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, black-footed 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