生态因子对红螯相手蟹捕食毛蚶苗种的影响

敌害生物的捕食在控制海洋底栖生物群落的丰度和组成中起着关键性的作用。以红螯相手蟹(Sesarma haematocheir)和毛蚶(Scapharca subcrenata)为试验对象,研究了红螯相手蟹的密度、规格、性别,以及毛蚶的密度、规格、海水温度和底质条件对毛蚶苗种存活的影响。结果表明,蟹表现出了第二种类型的功能反应,高密度底播毛蚶苗种可以显著提高成活率;当毛蚶苗种壳长达到20mm以上时,蟹的摄食速率显著下降;随着蟹个体的增大,其摄食速率显著增加,毛蚶的存活率下降;当蟹的密度逐渐增加的时候,同种个体之间的干扰竞争显著提高了毛蚶存活率;雄蟹凭借强有力的螯导致了更多毛蚶苗种的死亡;海水温度较低的春季和秋季底播毛蚶苗种可以显著提高成活率;底质条件的复杂性和异质性为毛蚶的存活提供了"庇护空间",从而减少了敌害生物捕食所带来的损失。

Impact of ecological factors on the predation of the bloody clam (Scapharca subcrenata) by crabs (Sesarma haematocheir)

Predation is a key determinant in the regulation of species abundance and composition in marine benthic communities. The effect of predator density, size, sex, prey density, size, and temperature, substrate condition on predation was investigated using the crab (Sesarma haematocheir) and bloody clam (Scapharca subcrenata). The results indicate that crabs displayed the type II functional response, S. subcrenata seeded at high density improved the survival rate significantly. The feeding rates of crabs decreased significantly when shell length of the clam reached 20 mm. The feeding rates increased as crab size increased, and the survival rate of the clam decreased significantly. Interference competition between conspecifics improved the clam survival rate significantly as crab density increased. Male crabs with stronger claws leaded to higher deaths of S. subcrenata. Releasing of S. subcrenata in spring and autumn at relatively low temperature improved survival rate. Substrate of complexity and heterogeneity provided more spatial refuges for the clam survival, which reduced the loss from predation.