Literaturdatenbank
Literaturdatenbank |
|
 |
|
Ronto, M. W. (2010). Etude comparative de la structure des populations d'astrochelys radiata (shaw, 1802) et de pyxis arachnoides (bell, 1827) entre le parc national de tsimanampetsotsa et la foret littorale du sud-ouest de madagascar. Unpublished thesis , Université de Antananarivo, Antananarivo.
Added by: Admin (06 Jan 2014 18:25:16 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: anon2010k View all bibliographic details  |
Categories: General Keywords: Astrochelys radiata, Habitat - habitat, Madagaskar - Madagascar, Pyxis arachnoides, Schildkröten - turtles + tortoises, Testudinidae Creators: Ronto Publisher: Université de Antananarivo (Antananarivo) |
Views: 4/514
Views index: 13% Popularity index: 3.25% |
| Abstract |
|
Testudinidae Geochelone Madagascar counts five species of terrestrial tortoises of which four are endemic, including the radiated tortoise Astrochelys radiata and the spider tortoise Pyxis arachnoides, endemics of the southern and south-western areas of the island. Nowadays, these species are classified as Critically Endangered on the IUCN Red List of Threatened species and listed on the CITES Appendix I, due to habitat loss and collection for the exotic pet trade and for human consumption. The level of these threats to the survival of the tortoises seemed to increase every year. In consequence, a study of the population structure of these species in their natural habitat appeared to be necessary. The National Park of Tsimanampetsotsa and the south-western littoral forest of Madagascar were hence chosen as study sites because the first is a protected area, and within the latter, collections of tortoises have been recorded. Transects were used to collect data during this study. Captured animals are marked individually by number, and then slackened. Morphometry, age and sex of each animal captured were recorded. Jolly-Seber method and Distance were used to estimate population size. Mann- Whithney "U" test was used to test variation of degree of disturbance, vegetation structure and population structure of these species between the study sites and that of Wicoxon, to estimate the probability of detection of the individuals according to distance. Population structure shows an important difference between the National Park and the littoral forest where these species are exploited; outside the protected area, we could notice: a reduction of population size, a deceleration of growth, a disproportionnality between different classes of age and an imbalance of sex-ratio. Conservation programs should be implemented as fast as possible, particularly outside the protected area, to fight against threats and pressures of which these species are victim, such as: the transfer of the littoral forest to the local community, establishment of a mixed brigade of tortoises against the illegal traffics , exploitation of the local taboo in the process of conservation and creation of the alternative activities to the local people and the poachers to ensure long term survival of these species.
Added by: Admin |