Edgar G J, Aoki M
Amakusa Marine Biological Laboratory, Kyushu University, 863-25, Tomioka, Reihoku-cho, Kumamoto-ken, Japan.
Oecologia. 1993 Mar;95(1):122-133. doi: 10.1007/BF00649515.
The possibility that resource limits constrain the growth of mobile epifaunal populations associated withSargassum patens plants was investigated by placing plants and associated animals into field microcosms which excluded fish predators, and then comparing faunal abundance and size-structure changes in different microcosm treatments with field populations. Four different micrososm treatments were set up: two treatments containing defaunated plants inoculated with caprellid amphipods, and two control treatments with natural faunas. The estimated secondary production of faunas enclosed in all microcosm treatments rapidly settled on a constant value (5 mg/day) which was similar to that determined in experiments conducted in Western Australia using the same microcosms but for faunas associated with a seagrass rather than a macroalga. These results support the hypothesis that the secondary production of epifaunal communities associated with macrophytes is constrained by quantifiable food resource ceilings. Predation by the most common fish species in the area, the wrasseHalichoeres tenuispinis, did not appear to alter macrofaunal production in theS. patens bed; however, it did greatly affect the faunal size-structure by eliminating most of the larger animals. The majority of epifaunal animals ≥ 2.0 mm sieve-size were consumed byH. tenuispinis, while negligible numbers of 0.5-mm sieve-size animals were captured. We postulate that food resource ceilings and predatory size-selectivity are widespread phenomena, affecting epifaunal populations at a variety of locations. Predation is predicted to generally increase rather than decrease faunal abundance because the consumption of each large invertebrate by a predator frees sufficient resources to feed several smaller individuals.
通过将植物及其相关动物放置在排除鱼类捕食者的野外微观环境中，并将不同微观环境处理下的动物丰度和大小结构变化与野外种群进行比较，研究了资源限制是否会抑制与展枝马尾藻植物相关的移动表生动物种群增长。设置了四种不同的微观环境处理：两种处理包含接种了麦杆虫双足虾的无动物植物，两种对照处理包含自然动物群落。所有微观环境处理中包含的动物的估计次级生产量迅速稳定在一个恒定值（5毫克/天），这与在西澳大利亚使用相同微观环境但针对与海草而非大型藻类相关的动物进行的实验中确定的值相似。这些结果支持了这样的假设，即与大型植物相关的表生动物群落的次级生产量受到可量化的食物资源上限的限制。该区域最常见的鱼类物种——细棘海猪鱼的捕食似乎并未改变展枝马尾藻床中的大型动物生产量；然而，它确实通过消灭大多数较大的动物极大地影响了动物的大小结构。大多数筛孔尺寸≥2.0毫米的表生动物被细棘海猪鱼捕食，而被捕食的筛孔尺寸为0.5毫米的动物数量可以忽略不计。我们推测食物资源上限和捕食性大小选择性是普遍存在的现象，会影响不同地点的表生动物种群。预计捕食通常会增加而非减少动物丰度，因为捕食者对每只大型无脊椎动物的消耗会释放出足够的资源来养活几只较小的个体。
