Collaborative research: Quantifying the influence of nonconsumptive predator effects on prey population dynamics

合作研究：量化非消耗性捕食者效应对猎物种群动态的影响

• 批准号: 1820540
• 负责人: James White
• 金额: $ 29.96万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-11-22 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1820540&HistoricalAwards=false
• 关键词: Collaborative; research; Quantifying; influence; nonconsumptive

Predators can affect populations of their prey in two ways: by consuming them ("consumptive effects" or "CE"s), or by causing the prey to change behavior to avoid contact with the predator. For example, prey often spend less time feeding and more time watching out for predators, which comes with the cost of lower food intake and thus slower growth. Such "non-consumptive effects" (NCEs) have been described for a wide range of terrestrial and marine prey species, from elk to clams, but mostly in short-term ( 1 month) experiments. These prior results suggest that in some cases, the behavioral changes (NCEs) have a bigger effect on prey populations than consumption by predators (CEs). However, those short-term, controlled experiments may artificially inflate the perceived importance of NCEs. Over longer time periods, prey may adapt or become acclimated to predation risk, and NCEs may become less important. Additionally, environmental variability (e.g., differences in the availability of the prey's food between study sites) may have a bigger effect on prey populations than NCEs do. This project will use a combination of short- (months) and long-term (years) field experiments and mathematical models to evaluate the role of NCEs on Florida oyster reefs. The prey species in this study is the eastern oyster, an important marine resource in the southeast US for harvesting and habitat creation; the main oyster predator is a mud crab. In this study, results from mathematical models of oyster populations will be compared to experimental data from the field to see whether including NCEs in the model leads to better model predictions. Better understanding of NCEs in oysters should improve management of that important marine resource. Furthermore, the mathematical model will be used to develop broader, generalizable conclusions about the importance of NCEs that could be applied to other important prey species. This project will provide data useful for oyster resource management, will support public education regarding the ecological importance of NCEs, and will enhance the scientific engagement of underrepresented groups in the study region. The project will support a partnership with the Guana Tolomato Matanzas National Estuarine Research Reserve in Florida, including data sharing, sponsoring an oyster management symposium, and funding the development of multimedia scientific outreach materials at the reserve that will be used by a large and diverse population of K-12 students in the surrounding community. The project will train a postdoctoral researcher, two graduate students, two undergraduate students, and research results will be disseminated by those students and the principal investigators at scientific conferences, in journal publications, and in online content through an ongoing partnership with a Florida public television station. Predators can alter prey population dynamics by causing fear-based shifts in prey traits (nonconsumptive effect, NCE). The importance of NCEs for prey populations - relative to direct consumption by predators (consumptive effects, CEs) - remains uncertain, particularly because short-term studies of NCEs cannot estimate their effect over multiple prey generations. This project addresses that knowledge gap by combining short- and long-term field experiments with population models to investigate the importance of NCEs on oyster population dynamics in a Florida estuary. The central question is whether accounting for NCEs improves the ability to predict long-term trends in oyster population abundance. Several types of NCEs are present in this system: exposure to water containing predator odors reduces oyster larval recruitment and causes juvenile oysters to increase shell thickness, reducing their somatic growth. In addition to CEs and NCEs , environmental gradients in stress, food, and propagule delivery are also present in this system. Those environmental factors can have strong effects on post-settlement survivorship, growth, and recruitment of oysters, so the relative importance of predator CEs and NCEs may vary along those spatial gradients as well. This project will consist of four components. (1) A series of short-term field experiments to test how NCEs vary with predator density and environmental variables, and whether one of the NCEs (increased shell thickness) actually reduces vulnerability to predators. (2) A population model, parameterized using experimental results; model simulations will quantify how the relative importance of NCEs should vary over time, space, and environmental gradients. (3) A longer-term (3.5 year) field experiment; the results from this experiment will be compared to model predictions to test whether accounting for NCEs improves predictions of long-term variation in oyster population dynamics. (4) A general form of the model will be developed to broadly investigate the effect of NCEs on non-equilibrium, transient population dynamics. By combining models and field experiments, this project will bridge the gap between the theoretical understanding of how NCEs affect population dynamics and empirical tests of that theory, advancing the field towards the goal of predicting how multiple interacting factors structure communities.

捕食者可以通过两种方式影响猎物的种群：通过消耗猎物（“消耗效应”或“CE”），或者通过使猎物改变行为以避免与捕食者接触，例如，猎物通常花更少的时间进食。需要更多时间警惕捕食者，这会导致食物摄入量减少，从而导致生长速度减慢，这种“非消耗效应”（NCE）已被描述为多种陆地和海洋猎物物种，从麋鹿到蛤蜊。 ,但主要是在短期（1个月）的实验中，这些先前的结果表明，在某些情况下，行为变化（NCE）对猎物种群的影响比捕食者的消耗（CE）更大。可能会人为地夸大 NCE 的重要性。随着时间的推移，猎物可能会适应或适应捕食风险，并且 NCE 可能会变得不那么重要，此外，环境变化（例如，猎物食物的可用性差异）。研究地点之间）对猎物种群的影响可能比 NCE 更大。该项目将结合短期（数月）和长期（数年）实地实验和数学模型来评估 NCE 对佛罗里达牡蛎礁的作用。本研究中的猎物物种是东部牡蛎，这是美国东南部用于捕捞和栖息地创造的重要海洋资源；主要牡蛎捕食者是青蟹。在本研究中，牡蛎种群数学模型的结果将与实验结果进行比较。数据进一步了解牡蛎中的 NCE 是否可以改善对这一重要海洋资源的管理。此外，该数学模型将用于得出关于牡蛎重要性的更广泛、可概括的结论。该项目将为牡蛎资源管理提供有用的数据，支持有关 NCE 的生态重要性的公众教育，并将增强研究区域代表性不足群体的科学参与。将支持与佛罗里达州瓜纳托洛马托马坦萨斯国家河口研究保护区的合作，包括数据共享、赞助牡蛎管理研讨会以及资助保护区多媒体科学宣传材料的开发，这些材料将供大量不同的 K 种群使用该项目将在周边社区培养一名博士后研究员、两名研究生、两名本科生，研究成果将由这些学生和主要研究人员在科学会议、期刊出版物和网上传播。通过与佛罗里达州公共电视台持续合作，捕食者可以通过引起猎物特征的恐惧变化（非消费效应，NCE）来改变猎物种群动态。NCE 对猎物种群的重要性 - 相对于捕食者的直接消费（消费效应）。效应，CE） - 仍然不确定，特别是因为 NCE 的短期研究无法估计它们对多个猎物世代的影响，该项目通过将短期和长期现场实验与种群模型相结合来调查其重要性，从而解决了这一知识差距。佛罗里达河口牡蛎种群动态的 NCE 的影响 核心问题是，考虑 NCE 是否可以提高预测牡蛎种群丰度长期趋势的能力。该系统中存在几种类型的 NCE：暴露于含有捕食者气味的水中会减少。牡蛎幼体的招募导致幼年牡蛎的壳厚度增加，从而减少其体细胞生长。除了CE和NCE之外，压力、食物和繁殖体输送的环境梯度也受到影响。这些环境因素会对牡蛎定居后的生存、生长和补充产生强烈影响，因此捕食者CE和NCE的相对重要性也可能随着这些空间梯度而变化。该项目将由四个部分组成。 (1) 一系列短期现场实验，以测试 NCE 如何随捕食者密度和环境变量变化，以及其中一个 NCE（增加的壳厚度）是否实际上容易受到捕食者的攻击。使用实验结果进行参数化；模型模拟将量化 NCE 的相对重要性如何随时间、空间和环境梯度变化。 (3) 将本实验的结果与模型进行比较； (4) 将开发模型的一般形式，以通过结合来广泛研究 NCE 对非平衡、瞬时种群动态的影响。模型和现场实验，该项目将弥合 NCE 如何影响种群动态的理论理解与该理论的实证检验之间的差距，推动该领域朝着预测多种因素如何相互作用结构群落的目标迈进。

项目成果

Environmental forcing and predator consumption outweigh the nonconsumptive effects of multiple predators on oyster reefs

环境强迫和捕食者的消耗超过了多种捕食者对牡蛎礁的非消耗性影响

• DOI: 10.1002/ecy.3041
• 发表时间: 2020-04
• 期刊: Ecology
• 影响因子: 4.8
• 作者: Kimbro, David L.;Tillotson, Hanna G.;White, J. Wilson
• 通讯作者: White, J. Wilson