Beta diversity patterns and their origins

Beta 多样性模式及其起源

• 批准号: RGPIN-2014-04176
• 负责人: Pither, Jason
• 金额: $ 1.75万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587650
• 关键词: Beta; diversity; patterns; their; origins

Accurately predicting how perturbations caused or exacerbated by humans - including climate change, habitat loss, and exotic species invasions - will affect the structure and functioning of communities and ecosystems is essential to devising effective adaptive management strategies. Key to achieving accurate predictions is an adequate understanding of the factors that govern variation in the taxonomic, functional, and phylogenetic composition of ecological communities. In particular, better information is required about the conditions that promote the importance of local assembly processes over contingencies related to the regional species pool. For example, if local communities are simply random subsets of the regional species pool, then local processes need not be invoked to explain variation in composition observed among communities. Insights into this issue can be gained by analyzing variation in community composition (called "beta diversity") using recently devised null models. These null models help to distinguish patterns that are consistent with a predominant role for local, deterministic drivers of community structure, from those consistent with stochastic assembly from the regional species pool. The few studies that have applied these methods thus far have yielded important and unanticipated discoveries, including, for example, the observation that tropical forests exhibit no more variation in taxonomic composition than temperate forests once differences in regional (gamma) diversity are accounted for. This finding suggests that much of the beta diversity that has been documented across the globe in a variety of study systems may not, as traditional thought, arise due to variation in local assembly processes. Instead, it might ultimately originate in historical / biogeographical processes that influence the characteristics of regional species pools. I propose to apply these null model methods broadly, across a variety of study systems that vary in key characteristics, including dispersal capacities of the taxa (e.g. terrestrial plants versus freshwater diatoms) and ecosystem type (e.g. terrestrial versus aquatic). The specific study systems include vascular plants of British Columbia forests, diatoms of the freshwater lakes of North America, macroinvertebrates in U.S. rivers, and zooplankton in U.S. lakes. I then propose to explore the implications that stochastic assembly and regional pool contingencies have for paleolimnology, an applied field with strong and persistent roots in classic beta diversity theory. Paleolimnologists use spatial and temporal patterns of beta diversity among freshwater diatoms (and other organisms) to infer environmental change. Although highly successful, the paleolimnological method is founded on outdated ideas about community assembly. My second objective is to conduct the first rigorous assessment of how the precision of paleolimnological transfer functions vary according to different assumptions about the roles of local determinism versus stochastic assembly and regional pool contingencies. The ultimate goal of this work is to improve upon current quantitative methods that largely ignore the potential for systematic variation in the importance of stochastic and deterministic assembly along environmental gradients.

准确地预测人类引起或加剧的扰动（包括气候变化，栖息地丧失和外来物种入侵）将如何影响社区和生态系统的结构和功能，对于设计有效的自适应管理策略至关重要。 实现准确预测的关键是对控制生态社区分类，功能和系统发育组成变异的因素的充分理解。 特别是，需要更好地了解促进与区域物种库相关的局部组装过程重要性的条件。例如，如果当地社区仅仅是区域物种池的随机子集，则不必调用本地过程来解释社区之间观察到的组成变化。 可以通过使用最近设计的无效模型来分析社区组成的变化（称为“ beta多样性”）来获得对此问题的见解。 这些无效模型有助于区分与与区域物种库的随机组装一致的局部确定性驱动因素的主要作用一致的模式。 迄今为止，少数应用这些方法的研究产生了重要且意外的发现，包括例如，一旦考虑到区域多样性差异（Gamma）多样性的差异，热带森林的分类构成没有比温带森林的差异更大的观察结果。 这一发现表明，在各种研究系统中已记录的许多Beta多样性可能不会像传统思想一样，是由于本地组装过程的变化而产生的。 取而代之的是，它最终可能起源于影响区域物种池特征的历史 /生物地理过程。 我建议将这些无效模型方法广泛应用于各种关键特征的研究系统，包括分类单元的分散能力（例如，陆生植物与淡水硅藻）和生态系统类型（例如，地陆和水生）。 具体的研究系统包括不列颠哥伦比亚省森林的血管植物，北美淡水湖的硅藻，美国河流中的大型无脊椎动物以及美国湖泊的浮游动物。 然后，我建议探索随机组装和区域池突发事件对古溶菌学具有的含义，这是一个应用的领域，这是经典beta多样性理论中坚固且持久根源的应用领域。 古杂种学家使用淡水硅藻（和其他生物）之间β多样性的空间和时间模式来推断环境变化。 尽管非常成功，但古老的方法是建立在有关社区集会过时的想法之上的。我的第二个目标是第一个严格的评估对古学转移函数的精度如何根据对局部确定论与随机组装和区域池意外事件的作用的不同假设的不同。 这项工作的最终目标是改善当前的定量方法，这些方法在很大程度上忽略了随机和确定性组装沿环境梯度的重要性的潜在变化的潜力。