Forbes Valery E, Lopez Glenn R
Marine Sciences Research Center, State University of New York, 11794, Stony Brook, NY, USA.
Oecologia. 1990 May;83(1):53-61. doi: 10.1007/BF00324634.
We test the hypothesis that body size and population density of the deposit-feeding gastropod, Hydrobia truncata, are greater in muddy than in sandy habitats as a result of faster growth on fine- compared to coarse-grained sediments. We refute this hypothesis using a combination of field measurements and laboratory experiments. Three out of three populations tested had higher maximal growth rates and two of three populations approached their asymptotic size more quickly on sand than on silt-clay fractions of natural sediment. Growth decreased with increasing snail density and was as high or higher on sand as on silt-clay at all densities. Two populations were more fecund on sand than on silt-clay, and fecundity of the third population was not affected by sediment type. We show that the smaller body sizes observed in snails from the sandiest habitat result from late recruitment of these snails, relative to the other populations.
由于在细颗粒沉积物上的生长速度比在粗颗粒沉积物上更快，沉积食性腹足动物截形扁卷螺（Hydrobia truncata）在泥质生境中的体型和种群密度要大于沙质生境。我们通过野外测量和实验室实验相结合的方式驳斥了这一假设。所测试的三个种群中，有三个种群在沙质沉积物上的最大生长速率更高，并且在三个种群中有两个种群在沙质沉积物上比在天然沉积物的粉砂-粘土部分更快地接近其渐近体型。生长随着蜗牛密度的增加而降低，并且在所有密度下，沙质沉积物上的生长与粉砂-粘土上的生长一样高或更高。有两个种群在沙质沉积物上的繁殖力高于粉砂-粘土，而第三个种群的繁殖力不受沉积物类型的影响。我们表明，在最沙质的生境中观察到的蜗牛体型较小是由于这些蜗牛相对于其他种群招募较晚所致。
