Climatic and Ecological Controls on the Holocene Range Expansion of Western Hemlock and Western Redcedar in the Interior Pacific Northwest

西北内陆地区西部铁杉和西部红杉全新世范围扩张的气候和生态控制

• 批准号: 0212917
• 负责人: Feng Sheng Hu
• 金额: $ 32.97万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0212917&HistoricalAwards=false
• 关键词: Climatic; Ecological; Controls; Holocene; Range

0212917HuThe main objectives of the proposed research are to determine Holocene migration lags of westernhemlock and western redcedar in the interior Pacific Northwest and to examine the relative importance of climatic change,dispersal limitation,and stand-level invasibility as controls of migration. These two species currently co-dominate late-successional forests in a coastal distributional range and an interior distributional range separated by a 160-km wide dispersal barrier of semi-arid grassland and pine forest. Preliminary data suggests that invasion of these species into the interior range lagged behind the establishment of suitable climatic conditions by 3000 years, longer than any migration lag hypothesized by previous studies. This possibility stands in sharp contrast to the inference from several decades of paleoecological studies in the coastal range that migration lags were generally unimportant in the heterogeneous landscapes of the Pacific Northwest where most species arrived shortly after deglaciation. Because of the dearth of paleoecologic and paleoclimatic data from the interior range, however, it remains uncertain to what extent the range expansion of hemlock and cedar into the interior lagged behind climatic change to suitable conditions and how climatic constraints, dispersal limitation, and stand-level invasibility affected their expansion. To address the research objectives, this study will employ a suite of paleoecologic tools and state-of-the-art paleoclimatic methods to reconstruct vegetation, fire disturbance, and climate at three pairs of sites across a latitudinal gradient in the interior range. Specifically, sediment cores from these sites will be analyzed for pollen,lignified stomata,wood fibers,and plant macrofossils to detect range expansion of hemlock and cedar at three spatial scales (between the coastal and interior ranges, within the interior range, and arrival adjacent to lakes).Macroscopic-charcoal analysis of these sediment cores will be used to identify fire events and assess the effect of fire on stand invasibility.Reconstructions of effective moisture and growing-season temperature will be made from oxygen-isotope and trace-element analyses as well as diatom and midget ransfer-functions.Chronological controls will be based on AMS 14 C dates of plant macrofossils,ages of tephra layers,and 210 Pb dates of bulk sediments.These results will beintegrated to quantify migration lags of hemlock and cedar and assess various scale-dependent migration controls.To our knowledge,this is the first comprehensive paleoecological study using independent measures of vegetation,disturbance,and climate to address the relative roles of dispersal limitation,stand-scale invasibility,and climatic constraints during range expansion.This project will result in a large multi-proxy data set relevant for understanding future range shifts on the fragmented landscapes of the northern temperate regions.Evidence of a large migration lag at the inter-range scale would suggest that long-distance dispersal events occur infrequently,and thus range shifts at similar scales during anticipated climatic change may be constrained by limited long-distance dispersal.In contrast,evidence of climatic limitation (i.e.,no migration lag)would imply that the relatively small-magnitude changes toward cooler and wetter climatic conditions in the last 4000-2000 years were necessary for the invasion of hemlock and cedar into the interior range,and thus these forests will be vulnerable to future warming. Contrasting migration lags across the coastal and interior ranges and within the interior range should offer insights into the patterns of plant migration in highly fragmented landscapes versus in the absence of a dispersal barrier.At the local scale,evidence for fire-mediated invasion would show that stand-scale invasibility is an additional important mechanism controlling the range expansion of these species.This multiple-proxy/multiple-scale approach represents a significant advance in interpreting Holocene records of plant migration.

0212917拟议研究的主要目标是确定西北太平洋内部西北部的西方洛克和西部redcedar的全新世迁移滞后，并研究气候变化，分散限制以及独立级别的不可侵犯的相对重要性，作为控制的迁移。目前，这两个物种在沿海分布范围内共同占领了晚期的森林，内部分布范围由半干旱草原和松树林的160公里宽的分散屏障隔开。初步数据表明，将这些物种侵入落后于建立合适气候条件的内部范围3000年，比以前研究假设的任何迁移滞后。这种可能性与沿海范围内几十年的古生态研究的推论形成了鲜明的对比，即在太平洋西北地区的异质景观中，大多数物种在退化后不久到达，迁移滞后通常并不重要。然而，由于内部范围内的古生态学和古气候数据的缺乏，它仍然不确定铁杉和雪松在气候变化到适当条件背后滞后的内部范围内的范围在多大程度上，以及如何限制气候限制，分散限制和独立的限制水平的不可侵犯性影响了他们的扩张。为了解决研究目标，本研究将采用一套古生物学工具和最先进的古气候方法来重建植被，火灾干扰和气候，并在内部范围内的纬度梯度上的三对地点进行。具体而言，将分析来自这些位点的沉积物核心，以分析花粉，木质化气孔，木纤维和植物大化石，以检测三个空间尺度（沿海和内部范围之间，内部范围内以及邻近的到达范围之间），在三个空间尺度上膨胀范围。对湖泊）。这些沉积物核心的宏观 - 炭分析将用于识别火灾事件并评估火对架子的影响。有效的水分和生长季节温度的重构将由氧相同位素和微量元素分析制成以及辅助剂和小型弹奏功能。教学控制将基于AMS 14 c植物大化石的日期，tephra层的年龄和210 pb的散装沉积物日期。这些结果将构成，以量化量子，以量化Hemlock and Cedar和Cedar和Cedar和Cedar和Cedar和Cedar和Cedar and Cedar and Cedar and cedar和cedar层。评估各种规模依赖性的迁移控制。在我们的知识中，这是使用独立的植被，干扰和气候的独立测量，以解决分散限制，站立尺度的入侵性以及在范围扩展中的气候约束的相对作用。该项目将导致大量的多型数据集有关了解北部温带区域零散景观的未来范围变化相关。 ，因此在预期气候变化期间以相似尺度的范围变化可能会受到有限的长距离散布的限制。在相反，气候限制的证据（即没有迁移滞后）暗示相对较小的障碍在凉爽和潮湿的气候上变化在过去的4000 - 2000年中，需要入侵铁杉和雪松进入内部范围，因此这些森林将容易受到未来变暖的影响。对比沿海和内部范围以及内部范围内的迁移滞后，应提供对高度分散景观中植物迁移模式的见解站立尺度的不可侵犯性是控制这些物种范围扩展的另一种重要机制。这种多种/多尺度的方法代表了解释植物迁移全新世记录的重大进步。

项目成果

Abrupt Holocene climate change and potential response to solar forcing in western Canada

• DOI: 10.1016/j.quascirev.2011.03.003
• 发表时间: 2011-05-01
• 期刊: QUATERNARY SCIENCE REVIEWS
• 影响因子: 4
• 作者: Gavin, Daniel G.;Henderson, Andrew C. G.;Hu, Feng Sheng
• 通讯作者: Hu, Feng Sheng

The Northern Inland Temperate Rainforest of British Columbia: Old Forests With a Young History?

• DOI: 10.3955/046.083.0107
• 发表时间: 2009-12-01
• 期刊: NORTHWEST SCIENCE
• 影响因子: 0.4
• 作者: Gavin, Daniel G.;Hu, Feng Sheng;Westover, Karlyn
• 通讯作者: Westover, Karlyn