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Early research on revegetation of severely disturbed alpine ecosystems in the Beartooth Mountains of Montana focused on the use of high seeding densities of native colonizer graminoid species and high rates of fertilization. Results showed that these methods tended to competitively exclude the establishment of other species and lifeforms in the community. Initial high applications of nitrogen did not increase long-term nutrient retention capabilities of disturbed sites, and when applications were discontinued, sharp declines resulted in site productivity that further retarded establishment of forbs and other species. In .recent years new perspectives of alpine revegetation have beenadopted that concentrate on more basic approaches. Research suggests that seed mixtures for harsh disturbances should include species with low nutrient requirements or nitrogen fixing symbionts in addition to high nutrient requiring graminoids, that seeding densities should be redu·ced, and that moderate applications·of balanced macronutrients will likely result in higher species richness and increased rates of succession.Species responses to revegetation treatments appear to be controlled by widely different physiological. characteristics and life history traits. Additional

Hosfield, R. T. and Chambers, J. C. 2005. Pleistocene geochronologies for fluvial sedimentary sequences: an archaeologist's perspective.ABSTRACT: Current models of Pleistocene fluvial system development and dynamics are assessed from the perspective of European Lower and Middle Palaeolithic stone tool assemblages recovered from fluvial secondary contexts. Fluvial activity is reviewed both in terms of Milankovitch-scale processes across the glacial/interglacial cycles of the Middle and Late Pleistocene, and in response to sub-Milankovitch scale, high-frequency, low-magnitude climatic oscillations. The chronological magnitude of individual phases of fluvial activity is explored in terms of radiocarbon-dated sequences from the Late Glacial and early Holocene periods.It is apparent that fluvial activity is associated with periods of climatic transition, both high and low magnitude, although system response is far more universal in the case of the high magnitude glacial/ interglacial transitions. Current geochronological tools do not permit the development of high-resolution sequences for Middle Pleistocene sediments, while localised erosion and variable system responses do not facilitate direct comparison with the ice core records. However, Late Glacial and early Holocene sequences indicate that individual fluvial activity phases are relatively brief in duration (e.g. 10 2 and 10 3 yr). From an archaeological perspective, secondary context assemblages can only be interpreted in terms of a floating geochronology, although the data also permit a reinvestigation of the problems of artefact reworking.

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