Vegetation dynamics during last 35,000 years at a cold desert locale: preferential loss of forbs with increased aridity
Vegetation dynamics during last 35,000 years at a cold desert locale: preferential loss of forbs with increased aridity
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过去 35,000 年寒冷沙漠地区的植被动态：随着干旱程度的增加，禾本科植物优先丧失
DOI：
10.1002/ecs2.1873
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发表时间：
2017
期刊：
影响因子：
2.7
通讯作者：
R. Tausch
中科院分区：
文献类型：
--
作者：
R. Nowak;C. Nowak;R. Tausch
古生态记录是更好地了解生态对气候响应的重要数据来源。为了帮助了解北美大盆地寒冷沙漠的植被-气候关系，我们分析了来自52个化石木卫虫的154个植物类群，这些植物类群跨越了800米的海拔梯度和过去35,000年（35 ka）的单一研究区域。植被进行了分析，由群落组合（CA），植物功能类型，和个别物种。一致的主要趋势增加干旱，因为冰期最大，CA的变化主要是单向的，尽管百年尺度的气候变化周期。杂类草和其它草本植物功能类型的丰富度在盛冰期15 ~ 26 ka达到高峰，然后在~15 ka逐渐下降。个别分类群的分析表明，一旦一个草本物种从研究区域消失，该物种没有重新出现。相比之下，木本（灌木和树木）物种丰富度达到峰值8至15万年期间和以下的博林Allerod快速变暖。然而，大多数树木类群，建立在这一时期的变暖，随后失去了气候变得更加干旱后，开始中全新世温度最高变暖~8 ka。与灌木相比，植物功能类型的这些变化降低了杂类草的相对丰富度（即，减少杂类草/灌木比例），这些变化持续到现在，尽管气候变冷和变暖的周期。我们的结论是，草本植物的相对重要性，在当前CA的大盆地寒冷的沙漠一直在下降，为过去的15万年。我们还推测，减少丰富的草本植物物种，在一定程度上，提供了外来物种的机会，建立和增殖在大盆地在过去的100年。因此，对过去植被变化的观察表明，随着未来气候变暖而增加的干旱将继续有利于我们寒冷沙漠地区的木本植被而不是草本植物，至少在入侵物种取代本土灌木物种之前。
Paleoecological records are an important source of data to better understand ecological responses to climate. To help understand vegetation–climate relationships in the Great Basin cold desert of North America, we analyzed 154 plant taxa from 52 fossil woodrat middens that spanned both an 800-m elevation gradient and the last 35,000 yr (35 ka) within a single study area. Vegetation was analyzed by community assemblage (CA), by plant functional type, and by individual species. Concordant with a predominant trend of increased aridity since glacial maximum, CA change was largely unidirectional despite centennial-scale cycles of climate variation. Richness of forb and other herbaceous plant functional types peaked from 15 to 26 ka during glacial maximum and then gradually decreased from ~15 ka to present. Analysis of individual taxa indicates that once a herbaceous species was lost from the study area, that species did not re-occur. In contrast, woody (shrubs and trees) species richness peaked from 8 to 15 ka during and following the Bolling-Allerod rapid warming. However, most tree taxa that established during this period of warming were subsequently lost as climate became more arid after the beginning of Mid-Holocene Temperature Maximum warming ~8 ka. These shifts in plant functional types decreased relative richness of forbs compared to shrubs (i.e., decreased forb/shrub ratio), and these shifts continue to the present despite intervening cycles of climate cooling and warming. We conclude that the relative importance of herbaceous species in current CAs of the Great Basin cold desert has been decreasing for the last 15 ka. We also speculate that decreased richness of herbaceous species has, in part, provided opportunities for exotic species to establish and proliferate in the Great Basin during the last 100 yr. Thus, observations of past vegetation change suggest that increased aridity with future climate warming will continue to favor woody vegetation over herbaceous species at our cold desert locale, at least until invasive species displace native shrub species.
影响因子：
8.8
作者：
Becklin KM;Medeiros JS;Sale KR;Ward JK
通讯作者：
Ward JK