Suchergebnisse

1 Patterns and processes in helminth parasite communities: an overview -- 2 Host populations as resources defining parasite community organization -- 3 Spatial scale and the processes structuring a guild of larval trematode parasites -- 4 Guild structure of larval trematodes in molluscan hosts: prevalence, dominance and significance in competition -- 5 Helminth communities in marine fishes -- 6 Helminth communities in freshwater fish: structured communities of stochastic assemblages? -- 7 Helminth communities of amphibians and reptiles: comparative approaches to understanding patterns and processes -- 8 Helminth communities in avian hosts: determinants of pattern -- 9 Helminth community of mammalian hosts: concepts at the infracommunity, component and compound community levels -- 10 Models for multi-species parasite-host communities -- 11 Free-living communities and alimentary tract helminths: hypotheses and pattern analyses -- 12 Concluding remarks.

The succulent and Nama-karoo form part of the arid south-western zone of Africa, a vast region of rugged landscapes and low treeless vegetation. Studies of this unique biome have yielded fascinating insights into the ecology of its flora and fauna. This book, originally published in 1999, is the first to synthesise these studies, presenting information on biogeographic patterns and life processes, form and function of animals and plants, foraging ecology, landscape-level dynamics and anthropogenic influences. Detailed analyses of the factors distinguishing the biota of the Karoo from that of other temperate deserts are given and generalisations about semi-arid ecosystems challenged. The ideas expounded, the ecological principles reviewed, and the results presented are relevant to all those working in the extensive arid and semi-arid regions of the world

The relationship between migration experience and family patterns among resi dents of the North and West is examined for three time periods-1940, 1970, and 1990. In general, an inverse association is observed between duration of residence in the North or West and family stability among African Americans. Although selective return migration to the South contributes to this association, it can account for only a minor part of the variation in family patterns by migration history. It is concluded that there is no evidence to support previous assumptions that southern migrants carried a dysfunctional family culture with them to the North and West, and thereby destabilized the nonsouthern African American family. Rather, changes indigenous to the North and West were responsible, for example, structural changes in the economy or the emergence of an inner-city "oppositional culture" that does not emphasize traditional family patterns or transitions.

One must always bemoan the lack of adequate statistics when discussing population problems in Afghanistan.1Few nations in Asia, however, have adequate data-collecting procedures: only 9 of the 41 Asian nations, encompassing about 8 per cent of Asia's total population, according to a recent UNO survey.