« Retourner aux résultats de recherche
par Souza De Azevedo, Victor 
Président du jury Dahdouh-Guebas, Farid
Promoteur Cannicci, Stefano;Fratini, Sara
Publication Non publié, 2021-08-31
Président du jury Dahdouh-Guebas, Farid
Promoteur Cannicci, Stefano;Fratini, Sara
Publication Non publié, 2021-08-31
Mémoire
| Résumé : | The giant otter (Pteronura brasiliensis) is an endemic mammal from South America. Groupssettle their territory nearby the most diverse freshwater streams. It is estimated that in the lastcentury nearly 400,000 individuals died from commercial hunting. Currently, the species faceshabitat loss as the main threat, an aspect associated with two constraints: deforestation, foragrobusiness and logging companies, and the fires that have intensified in recent years due toclimate change. The aim of this study was to build a database of the species’ distribution and toinvestigate how habitat loss has influenced its demography in the last 30 years, associatingthese values with phylogeographic regions that were already defined for this species.Intersections of burned and deforested areas with potential group territories were obtained bygeoprocessing and analysed via generalised linear models. Differences between constraintswere verified via Kruskal-Wallis test for the periods and regions. GLZ outcomes showed thatgroups declined their count values when deforestation rates assumed higher values (6.78e-08).The same pattern was not seen with fires. The post hoc for Kruskal-Wallis revealed that theregions showed significant differences for deforestation rates and only Iténez for fires. Theincrease of areas burned and logged suggests that fragmentation in South America mayintensify the isolation of populations, confirmed by previous studies of haplotypic diversity forthe species. This study shows that giant otter groups are highly dependent on vegetation in theirhabitat and the constant increase in deforestation can intensify fragmentation betweenpopulations and accelerate their extinction process. |
