长期以来,通过密度依赖性(DD)调节种群一直是生态系统研究的中心原则。作为调节人口的一个重要因素,DD对于理解压力源对人群的风险也至关重要,包括将其纳入用于此目的的人口模型中。然而,研究密度依赖性调节是具有挑战性的,因为它可以通过各种机制发生,以及他们在现场的身份,以及对个人和人口的后果的量化,可能很难。我们进行了有针对性的文献综述,特别是针对淡水鱼和小型啮齿动物种群的负DD的经验实验室或实地研究。在农药生态风险评估(ERA)中考虑了两个脊椎动物群体。我们发现,导致DD阴性的最常见原因是食物(19个审查的鱼类研究中有63%,25个哺乳动物研究的40%)或空间限制(哺乳动物研究的32%)。此外,据报道,营养相互作用是种群调节的原因,捕食主要影响小型哺乳动物种群(占哺乳动物研究的36%)和食人族影响淡水鱼(26%)。以淡水鱼为例,63%的研究是实验性的(即,长度为数周或数月)。他们通常关注DD的个体层面的原因和影响,持续时间很短。此外,DD主要影响鱼类的幼鱼生长和存活(68%)。另一方面,对小型哺乳动物的研究主要基于时间序列分析较长时间内的田间种群特性(68%)。DD主要影响亚成年和成年哺乳动物阶段的存活,在较小程度上,繁殖(60%vs.36%)。此外,经常观察到延迟DD(56%).最后,我们对未来的研究路径提出了建议,为将DD纳入为ERA开发的人口模型提供建议,并充分利用现有数据。
The regulation of populations through density dependence (DD) has long been a central tenet of studies of ecological systems. As an important factor in regulating populations, DD is also crucial for understanding risks to populations from stressors, including its incorporation into population models applied for this purpose. However, study of density-dependent regulation is challenging because it can occur through various mechanisms, and their identification in the field, as well as the quantification of the consequences on individuals and populations, can be difficult. We conducted a targeted literature
review specifically focusing on empirical laboratory or field studies addressing negative DD in freshwater fish and small rodent populations, two vertebrate groups considered in pesticide Ecological Risk Assessment (ERA). We found that the most commonly recognized causes of negative DD were food (63% of 19 reviewed fish studies, 40% of 25 mammal studies) or space limitations (32% of mammal studies). In addition, trophic interactions were reported as causes of population regulation, with predation shaping mostly small mammal populations (36% of the mammal studies) and cannibalism impacting freshwater fish (26%). In the case of freshwater fish, 63% of the studies were experimental (i.e., with a length of weeks or months). They generally focused on the individual-level causes and effects of DD, and had a short duration. Moreover, DD affected mostly juvenile growth and survival of fish (68%). On the other hand, studies on small mammals were mainly based on time series analyzing field population properties over longer timespans (68%). Density dependence primarily affected survival in subadult and adult mammal stages and, to a lesser extent, reproduction (60% vs. 36%). Furthermore, delayed DD was often observed (56%). We conclude by making suggestions on future research paths, providing recommendations for including DD in population models developed for ERA, and making the best use of the available data. Integr Environ Assess Manag 2023;00:1-12. © 2023 Syngenta Crop Protection. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).