Sökning: "population decline"
Visar resultat 16 - 20 av 348 avhandlingar innehållade orden population decline.
16. Population size and genetic diversity of Nigerian lions (Panthera leo)
Sammanfattning : High growth rate in human populations, agricultural developments and industrialization have impinged negatively on the natural habitats of most large carnivores, causing fragmentation, isolation and consequently reduction in population size. Lions (Panthera leo) that once roamed most parts of Southern Europe, Asia, the Middle East, North America, northern part of South America and most parts of Africa are today found only in parts of sub-Saharan Africa and at a single site in India. LÄS MER
17. Making the Most of It? : Understanding the social and productive dynamics of small farmers in semi-arid Iringa, Tanzania
Sammanfattning : While much of semi-arid Africa is still sparsely populated with unused land, there are everywhere pockets of high and increasing population density in attractive locations. Small-scale farmers can respond to beginning land-scarcity in a number of ways. LÄS MER
18. From the migrations of herders and farmers to the colonial era and the modern-day : Genetic inferences on African demographic history
Sammanfattning : Africa is the birthplace of the human species and home to great linguistic, cultural, and genetic diversity. Despite this, the genetics of the peoples of the continent remains understudied. In this thesis, I apply population genetic approaches, to contribute to the knowledge of human demographic history in Africa. LÄS MER
19. Ecology and conservation of the moth Dysauxes ancilla
Sammanfattning : The ecology of the moth Dysauxes ancilla was studied in the only Swedish breeding area at Beijershamn, situated on the Baltic island of Öland. The population is a northern outpost, separated from the species´ continous distribution area in middle- and southeast Europe. LÄS MER
20. Studies of Secondary Prevention after Coronary Heart Disease with Special Reference to Determinants of Recurrent Event Rate
Sammanfattning : Objectives. The first aim was to examine the effects of secondary prevention with a focus on determinants in the risk of recurrent coronary heart disease (CHD). LÄS MER