Wells P V
Science. 1966 Aug 26;153(3739):970-5. doi: 10.1126/science.153.3739.970.
Eight Pleistocene wood rat middens at elevations of 1200, 880, and 600 meters in the Chihuahuan Desert contain abundant macrofossils of pinyon pine, juniper, shrubby liveoak, and Opuntia, together with smaller quantities of Agave lecheguilla and other xerophytes of existing desert vegetation, which in dicate a xerophilous woodland vegetation in the lowlands, as much as 800 meters below existing woodland, during the Wisconsin pluvial. Ten radiocarbon dates show ages that range from 11,560 to 14,800 and 16,250 to 20,000 years, and to more than 40,000 years. Absence of most mesophytic montane species in deposits as high as 1200 meters indicates a lack of equivalent downward dis placement for the ponderosa pine zone or other zones of montane vegetation. Uneven stocking of isolated peaks in the Chihuahuan Desert province with montane species suggests that long-distance transport of propagules, rather than former continuity, may account for the disjunct distributions of many species.
奇瓦瓦沙漠中海拔1200米、880米和600米处的8个更新世林鼠 midden 含有丰富的矮松、杜松、灌木状栎树和仙人掌的大化石，还有少量的龙舌兰和现存沙漠植被中的其他旱生植物，这表明在威斯康星多雨期，低地存在着一种旱生林地植被，比现存林地低达800米。十个放射性碳年代测定结果显示，其年代范围从11560年到14800年、16250年到20000年，以及超过40000年。在高达1200米的沉积物中没有大多数中生山地物种，这表明黄松地带或其他山地植被带缺乏同等程度的向下位移。奇瓦瓦沙漠省孤立山峰上山地物种的分布不均衡，这表明繁殖体的远距离传播，而非以前的连续性，可能是许多物种间断分布的原因。
