MASS MORTALITY OF DIADEMA-ANTILLARUM .2. EFFECTS ON POPULATION-DENSITIES AND GRAZING INTENSITY OF PARROTFISHES AND SURGEONFISHES
MASS MORTALITY OF DIADEMA-ANTILLARUM .2. EFFECTS ON POPULATION-DENSITIES AND GRAZING INTENSITY OF PARROTFISHES AND SURGEONFISHES
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DOI：
10.1007/bf01313160
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发表时间：
1990-01-01
期刊：
影响因子：
2.4
通讯作者：
CARPENTER, RC
中科院分区：
文献类型：
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作者：
CARPENTER, RC
据推测，草食性鱼类和常规的海胆迪亚德马antillarum菲利普竞争底栖藻类作为其主要食物资源。大量死亡的D.在1984年2月，antillarum提供了一个机会来检验草食性鱼类和海胆以前竞争的假设。视觉普查的草食性鱼类进行了4年以上的四个礁区Tague湾礁，圣克鲁瓦，美属维尔京群岛，之前和之后的大规模死亡率表明，人口密度增加约三倍，在backreef和浅（2米）forereef区和两倍，四倍，分别在中间（5米）和深（10米）forereef区。少年鹦嘴鱼构成的主要组成部分，这些增加，除了在浅forefreef的棘鱼成为最丰富的。草食性鱼类的放牧强度增加后，立即在四个珊瑚礁区的大规模死亡。这些数据支持这一假设，即对藻类资源的剥削性竞争发生在海胆大规模死亡之前，尽管不能完全否定其他假设。尽管草食性鱼类的丰度和摄食量增加，但藻类群落的覆盖率和生物量继续增加，表明鱼类摄食量的增加并不能弥补D. Antillarum对藻类丰度和群落结构的控制作用。
It has been hypothesized that herbivorous fishes and the regular echinoid Diadema antillarum Philippi compete for benthic algae as their major food resource. Mass mortality of D. antillarum in February 1984 provided the opportunity to test the hypothesis that herbivorous fishes and sea urchins were competing previously. Visual censuses of herbivorous fishes conducted over 4 yr in four reef zones on Tague Bay Reef, St. Croix, U.S. Virgin Islands, before and after the mass mortality indicated that population densities increased approximately three-fold in backreef and shallow (2 m) forereef zones and two-fold, and four-fold in mid (5 m) and deep (10 m) forereef zones, respectively. Juvenile parrotfishes constituted the major component of these increases, except in the shallow forereef where acanthurids became most abundant. Grazing intensity by herbivorous fishes increased in three of the four reef zones immediately following the mass mortality. These data support the hypothesis that exploitative competition for algal resources was occurring prior to the sea urchin mass-mortality, although alternative hypotheses cannot be discounted completely. Despite the increases in the abundances of, and grazing by, herbivorous fishes, the algal community continued to increase in percent cover and biomass, indicating that increased grazing by fishes does not compensate for the loss of grazing by D. antillarum in controlling algal abundance and community structure.