Doctoral Dissertation Research: Does Change in Fine-Scale Soil Properties After Fire Stimulate Exotic Species Colonization?

火是美国西部大多数森林生态系统的自然组成部分。森林管理者利用燃料减少项目来减轻火灾的严重程度，往往没有考虑到引进非本地植物物种的潜在负面生态后果。火灾后非本地物种的建立和传播可能会显着改变本地植物群落的恢复能力。火灾的严重程度、资源分布和土壤变化等因素都对非本地植物物种在烧毁地区的生长地点和方式起着重要作用。这个博士论文研究项目通过研究从燃烧前到燃烧后条件的微站点变化，解决了低严重度火灾后森林/草原交错带的入侵潜力。拟议的研究的两个研究问题是：1）是否有显着差异的生物（植被属性）和非生物（土壤水分，温度，养分）微立地条件下，整个黄松/草原交错带的科罗拉多前线范围以下低严重火灾，这将使网站更具侵略性？2)在火灾后的景观，低严重性火灾后，如何影响非本地植物物种的殖民模式的微网站模式？在规定的焚烧之前的几个季节里，从沿着这一森林/草地交错带的几个研究地点收集的数据提供了关于在接近正常条件的时候土壤湿度和温度以及植被结构变化的资料。在规定的燃烧后，微生境模式的变化可能会在整个生态交错区有所不同，并影响本地和非本地物种殖民地的网站的可用性。迄今为止，许多关于火灾影响的研究都是在较粗的尺度上解决这个问题的。本研究采用了更精细的尺度方法，以确定从草原基质到森林景观的非本地人的传播机制。这项研究将有助于理解的重要性，微站点条件和它们的影响的潜力，非本地植物物种移动后，低严重火灾的交错带。使用这些信息将不仅有助于全面了解在何种程度上最近被烧毁的地区容易受到入侵的非本地物种在细尺度，但也将有助于这些细尺度机制整合到景观水平的干扰反应。这项研究将提供必要的基本信息，以支持目前和未来的森林管理决策，在美国西部，在规定的火灾和非本地物种控制。作为博士论文研究改进奖，该奖项将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Fire is a natural part of most forest ecosystems in the western United States. Forest managers utilize fuel reduction projects to lessen fire severity, often without considering potential negative ecological consequences of non-native plant species introductions. The establishment and spread of non-native species following fire may significantly alter the ability of native plant communities to recover. Factors such as fire severity, resource distribution, and soil alterations all play a role in where and how non-native plant species may establish in burned areas. This doctoral dissertation research project addresses the invasion potential across the forest/grassland ecotone following low severity fire by studying microsite changes from pre- to post-burn conditions. The two research questions of the proposed study are: 1) Are there significant differences in the biotic (vegetation attributes) and abiotic (soil moisture, temperature, nutrients) microsite conditions across the ponderosa pine/grassland ecotone of the Colorado Front Range following low severity fire, which would make the site more invasible? 2) In the post-fire landscape, following low severity fire, how are non-native plant species colonization patterns affected by the microsite patterns? Data collected from several research sites along this forest/grassland ecotone over the course of several seasons prior to prescribed burning provide information on variation in soil moisture and temperature and vegetation structure during times of near normal conditions. Following prescribed burning, the changes in microsite patterns may vary across the ecotone and impact the availability of sites for native and non-native species colonization. Many of the studies of fire effects to date address this question at coarser scales. This research applies a more fine scale approach to determine the mechanisms involved in the spread of non-natives into the forested landscape from a grassland matrix. This research will contribute to the understanding of the importance of microsite conditions and their effects on the potential for non-native plant species to move across ecotones after low severity fire. The use of this information will contribute not only to the overall understanding of the degree to which a recently burned area is susceptible to invasion by non-native species at the fine scale, but will also contribute to the integration of these fine scale mechanisms into landscape level responses to disturbance. This research will provide fundamental information that is necessary to support present and future forest management decisions in the western United States, in regards to prescribed fires and non-native species control. As a Doctoral Dissertation Research Improvement award, this award will provide support to enable a promising student to establish a strong independent research career.