Ex situ conservation strategies
14.1 Takhi or Przewalski’s horse is extinct in the wild
extinct in the wild –
individuals of a
species remain alive
only in captivity
Ex Takhi is no
longer found in
their native
Mongolia but is
doing well after
reintroduction into a
national park
14.2 Model of biodiversity conservation showing in situ and ex situ conservation efforts
-ex situ and in situ conservation are complementary strategies and ex-situ
populations can be released periodically in the wild to augment in situ
conservation efforts
Ex situ conservation efforts have certain basic limitations when compared
with in situ conservation
1) Cost is often high
2) population size and genetic variability
-will usually be much smaller in ex situ conservation than is needed to
prevent genetic drift
-captive populations are often extremely inbred Figure 14.5
-some species breed easily in captivity and surplus animals must be dealt
with
Figure 14.5 Captive populations were often extensively inbred.
Ex situ conservation efforts have certain basic limitations when compared
with in situ conservation
3) Adaptation and learning skills
-adapt to captive environment and may not function well in situ
-may be ignorant of their natural environment or may not have learned
from parents
4) continuity
-requires a continuous supply funds and institutional policies
Ex. break-up of the former Soviet Union left many zoos without funds
5) concentration
-if ex situ site is destroyed by catastrophe (fire, hurricane, or epidemic),
there is a possibility that an entire population of an endangered species
could be destroyed
-if they breed and do well, what is to be done with surplus organisms
Zoos and Aquaria
-2000 in the world (House 3000 mammal, bird, and reptile species and
about 600,000 individual fish)
-have decreased their collections in the wild by maintaining breeding
colonies and sharing animals Figure 14.7
Table 14.1
Figure 14.3
Figure 14.7 Aquariums educate people and have breding programs
14.3( A) Visitors to a zoo in Japan enjoy emperor penguins. (B) Dental surgery on a captive Asian elephant
Zoos use a number of specialized techniques to maintain breeding
colonies
1) cross fostering/artificial incubation
-foster parents are used to raise offspring from another species unable to
raise their own young
Ex bald eagles produce one clutch of eggs per year. If some of the eggs
are removed and put under birds of a related species, the bald eagle
will produce a second clutch
2) Artificial insemination (AI)
Ex . Successful technique used for giant pandas Box 14.1
3) Embryo transfer
Ex. rare bongo embryos transferred to the common and related eland
Figure 14.4
4) Reversing extinction with new genetic technology Read Box 14.2
Box 14.1 Giant pandas reproduced successfully in captivity due to artificial insemination
Box 14.1 Pandas were once widely found in southeast. China
14.4 This bongo calf was produced by embryo transfer using an eland as a surrogate mother
In 2003, an extinct ibex was cloned, but was deformed and died after birth from a surrogate goat.
Breeds of domestic animals and crop varieties or cultivars are also
important targets for ex situ conservation
-of the 3831 breeds of ass, water buffalo, cattle, goat, horse, pig, and
sheep that existed during the last 100 years, 16% are extinct and an
additional 23% are rare and in danger of extinction—About 1/3 breeds
of livestock are extinct or endangered
Figure 14.6
-
14.6 Soay sheep are a relict breed of sheep living in the St. Kilda Islands
Botanic Gardens and Arboreta
-1600 botanical gardens and arboreta (House about 80,000 species (30%
world's flora)) Figures 14.8
-plants are easier to maintain in controlled conditions:
1) adequate population samples can often be established from seeds,
cuttings, rhizomes, and tissue culture
2) most have similar basic needs for light, water, and minerals that can be
readily supplied in greenhouses and gardens
3) often can be grown at high densities
4) most reproduce readily and can be manipulated by hand pollination
Figure 14.8 Botanical gardens (Gardens by the Bay in Singapore) attract and educate visitors.
Seed banks
-collections of seeds from wild and cultivated plants
-focused on about 100 plant species that make up >90% of human food
consumption and includes about two million collections
-often stored in cold, dry conditions that slow metabolism or they are
frozen as low as 196 degrees Celsius Ex. National Center for Genetic
Resources Preservation (formerly USDA National Seed Storage
Laboratory) at Fort Collins, Colorado
Figure 14.9
14.9 (A) The National Center for Genetic Resources Preservation; (B) Seeds are sorted, cataloged,
and (C) stored in liquid nitrogen to preserve genetic diversity (D).
About 96% of the raw genetic variation necessary for modern agriculture
comes from developing countries (India, Ethiopia, Peru, Mexico,
Indonesia, and China), yet breeding programs take place in North
America and Europe Figure 14.10
-like animal breeds, many common crops are threatened by low genetic
diversity Box 14.3 Seed savers and crop varieties (cultivars)
-in the past, these resources were collected for free and seed companies
made huge profits. This inequity was addressed at the International
Convention on Biological Diversity (started in 1993).
14.10 Crop species show high genetic diversity in certain areas of the world
Box 14.3 The Seed Savers Exchange produces heirloom varieties of crop plants
International Convention on Biological Diversity made the following
recomendations:
1) Countries have a right to control access to their biological diversity
-should be paid for its use
-collectors should get permission from the host country, local community,
and the landowner
2) Countries have a responsibility to inventory biological diversity and
protect it
3) As much as possible, research, breeding, and production should take
place in the countries where the biological resources occur
Ex. Merck Pharmaceuticals and Costa Rica signed an agreement where
the country got one million to allow the company to screen drugs and
gets five million for any new drug that is developed
Seed Sampling Strategies to Consider: