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1.
Flume nets of various lengths and a 3-m seine were used to sample the fishes and macrocrustaceans using a flooded Louisiana salt marsh and the adjacent tidal creek. The experiment allowed for species-specific comparisons of the flooded marsh at the creek edge versus the interior. Of the 37,667 organisms collected in flume nets from January through November 1989, 89% were decapods (nine species) and 11% were fish (29 species). An additional 18,539 organisms (75% decapods and 25% fish) were collected from concurrent seine samples taken from July through November. Comparison of catches among different flume lengths and low tide versus high tide seine collections revealed distinct patterns of marsh habitat utilization. Densities of most organisms were highest within 3 m of the water’s edge, but significant numbers of marsh-resident fish species used the interior marshes. The edge marshes appeared to be used by both transient and resident species; however, the interior marshes were used primarily by marsh-resident species (Cyprinodontiformes andPalaemonetes sp.) that are excellent food sources for adult transient-species. Four zonations of marsh use are described for transients, residents, and rare species. 相似文献
2.
Fishes and invertebrate macrofauna (nekton) were sampled biweekly (July through October 1985) from the surface of tidal freshwater marshes. Samples were collected with flume nets at three different stream orders (orders 2, 3 and 4+) along a marsh stream order gradient. Twenty-five species of fishes (5,610 individuals, 17.072 kg preserved wet weight) representing 13 families, and three species of invertebrates (19,570 individuals, 13.026 kg preserved wet weight) were collected. The most abundant species were grass shrimp (Palaemonetes pugio), mummichogs (Fundulus heteroclitus), banded killifish (F. diaphanus), inland silversides (Menidia beryllina), and blue crabs (Callinectes sapidus). Invertebrate catches (mostly grass shrimp and blue crabs) were not significantly different among stations. Total numbers of fishes were significantly greater at both headwater (order 2) and main creek (order 3) stations than river (order 4+) stations, but catches of headwater and main creek stations were not significantly different. The relationship between marsh stream order and fish abundance may partly be related to the distribution of submerged aquatic vegetation (SAV) within marsh tidal creeks. Submerged aquatic vegetation decreases in abundance with increasing stream order. Some species may use SAV as a refuge from predators or as a foraging area during low tide when the marsh surface is inaccessible. The presence of SAV in tidal creeks may enhance the habitat value of adjacent marshes. 相似文献
3.
The surface of the salt marsh is an important, but largely unrecognized, site for fish reproduction and larval growth. In an attempt to determine the composition and distribution of fishes utilizing these habitats, we sampled larval and juvenile fish with plankton nets, dip nets, and traps at a variety of microhabitats (tidal and nontidal ponds and ditches and the marsh surface) in three New Jersey high marshes. Two of the three marshes had been altered for mosquito control. During April to September 1980, we collected over 2,400 larvae and juveniles. All study sites were dominated by the larvae of the resident killifishes (Fundulus heteroclitus, Cyprinodon variegatus, F. luciae, andLucania parva) and less commonlyMenidia beryllina. However, the occurrence and abundance of each species varied with microhabitat. Larval production in all three marshes peaked during June–July, but extended from May until September. In most instances juveniles of the dominant fishes had microhabitat preferences similar to the larvae. High marshes may be more important for fish production than previously recognized because they serve as nursery areas for the resident killifishes. 相似文献
4.
Salt marsh habitats influenced by southern California's mixed, semi-diurnal tides are, on average, accessible to fishes less than 16% of the time. However, five species (four natives, one oxotic) and a variety of juvenile and adult size classes were collected on the marsh surface during a year-long sampling from June 1997 through June 1998 at Sweetwater Marsh National Wildlife Refuge on San Diego Bay.Fundulus parvipinis andGillichthys mirabilis were the most abundant fish species using the marsh. Analyses of their guts revealed that the marsh surface provides a rich foraging area for fishes on high spring tides.F. parvipinnis with marsh access consumed six times as much food as fishes restricted to creek habitats (on a g-food g-fish?1 basis) and also fed on additional prey types. Because the salt marsh is an important foraging area for fishes, we recommend that restoration projects (especially those intended to mitigate lost fish habitat) include vegetated areas with interconnecting tidal creeks. 相似文献
5.
In a continuing effort to monitor the fish response to marsh restoration (resumed tidal flow, creation of creeks), we compared
qualitative and quantitative data on species richness, abundance, assemblage structure and growth between pre-restoration
and post-restoration conditions at two former salt hay farms relative to a reference marsh in the mesohaline portion of Delaware
Bay. The most extensive comparison, during April–November 1998, sampled fish populations in large marsh creeks with otter
trawls and in small marsh creeks with weirs. Species richness and abundance increased dramatically after restoration. Subsequent
comparisons indicated that fish size, assemblage structure, and growth of one of the dominant species,Micropogonias undulatus, was similar between reference and restored marshes 1 and 2 yr post-restoration. Total fish abundance and abundance of the
dominant species was greater, often by an order of magnitude, in one of the older restored sites (2 yr post-restoration),
while the other restored site (1 yr post-restoration) had values similar to the reference marsh. The success of the restoration
at the time of this study suggests that return of the tidal flow and increased marsh area and edge in intertidal and subtidal
creeks relative to the former salt hay farms contributed to the quick response of resident and transient young-of-the-year
fishes. 相似文献
6.
We sampled nekton (fishes and decapod crustaceans) in submerged aquatic vegetation (SAV) (Potanogeton nodosus, Najas guadalupensis), in emergent marsh vegetation (Sagittaria spp. andScirpus americanus), and over unvegetated bottom associated with three islands in the Atchafalaya River Delta, Louisiana. The purpose of our study was to quantify nekton densities in these major aquatic habitat types and to document the relative importance of these areas to numerically dominant aquatic organisms. We collected a total of 33 species of fishes and 7 species of crustaceans in 298 1-m2 throw trap samples taken over three seasons: summer (July and August 1994), fall (September and October 1994), and spring (May and June 1995). Fishes numerically accounted for >65% of the total organisms collected. Vegetated areas generally supported much higher nekton densities than unvegetated sites, although bay anchoviesAnchoa mitchilli were more abundant over unvegetated bottom than in most vegetated habitat types. Among vegetation types, most species showed no apparent preference between SAV and marsh. However, inland silversidesMenidia beryllina and freshwater gobiesGobionellus shufeldti were most abundant inScirpus marsh in summer, and blue crabsCallinectes sapidus were most abundant in SAV (Potamogeton) in spring. Several species (sheepshead minnowCyprinodon variegatus, rainwater killifishLucania parva, and blue crab) apparently selected the vegetated backmarsh of islands (opposite of riverside) over stream-sideScirpus marsh. Freshwater gobies, in contrast, were most abundant in streamsideScirpus marsh. Densities of juvenile blue crabs were high (up to 17 m−2) in vegetated delta habitat types and comparable to values reported from more saline regions of Gulf Coast estuaries. Shallow vegetated habitat types of the Atchafalaya River Delta and other tidal freshwater systems of the Gulf Coast may be important nursery areas for blue crabs and other estuarine species. 相似文献
7.
Few studies concerning tide-restricted and restoring salt marshes emphasize fishes and decapod crustaceans (nekton) despite
their ecological significance. This study quantifies nekton utilization of three New England salt marshes under tide-restricted
and restoring conditions (Hatches Harbor, Massachusetts; Sachuest Point and Galilee, Rhode Island). The degree of tidal restriction
differed among marshes allowing for an examination of nekton utilization patterns along a gradient of tidal restriction and
subsequent restoration. Based on sampling in shallow subtidal creeks and pools, nekton density and richness were significantly
lower in the restricted marsh compared to the unrestricted marsh only at the most tide-restricted site (Sachuest Point). The
dissimilarity in community composition between the unrestricted and restricted marsh sites increased with more pronounced
tidal restriction. The increase in nekton density resulting from tidal restoration was positively related to the increase
in tidal range. Species richness only increased with restoration at the most tide-restricted site; no significant change was
observed at the other two sites. These patterns suggest that only severe tidal restrictions significantly reduce the habitat
value of New England salt marshes for shallow subtidal nekton. This study suggests that the greatest responses by nekton,
and the most dramatic shift towards a more natural nekton assemblage, will occur with restoration of severely restricted salt
marshes. 相似文献
8.
Janet M. Fischer Tara Reed-Andersen Jennifer L. Klug Alice G. Chalmers 《Estuaries and Coasts》2000,23(4):565-571
Geomorphology may be an important predictor of vegetation pattern in systems where suceptibility to disturbance is unevenly
distributed across the landscape. Salt marsh communities exhibit spatial pattern in vegetation at a variety of spatial scales.
In coastal Georgia, the low marsh is a virtual monoculture ofSpartina alterniflora interspersed with patches of species that are more typical of the high marsh. These localized disturbances are most likely
created by wrack mats, mats of dead vegetation which can compact and smother underlying vegetation creating bare patches for
colonization by high marsh species. We investigated the spatial pattern of disturbed patches along a 2 km section of Dean
Creek, a tidal creek at the southwestern end of Sapelo Island, Georgia, U.S. We used a discriminant model to explore the relationship
between tidal creek morphology (e.g., the presence of drainage channels and creek bends) and the spatial distribution of disturbed
patches. The model predicted vegetation pattern along the creek with relatively high accuracy (>70%). Areas where water movement
is slowed or multidirectional (e.g., along creek bends and near drainage channels) were most susceptible to disturbance. Our
findings suggest an important functional linkage between geomorphology and vegetation pattern in salt marsh communities. 相似文献
9.
A fundamental question in ecology is how biological interactions and biogeographic processes interact to determine the biodiversity
of local sites. We quantified patterns of plant species diversity on transects across elevation at 59 salt marsh sites in
Georgia and 49 sites in Texas. Although these regions have similar climates and floras, we anticipated that diversity might
differ because of differences in tidal regime. Diversity was measured at global, regional, site, and plot scales to consider
processes occurring at all levels. Species pools were similar between regions. Texas had greater diversity at the site and
plot scales, suggesting that processes occurring at the site scale differed. The greater diversity of Texas sites and plots
was associated with wider distributions of individual species across the marsh landscape and proportionally more middle marsh
(a high diversity zone) and less low marsh (a low diversity zone) than in Georgia marshes. Preliminary data suggested that
these differences were not due to differences in salinity regime or standing biomass between regions, leaving differences
in tidal regime as the most plausible hypothesis accounting for differences in plant diversity. We speculate that the less-predictable
tidal regime in Texas leads to temporal variation in abiotic conditions that limit the ability of any one species to competitively
exclude others from particular marsh zones. 相似文献
10.
Juan Pablo Isacch Daniel Augusto Cardoni Oscar Osvaldo Iribarne 《Estuaries and Coasts》2014,37(1):229-239
We studied variation in bird assemblages with plant associations for three different coastal marshes from Southeastern South America (SESA) and assessed how marsh bird assemblages related to nearby upland bird assemblages. We surveyed bird species and plant structure along the tidal gradient of each locality from the low tide level to the upper habitats bordering coastal marshes. Twenty species frequently used coastal marshes, including relatively few migratory species. We found that birds occurring in SESA coastal marshes do not have distributions constrained to coastal marshes. Nonetheless, four bird assemblages were recognized in association with vegetation types and/or sites. Among the recorded coastal marsh species, the bay-capped wren-spinetail (Spartonoica maluroides) is both the most frequent and the most habitat constrained. Bird richness increases steadily along the tidal gradient associated with the increase in vegetation structure, suggesting that bird richness is directly explained by vegetation and indirectly by the physical conditions influencing vegetation structure. Results highlight the importance of SESA middle marshes as habitat for conservation of some threatened SESA grassland birds. 相似文献
11.
We examined the 5-yr (1996–2000) response of subtidal marsh creek fishes (2,793 trawls, 47 species, 30,719 fish) to a large
marsh restoration project in the upper Delaware Bay, and found that the salinity gradient covaried along with marsh surface
vegetation type among two treated and one untreated reference sites, confounding direct comparison of fish utilization. Examination
of environmental correlates with monthly yearly trends highlighted differences between potential mechanism driving assemblage
dynamics either intrinsic or extrinsic to the marshes. Within-site and among-site differences in fish assemblage, as described
by principal components analysis, correlated poorly with marsh vegetation on both seasonal and interannual scales and appeared
to driven by larval supply. Assemblage dynamics could be expalined in part by the occurrence of juveniles of transient marine
fishes along a salinity gradient (0–15.2%) range in monthly site mean), but were largely determined by fluctuations in the
distribution of two transient species: young-of-the-year bay anchovyAnchoa mitchilli and Atlantic croakerMicropogonias undulatus. A minor mode in variance, driven by locally spawned species, was moderately correlated with environmental parameters. Analysis
of marshes on an individual basis did not discern additional important gradients. Our findings are in contrast to those in
systems dominated by resident species, probably because transient fishes, which often dominante the system, are more plastic
to the nature of ecological services or are affected as much by environment outside of the marsh as by that in the marsh. 相似文献
12.
Tidal marsh functions are driven by interactions between tides, landscape morphology, and emergent vegetation. Less often considered are the diurnal pattern of tide extremes and seasonal variation of solar insolation in the mix of tidal marsh driver interactions. This work demonstrates how high-frequency hydroperiod and water temperature variability emerges from disparate timescale interactions between tidal marsh morphology, tidal harmonics, and meteorology in the San Francisco Estuary. We compare the tidal and residual flow and temperature response of neighboring tidal sloughs, one possessing natural tidal marsh morphology, and one that is modified for water control. We show that the natural tidal marsh is tuned to lunar phase and produces tidal and fortnight water temperature variability through interacting tide, meteorology, and geomorphic linkages. In contrast, temperature variability is dampened in the modified slough where overbank marsh plain connection is severed by levees. Despite geomorphic differences, a key finding is that both sloughs are heat sinks in summer by latent heat flux-driven residual upstream water advection and sensible and long-wave heat transfer. The precession of a 335-year tidal harmonic assures that these dynamics will shift in the future. Water temperature regulation appears to be a key function of natural tidal sloughs that depends critically on geomorphic mediation. We investigate approaches to untangling the relative influence of sun versus tide on residual water and temperature transport as a function of system morphology. The findings of this study likely have ecological consequences and suggest physical process metrics for tidal marsh restoration performance. 相似文献
13.
The mummichog,Fundulus heteroclitus, is one of the most abundant macrofaunal components of salt marsh ecosystems along the east coast of the United States. During April–November 1998, we determined the habitat use and movement patterns of young-of-the-year (YOY) and adult mummichogs in a restored marsh, formerly a salt hay farm, and an adjacent creek in order to expand our understanding of the ecology of the species and evaluate the success of the restoration. Four major fish habitat types (large first-order natural creek, second-order created creek, linear drainage ditch, and marsh surface) were identified within the study site. Patterns of relative abundance and mark and recapture using coded wire tags were used to determine the habitat use, tidal movements, home range, and site fidelity of the species within these habitat types. A total of 14,784 fish, ranging from 20–100 mm SL, were captured with wire mesh traps and tagged, and 1,521 (10.3%) fish were recaptured. A variety of gears were used to attempt to recapture fish across all habitat types, including wire mesh traps, push nets, and otter trawls. Based on abundance and recaptures of tagged fish, the YOY and adults primarily used the shallow subtidal and intertidal areas of the created creek, the intertidal drainage ditches, and the marsh surface of the restored marsh but not the larger, first-order natural creek. At low tide, large numbers were found in the subtidal areas of the created creek; these then moved onto the marsh surface on the flooding tide. Elevation, and thus hydroperiod, appeared to influence the microscale use of the marsh surface. We estimated the home range of adults and large YOY (20–100 mm SL) to be 15 ha at high tide, which was much larger than previously quantified. There was strong site fidelity to the created creek at low tide. The habitat use and movement patterns of the mummichog appeared similar to that reported for natural marshes. Coupled with the results of other studies on the feeding, growth, and production of this species in this restoreh, the species appeared to have responded well to the restoration. 相似文献
14.
Salt marshes are widely believed to serve as nurseries for many fishes and crustaceans of fishery value as a result of the high production of vascular plant detritus and the protection from predation offered by shallow, spatially complex habitats. Comparisons of the yields of species which reside in salt marsh habitats during critical life history stages (such as penaeid shrimp) with the area of such habitats and their greater densities in flooded marshes and associated tidal creeks support the premise that marshes enhance the yield of such species. A range of evidence, including the amount of detrital export from marshes, the poor nutritive value of vascular plant detritus, and natural diets, casts doubt on the notion that production of fishery species is based on the direct consumption of marsh grass detritus or predominantly on food chains based on this detritus. Vascular plants and associated algae may, however, contribute to the production of prey species. The limited observations available support the hypothesis that salt marshes offer significant escape from mortality due to predation, but there have been yet few experimental tests of this hypothesis. Knowledge of relative importance of the food and refuge functions in support of living resources is of practical value in marsh and fisheries management. Better understanding of these roles is important to the effective evaluation of the effects of coastal habitat modifications on fisheries resources and design of alterations to minimize the losses of these values. 相似文献
15.
Beach seines are widely used to estimate the density and species richness of fishes in estuaries. We evaluated the causes
and extent of bias in estimates from seines using a series of field experiments in small estuaries in southern California,
USA. Seining in spatially paired areas that were either enclosed by block nets or not, revealed that seines used without block
nets und erestimated density by more than 4-fold and species richness by more than 2-fold relative to blocked areas. Seining
in paired blocked areas with seines of two lengths revealed that net length affected estimates of density, but not species
richness; a 7.6-m long seine produced 1.6-fold higher estimates of total density than did a 15.2-m long seine due to increased
catches of demersal fishes, but not midwater species. Paired sampling in blocked areas also revealed that many fishes initially
evaded capture by the seine. Estimates of density but not species richness were significantly higher in areas through which
a seine was swept 5 times compared to once. This was due to higher catches of demersal fishes but not midwater fishes in areas
seined 5 times. Repeated seining through blocked areas revealed that the vast majority (90% or more) of species and individuals
of midwater fishes were captured within the first 5 sweeps, compared to only about 50% of the individuals of demersal species.
A mark-recapture study in blocked areas revealed lower probabilities of capture for demersal species relative to midwater
species. 相似文献
16.
Comparison of the relative abundance of fish species from different life-history groups and their temporal patterns of estuarine habitat use from two estuaries north and south of Cape Cod indicates that the Cape acts as a zoogeographic boundary. Between April 1988 and December 1989, monthly seine and trawl samples were collected from nearshore, shallow-water marsh, and beach and deeper open-water habitats in Wells Harbor, Maine, and Waquoit Bay, Massachusetts. Forty-eight species and 80,341 individuals were collected from Waquoit Bay compared to 24 species and 22,561 individuals from Wells Harbor. Waquoit Bay had proportionally fewer resident species and more marine, nursery, and occasional species than Wells Harbor. Annual density and biomass values were greater across all habitats in Waquoit Bay, with the summer values from the marsh habitat an order of magnitude higher than comparable summer data from the Wells habitats. We suggest that marsh and beach habitats provide a nursery area for young-of-the-year fishes, while deeper, open-water habitats serve as a corridor for fishes moving to nearshore habitats or serve as a refuge during low tide. 相似文献
17.
Small purse seines are well suited to sampling open water habitats in estuaries, yet little is known about how variation in
their design affects estimates of density and species richness of estuarine fishes. We tested whether purse seine size (length
and depth) affected estimates of density or species richness of fishes in San Dieguito Lagoon, southern California, U.S.A.
Twenty-one species were captured, with the open water speciesAtherinops affinis dominating the catch. The larger net (36.4 m long × 3.6 m deep) produced higher estimates of density than the smaller net
(18.2 m long × 2.4 m deep). The average number of species captured per sample was lower for the smaller net than the larger
net, but species accumulation curves for the small and large nets were similar, indicating that the difference in the number
of species per sample was primarily caused by the larger area sampled by the larger purse seine. Sampling with the larger
purse seine was more time efficient than the smaller seine. We found small purse seines to be useful tools for sampling fishes
in open water habitats in a small estuary, but we recommend that care be taken in selecting the size of a purse seine. 相似文献
18.
Fish communities in tidal tributaries have received considerable attention, but the relative value of nontidal tributaries (having a tidal amplitude of <?5 cm) may represent an under-valued habitat. A multi-gear sampling approach was used to collect fish and macroinvertebrates from one tidal and two nontidal tributaries to describe and compare the respective nekton communities and habitat use patterns. Nekton communities in tidal and nontidal tributaries were markedly different even though habitats were similar (e.g., temperature, DO, depths, shoreline vegetation). While catch-per-unit-effort (CPUE) of estuarine-dependent species (e.g., red drum, spot, common snook) was lower in nontidal tributaries, the overall nekton CPUE was twice that of the tidal tributary, and the community was comprised mostly of freshwater marsh species (e.g., eastern mosquitofish, sailfin molly, bluefin killifish). Based on the life histories of the fishes that differed between tributary types, the proximity of coastal inlets and availability of effective larval transport mechanisms for estuarine-dependent species may be greater determinants of community differences than factors related to tributary size or shoreline habitat type. These results recognize smaller nontidal tributaries as undervalued nursery habitats and suggest the function as secondary nursery habitats is a critical service to the overall estuarine community. 相似文献
19.
Ilia Rochlin Mary-Jane James-Pirri Susan C. Adamowicz Mary E. Dempsey Thomas Iwanejko Dominick V. Ninivaggi 《Estuaries and Coasts》2012,35(3):727-742
An integrated marsh management (IMM) project in an urbanized watershed on Long Island, New York, USA, aimed to mitigate salt marsh degradation and to reduce mosquito production by an innovative combination of restoration and open marsh water management methods. The grid ditch network at two treatment marshes was replaced with naturalized tidal channels and ponds. Effects of the hydrologic alterations were monitored utilizing a before–after–control–impact approach. The treatment marshes experienced a number of beneficial outcomes including a fourfold reduction in the invasive Phragmites australis and increased native vegetation cover in the most degraded portions of the marsh, increased abundance and diversity of marsh killifish and estuarine nekton species, higher shorebird and waterfowl densities, and increased avian species diversity. The successful implementation of IMM concept led to improved marsh health and diminished mosquito production. Therefore, this study may serve as a template for similar large-scale integrated salt marsh restoration projects. 相似文献
20.
Theresa L. Sinicrope Pamela G. Hine R. Scott Warren William A. Niering 《Estuaries and Coasts》1990,13(1):25-30
The restoration of a 20 ha tidal marsh, impounded for 32, yr, in Stonington, Connecticut was studied to document vegetation change 10 yr after the reintroduction of tidal flushing. These data were then compared to a 1976 survey of the same marsh when it was in its freshest state and dominanted byTypha angustifolia. Currently,T. angustifolia remains vigorous only along the upland borders and in the upper reaches of the valley marsh. Live coverage ofT. angustifolia has declined from 74% to 16% and surviving stands are mostly stunted and depauperate. Other brackish species have also been adversely effected, except forPhragmites australis which has increased. In contrast, the salt marsh speciesSpartina alterniflora has dramatically expanded, from <1% to 45% cover over the last decade. Locally, high marsh species have also become established, covering another 20% of the marsh. 相似文献