The first observations of Ischnochiton (Mollusca, Polyplacophora) movement behaviour, with comparison between habitats differing in complexity

PeerJ

article

Kiran Liversage¹  Kirsten Benkendorff² 

[1] Estonian Marine Institute, University of Tartu;Marine Ecology Research Centre, Southern Cross University

关键词: Rock-pool;    Distribution;    Dispersal;    Chitons;    Habitat structure;    Intertidal boulder-field;   

DOI  :  10.7717/peerj.4180

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Most species of Ischnochiton are habitat specialists and are almost always found underneath unstable marine hard-substrata such as boulders. The difficulty of experimenting on these chitons without causing disturbance means little is known about their ecology despite their importance as a group that often contributes greatly to coastal species diversity. In the present study we measured among-boulder distributional patterns of Ischnochiton smaragdinus, and used time-lapse photography to quantify movement behaviours within different habitat types (pebble substrata and rock-platform). In intertidal rock-pools in South Australia, I. smaragdinus were significantly overdispersed among boulders, as most boulders had few individuals but a small proportion harboured large populations. I. smaragdinus individuals emerge from underneath boulders during nocturnal low-tides and move amongst the inter-boulder matrix (pebbles or rock-platform). Seventy-two percent of chitons in the pebble matrix did not move from one pebble to another within the periods of observation (55–130 min) but a small proportion moved across as many as five pebbles per hour, indicating a capacity for adults to migrate among disconnected habitat patches. Chitons moved faster and movement paths were less tortuous across rock-platform compared to pebble substrata, which included more discontinuities among substratum patches. Overall, we show that patterns of distribution at the boulder-scale, such as the observed overdispersion, must be set largely by active dispersal of adults across the substratum, and that differing substratum-types may affect the degree of adult dispersal for this and possibly other under-boulder chiton species.

【 授权许可】

CC BY