Systematic deviations from linear size spectra of lake fish communities are correlated with predator-prey interactions and lake-use intensity
Systematic deviations from linear size spectra of lake fish communities are correlated with predator-prey interactions and lake-use intensity
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DOI：
10.1111/oik.05355
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发表时间：
2019-01-01
期刊：
影响因子：
3.4
通讯作者：
Brucet, Sandra
中科院分区：
文献类型：
--
作者：
Arranz, Ignasi;Hsieh, Chih-hao;Brucet, Sandra
生物体在对数尺度下的大小结构（即大小谱）通常可以用具有负斜率的线性函数来描述;然而，在自然系统中经常发现与线性的实质性偏差。理论研究表明，更大的非线性与高捕食者-猎物的大小比，但低的捕食者-猎物的丰度比的社区规模谱，然而，捕食者-猎物的非线性结构的影响的经验评估仍然很少。在这里，我们的目标是经验性地探索特定大小的残差（即对数鱼类丰度和对数平均鱼的大小之间的线性回归的偏差）的模式，通过使用在74个德国湖泊的鱼类群落的大小谱。我们发现，非线性是强大的湖泊与高捕食者-猎物的丰度比，但在低捕食者-猎物的大小比。更具体地说，我们的研究结果表明，只有大型捕食者，即使发生在低丰度，可以控制密度的猎物鱼类在一个社会中的一个广泛的大小类，从而促进线性的大小谱。反过来，缺乏大型捕食鱼类可能会导致高丰度的鱼类在中间大小类，导致在这些湖泊的非线性尺寸谱。此外，这些湖泊的特点是人类使用更频繁，包括高捕鱼压力和高总磷浓度，这对大型掠食性鱼类的丰度产生了负面影响。我们的研究结果表明，非线性尺寸谱可能反映的动力学过程可能引起的捕食者-猎物的相互作用。这为粒度谱的研究开辟了一个新的视角，并可用于进一步量化水生食物网的能量转移效率。
Size structure of organisms at logarithmic scale (i.e. size spectrum) can often be described by a linear function with a negative slope; however, substantial deviations from linearity have often been found in natural systems. Theoretical studies suggest that greater nonlinearity in community size spectrum is associated with high predator-prey size ratios but low predator-prey abundance ratios; however, empirical evaluation of the effects of predator-prey interactions on nonlinear structures remains scarce. Here, we aim to empirically explore the pattern of the size-specific residuals (i.e. deviations from the linear regression between the logarithmic fish abundance and the logarithmic mean fish size) by using size spectra of fish communities in 74 German lakes. We found that nonlinearity was strong in lakes with high predator-prey abundance ratios but at low predator-prey size ratios. More specifically, our results suggest that only large predators, even if occurring in low abundances, can control the density of prey fishes in a broad range of size classes in a community and thus promote linearity in the size spectrum. In turn, the lack of large predator fishes may cause high abundances of fish in intermediate size classes, resulting in nonlinear size spectra in these lakes. Moreover, these lakes were characterized by a more intense human use including high fishing pressure and high total phosphorus concentrations, which have negative impacts on the abundance of large, predatory fish. Our findings indicate that nonlinear size spectra may reflect dynamical processes potentially caused by predator-prey interactions. This opens a new perspective in the research on size spectrum, and can be relevant to further quantify the efficiency of energy transfer in aquatic food webs.