Dissertation Research: Anthropogenic Landscapes? The Effect of Prehistoric Human Populations on Fire Frequency and Vegetation on the Northern Columbia Plateau

在唐纳德·格雷森博士的指导下，伊丽莎白·沙尔夫女士将为她的博士论文收集数据。沙尔夫女士希望确定史前美洲原住民对其环境的影响。这是一个辩论非常激烈的话题，答案很重要，因为它有助于确定衡量人类行动的自然环境基线。许多科学家认为，史前技术水平如此之低，以至于在欧洲殖民之前，植被基本上保持在原始状态，环境记录中明确表明的变化是由于气候变化或其他非人类原因。然而，其他人坚持认为，即使没有金属工具和大规模的森林砍伐，史前美洲原住民的行动也产生了重大影响，主要是通过意外和故意的焚烧。当人类大量存在时，就会引发火灾，而且火灾比雷击等其他行为引起的火灾发生得更频繁。更频繁的燃烧对生态的影响与此类事件在时间上分布更广的情况截然不同。为了研究这个问题，沙尔夫女士将从华盛顿州的一系列湖盆中收集岩心。她选择了一个进行了广泛考古研究的地区，可以计算出史前人口密度随时间的变化。通过对火山灰和放射性碳测定的研究，可以准确地确定岩心的年代。氧同位素比率的分析将提供有关气候变化的信息。花粉和木炭将分别为重建植被和火灾历史提供依据。孢子孢子虫的计数用于监测食草动物的密度，因为这些与冲入每个盆地的粪便的数量有关。通过对这些互补数据库的统计分析，可以了解人类活动对植被的影响。这项研究之所以重要，有几个原因。它将提供关于长期人类与环境相互作用的信息，这是地理学家、古生态学家和考古学家感兴趣的问题。它还将帮助培养一位有前途的年轻科学家。

Under the direction of Dr. Donald Grayson, MS Elizabeth Scharf will collect data for her doctoral dissertation. MS Scharf wishes to determine the effect that prehistoric Native Americans had on their environment. This is a very strongly debated topic and the answer is important because it helps to determine the natural environmental baseline against which human actions should be measured. Many scientists have argued that the level of prehistoric technology was so low, that prior to European colonization, vegetation was maintained in an essentially pristine condition and that the changes which are clearly indicated in the environmental record were due to climate change or other non-human causes. Others however have maintained that even without metal implements and large scale forest clearance, actions by prehistoric Native Americans had a significant effect, primarily through accidental and purposeful burning. When present in significant numbers, humans cause fires and these occur more frequently than those resulting from other actions such as lightning strikes. The ecological effects of more frequent burning are very different from situations where such episodes are more widely spaced in time. To examine this question MS Scharf will collect cores from a series of lake basins in Washington State. She has chosen a region where extensive archaeological research has been conducted and changes in prehistoric population densities can be calculated over time. Through the study of volcanic tephra and radiocarbon determinations, segments of the cores can be accurately dated. Analysis of oxygen isotope ratios will provide information on climate change. Pollen and charcoal respectively will provide the bases for reconstructing vegetation and fire history. Counts of the spore Sporomiella serve to monitor herbivore density since these relate to the amount of dung being washed into each basin. Through statistical analysis of these complementary data bases, the effect of human agency on vegetation can be addressed. This research is important for several reasons. It will provide information on long term human-environment interaction, an issue of interest to geographers, paleoecologists and archaeologists. It will also assist in training a promising young scientist.