Chanket Wannarat, Wangkulangkul Kringpaka
Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand,
Zoolog Sci. 2019 Aug;36(4):330-338. doi: 10.2108/zs180196.
Many sea urchin species excavate pits in sedimentary rock, transforming primary rocky substrates into sea urchins' pits. These pits are not only used as their home but seem to harbor a distinct assemblage of organisms. We investigated small-scale spatial variation in community of macroinvertebrates by comparing community composition of epilithic macroinvertebrates between those found on unmodified rocky substrate, inside pits occupied by rock-boring sea urchin (Lamarck, 1816), and unoccupied pits, on an intertidal rocky shore in southern Thailand. Size structures of macroinvertebrates were compared between pits and analyses were performed to investigate whether the use of habitat depends on availability of space, or biological interactions between sea urchins and other macroinvertebrates. Size structure of the most abundant mobile fauna, top shells Gmelin, 1791, were also analyzed to assess whether they exhibit ontogenetic changes in habitat use. Although a few species were found in all habitat types, community compositions were different. Chitons and limpets were found exclusively on unmodified substrate; whereas relatively large-sized gastropods inhabited unoccupied pits, and occupied pits harbored small-sized crustacean and gastropod species. Generally, in occupied pits, small-sized faunas were more abundant than larger faunas, suggesting that sea urchin's body may function as a biogenic structure providing refugia for small-sized individuals. In unoccupied pits volume of all macroinvertebrates increased as available space increased. This was not observed in occupied pits, where disturbances due to sea urchin's activities may be more important in determining habitat use.
许多海胆物种会在沉积岩中挖掘坑洞，将原始的岩石基质转变为海胆坑。这些坑洞不仅被用作它们的家，而且似乎还栖息着独特的生物群落。我们通过比较泰国南部潮间带岩石海岸上未改造的岩石基质上、钻岩海胆（拉马克，1816年）占据的坑洞内部以及未被占据的坑洞上的附石大型无脊椎动物群落组成，研究了大型无脊椎动物群落的小尺度空间变化。比较了坑洞之间大型无脊椎动物的大小结构，并进行了分析，以研究栖息地的利用是否取决于空间的可用性，或者海胆与其他大型无脊椎动物之间的生物相互作用。还分析了最丰富的移动动物——荔枝螺（梅林，1791年）的大小结构，以评估它们在栖息地利用方面是否表现出个体发育变化。尽管在所有栖息地类型中都发现了一些物种，但群落组成有所不同。石鳖和帽贝仅在未改造的基质上被发现；而相对较大的腹足类动物栖息在未被占据的坑洞中，被占据的坑洞则栖息着小型甲壳类动物和腹足类物种。一般来说，在被占据的坑洞中，小型动物比大型动物更为丰富，这表明海胆的身体可能起到生物源结构的作用，为小型个体提供避难所。在未被占据的坑洞中，随着可用空间的增加，所有大型无脊椎动物的数量都有所增加。而在被占据的坑洞中则未观察到这种情况，在被占据的坑洞中，海胆活动造成的干扰在决定栖息地利用方面可能更为重要。
