Species conservation strategies

Talbotiella gentii: genetic variation and conservation

David Boshier, Daniel Dompreh and Mike Swaine

100km

MSD

ME

WE

D SD

SM

Krobo

Worobong

Bandai Hills

Yongwa

Sapawsu

Forest Reserves in Ghana and distribution of Talbotiella gentii

Dompreh, 2008

Records of Talbotiella populations in GhanaRed dots = Extant populations, Yellow dots = Extinct populations.

Sapawsu

Yogaga

Bandai

Yongwa

Talbotiella gentii

15 of 28 populationsnow extinct

Most of those extinctare outside reserves

Threats inside and outside reserves from fires, firewood cutting

Populations range in size from 2-500 adult trees

1982

1990

2005

Damage of Talbotiella population at Krobo mountain from fire and fuelwood exploitation over 23 years

Aburi Botanical Gardens

Conservation alternatives

• Preservation of actual diversity

• Conservation of evolutionary potential

• Mantain options for future generations, while satisfying present needs

How big is “big enough”?

• 50/500 rule (Franklin 1980)• 50 - inbreeding depression to acceptable level• 500 - sufficient for new variation from mutation to

replace that lost by genetic drift

• effective population size (Ne) more critical than survey numbers (N) - may need 5,000!

• in trees Ne smaller than N due to: overlapping generations, dioecy, asynchronous flowering, fecundity differences between individuals

Where should we conserve?

In situ - reserve system of undisturbed, protected areas within natural distribution (ecosystem based)

Ex situ - artificial maintenance of populations outside natural distribution (species based)

In situ Ex situ

Conservation of biodiversity in situ : trees as a paradigm

• Ideal reserve model• Emphasis: large, continuous, protected areas• Limitations: location, size, security, biology:

– movement of animals

– extensive distribution of many species

– gene flow between populations

– upland, non agricultural areas

essential but not sufficient

Conservation of biodiversity ex situ : methods and limitations

•Seed banks - problems of regeneration•Plantations - changes in gene frequencies, few

populations•Botanical gardens - deficiencies for gene pool

conservation

• Useful, but resources limit application to few species (usually commercial)

• Last possibility holding for highly endangered species

• Complementary to other approaches

Conservation of biodiversity ex situ : methods and limitations

Bottleneck genetic drift

Table 3 Within population genetic variability in Talbotiella gentii, estimated by percentage of polymorphic loci for 83 RAPDs polymorphic bands (8 primers)Population Population size No. of samples % polymorphic loci

AbiriwapongBotriansaYongwaNayomDoorkperSapawsuHospitalChaletAjena KuwereKroboYogoga HotelBooboheneOseikromSenkyesoKwame Addo

>1002

>1003921

>502

>50>5016

>20112720623

162

1355828648552222

16.32.1

13.65.23.98.10.88.44.83.17.77.94.42.12.12.12.1

Figure 3. Effect of geographic distance of pollen source on initial fruit set in Talbotiella gentii

Talbotiella gentiieach group summarize on wall chart paper or PowerPoint

Remember - need a conservation objective- prioritize actions – resources are limited

list problems by type- genetic, which pops. too small? which are different?- other types of problems

which conservation methods - in situ, ex situ, circa situm?who? will do, what? where?how will you pay for it?