Aquatic Ecology and Water Quality Management Group, Wageningen University and Research centre, Wageningen University P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
Aquatic Ecology and Water Quality Management Group, Wageningen University and Research centre, Wageningen University P.O. Box 47, 6700 AA, Wageningen, The Netherlands ; Alterra, Wageningen University and Research centre P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
Ecol Evol. 2015 Apr;5(8):1563-75. doi: 10.1002/ece3.1425. Epub 2015 Mar 17.
Quantifying and understanding movement is critical for a wide range of questions in basic and applied ecology. Movement ecology is also fostered by technological advances that allow automated tracking for a wide range of animal species. However, for aquatic macroinvertebrates, such detailed methods do not yet exist. We developed a video tracking method for two different species of benthic macroinvertebrates, the crawling isopod Asellus aquaticus and the swimming fresh water amphipod Gammarus pulex. We tested the effects of different light sources and marking techniques on their movement behavior to establish the possibilities and limitations of the experimental protocol and to ensure that the basic handling of test specimens would not bias conclusions drawn from movement path analyses. To demonstrate the versatility of our method, we studied the influence of varying population densities on different movement parameters related to resting behavior, directionality, and step lengths. We found that our method allows studying species with different modes of dispersal and under different conditions. For example, we found that gammarids spend more time moving at higher population densities, while asellids rest more under similar conditions. At the same time, in response to higher densities, gammarids mostly decreased average step lengths, whereas asellids did not. Gammarids, however, were also more sensitive to general handling and marking than asellids. Our protocol for marking and video tracking can be easily adopted for other species of aquatic macroinvertebrates or testing conditions, for example, presence or absence of food sources, shelter, or predator cues. Nevertheless, limitations with regard to the marking protocol, material, and a species' physical build need to be considered and tested before a wider application, particularly for swimming species. Data obtained with this approach can deepen the understanding of population dynamics on larger spatial scales and of the effects of different management strategies on a species' dispersal potential.
量化和理解运动对于基础和应用生态学的广泛问题至关重要。运动生态学也得益于技术进步，这些技术进步允许对广泛的动物物种进行自动跟踪。然而，对于水生大型无脊椎动物，还没有这样详细的方法。我们为两种不同的底栖大型无脊椎动物开发了一种视频跟踪方法，即爬行等足目动物 Aquilus aquaticus 和游泳淡水端足目动物 Gammarus pulex。我们测试了不同光源和标记技术对它们运动行为的影响，以确定实验方案的可能性和局限性，并确保对测试标本的基本处理不会影响从运动路径分析中得出的结论。为了展示我们方法的多功能性，我们研究了不同种群密度对与休息行为、方向性和步长相关的不同运动参数的影响。我们发现，我们的方法允许研究具有不同扩散方式和不同条件的物种。例如，我们发现，在更高的种群密度下，gammarids 会花更多的时间移动，而在类似条件下，asellids 则会休息更多。与此同时，gammarids 对更高的密度做出的反应是主要减少平均步长，而 asellids 则不会。然而，gammarids 对一般处理和标记比 asellids 更敏感。我们的标记和视频跟踪协议可以很容易地应用于其他水生大型无脊椎动物或测试条件，例如食物源、遮蔽物或捕食者线索的存在或不存在。然而，在更广泛的应用之前，需要考虑和测试标记协议、材料和物种的物理结构方面的限制，特别是对于游泳物种。通过这种方法获得的数据可以加深对更大空间尺度上种群动态的理解，以及不同管理策略对物种扩散潜力的影响。
