Wrack resource use by intertidal consumers on sandy beaches. (31st May 2019)

• Record Type: Journal Article
• Authors: Michaud, Kristen M.; Emery, Kyle A.; Dugan, Jenifer E.; Hubbard, David M.; Miller, Robert J.
• Is Part Of: Estuarine, coastal and shelf science. Volume 221(2019)
• Page Start: 66
• Page End: 71
• Publication Date: 2019-05-31
• Subjects: Niche separation -- Consumer-resource dynamics -- Subsidies -- Drift macrophytes -- Macroinvertebrates -- Megalorchestia spp; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2019.03.014
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: The coexistence of ecologically similar species is often assumed to be facilitated by differential resource and habitat use. For sandy beach ecosystems characterized by low primary productivity, a suite of intertidal consumers relies on subsidies of allochthonous marine macrophytes, or wrack, as both food and habitat. To investigate how intertidal consumers may partition macrophyte wrack resources on sandy beaches, we measured individual consumption rates of four talitrid amphipod species ( Megalorchestia spp .) on five macrophyte species in laboratory and field trials. Laboratory rates of consumption of macrophytes differed significantly among consumers, but general patterns were similar. Feather boa kelp ( Egregia menziesii), was consumed at the highest rate by all species, rather than the more abundant giant kelp ( Macrocystis pyrifera). In the field trials, talitrid amphipods were more abundant under experimental wrack patches containing kelps, and consumption of feather boa kelp was higher than for giant kelp or surf grass ( Phyllospadix torreyi ). Our results demonstrate that a suite of co-occurring talitrid amphipod species rely heavily on kelp wrack and suggest that these abundant intertidal consumers do not partition wrack resources. Highlights: Feeding rates suggest that wrack consumers do not partition food resources. Talitrid amphipods consumed a less abundant kelp species at a higher rate. Consumers preferentially colonized wrack patches containing kelps.