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

基本信息

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

项目摘要

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：通过食用“消耗效果”或“ CE”），或者通过导致改变行为的猎物以避免与捕食者接触。例如，猎物通常会花费更少的时间喂食，而更多的时间注意捕食者，这是由于食物摄入量降低而增长的成本较慢。已经描述了这种“非消耗效应”（NCE）（NCES），用于从麋鹿到蛤的各种陆地和海洋猎物物种，但主要是在短期（1个月）实验中。这些先前的结果表明，在某些情况下，行为变化（NCE）对猎物人群的影响比捕食者（CES）的消费更大。但是，这些短期，受控的实验可能会人为地膨胀NCE的感知重要性。在较长的时间段内，猎物可能会适应或适应捕食风险，而NCE可能变得不那么重要。此外，环境变异性（例如，研究地点之间猎物食物的可用性差异）可能对猎物人群的影响比NCE更大。该项目将结合短期（月）和长期（年）实地实验和数学模型的组合来评估NCE在佛罗里达牡蛎礁上的作用。这项研究中的猎物是东方牡蛎，这是美国东南部的重要海洋资源，用于收获和栖息地创造。主要的牡蛎捕食者是泥蟹。在这项研究中，将将牡蛎种群数学模型的结果与现场的实验数据进行比较，以查看在模型中包括NCE是否会导致更好的模型预测。对牡蛎中NCE的更好理解应改善对这一重要海洋资源的管理。此外，数学模型将用于制定更广泛的，可推广的结论，内容涉及可以应用于其他重要猎物的重要性。该项目将为牡蛎资源管理提供有用的数据，将支持有关NCE的生态重要性的公共教育，并将增强研究区域中代表性不足的群体的科学参与。该项目将支持与佛罗里达州的Guana Tolomato Matanzas国家河口研究保护区建立合作伙伴关系，包括数据共享，赞助牡蛎管理研讨会，并资助了该保护区的多媒体科学外展材料的开发，该材料将由周围社区中大型和多样化的K-12学生使用。该项目将培训一名博士后研究人员，两名研究生，两名本科生，研究结果将由科学会议，期刊出版物中的这些学生和主要研究人员传播，并通过与佛罗里达州公共电视台的持续合作在线内容。捕食者可以通过引起猎物特征的基于恐惧的转移（不需要的效果，NCE）来改变猎物人口动态。 NCES对猎物种群的重要性 - 相对于捕食者的直接消费（CES，CES） - 尤其是因为对NCES的短期研究无法估计其在多个猎物中的影响。该项目通过将短期和长期现场实验与人群模型相结合，以研究NCES对佛罗里达州河口中牡蛎人口动态的重要性来解决知识差距。核心问题是，对NCE的解释是否会提高预测牡蛎人口丰度长期趋势的能力。该系统中存在几种类型的NCE：接触含有捕食者气味的水会减少牡蛎幼虫的募集，并导致少年牡蛎增加壳的厚度，从而减少其体细胞生长。除了CES和NCE外，该系统还存在压力，食物和繁殖时的环境梯度。这些环境因素可能对牡蛎的分配后存活，生长和募集产生强大的影响，因此捕食者和NCES的相对重要性在这些空间梯度上也可能有所不同。该项目将由四个组件组成。（1）一系列短期现场实验，以测试NCES如何随捕食者的密度和环境变量而变化，以及其中一个NCE（壳厚度增加）是否实际上会减少对捕食者的脆弱性。（2）使用实验结果进行参数化的种群模型；模型模拟将量化NCE的相对重要性应随着时间，空间和环境梯度的变化。（3）长期（3。5年）实验实验；该实验的结果将与模型预测进行比较，以测试NCE的核算是否改善了长期变化的预测（4）该模型的一般形式将被开发出来，以广泛研究NCE对非平衡，瞬态种群动力学的影响。通过结合模型和现场实验，该项目将弥合对NCE的理论理解如何影响人群动态和该理论的经验检验之间的差距，并将现场推进到预测多个相互作用因素如何结构社区的目标。