Quetglas Antoni, Rueda Lucía, Alvarez-Berastegui Diego, Guijarro Beatriz, Massutí Enric
Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma de Mallorca, Spain.
SOCIB-Balearic Islands Coastal Observing and Forecasting System, Palma de Mallorca, Spain.
PLoS One. 2016 Feb 9;11(2):e0148770. doi: 10.1371/journal.pone.0148770. eCollection 2016.
According to their main life history traits, organisms can be arranged in a continuum from fast (species with small body size, short lifespan and high fecundity) to slow (species with opposite characteristics). Life history determines the responses of organisms to natural and anthropogenic factors, as slow species are expected to be more sensitive than fast species to perturbations. Owing to their contrasting traits, cephalopods and elasmobranchs are typical examples of fast and slow strategies, respectively. We investigated the responses of these two contrasting strategies to fishing exploitation and environmental conditions (temperature, productivity and depth) using generalized additive models. Our results confirmed the foreseen contrasting responses of cephalopods and elasmobranchs to natural (environment) and anthropogenic (harvesting) influences. Even though a priori foreseen, we did expect neither the clear-cut differential responses between groups nor the homogeneous sensitivity to the same factors within the two taxonomic groups. Apart from depth, which affected both groups equally, cephalopods and elasmobranchs were exclusively affected by environmental conditions and fishing exploitation, respectively. Owing to its short, annual cycle, cephalopods do not have overlapping generations and consequently lack the buffering effects conferred by different age classes observed in multi-aged species such as elasmobranchs. We suggest that cephalopods are sensitive to short-term perturbations, such as seasonal environmental changes, because they lack this buffering effect but they are in turn not influenced by continuous, long-term moderate disturbances such as fishing because of its high population growth and turnover. The contrary would apply to elasmobranchs, whose multi-aged population structure would buffer the seasonal environmental effects, but they would display strong responses to uninterrupted harvesting due to its low population resilience. Besides providing empirical evidence to the theoretically predicted contrasting responses of cephalopods and elasmobranchs to disturbances, our results are useful for the sustainable exploitation of these resources.
根据生物体的主要生活史特征，可将其按从快（体型小、寿命短、繁殖力高的物种）到慢（具有相反特征的物种）的连续统一体进行排列。生活史决定了生物体对自然和人为因素的反应，因为慢生物种预计比快生物种对干扰更敏感。由于它们具有截然不同的特征，头足类动物和板鳃亚类动物分别是快速和慢速策略的典型例子。我们使用广义相加模型研究了这两种截然不同的策略对渔业开发和环境条件（温度、生产力和深度）的反应。我们的结果证实了头足类动物和板鳃亚类动物对自然（环境）和人为（捕捞）影响的预期不同反应。尽管是先验预测，但我们既没有料到两组之间会有明确的差异反应，也没有料到两个分类组内对相同因素的敏感性会是均匀的。除了对两组影响相同的深度外，头足类动物和板鳃亚类动物分别仅受环境条件和渔业开发的影响。由于头足类动物的生命周期短，为一年，没有世代重叠，因此缺乏在板鳃亚类等多龄物种中观察到的不同年龄组所赋予的缓冲效应。我们认为，头足类动物对短期干扰（如季节性环境变化）敏感，因为它们缺乏这种缓冲效应，但由于其高种群增长率和周转率，它们不会受到诸如捕捞等持续的长期适度干扰的影响。相反的情况适用于板鳃亚类动物，其多龄种群结构会缓冲季节性环境影响，但由于其低种群恢复力会对不间断的捕捞表现出强烈反应。除了为理论上预测的头足类动物和板鳃亚类动物对干扰的不同反应提供实证证据外，我们的结果对于这些资源的可持续开发也很有用。
