Patterns of Community Assembly in Serpentine Grasslands: The Roles of Initial Plant Composition and Functional Complementarity

蛇纹草原群落聚集模式：初始植物组成和功能互补的作用

• 批准号: 0213187
• 负责人: David Hooper
• 金额: --
• 依托单位: Western Washington University
• 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 2008-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0213187&HistoricalAwards=false
• 关键词: Patterns; Community; Assembly; Serpentine; Grasslands

0213187HooperThe search for patterns of community assembly has occupied the last 25 years incommunity ecology and remains controversial today. A commonly sought assembly rule is thatspecies coexistence in communities will be enhanced by differences in traits related tocompetition for limiting resources (i.e., that niche overlap is minimized). Put another way, dospecies from complementary guilds or functional groups have a better chance of persisting thanthose with strong overlap in resource use characteristics? Evidence for the role ofcomplementarity among plant groups in structuring communities is sporadic. The balancebetween rates of external stochastic processes (such as disturbance or priority effects ofcolonization) compared to internal community dynamics (such as competition or facilitation)may be critical in determining the degree to which internal assembly dynamics are manifested.Gaining further insight into this question is critical for understanding how communities might bestructured, and for the implications of that structure for ecosystem dynamics.We propose a five-year experiment to assess the roles of initial plant composition andfunctional complementarity in structuring communities of serpentine annual grasslands. Weseek to test several hypotheses centered on the following questions, generally grouped into twothemes: 1) Does the initial composition of a community shape its subsequent development? If so,for how long? Are there different stable endpoints? 2) To what extent does complementaryresource use (i.e., niche differentiation) versus dominance among plant species govern patternsof community development? Are other factors, such as seed input or climatic conditions moreimportant in determining community composition? Our goal is not to prove or disprove thepredominance of assembly rules, but rather to better understand the conditions under which theymight strongly influence community composition versus be overwhelmed by other factors.We will use as our experimental system a series of California serpentine grasslandcommunities that vary in functional group composition and richness. Functional compositionhas been maintained since the plots were established in 1992. In fall 1999 and 2000, seeds of sixadditional species (3 species each from two groups) were added to test the effects of functionalcharacteristics and diversity on invasibility of ecosystems. Thus we now have a system withtreatments that differ in initial functional composition, that have had common seed sources for anumber of additional species, and that will be subject to continuing seed rain from surroundinggrasslands. Our plan is to track changes in community composition over the next five years asthe communities develop from their initially different starting points. Monitoring of vegetation changes in these experimental communities through the next several years provides a unique opportunity to gain insight into interactions among a variety of processes that help shape ecological communities.

0213187 -Hooper在过去的25年中，寻找社区大会的模式占据了不满的生态，并在今天仍然存在争议。一个普遍寻求的集会规则是，社区中的物种共存将通过与限制资源相关的特征差异（即，利基市场重叠被最小化）来增强。换句话说，互补行会或官能团的介绍者有更好的机会在资源使用特征上持续存在强烈重叠的thathose？植物群体在结构群落中的作用的证据是零星的。与内部社区动态（例如竞争或促进）相比，外部随机过程率（例如干扰或优先级影响）之间的平衡可能在确定内部组装动力学的程度上至关重要在结构蛇形年度草原社区的结构社区中的功能互补性。 Weseek测试以以下问题为中心的几个假设，通常分为TWOTHEMES：1）社区的初始组成是否会塑造其随后的发展？如果是这样，多长时间？有不同的稳定端点吗？ 2）在多大程度上，互补的利用（即利基区分）与植物物种之间的主导地位管理社区发展的模式？在确定社区组成时，其他因素（例如种子输入或气候条件）是否更重要？我们的目标不是证明或反驳集会规则的优势，而是要更好地理解他们的观点强烈影响社区组成的条件，而不是其他因素被其他因素淹没。自1992年建立了该地块以来，保持了功能组成。在1999年和2000年，添加了六个additional物种的种子（分别来自两组3种），以测试功能示率和多样性对生态系统不可侵犯的影响。因此，我们现在有一个与初始功能组成不同的系统进行处理的系统，这些功能组合物具有针对其他物种的常见种子来源，并且会受到周围草地的持续种子雨水。我们的计划是跟踪未来五年内社区构图的变化，因为社区从最初不同的起点发展。 在接下来的几年中，监测这些实验性群落中的植被变化，为有助于塑造生态社区的各种过程之间的相互作用提供了一个独特的机会。