936 resultados para Emergence Traps
Resumo:
Was the spread of agropastoralism from the Fertile Crescent throughout Europe influenced by rapid climatic shifts? We here generate idealized climate events using palaeoclimate records. In a mathematical model of regional sociocultural development, these events disturb the subsistence base of simulated forager and farmer societies. We evaluate the regional simulated transition timings and durations against a published large set of radiocarbon dates for western Eurasia; the model is able to realistically hindcast much of the inhomogeneous space-time evolution of regional Neolithic transitions. Our study shows that the inclusion of climate events improves the simulation of typical lags between cultural complexes, but that the overall difference to a model without climate events is not significant. Climate events may not have been as important for early sociocultural dynamics as endogenous factors.
Resumo:
Life-cycle characteristics of the free-swimming lysianassoid amphipod Cyclocaris guilelmi were investigated and compared to those of other regularly appearing amphipods in the Arctic deep-sea community. In this context we analysed time-series data of meso- and bathypelagic amphipods collected as swimmers in moored sediment traps from 2004 to 2008 at the deep-sea long-term observatory HAUSGARTEN (79°N/4°E) in the eastern Fram Strait, Arctic Ocean. Six mesopelagic and three bathypelagic deep-sea amphipod species regularly occurred in the traps. The lysianassoid C. guilelmi showed a stable interannual population size and seasonal peaks in its occurrence from August to February during the five-year sampling period. The investigation of its population structure and reproduction ecology indicated year-round breeding behavior of this species. Up to 4 cohorts consisting mainly of juvenile and female C. guilelmi were observed. We conclude that C. guilelmi plays an important role within the Arctic amphipod deep water community.
