Impacts of habitat degradation on Fundulus heteroclitus (Linnaeus) in urban tidal salt marshes in New York
Item
-
Title
-
Impacts of habitat degradation on Fundulus heteroclitus (Linnaeus) in urban tidal salt marshes in New York
-
Identifier
-
d_2009_2013:42de7287a9fa:10103
-
identifier
-
10181
-
Creator
-
Goto, Daisuke,
-
Contributor
-
William G. Wallace
-
Date
-
2009
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Ecology | Biological oceanography | Environmental science | Fish bioenergetics | Forage fish | Metal trophic transfer | Salt marshes | Trophic ecology | Zoobenthos
-
Abstract
-
Despite considerable improvements in water quality over the last few decades, the ecological integrity of benthic habitats in the Arthur Kill (AK), New York, USA, largely remains altered. This dissertation explores how altered ecological status of benthic habitats directly and indirectly (via food webs) affected a resident forage fish, mummichogs (Fundulus heteroclitus ), in highly urbanized tidal salt marshes in AK. A substantial portion of total abundance and biomass of benthic macroinvertebrates (a primary prey resource for mummichogs) in AK were comprised of only a few opportunistic oligochaete and polychaete species. And these alterations in benthic macroinfaunal communities in AK were strongly associated with the sediment-associated mercury level. Alterations in the AK benthic macroinfaunal assemblages were generally reflected in diet habits and strategies of mummichogs; a generalized feeding strategy with a broad diet niche breadth of mummichogs shifted to more specialized strategies for many of the AK populations. Although decapods (especially Palaemonetes spp.) were the predominant prey for all populations of mummichogs, the length-specific maximum sizes of Palaemonetes spp. ingested by some of the AK populations of mummichogs were about 2-fold smaller than those ingested by the reference population. These shifts in feeding habits were compensated for with an increased consumption of polychaetes by most of the AK populations and polychaetes contributed up to more than 40% of their gut contents. Partial trophic decoupling between mummichogs and dominant benthic macroinvertebrates had further implications for biogeochemical cycling of trace metals and energy transfer in AK. Alterations in benthic macroinfaunal prey communities reduced trophic transfer efficiency (i.e., exposure levels) of metals to mummichogs. Furthermore, despite their compensatory food consumption, most of the AK populations of mummichogs had considerably elevated total metabolism, resulting in substantially reduced growth conversion efficiency. This reduction in energy conversion efficiency at the individual level can cascade through trophic chains, potentially leading to energetic bottlenecks at the community level. Altered salt marsh trophic structures in AK and their resultant impacts on mummichog (a crucial trophic link in urban estuaries) bioenergetics may thus disrupt energy translocation in this severely degraded coastal ecosystem.
-
Type
-
dissertation
-
Source
-
2009_2013.csv
-
degree
-
Ph.D.
-
Program
-
Biology
