Collaborative Research: Late Holocene Expansion of Utah Juniper in Wyoming: A Model System for Studying Ecology of Natural Invasions

由于迁徙、气候变化或土地利用导致的本土物种在当地和地区的扩张为研究入侵的模式和影响提供了额外的机会。持续不断的自然入侵为预测未来气候和土地利用变化时的生物运动和后果提供了模型系统。这笔赠款将使用古生态和生态学方法来研究犹他州刺柏在怀俄明州中东部和邻近的蒙大拿州持续入侵的情况，该入侵始于犹他州刺柏在全新世晚期越过落基山脉和大陆分水岭。这次入侵可以被展示为解决关于自然入侵的中心问题的一个模式系统，因为：(1)它正在进行，并且已经持续了至少2000年，足够长的时间来涵盖长距离和短距离的扩散事件以及在较老地点的人口涌入；(2)它可以用前所未有的时空分辨率记录下来，使用的是树木化石、基于树木年轮的人口分析以及地面和航空重复摄影；(3)它有可能产生重要的假设，并提供不同的机会来研究代表不同入侵阶段的不同地点的种群动态、遗传后果和生态系统影响，以及(4)它强调了历史证据在重新审视当前关于牧场树木入侵的范式方面的价值。

9806574Jackson Local and regional expansion of native species due to migration, climate change or land use offer additional opportunities to study patterns and effects of invasion. Ongoing, natural invasions provide model systems to forecast biotic movements and consequences as climate and land use change in the future. This grant will use paleoecological and ecological methods to study the ongoing invasion of Utah juniper (Juniperus osteosperma) in central and eastern Wyoming and adjacent Montana, initiated when Utah juniper crossed the Rocky Mountains and the Continental Divide during the late Holocene. This invasion can be showcased as a model system for addressing central issues about natural invasions because: (1) it is ongoing and has been proceeding for at least 2000 years, long enough to encompass both long and short-distance dispersal events as well as population infilling at older sites; (2) it can be documented at unprecedented spatiotemporal resolution using fossil woodrat-middens, tree-ring based demographic analyses, and both ground and aerial repeat photography; (3) it has the potential to generate important hypotheses as well as provide diverse opportunities to study population dynamics, genetic consequences, and ecosystem effects across a chronosequence of sites representing different stages of invasion, and (4) it underscores the value of historical evidence in reexamining current paradigms about tree invasions in rangelands.