Fertilization of terrestrial vegetation by spawning Pacific salmon: the role of flooding and predator activity
Fertilization of terrestrial vegetation by spawning Pacific salmon: the role of flooding and predator activity
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DOI：
10.2307/3546545
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发表时间：
1998-10-01
期刊：
影响因子：
3.4
通讯作者：
Schell, DM
中科院分区：
文献类型：
--
作者：
Ben-David, M;Hanley, TA;Schell, DM
产卵的太平洋鲑鱼（Onchorhynchus）将来自海洋的营养物质输送到溪流和河流中。随后，这些来自海洋的营养物质通过分解和捕食被纳入淡水和陆地食物网。本研究利用稳定同位素分析研究了太平洋鲑鱼产卵对陆地植被的影响。我们假设，与生长在其他地方的相同物种相比，靠近溪流或有鱼食性捕食者活动的地区的陆地植被将显示出更高的三角洲（15）N值。还调查了在三角洲（15）N升高时观察到的太平洋鲑鱼产卵对陆地消费者的影响。从河流到高原森林（0 ~ 1000 m）的18个样带中5种植物的数据表明，随着距离河流和相对海拔的增加，5种植物中有3种的δ (15)N值显著降低。在鱼食性捕食者积极利用的地点，植物的δ (15)N值高于生长在其他地方的相同植物，与溪流附近的测量值相似。随着离溪流距离的增加，小型哺乳动物肌肉中的δ (15)N值减少，δ (13)C值增加，这表明这种特征不是直接消耗鲑鱼尸体的结果，而是通过陆地植被间接吸收海洋来源的氮的结果。这些结果表明，鲑鱼尸体有助于河岸植被可利用的氮池。海洋来源氮的空间分布明显取决于洪水和鱼食性捕食者的活动模式。然而，这些氮添加到河岸带的重要性将取决于氮是否是该系统中植物生长的限制因素，并需要进一步研究。
Spawning Pacific salmon (Onchorhynchus) transport marine-derived nutrients into streams and rivers. Subsequently, these marine-derived nutrients are incorporated into freshwater and terrestrial food webs through decomposition and predation. In this study, we investigated the influence of spawning Pacific salmon on terrestrial vegetation using stable isotope analysis. We hypothesized that terrestrial vegetation near streams or in areas with activity of piscivorous predators will show higher delta(15)N values compared with the same species growing elsewhere. The influence of spawning Pacific salmon as observed in elevated delta(15)N in terrestrial consumers was also investigated. Data collected from five species of plants in 18 transects from the stream to the upland forest (0 to 1000 m) indicated that a significant decrease in delta(15)N values occurred with increase in distance and relative elevation from the stream in three of the five plant species sampled. Values of delta(15)N in plants at sites actively used by piscivorous predators were higher than those of the same plants growing elsewhere, and similar to values measured near the stream. A decrease in values of delta(15)N and increase in values of delta(13)C in muscles of small mammals, with increase in distance from the stream, indicated that this signature was not a result of direct consumption of salmon carcasses but rather an indirect assimilation of marine-derived nitrogen through terrestrial vegetation. These results indicate that salmon carcasses contribute to the nitrogen pool available to riparian vegetation. The spatial distribution of the marine-derived nitrogen is apparently determined by flooding and the activity patterns of piscivorous predators. The importance of these nitrogen additions to the riparian zone, however, will depend on whether nitrogen is a limiting factor to plant growth in this system, and requires further investigation.