Multidecadal changes in the demersal community structure in an urban bay: Shift from a bottom- to a top-heavy pyramid
Multidecadal changes in the demersal community structure in an urban bay: Shift from a bottom- to a top-heavy pyramid
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城市海湾底层群落结构的数十年变化：从底部金字塔到顶部重金字塔的转变
DOI：
10.1016/j.pocean.2022.102767
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发表时间：
2022
影响因子：
4.1
通讯作者：
Shimizu Makoto
中科院分区：
文献类型：
--
作者：
Xia Shujuan;Yamakawa Takashi;Kuroki Mari;Horiguchi Toshihiro;Kodama Keita;Shiraishi Hiroaki;Shimizu Makoto
城市海湾的鱼类群落结构随着时间的推移而发生变化，由于人类活动，导致物种丰富度，多样性，鱼类组合组成和丰度的变化。东京湾是日本富营养化程度最高的城市海湾之一，每年夏季海湾底层水体都会出现缺氧现象。因此，在过去的几十年里，海湾的底栖生物群落在分类组成上发生了巨大的变化。我们分析了数据，从底拖网调查跨越35年来的特点几十年的变化，在东京湾的底栖生物群落的身体大小谱的斜率，作为一个可靠的指标，代表社会结构的变化。我们发现，由于小型甲壳类生物量的减少和大型板鳃类生物量的增加，群落从过去（1977-1995）的底部重金字塔转变为近年来（2003-2019）的顶部重金字塔。人类引起的缺氧可以促进头重脚轻的金字塔的形成，因为它会大量减少小型个体的数量。能源补贴的存在，以大规模的个人从内浅和外海湾地区以及远洋社区提供了一个可能的解释，头重脚轻的金字塔的持久性。
Fish community structures in urban bays have changed over time as a result of anthropogenic activities, leading to changes in species richness, diversity, fish assemblage composition, and abundance. Tokyo Bay is one of the most eutrophic urban bays in Japan, and hypoxia occurs every summer in the bottom water of the bay. Accordingly, the demersal community in the bay has undergone drastic changes in taxonomic composition over the past several decades. We analyzed data from a bottom trawl survey spanning 35 years to characterize multidecadal changes in the slopes of body size spectra of the demersal community in Tokyo Bay, as a reliable index to represent shifts in community structure. We found that the community shifted from bottom-heavy pyramids in the past (1977–1995) to top-heavy pyramids in recent years (2003–2019) due to a decrease in the biomass of small-sized crustaceans and an increase in the biomass of large-sized elasmobranchs. Human-induced hypoxia can promote the formation of top-heavy pyramids, as it decimates the number of small-sized individuals. The existence of energy subsidies to large-sized individuals from the inner-shallow and outer bay areas as well as the pelagic community provides a possible explanation for the persistence of top-heavy pyramids.