Talitrids on the upper shore and strandline

Description of Talitrids on the upper shore and strandline


flag A2.211
creatorIdentity remo
creationTime 2017-08-16T16:38:13.038
lastMaintainerIdentity remo
modificationTime 2016-03-16T18:42:49
id 2770
imageSize 0 Bytes

A community of sandhoppers (talitrid amphipods) may occur on any shore where driftlines of decomposing seaweed and other debris accumulate on the strandline. The biotope occurs most frequently on medium and fine sandy shores, but may also occur on a wide variety of sediment shores composed of muddy sediment, shingle and mixed substrata, or on rocky shores. The decaying seaweed provides cover and humidity for the sandhopper Talitrus saltator. In places on sand that regularly accumulate larger amounts of weed, Talorchestia deshayesii is often present. Oligochaetes, mainly enchytraeids, can occur where the stranded debris remains damp as a result of freshwater seepage across the shore or mass accumulation of weed in shaded situations. On shingle and gravel shores and behind saltmarshes the strandline talitrid species tend to be mainly Orchestia species. Abundances of the characterising species tend to be highly patchy. Two characterising species lists are presented below. They are derived from two sets of data, which were analysed separately. The first shows data from infaunal samples, the second shows data from epifaunal samples. The epifaunal lists contains no counts per square metre, as the data were collected on the SACFOR scale. Situation: This unit may occur on the same shore as a range of sediment (especially sandy) biotopes, where driftlines of algae and other debris accumulate on the upper shore. These biotopes include units A2.111, A2.221, A2.222, A2.223, and A2.231. The biotope also occurs at the back of boulder, cobble and pebble shores, above mixed sediment and rocky biotopes. Temporal variation: This biotope varies in its position between spring and neap tides, and as a result of changing weather. After storms, it may extend into the fore dunes, during spring tides it will occur high on the shore, and during neaps the greatest numbers of talitrids may be found at or just below MHWN level. The amount of debris washed up on strandlines, and hence the extent of this biotope, may also vary significantly depending on factors such as recent storms or high tides.