Kohn Alan J
Department of Zoology, University of Washington, 98195, Seattle, Washington, USA.
Oecologia. 1983 Dec;60(3):293-301. doi: 10.1007/BF00376841.
Frequency and per cent cover of particular substratum types are shown to be important factors influencing abundance and diversity of mobile, predatory benthic invertebrates on spatially complex coral reef platforms. The most favorable portions of reefs for the gastropod Conus have <20% cover of algal-bound sand and <20% cover of living coral. The former microhabitat provides diurnal shelter for smaller Conus, harbors dense prey populations, and is typically interspersed with sand- and rubble-filled depressions in which many of the gastropods shelter during the day. In Micronesia and Australian Great Barrier Reef censuses, 39 1x10-m transects on favorable habitat supported an average of 7 Conus of 3 species. In striking contrast, portions of reef with >20% living coral are most unfavorable for Conus. Here density averaged 0.3 individual/10 m, in 17 transects. Living coral harbors few suitable prey organisms, and contact with it elicits a strong avoidance response by Conus. Comparison of subtidal reef and intertidal bench habitats indicates that species diversity and population density are inversely related, but within both habitat types these attributes of Conus assemblages are positively associated.
特定基质类型的频率和覆盖百分比被证明是影响空间复杂珊瑚礁平台上活动的、掠食性底栖无脊椎动物丰度和多样性的重要因素。对于腹足纲芋螺来说，珊瑚礁最适宜的区域藻类附着沙覆盖小于20%，活珊瑚覆盖小于20%。前一种微生境为较小的芋螺提供日间庇护所，容纳密集的猎物种群，并且通常散布着充满沙子和碎石的洼地，许多腹足纲动物白天在其中躲避。在密克罗尼西亚和澳大利亚大堡礁的普查中，在适宜栖息地的39个1×10米样带上平均有3种7只芋螺。形成鲜明对比的是，活珊瑚覆盖大于20%的珊瑚礁区域对芋螺最不利。在17个样带中，这里的密度平均为0.3只/10米。活珊瑚中适合的猎物生物很少，与活珊瑚接触会引发芋螺强烈的回避反应。潮下带珊瑚礁和潮间带台地栖息地的比较表明，物种多样性和种群密度呈负相关，但在这两种栖息地类型中，芋螺群落的这些属性呈正相关。
