深圳福田红树林生态造林方法技术研究

为了增加深圳红树林生物多样性而引种海南岛的银叶树、海芒果、海桑、水椰、海莲、地瓣海桑、正红树等,其技术关键是抗低温使引种成功,为了大面积造林成功,选择当地优势种秋茄,桐花树、白骨壤及木榄进行繁殖试验,其关键问题是不同种类适合于不同水深及淤泥深度,大面积造林成功的技术关键是种植时间、插植方法等。     

Holocene Man in North America: The Ecological Setting and Climatic Background

Abstract

Patterns of human occupation and vegetation are delineated on maps of North America for one thousand year intervals through the Holocene. The raw data for this review include radiocarbon-dated pollen cores and archaeological information and treering records. Dynamic changes in the Laurentide Ice limits and major ecotones are observed through the middle Holocene, when both features reach essentially post-glacial stability. Significant changes in the vegetation boundaries continue to the present, but the scale of change is much diminished.

Early Holocene occupation apparently expanded from Alaska south to California, then east, parallel to the southern boundary of the grasslands, to the Mississippi River and northeastward to the east coast. The absence of occpuation in late-Atlantic time is noted through much of the Great Plains and continued until about 4,000 BP. Within the next millennium, evidence of human occupation virtually covered the United States (except for the northwest) and much of coastal Canada.

Environmental conditions and occupation over North America are reviewed within the framework of Holocene climatic episodes.     

Man the nanoscopes

New light microscopy techniques are pushing the limits of resolution to 50 nm and below. Fluorescence microscopy that rivals electron microscopy in resolution but operates on intact cells may be within reach.