Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types

Aquatic Biology
Louisiana Department of Wildlife and Fisheries; US Fish and Wildlife Service; International Crane Foundation
By:  and 



Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes.

Publication type Article
Publication Subtype Journal Article
Title Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types
Series title Aquatic Biology
DOI 10.3354/ab00499
Volume 18
Issue 2
Year Published 2013
Language English
Publisher Inter-Research
Publisher location Oldendorf
Contributing office(s) Coop Res Unit Atlanta
Description 12 p.
First page 149
Last page 160
Online Only (Y/N) N
Additional Online Files (Y/N) N
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