) Habitat fragmentation
Habitat modification and
destruction
• >95% of central California’s marshes were
drained and converted before 1900.
– Rana aurora draytonii (California red-legged
frog), once California’s most common frog, all
but disappeared
– Thamnophis gigas (giant garter snake), slowly
declined, now almost extinct
Habitat
destruction:
Habitat modification and
destruction
• In Florida, habitat conversion may have
been responsible for a decline in
Ambystoma cingulatum
– 200-300 per night between 1970-1972
– <1 per night after habitat conversion in 19901992
• Anniella pulchra declines correlated with
introduced plant spp.
Habitat modification and
destruction
• Often works in tandem with weedy or introduced
species
– In Arizona, alteration of hydrologic regime enables
crayfish, game fish and bullfrogs to persist where they
otherwise couldn’t
– Argentine ants expanding range into U.S. deserts by
utilizing lawns and other landscaping features.
Decline in Phrynosoma coronatum and P. cornutum
correlated with spread of fire ants
Habitat Fragmentation
Introduced species
• Declines (and extinctions) in many island species
attributable to introduced exotics
– Dogs and cats: Cyclura carinata in Caicos Islands
– Cats: Brachylophus iguanas in the South Pacific
– Goats: Crotalus unicolor on Aruba Island
– Sheep, goats, rats: Sphenodon in New Zealand
– Introduced fish in California’s high elevation lakes:
Rana muscosa and Thamnophis spp.
– Fire ants impacting Texas horned lizard (P. cornutum)
and Coast horned lizard (P. coronutum)
– Small Indian Mongoose: 7 species of reptile and
amphibian from Puerto Rico
Introduced Species: Herps
• Bullfrog: western U.S, C. and S. America,
England, France, Asia, many other places
• Boiga irregularis: Guam
– Wiping out geckos and skinks (all birds, bats,
many small mammals already gone)
• Introduced herp assemblages at ports-ofcall
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Introduced Herps by State
(Simberloff et al. 1996)
40
35
30
25
20
15
10
5
0
Pollution
– Acid rain:
• Ambystoma tigrinum in the Rocky Mountains
• Bufo calamita in Britain
– Selenium/agriculture runoff:
• Thamnophis gigas in California’s Central Valley
– Pesticide wafting: Rana and Bufo spp. in the
Sierra Nevada
Pollution
• Solid Waste: marine turtles
• PCB’s: effect endocrine systems of aquatic
frogs and turtles
• Acidic runoff from mines: Rana
tarahumarae in Arizona
Pollution
• Biomagnification
– The increase in the
concentration of
bioaccumulated toxic
chemicals in organisms higher
on the food chain due to
preferential storage of the toxic
chemical in edible body parts
• There is abundant evidence
that some carnivores at the
ends of longer food chains
(crocodiles, alligators,
snakes) suffered serious
declines in fecundity and
hence in population size
because of this phenomenon
Anthropogenic eutrophication
Directly Impacts aquatic turtle, alligator, snake populations
• Nutrients released, triggering
chain of events
Over-harvesting
Commercial collecting: Food
• Frogs: U.S., Europe, SE
Aisa, Africa
– Late 1800’s: extreme
decline in availability
of California redlegged frogs partially
attributable to
collecting pressure
– 1976- 2.5 million KG
frog legs imported into
U.S.
– Annual consumption in
France: 2.7-3.6 million
KG frog legs
Commercial collecting: Food
• Declines in Iguana iguana and Ctenosaura
similis
• Monitors, pythons, tortoises, sea turtles
Commercial collecting: SE
Asian Turtle Crisis
• 12 million turtles sold per year in China’s food
markets
• China’s and Vietnam’s turtle populations
depleted: now imported from all around the
world, including the U.S.
• Many of China’s turtles were only known from
the food markets: no natural history or
distribution information available
• Many of those turtles have not been seen in
markets for years
Commercial collecting: SE
Asian Turtle Crisis
• Low reproductive rate
combined with great
importance placed on
age of turtle has dire
consequences for
natural populations
The bycatch problem:
Commercial exploitation for
skins
• Civil war: Thousands of American alligators
killed for skins
• Legal importation of 304,189 pairs of Boa
constrictor boots and 176,204 pairs of Python
reticulatus into U.S in 1981 (all harvested from
the wild)
• >1 million crocodile skins per year from 1980 to
1985
• >12 million tegu skins during same period
Commercial exploitation for
skins
• Most species harvested
for skins are long-lived
• Until recently all have
been harvested from the
wild
• Some progress being
made to establish farms
for commercially
important species
• The vast majority of skins
are still collected from
wild animals
Traditional and Modern
Medicine
• Bufo alvarius and Phyllomedusa bicolor used in
shamanistic rituals
• Snake venom used in antivenin and
anticoagulant drugs
• Batrachotoxin used in research to probe for
voltage-sensitive sodium channels
• Rattlesnake “shaker muscle” used in physiology
studies
Pets
• In Florida, 119,831 herps removed from the wild
between 1990-1992
• 74,000 box turtles exported as pets between
1992-1994
• Habitat destruction often accompanies collecting
for pets
• Very little record kept regarding #’s of animals
collected as pets from the wild
Pet trade
• “In the United States, the retail trade in live reptiles,
amphibians, and related products is worth a
minimum of two billion dollars annually” -Joseph Franke
MS and Teresa Telecky
• If you wish a reptile as pet make sure you are
dealing with dealer that can be trusted. Find out
where the animals come from
Research
• For scientific collections: usually very
small impact
• For bio and medical training
– In early 1970’s 15 million leopard frogs
collected from the wild
– 1970-1971: 10 tons of leopard frogs collected
from one western state
– 250 lbs collected 4 years later
Traffic Mortality – Roadkill!
Increases mortality of individuals and also decreases gene flow
Matthew Aresco, a 4th year PhD student in
the Department of Biological Science at
Florida State University built a temporary
fence to divert turtles (and other wildlife, >
41 species) away from the road and into a
culvert that joined the two lakes. Over the
past 2.5 years he has monitored the
temporary fence at least twice per day and
maintained it at his personal expense (at
least $2000 out-of-pocket).
Species such as frogs, snapping turtles,
large softshell turtles, alligators, and most
mammals can climb over this low fence.
The fence only covers 2000' - 3000' of the
"killing zone".
Permanent guidewall and culvert system
recently constructed at Paynes Prairie on
US Highway 441 south of Gainesville,
Florida.
Persecution
http://www.rattlesnakeroundup.com/index.html
Rattlesnake Roundups
• Occur in several
southeastern states
• Run by either non-profit
Jaycee’s clubs or forprofit companies
• 5 Crotalus spp. are
targets; other harmless
snakes taken
incidentally
• Collecting methods
often unethical
•
Rattlesnake Roundups
Snakes often stockpiled by
collectors for long periods of time
At roundup, measured, weighed,
poked fun at, submitted to stresses
and injuries
Often skinned alive, in public
Rattlesnake Roundups
• Justified as a way to “educate
the public”
• Also, to collect venom for
research/antivenin industry
• Claims that there’s no effect,
or a beneficial effect, on native
populations
• However, effects of roundups
on wild populations largely
undocumented
Rattlesnake roundups
• The only organized events in the U.S. in
which profits are made off the unregulated
harvest of a vertebrate group
•
• WHY?
Declining Amphibians-History
• In 1989, at an international
herp conference, workers
expressed concern that
their study organisms
weren’t as common as
they once were
Declining Amphibians• Species extinctions and population declines
around the world prior to 1990
• Subsequent studies have documented declines
as they happen
• Few patterns emerged, other than that the most
precipitous declines were among Anurans
Declining Amphibians• Many of the same causes found for other
biodiversity losses:
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–
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Habitat loss
Pollution, acid rain
Exotic species
Collecting
Amphibian Decline:
What’s happening to all the frogs?
http://www.amphibiaweb.org/aw/declines/extinct.html#declines
Evidence of a complex problem
Two specimens of deformed
frogs (Rana pipiens) from
Vermont with missing parts of
their hind limbs
Deformed Pacific Treefrog,
Hyla regilla, from Oregon,
with supernumerary hind
limbs
What’s causing these
Deformities/Declines?
1) predation and/or cannibalism?
predation and/or
cannibalism, whereby
some predator (even other
tadpoles) may be nipping
the limbs off of tadpoles
2) CHEMICAL POLLUTANTS?
Retinoic Acid:
Main effects of RA on amphibian limbsMethoprene?
Atrazine:
Diazinon:
Suppresses cholinesterase (nervous system)
Hayes found hermaphroditism in frogs at levels
as low as 0.1 ppb. Even with today's limits, levels
of 40 ppb atrazine have been measured in rain
and spring water in parts of the Midwest, while
atrazine in agricultural runoff can be present at
several parts per million.
Ribeiroia cercariae
3) Parasites?
 http://www.jcu.edu.au/school/phtm/
PHTM/frogs/ampdis.htm
 Ribeiroia ondatrae
(trematodes)
Johnson et al. exposed tadpole Pacific tree frog (Hyla regilla) to the cercaria of
a trematode parasite, Ribeiroia. They found that as the number of parasites
per tadpoles rises, the percentage of abnormalities increases while survival
decreases.
http://news-info.wustl.edu/tips/page/normal/961.html
Parasites cont.
Spirometra erinacei (tapeworm)
Pathogens?
 Chytrid Fungus (Batrachochytrium
dendrobatidis)
 Mucor amphibiorum
 Infected frogs and toads have
fungi disseminated through their
internal organs and skin
Infected frogs may:
• have discoloured skin
• be sloughing, or peeling, on
the outside layers of its skin.
This can vary from obvious
peeling of skin (particularly
on the feet), to a roughness
of the frog's skin that you
can barely see
• sit out in the open, not
protecting itself by hiding
4) Climate Change?
Increase in temperature seems to be
impacting amphibian populations
5) Habitat Loss
7) Exotic species
• Bullfrog
UV Radiation
• UVB Radiation?
– Blaustein vs Adams
and Corn
Laws and Regulations: CITES
• Convention on International Trade in
Endangered Species of Wild Fauna and Flora
established by IUCN in 1973
– Regulates international trade in species of concern
– Mandates that international trade in endangered
species is unlawful
– Nearly 600 species of amphibian and reptile are
covered
Laws and Regulations: ESA
• Signed into law by Nixon in 1973
– Far-reaching law; protects both domestic and foreign
animals and plants
– Prohibits “take” of species of concern
– Mandates that FWS and NMFS monitor populations
and develop a recovery strategy
Laws and Regulations: ESA
listing process
• Anyone can petition to list a species
– Must provide sound scientific basis for listing
– FWS or NMFS reviews petition, may conduct
additional research, must make findings according to
predetermined time schedule
– Decision to list or not published in Federal Register,
including basis for decision
Laws and Regulations: ESA
recovery process
• FWS or NMFS drafts a Recovery Plan for the
species in question
– Delineates tasks and criteria needed for the recovery
of a species
– Solicits public and expert comment on draft Recovery
Plan
– Revises draft, issues final recovery plan
• Includes dollar estimates needed for recovery
• Not a binding document
– Species is delisted or downlisted as criteria from
Recovery Plan are met
– Critical habitat may be designated later
ESA: Herp Listing Status
100
99
75
49
50
25
1
0
5
Endangered
EmE
SAT
Threatened
ESA: Insular and Continental
Amphibians and Reptiles
98
100
75
island
continental
marine
48
50
25
8
0
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12
10
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8
6
4
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ESA: Herps with Recovery Plans
123
125
100
75
recovery plans
listed species
50
31
25
32
13
0
amphibians (42%)
reptiles (26%)
ESA: Herps with Critical Habitat
134
140
120
100
80
Yes
No
60
40
19
20
0
14% w/Critical Habitat
ESA: U. S. Listings of Herps by
Year
10000
Amphibians
Reptiles
All species
100
10
2000
1998
1996
1994
1992
1990
1988
1986
1984
1982
1
1980
# Listed
1000
ESA Listed Amphibians and
Reptiles by Group
45
41
40
37
35
30
24
25
20
15
19
17
14
10
5
0
2
Anura
Urodela
Chelonia
Crocodylia
Rhynchocephalia
Sauria
Serpentes
100
0.
8
0.
9
16
.8
3.
9
0.
4
100
90
80
70
60
50
40
30
20
10
0
95
.8
% of ESA Listed Species by
Group
Anura
Urodela
Chelonia
Crocodylia
Rhyncocephalia
Sauria
Serpentes
Human Population Density &
# ESA Listed Herps
3
Rept. = 0.3426x + 1.3969
R2 = 0.2383
F 1,36 = 11.26, p = 0.002
ln # listed
2.5
2
1.5
Amph.= 0.0453x + 0.5344
R2 = 0.0108
F 1,22 = 0.24, p = 0.63
1
0.5
0
-6
-4
-2
0
ln state population density
2
4
American alligator:
an ESA success story
• American alligator was listed as threatened
under precursuer to ESA in 1967.
• All subsequent “take” was illegal
• Captive breeding and farming “ranches”
proliferated
• Eggs collected in wild, incubated, then released
when hatched
• Alligator recovered, delisted in 1987
• Now subject of 60 million $/ year industry
State laws and herps
• Usually protected by state
game and fish agency
• Funding through sales of
fishing and hunting licenses (PR act and D-J act, respectively)
• Often need fishing or hunting
license to collect
• Often may not collect for sale
• Bag limits, quotas imposed
• States may have ESA-type
legislation
What can I do?
• Adopt a conservation ethic
• Work directly in the area of conservation
– Help conduct research
– Assist with conservation organizations
– Become involved politically
• Educate yourself, family & friends about the importance
of herps in the ecosystem
• Educate yourself, family & friends about the importance
of having better “green” life choices
– Try to have a lifestyle that incorporates sustainable methods
– Support companies that work towards sustainability & are
supportive of the environment
– Elect officials that support environmental policies
Conservation Groups
•
•
•
•
•
Conservation International
The Wildlife Society
Society for Conservation Biology
The Wilderness Society
Center for Biological Diversity
Conservation Journals
•
•
•
•
Conservation Biology
Biological Conservation
Southwest Naturalist
Journal of Wildlife
Management, Wildlife
Society Bulletin
• Chelonian Conservation
and Biology
When it comes to conservation
and all the things of your life keep in mind these
words
I am only one, but I am one.
I cannot do everything, but I can do Something.
I will not let what I cannot do interfere with what I
can do.
Edward Everett Hale