Transcript Ch13 Student Presentation

Three basic approaches used to establish new populations of animals and
plants
1) Reintroduction program
-release of captive-bred or wild-collected individuals in a site within the
historic range of the species
Ex. Reintroduction of gray wolves into Yellowstone, Box 13.1, blackfooted ferrets Fig. 13.1, and kestrels Fig. 13.2
2) Augmentation Program
Box 13.1 A gray wolf in Yellowstone National Park
Box 13.1 Wolves in WY, ID, and MT have been increasing following the reintroductions at
Yellowstone area
13.1 (A) Black-footed ferret born at a captive colony; (B) Ferrets experience the range where they
will be released
13.2 For the first four years of a kestrel reintroduction program all offspring were captive-reared
3) Introduction Program
13.3 California condor chicks raised in captivity are fed by researchers using puppets
Six Considerations for successful programs
Case studies involving reintroduction in animals
1) Kemp's Ridley sea turtles
-collect eggs from beaches in Mexico, hatch and release at PINS
-unsuccessful as many are lost to commercial fishing and laws have been
passed requiring turtle extruders in nets
2) Red Wolves
-successful on wildlife refuge in Northeastern North Carolina but
landowners near the refuge do not want them on their land and
hybridization with abundant coyotes is a major problem
3) New Zealand Kakapo
–largest parrot species in the world that is also flightless, nocturnal, and
solitary. Believed extinct because of introduced mammal predators but
two remaining populations were discovered and wild collected
populations released on offshore islands without predators
4) Big Bend Gambusia
-single spring dried up in 1954. In 1955, the fish was discovered in an
artificial pond. Captive breeding allowed for the introduction of these
fish into artificial ponds and in 1983, it was reintroduced into its
original spring
13.4 Puffins reintroduced on island off Maine’s coast. Were attracted back to mate using decoys
5) Atlantic puffins virtually eliminated due to overharvesting eggs and
meat. 900 chicks reintroduced to island, which now has 101 breeding
pairs
Establishing New Plant Populations
-plant naturally dispersed fruits and seeds to new sites and they will
disperse by anemo-, hydro-, and zoochory
-site selection for new populations is critical and sites for reintroduction
must be as similar as possible to where parent plants are obtained
-plant populations typically fail to establish from seeds, in one study six
species of annual plants were planted at 48 apparently suitable sites
and only one population persisted
Ex. jewelweed (Balsaminaceae-Touch-me-not) Impatiens capensis can be
established from seed Figure 13.5
-conservation biologists may headstart this process with wild-collected or
greenhouse grown plants instead of using seeds Figure 13.6
-even transplants may require fencing to exclude animals, controlled
burns, planting other species to provide shade and litter, and adding
soil minerals
13.5 Sometimes a new plant population can be established by the introduction of seeds
13.6 Seedlings of rare plant species being grown on a greenhouse bench then planted in the wild
Plant Reintroduction Case Studies
1) Mead’s milkweed is a threatened tall-grass prairie species that does
better as juveniles and in burned prairie Figure 13.7
2) Eight rare, New England wildflowers were established at 596 plots in
two sites in Massachusetts using seeds, seedlings, and adult plants by
Drayton and Primack (2012). After two years all eight had at least
15% of the plots with plants. For six species, establishment was
greater using seedlings and adults rather than seeds but 13 years later
none persisted. One, bloodroot (Fig. 13.8), persisted with plants on
25% of plots. DIFFICULT to establish new plant populations and
long term monitoring is required to determine success of
reintroduction.
Figure 13.8 Bloodroot is a perennial wildflower that was a successful reintroduction
13.7 Planted seedling and juvenile Mead’s milkweeds are evaluated in a reintroduction experiment
-
a great book on plant reintroductions is: Falk, D.A., C. M. Miller, and
M. Olwell. (eds.) 1996. Restoring diversity: Strategies for
reintroduction of endangered plants. Washington, D. C.: Island
Press.
- it includes a successful case from
Texas called the Texas Snowbell,
which is a success story involving
private land owners that established
the plant on their ranches using
wild-collected seeds obtained by
rancher J. David Bamberger and
grown at the San Antonio Botanical
Garden
Status of new populations of endangered species
-US Endangered Species Act (ESA) recognizes two categories of
experimental populations:
1) "Experimental Essential"
-considered essential to the survival of an endangered species and are
rigidly protected as naturally occurring populations
2) "Experimental Nonessential"
-not protected under the ESA
Ex. Texas Snowbells and Gray Wolves in Yellowstone so landowners
would be less inclined to oppose reintroduction
-in many cases, proposals are made to compensate for damaging habitats
or eradicating populations of endangered species by creating new
habitat or populations elsewhere = mitigation
-problems with creating these new "habitats" are:
1) reintroduction may not be successful
2) artificial ecosystems are not equivalent to natural ecosystems in terms
of richness or ecosystem services