Distribution differences and active habitat choices of invertebrates between macrophytes of different morphological complexity

Abstract

This study explores: (1) whether the abundance of macroinvertebrates differs between macrophytes differing in both morphological complexity and tolerance to nutrient enrichment; (2) whether the distribution of invertebrates between macrophytes is due to active habitat choice; and (3) whether invertebrates prefer structurally complex to simple macrophytes. Macroinvertebrate abundance was compared between two common soft-bottom plants in the Baltic Sea that are tolerant to eutrophication, Myriophyllum spicatum and Potamogeton pectinatus, and one common plant that is sensitive to eutrophication, Chara baltica. Both field sampling and habitat choice experiments were conducted. We recorded higher total macroinvertebrate abundance on the structurally complex M. spicatum than on the more simply structured P. pectinatus and C. baltica, but found no difference in macroinvertebrate abundance between P. pectinatus and C. baltica. In accordance with the field results, our experiment indicated that the crustacean Gammarus oceanicus actively chose M. spicatum over the other macrophytes. Besides, we found that G. oceanicus actively preferred complex to simply structured artificial plants, indicating that the animal distribution was at least partly driven by differences in morphological complexity between plant species. In contrast, the gastropod Theodoxus fluviatilis did not make an active habitat choice between the plants. Our findings suggest that human-induced changes in vegetation composition can affect the faunal community. Increased abundance of structurally complex macrophytes, for example, M. spicatum, can result in increased abundance of macroinvertebrates, particularly mobile arthropods that may actively choose a more structurally complex macrophyte.

Macrofaunistic Diversity in Vallisneria americana Michx. in a Tropical Wetland, Southern Gulf of Mexico

“…The greater abundance and diversity of fauna associated with SAV is explained considering the part the vegetation plays as feeding and nursery areas, and as physical refuges against predators (Moskness & Heck, 2006;Pelicice & Agostinho, 2006;Rozas & Minello, 2006;Genkai-Kato, 2007;Hansen et al, 2011). SAV is also a key component in maintaining ecosystem function, particularly in shallow systems with bottom-up trophic dynamics (Ni, 2001;Jaschinski & Sommer, 2008).…”

“…The high diversity values that have been recorded for aquatic invertebrates and fish in structured habitats are threatened by the drastic reduction in the surface area of limnetic ecosystems, as has been documented for several areas of the USA (Revenga et al, 2005;Dudgeon et al, 2006). The records of species that are threatened or in danger of extinction should thus be complemented in the short term with an analysis of their distribution patterns in habitats with a high biodiversity such SAV (for examples; Rozas & Minello, 2006;Genkai-Kato, 2007;Hansen et al, 2011), as these are drastically decreasing or disappearing in the wetlands of southeastern Mexico and, in general, on a global scale (Sheridan et al, 2003;Sánchez et al, 2007;Schloesser & Manny, 2007;Best et al, 2008). Considering the above, it has become necessary to carry out short term studies focused on understanding the dynamics, reproduction and production of macrophytes (Ruiz-Carrera & Sánchez, 2008;Liu et al, 2009), and to prepare inventories of species associated with SAV, together with their distribution, particularly in ecosystems and regions where information is still limited and social and economic situations prevent conservation programmes from being successful (Fisher & Christopher, 2007;Kiwango & Wolanski, 2008).…”

“…Among these habitats, submerged aquatic vegetation (SAV), harbour a high diversity of molluscs, macrocrustaceans and fish, by favouring a greater survival and growth of the associated populations (Minello & Zimmerman, 1991;Pelicice & Agostinho, 2006;Rozas & Minello, 2006;Cetra & Petrere, 2007;Genkai-Kato, 2007;Hansen et al, 2011). In structured habitats, as SAV, the faunistic diversity tends to be greater and mortality rate have a tendency to be lower than in non-structured habitats (Taniguchi et al, 2003;Gullström et al, 2008), although with exceptions (Bogut et al, 2007;Schultz & Kruschel, 2010).…”

“…In structured habitats, as SAV, the faunistic diversity tends to be greater and mortality rate have a tendency to be lower than in non-structured habitats (Taniguchi et al, 2003;Gullström et al, 2008), although with exceptions (Bogut et al, 2007;Schultz & Kruschel, 2010). In particular, SAV in coastal ecosystems provides structured habitats that shelter a greater abundance and diversity of invertebrates and fish, where species use the habitat to obtain protection against predators, and as feeding and reproduction areas (Minello & Zimmerman, 1991;Rozas & Minello, 2006;Genkai-Kato, 2007;Hansen et al, 2011).…”

Evaluation of a new sampling method for assessing Cladocera richness (Crustacea, Branchiopoda) in macrophyte-rich wetlands

“…Standard methods for sampling zooplankton have also been used (Maia-Barbosa et al, 2008;Kruk et al, 2009). These sampling methods may not be appropriate for particular environments, such as shallow wetlands macrophytes rich, because greater effort would be needed to try to minimize the possible effects of spatial scales, such as depth, architecture and richness of macrophytes (Vieira et al, 2007;Thomaz et al, 2008;Hansen et al, 2011;Lucena-Moya and Duggan, 2011).…”