A Reply to Bellezza
A Reply to Bellezza
复制标题
对贝莱扎的回复
DOI：
10.1086/692996
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发表时间：
2017
影响因子：
2.2
通讯作者：
Bocinsky, R. Kyle
中科院分区：
文献类型：
--
作者：
d’Alpoim Guedes, Jade;Bocinsky, R. Kyle
我们感谢Bellezza博士对我们的论文所作的富有洞察力的评论。他提出了关于气候和大陆性质的重要观点。我们同意Bellezza的观点，即青藏高原中西部现有气象站数据密度较低，导致任何建模重建的准确性都较低。出于这些原因，我们的分析集中在更好地理解青藏高原东部，那里可用的气象站数量更多，提高了重建的准确性。我们希望未来能向外国研究人员提供更多青藏高原中西部地区的气象数据，这两个地区对西藏现代农业至关重要，以便研究人员能够更准确地绘制出该地区农田变化的图景。在他的评论中，Bellezza仔细审查了我们对青藏高原海拔边界的定义，以及这如何影响对农业耕地比例的解释。在我们的论文中，我们遵循了Chen等人(2015b)的方法，他将青藏高原东北部的海拔下限定义为1500米ASL。我们同意，这个海拔下限是有问题的。正如Bellezza指出的那样，设定这个低海拔极限包括大片农田，如青藏高原东北部的柴达木盆地和西宁。我们在补充信息中重新创建了分析，将海拔限制设置为2700米ASL，以消除这些较低海拔的地区。根据GLC-Share的数据，青藏高原只有770平方公里的耕地面积在海拔4,000米以上，或∼4.7%的耕地面积在海拔2,700米以上(∼为16,500平方公里)。图1显示了青藏高原海拔2700米以上的耕地的经验累积概率密度分布；海拔2700米以上的农作物占主导土地的95%低于海拔3980米。如果我们像Bellezza建议的那样，将我们分析的区域限制在西藏东部或中西部，这可能会进一步改变这些数字。不管人们如何定义青藏高原，Bellezza呼吁对当代和古代农业农田数据进行实地核查是有充分理由的。在考古方面，我们认为考古学家有必要超越在遗址中发现的种子代表原地种植的假设，因为这忽视了这样一个事实，即早期藏人可能像今天一样从事广泛的贸易网络(d‘Alpoim Guedes 2015；d’Alpoim Guedes，Bocinsky和Butler 2015；d‘Alpoim Guedes，Manning和Bocinsky 2016)。为了建立真实的作物生态位模型，在高原工作的考古学家应该开发出方法，通过放射性碳测年、植硅体和化学分析来识别古代田野，这样我们就能够确定人类过去真正从事农业的地方。呼吁掌握当代农业的真实程度也是及时的。青藏高原正在经历的气候变化比低海拔地区的幅度要大得多。自1960年以来，西藏自治区的气温每十年飙升0.47摄氏度--几乎是全球平均气温的两倍(Chen等人。2015A)。事实上，青藏高原上的最后100年代表着高原上过去2000年历史上最温暖的几年(Chen等人。2015A)。当务之急是，人种学家在我们了解农作物曾经的位置之前，记录下这些作物的当前和历史边界。这些边界正在波动，在快速变暖的世界中也将继续波动。
We are grateful for the insightful comments provided by Dr. Bellezza on our paper. He raises vital points about the nature of climate and continentality. We agree with Bellezza that the low density of available weather station data from the central and western Tibetan Plateau would result in a lower degree of accuracy in any modeled reconstruction. Our analysis focused, for these reasons, on the better-understood eastern Tibetan Plateau, where higher numbers of available weather stations improve the accuracy of reconstructions. We hope that in the future more weather data from the central and western Tibetan Plateau, both areas crucial to modern Tibetan agriculture, will be made available to foreign researchers so that researchers can create a more accurate picture of changing cropland across this area. In his comment Bellezza scrutinized our definition of the altitudinal boundary of the Tibetan Plateau and how this affects interpretations of percentage of cropland allotted to agriculture. In our paper we followed the methods used by Chen et al.(2015b), who defined the northeastern Tibetan Plateau as having a lower altitudinal limit of 1,500 m asl. We agree that this lower altitudinal limit is problematic. As Bellezza points out, setting the altitudinal limit this low includes large tracts of agricultural land such as the Qaidam Basin and Xining on the northeastern Tibetan Plateau. We have recreated the analysis in our supplemental information by setting the altitudinal limit at 2,700 m asl to eliminate these areas of lower altitude. According to GLC-SHARE, only∼ 770 km2 of cropland-dominant land on the Tibetan Plateau is above 4,000 m asl, or∼ 4.7% of cropland-dominant land is above 2,700 m asl (∼ 16,500 km2). Figure 1 presents a revised empirical cumulative probability density distribution of the elevations of cropland-dominant land on the Tibetan Plateau above 2,700 m asl; 95% of crop-dominant land above 2,700 m asl is below 3,980 m asl. If we constrained the area in our analysis to east or west-central Tibet as suggested by Bellezza, this might change these figures further. Regardless of how one defines the Tibetan Plateau, Bellezza’s call to ground truth contemporary and ancient agricultural cropland data is well warranted. On the archaeological front, we have argued that it is necessary for archaeologists to move beyond the assumption that seeds found in sites represent in situ cultivation, as this neglects the fact that early Tibetans likely engaged in extensive networks of trade much as they do today (d’Alpoim Guedes 2015; d’Alpoim Guedes, Bocinsky, and Butler 2015; d’Alpoim Guedes, Manning, and Bocinsky 2016). To ground truth crop niche models, archaeologists working on the plateau should develop methods to identify ancient fields through radiocarbon dating and phytolith and chemical analyses so that we are able to identify where humans actually practiced agriculture in the past. The call to ground truth the extent of contemporary agriculture is also timely. The Tibetan Plateau is experiencing climate change at a much higher amplitude than lower-altitude locations. Temperatures in the Tibet Autonomous Region have soared by 0.47 C per decade since 1960—at nearly twice the rate of the global average (Chen et al. 2015a). Indeed, the last 100 years on the Tibetan Plateau represent the warmest years in the last 2,000 years of history on the Plateau (Chen et al. 2015a). It is urgent for ethnographers to document the current and historic boundaries of crops before our understanding of where these once lay is lost. These boundaries are fluctuating and will continue to fluctuate in a rapidly warming world.
影响因子：
2.2
作者：
Guedes, Jade d'Alpoim;Manning, Sturt W.;Bocinsky, R. Kyle
通讯作者：
Bocinsky, R. Kyle