Collaborative Research: A mechanistic understanding of biogeographic patterns and life histories in benthic organisms in advective coastal environments

在海洋中建立和维持物种边界的生物和物理机制是有争议的。造成这种情况的因素是，浮游生物幼虫被运送到其出生范围之外的物种的后代，以及被移植到其自然分布地区以外的地区后茁壮成长的成虫。然而，为什么底栖生物的幼虫的远距离传播会在进化的时间尺度上持续存在，这一点尚不清楚。有更多的幼虫从出生栖息地分散，这似乎是有利的。此外，众所周知，较长的幼虫期增加了物种持久性的生殖产出，使有利等位基因的种群保留可能性降低，并降低了种群的遗传多样性。co - pi表明，物种范围边界的维持是由一种类似于沿海海洋中等位基因频率/遗传曲线的功能所控制的。与生物多样性理论的其他最新进展一样，这项工作表明，维持物种内部等位基因分布的条件与维持物种本身分布的条件之间存在趋同。这种理论的融合为物种间和物种内竞争在平流环境中的发展提供了大量的机会。它可能会统一遗传和种群水平的理论，并创建一个整体的观点，生命在平生环境。从初步工作中可以清楚地看出，综合将主要取决于分散模式和成功繁殖产出之间的权衡。这一理论将通过推动其分析极限和利用广泛的现有数据库来定量地限制繁殖和分散的权衡来发展。例如，虽然幼虫数量与质量之间的权衡（即许多“能量廉价”的幼虫与少数“高度供应”的个体）长期以来一直是定性模型的主题，但它们尚未被定量定义为不同底栖海洋分类群的生活史特征。结合分析发展和观察到的生活史权衡，将提供1)一系列扩散策略的进化稳定状态；2)将物种边界定义为物理（如温度和沿岸洋流变化）和生物（如幼虫死亡率）参数的函数的机制；3)局部保留幼虫的扩散行为的定量起源，并导致物种间和物种内适应度之间的关系。这些发现将预测物种边界位置和作为当地环流、环境条件及其梯度的各种扩散策略的存在/不存在。这些预测将通过广泛的文献和数据库搜索收集到的物种范围数据进行检验。更广泛的影响：这项研究将使我们更好地了解由于地球气候变化而发生的物种范围。例如，这项研究将测试一个假设，即变暖有利于幼虫浮游持续时间较长的物种。因此，随着气候变暖，现在以直接发育物种为主的高纬度地区将转变为浮游生物分散和直接发育的混合体。这项研究将使管理者了解栖息地的破坏是如何通过改变沿岸来源和浮游生物幼虫的运输来改变物种范围的。物种范围的定量理论也将帮助管理人员了解是什么设定了最近引进的外来物种的最终限制，从而改进管理策略。这项建议包括以下教育部分。两名研究生将接受定量系统地理学和生物地理学领域的前沿技术培训。此外，每年有两名本科生将协助项目的各个方面，并将在全国会议上介绍他们的工作。指导学生向NSF提交REU提案。本科生将在路易斯·斯托克斯少数民族参与联盟（Louis Stokes Alliance for Minority Participation）的帮助下招募，佐治亚大学是该联盟的旗舰成员。本科生也将从UNH的研究和发现项目中招募，从本科生研究机会有限的学院招募。

The biological and physical mechanisms that establish and maintain species boundaries in the ocean are controversial. Contributing factors are offspring of species with planktonic larvae being physically transported outside their natal range, and adults thriving when transplanted into regions immediately beyond their natural distributions. It is unclear, however, why long-distance dispersal of a benthic organism's larva should persist on evolutionary timescales. There is more larval dispersal from natal habitat than would seem propitious. Furthermore, long larval duration is known to increase reproductive output for species persistence, makes population retention of favorable alleles less likely, and reduces the genetic diversity of the population.The Co-PIs have shown that maintenance of range boundaries for a species are governed by a function analogous to that derived for allelic frequency/genetic clines in the coastal ocean. As with other recent advances in biodiversity theory, this work suggests a convergence between conditions that maintain the distribution of alleles within species and those that maintain the distribution of species themselves. This confluence of theory provides substantial opportunity for development of inter- and intra-species competition in an advective environment. It potentially would unify genetic and population-level theory, and create a holistic view of life in advective environs. It is clear from preliminary work that a synthesis would depend critically on tradeoffs between dispersal mode and successful reproductive output. The theory would be developed both by pushing its analytical envelope, and by drawing upon extensive, existing databases to quantitatively constrain reproductive and dispersal tradeoffs. For example, although tradeoffs between larval quantity versus quality (i.e., many "energetically cheap" larvae versus few "highly provisioned" individuals) have long been the subject of qualitative models, they have not been quantitatively defined for life history characteristics of different benthic marine taxa. Combining analytical developments and observed life-history tradeoffs would provide 1) evolutionarily stable states for a range of dispersal strategies, 2) mechanisms that define species boundaries as a function of physical (e.g., temperature and alongshore variation in currents) and biological (like larval mortality) parameters and 3) quantitative origins of dispersal behaviors that would locally retain larvae, and result in relationships between inter- and intra-species fitness. Such findings would predict species boundary locations and the presence/absence of various dispersal strategies as a function of local circulation, environmental conditions and their gradients. Predictions would be tested against data on species ranges gathered as part of an extensive literature and database search. Broader impacts: This research would allow a better mechanistic understanding species' ranges that occur due to changes in the Earth's climate. For example, this study will test the hypothesis that warming favors species with longer larval planktonic duration. Therefore, high-latitude areas now dominated by species with direct development would shift to a mixture of planktonic dispersers and direct developers as the climate warms. The research would allow managers to understand how disruption to habitat can alter species ranges by changing alongshore sources and transport of planktonic larvae. A quantitative theory of species range will also help managers understand what sets the ultimate limits of recently introduced exotic species, allowing improvement of management strategies. This proposal includes the following education components. Two graduate students will be trained in cutting-edge techniques in the fields of quantitative phylogeography and biogeography. In addition, two undergraduate students each year will assist with all aspects of the project and will present their work at a national meeting. The students will be mentored to write REU proposals to NSF. Undergraduates will be recruited with the help of the Louis Stokes Alliance for Minority Participation, of which UGA is a flagship member. Undergraduates will also be recruited from the Research and Discovery Program at UNH, from colleges with limited opportunities for undergraduate research.