Habitat complexity and community composition: relationships between different ecosystem engineers and the associated macroinvertebrate assemblages

Abstract

Several species of ecosystem engineers inhabiting coastal environments have been reported structuring different kinds of communities. The magnitude of this influence often depends on the habitat complexity introduced by the engineers. It is commonly accepted that an increase in habitat complexity will result in an increase in diversity and/or abundance in the associated fauna. The rocky salt marshes along the coast of Patagonia are dominated by cordgrasses, mussels, and barnacles forming a mosaic of engineered habitats with different complexity. This system allows us to address the following questions: how different is a macroinvertebrate assemblage when dominated by different ecosystem engineers? And, is there a positive relationship between increasing habitat complexity and the species richness, diversity and total density of the assemblages? To address these questions, we compared the three ecological scenarios with decreasing habitat complexity: cordgrass-mussel, mussel, and barnacle-engineered habitats. We found a total of 22 taxa mostly crustaceans and polychaetes common to all scenarios. The three engineered habitats showed different macroinvertebrate assemblages, mainly due to differences in individual abundances of some taxa. The cryptogenic amphipod Orchestia gammarella was found strictly associated with the cordgrass-mussel habitat. Species richness and diversity were positively related with habitat complexity while total density showed the opposite trend. Our study suggests that species vary their relative distribution and abundances in response to different habitat complexity. Nevertheless, the direction (i.e., neutral, positive or negative) and intensity of the community's response seem to depend on the physiological requirements of the different species and their efficiency to readjust their local spatial distribution in the short term.

The role of the physical structure of Spartina densiflora Brong. in structuring macroinvertebrate assemblages

“…In this kind of coastal marshes, the crevices and tide pools across the intertidal are literally filled up with Spartina rhizomes and roots, shell fragments and sand, what makes it look like as environmental hybrid between a rocky intertidal and a muddy salt marsh. The addition of new and abundant biogenic structure on top of a rocky wave-cut platform may have important consequences for the local faunal assemblages (Bortolus et al 2009;Sueiro et al 2010).…”

Histological Study on the Reversal Gonadal Activity in the Mussel Lithophaga truncata (Gray, 1843) during Testicular Phagocytosis (Pelecypoda - Mytilidae)

“…The external environmental and exogenous factors regulate gametogenesis and spawning in marine bivalves (Boltovskoy, et al 2011). The reproductive cycle in marine pelecypods may take place annually, half annually or continuously depending on the species and environmental conditions (Sueiro, et al 2011;Naval, 2013). Gametogenesis can be energetically accelerated from two sources: stored reserves in the mantle tissue (Bhaby, et al 2014); recently ingested nutrients (Bhaby, et al 2013); or a combination of both (Sueiro, 2014).…”

Comparison of life history traits of Tanais dulongii (Tanaidacea: Tanaididae) in natural and artificial marine environments of the south-western Atlantic

“…Tanais dulongii lives in self-constructed tubes and feeds principally on detritus and algae, and it is commonly found in benthic environments of Argentina (Adami et al 2004;Sueiro et al 2011;Rumbold et al 2012Rumbold et al , 2014. Several aspects of the biology of this species have been studied, such as behaviour, development, reproduction, morphometry and population dynamics (Johnson and Attramadal 1982a, b;Borowsky 1983;Perez-Ruzafa and Sanz 1993;Hamers and Franke 2000;Rumbold et al 2012Rumbold et al , 2014Rumbold et al , 2015, but interpopulational comparative studies are scarce (Pennafirme and Soares-Gomes 2009;Rumbold et al 2014).…”