共查询到20条相似文献，搜索用时 28 毫秒
1.
The flooded intertidal zone in coastal estuarine systems (e.g., mangroves and salt marshes) is thought to provide nekton with
both food and refuge from predators. The primary aim of this study was to identify the relative contribution of root structure,
shading, and leaf litter, all characteristic features of mangrove forests, in shaping the intertidal distribution of tidally
migrating fishes. We manipulated the structure and shade in 9-m2 sample plots in a shallow, mangrove-fringed, intertidal embayment in Tampa Bay, Florida. In a separate field experiment,
we compared fish association with standing mangrove leaf litter and bare sand substrate. Shade and leaf litter had a water
depthdependent effect on the distribution of the fish; no effect was associated with the presence of mangrove roots. In shallow
water (<45 cm), fish were captured primarily in plots without shade, but this distribution shifted progressively with increasing
water depth, so that when water was greater than 55 cm most fish were captured in shaded plots. Fish were more frequently
associated with, and feeding in, plots covered in leaf litter than bare sand plots. This relationship did not persist at depths
greater than 15 cm because fish abundance declined gratly. Tethering experiments usingCyprinodon variegatus demonstrated that predation pressure was quadratically correlated with water depth (inflexion point approximately 60 cm).
Our results suggest that small fishes will abandon well-lighted foraging grounds in favor of the potential refuge of shaded
waters as water depth increases. We suggest that studies of intertidal nekton should be carefully interpreted in the context
of water depth. 相似文献
2.
To determine the role of mangroves for fisheries in the arid region of the Persian Gulf, we investigated fish community structure and trophic diversity in intertidal creeks with and without mangroves. Fish community abundances and biomass were compared across habitats and seasons. To identify variations in overall community trophic niches among habitats and seasons, we measured niches with size-corrected standard ellipse areas (SEAc) calculated from C and N stable isotope values. Although there was a slightly greater species richness occurred in mangrove creeks, we found a general similarity in the diversity patterns in creeks with and without mangroves. Also, there were no consistent differences in fish abundance or biomass for mangrove vs. non-mangrove fish collections. Community trophic diversity measured as SEAc also showed no significant difference between mangrove and non-mangrove sites. Instead, strong seasonal patterns were observed in the fish assemblages. Winter samples had consistently higher fish abundance and biomass than summer samples. Winter SEAc values were significantly higher, indicating that the fish community had a larger isotopic niche in winter than summer. Overall, we found that seasonality was much stronger than habitat in determining fish community structure and trophic diversity in the mangrove and non-mangrove ecosystems of Qeshm Island, Iran. 相似文献
3.
4.
Trawl collections indicate that the fish community of the Belize barrier reef lagoon is dominated numerically and in biomass by grunts (Haemulidae), especiallyHaemulon sciurus andHaemulon flavolineatum. Although the gear selected for small sizes, length frequency analysis indicated seasonality in recruitment of the dominant species of grunts. Apogonids and tetraodontiform fishes were also dominant components of the community. Most fishes collected were juveniles of species that occur as adults on the main reef, or were small species that are resident in the lagoon. Of three habitats sampled, the mangrove creek had the greatest relative abundance and biomass of fishes, followed by the seagrass bed and the sand-rubble zone. There were no significant seasonal differences in fish relative abundance or biomass. Community structure analysis indicated a uniqueness in the mangrove fish community. Diversity (H′) was high, and was due to high species richness and evenness of distribution of individuals among species. The Belize barrier reef lagoon serves as an important nursery habitat for juvenile fishes. 相似文献
5.
A bimonthly study of the spatial variations in fish assemblages in the six mangrove creeks along the western coast of Taiwan was conducted from February 1996 to February 1997. Fyke nets were used to collect fishes in each of three creeks in the north (subtropical) and south (tropical) regions. A total of 79 fish species belonging to 33 families were collected and, of these, the Gobiidae, Mugilidae, Leiognathidae, and Cichlidae were the most diverse families. The fish assemblages in each creek were dominated by a small number of small fishes, most of which are the young of commercially important species. Their life cycles occurred to some extent in estuarine environments. Analyses by classification and ordination separated the assemblages into a northern group and a southern group and showed that the assemblages were far more temporally varied in the southern creeks than in the northern creeks. Fifty fish species were recorded in the northern creeks and 49 fish species in the southern creeks, with 20 species present in both regions. No significant difference in number of species per netting was detected between the regions. The number of individuals and biomass per netting were greater in the northern creeks than in the southern creeks. Rainfall and organic content of sediments may be responsible for the difference in fish abundance between the regions. In the northern creeks the assemblages were dominated by Liza macrolepis and Liza affinis in winter and spring, but the assemblages were more diverse in summer and fall. In the southern creeks, the assemblages were always characterized by several species and their dominance varied from month to month. The differences in the assemblage structure in northern and southern mangrove creeks are likely due to the oceanic current patterns around Taiwan. 相似文献
6.
Fish and decapod entry into small (1.5 m2) artificial seagrass habitats positioned on an open sand area in a New Jersey estuary was examined to determine if immigration varied between day and night. To encounter the structured habitats, colonizers had to cross an expanse of bare sand, with its presumably higher predation risk. Contrasts in abundance in the artificial seagrass plots between dawn and dusk indicated higher nighttime immigration for four species, including the fishesFundulus heteroclitus andMyoxocephalus aenaeus, and the caridean shrimpsPalaemonetes vulgaris andHippolyte pleuracanthus. Size-frequency distributions of colonizers varied between day and night for two fish species,Menidia menidia andSyngnathus fuscus, with a greater proportion of smaller individuals immigrating to the artificial seagrass at night.Callinectes sapidus also displayed a diel contrast in size distribution but, for this species, proportionately more small individuals colonized the plots during the day. We suggest that diel variability in predation risk and/or diel patterns in motor activity may be responsible for these patterns in immigration. 相似文献
7.
Variation with Depth in Temperate Seagrass-Associated Fish Assemblages in Southern Victoria,Australia 总被引：1，自引：0，他引：1
Neil Hutchinson Gregory P Jenkins Andrew Brown Timothy M Smith 《Estuaries and Coasts》2014,37(4):801-814
Variability in the abundance and distribution of seagrass-associated fish assemblages was examined at different depths in a temperate bay in southern Australia. Depth differences in seagrass-associated fish assemblages are poorly known but this information is critical given that seagrass loss can occur at specific depths depending on the cause. Overall, 69 species of fish from 26 families were recorded, with higher species richness in shallow than deep beds, with 12 species found only in deep beds and 22 species found only in shallow beds. While the total fish abundance (i.e. abundance of all species recorded) varied between years and seasons, and to some extent between sites, it was significantly higher in shallow than deep seagrass beds in the majority of cases. Although there was some variation between sites, seagrass tended to be longer and have a higher biomass in shallow than deep beds during both spring and autumn throughout the study. A positive relationship between seagrass biomass/length and total fish abundance/species richness was apparent. Assemblage structure tended to be distinct at each depth, with the largest species recorded in shallow seagrass. Large numbers of small schooling fish, such as atherinids, dominated in shallow seagrass but were not found in deep seagrass. Loss of seagrass could therefore have varying implications for distinct assemblages found at different depths. 相似文献
8.
Guogui Chen Wei Hong Xuan Gu Ken W. Krauss Kaiyuan Zhao Haifeng Fu Luzhen Chen Mao Wang Wenqing Wang 《Sedimentology》2023,70(1):31-47
Coastal wetlands are key features of the Earth's surface and are characterized by a diverse array of coupled geomorphological and biological processes. However, the links between the distribution of biodiversity (for example, species and structural diversity) and the formation of coastal geomorphology are not well-understood on a landscape scale most useful to coastal zone managers. This study describes the relationship between select geomorphological and biological mangrove community features (i.e. species composition and functional root type) in a landscape-distributed coastal zone of Dongzhaigang Bay, north-eastern Hainan Island, China. A total of 11 mangrove species and five functional aerial root types were encountered, with the location of species by root types being controlled by the elevation of the soil surface. Plank roots, prop roots and pneumatophores occupied the lowest intertidal elevations, while knee roots and fibrous roots of the mangrove fern, Acrostichum aureum, preferred the highest intertidal elevations. Surface sediment deposition in areas with mangroves was greater than deposition in non-mangrove forest zones, establishing an important biological mechanism for this large-area response because surface erosion/compaction was also more prominent within mangrove roots. Indeed, functional root type influenced the magnitude of deposition, erosion and compaction, with knee roots and pneumatophores being more effective in promoting deposition and preventing surface erosion/compaction than prop roots. These results indicate a potential role for vegetation type (especially functional root type) to influence coastal geomorphological processes at large landscape scales. While soil surface elevation is correlated to the distribution of mangrove species and functional root types, a significant feedback exists between elevation change and the capacity of those root types to influence coastal geomorphological differentiation within sustainable intertidal elevations. An enhanced understanding of geomorphological development, mangrove species distribution and functional root type may improve management to support nature-based solutions that adjust more effectively to sea-level rise through feedbacks. 相似文献
9.
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
10.
Nicole Poret Robert R. Twilley Victor H. Rivera-Monroy Carlos Coronado-Molina 《Estuaries and Coasts》2007,30(3):491-496
Mangrove root decomposition rates were measured by distributing mesh bags containing fine root material across six sites with
different soil fertility and hydroperiod to compare ambient differences to substrate quality. Roots from a site with lower
soil phosphorus concentration were used as a reference and compared to ambient roots at five other sites with increased phosphorus
concentration. Four mesh bags of each root type (ambient versus reference), separated into four 10-cm replicate intervals,
were buried up to 42 cm depth at each site and incubated for 250 d (initiation in May 2004). Mass loss of ambient mangrove
roots was significant at all study sites and ranged from 17% to 54%; there was no significant difference with depth at any
one site. Reference decomposition constants (−k) ranged from 0.0012 to 0.0018 d−1 among Taylor Slough sites compared to 0.0023–0.0028 d−1 among Shark River sites, indicating slower decomposition rates associated with lower soil phosphorous and longer flood duration.
Reference roots had similar decomposition rates as ambient roots in four of the six sites, and there were no significant correlations
between indices of root substrate quality and decomposition rates. Among these distinct landscape gradients of south Florida
mangroves, soil environmental conditions have a greater effect on belowground root decomposition than root substrate quality. 相似文献
11.
E. C. Milbrandt J. M. Greenawalt-Boswell P. D. Sokoloff S. A. Bortone 《Estuaries and Coasts》2006,29(6):979-984
Although hurricane disturbance is a natural occurrence in mangrove forests, the effect of widespread human alterations on
the resiliency of estuarine habitats is unknown. The resiliency of mangrove forests in southwest Florida to the 2004 hurricane
season was evaluated by determining the immediate response of mangroves to a catastrophic hurricane in areas with restricted
and unrestricted tidal connections. The landfall of Hurricane Charley, a category 4 storm, left pronounced disturbances to
mangrove forests on southwest Florida barrier islands. A significant and negative relationship between canopy loss and distance
from the eyewall was observed. While a species-specific response to the hurricane was expected, no significant differences
were found among species in the size of severely impacted trees. In the region farthest from the eyewall, increases in canopy
density indicated that refoliation and recovery occurred relatively quickly. There were no increases or decreases in canopy
density in regions closer to the eyewall where there were complete losses of crown structures. In pre-hurricane surveys, plots
located in areas of management concern (i.e., restricted connection) had significantly lower stem diameter at breast height
and higher stem densities than plots with unrestricted connection. These differences partially dictated the severity of effect
from the hurricane. There were also significantly lower red mangrove (Rhizophora mangle) seedling densities in plots with restricted connections. These observations suggest that delays in forest recovery are possible
in severely impacted areas if either the delivery of propagules or the production of seedlings is reduced by habitat fragmentation. 相似文献
12.
Rachel J. Harris Eric C. Milbrandt Edwin M. EverhamIII Brian D. Bovard 《Estuaries and Coasts》2010,33(5):1176-1185
The effects of reduced tidal flushing on post-hurricane mangrove recovery were measured across a gradient of hurricane disturbance
(in order of decreasing wind intensity: Captiva, North Sanibel, Central Sanibel, and East Sanibel). Each region consisted
of replicate study plots with either reduced tidal exchange (tidally restricted location) or an open tidal connection (tidally
unrestricted location). Locations with reduced tidal exchange displayed significantly lower (two-way ANOVA, p ≤ 0.0001) tidal amplitude, decreased seedling densities, and decreased productivity (recruitment, growth, and litter fall)
when compared to the tidally unrestricted locations. Results also indicated significant regional variations in measures of
mangrove stand structure (seedlings and canopy) and productivity (recruitment, growth, and litter fall) up to 4-years post-hurricane
disturbance. These findings suggest that the legacy effects from hurricane disturbance vary with degree of wind intensity,
acting both independently and synergistically with the effects of tidal restriction to influence post-hurricane mangrove structure
and function. 相似文献
13.
Fish community ecology in an Altered River delta: Spatial patterns in species composition, life history strategies, and biomass 总被引：1，自引：0，他引：1
Matthew L. Nobriga Frederick Feyrer Randall D. Baxter Michael Chotkowski 《Estuaries and Coasts》2005,28(5):776-785
We sampled nearshore fishes in the Sacramento-San Joaquin Delta, California, United States, during 2001 and 2003 with beach seines and gill nets. We addressed three questions. How and why did fish assemblages vary, and what local habitat features best explained the variation? Did spatial variation in assemblages reflect greater success of particular life history strategies? Did fish biomass vary among years or, across habitats? Nonmetric multidimensional scaling showed that habitat variables had more influence on fish assemblages than temporal variables. Results from both gear types indicated fish assemblages varied between Sacramento and San Joaquin River sampling sites. Results from gill net sampling were less pronounced than those from beach seine sampling. The Sacramento and San Joaquin river sites differed most notably in terms of water clarity and abundance of submerged aquatic vegetation (SAV), suggesting a link between these habitat characteristics and fish relative abundance. Among-site differences in the relative abundance of periodic and equilibrium strategist species suggested a gradient in the importance of abiotic versus biotic community structuring mechanisms. Fish biomass varied among years, but was generally higher in SAV-dominated habitats than the turbid, open habitats in which we found highest abundances of striped bassMorone saxatilis and special-status native fishes such as delta smeltHypomesus transpacificus, Chinook salmonOncorhyncus tschawytscha, and splittailPogonichthys macrolepidotus. The low abundance of special-status fishes in the comparatively productive SAV-dominated habitats suggests these species would benefit more from large-scale restoration actions that result in abiotic variability that mirrors natural river-estuary habitat than from actions that emphasize local (site-specific) productivity. 相似文献
14.
The zonation patterns ofAvicennia bicolor andRhizophora racemosa were studied in a mangrove forest on the Pacific Coast of Costa Rica. Comparisons were made between the establishment, survival, and growth of both species in three plots, 1 ha each, located along the flooding gradient. Based on cohort analysis and reciprocal planting observations, it was concluded that species zonation was primarily regulated by the depth of tidal inundation and the differential ability of the propagules to become established. However, tidal sorting was not the only operative factor related to inundation. Drought and probably high soil salinities limited the survival and growth ofR. racemosa in the landward sections of the forest. Tidal sorting, however, confined propagules to zones where they probably had the highest likelihood of contributing to another generation. 相似文献
15.
Jason C. Wyda Linda A. Deegan Jeffrey E. Hughes Melissa J. Weaver 《Estuaries and Coasts》2002,25(1):86-100
Estuarine seagrass ecosystems provide important habitat for fish and invertebrates and changes in these systems may alter their ability to support fish. The response of fish assemblages to alteration of eelgrass (Zostera marina) ecosystems in two ecoregions of the Mid-Atlantic Bight (Buzzards Bay and Chesapeake Bay) was evaluated by sampling historical eelgrass sites that currently span a broad range of stress and habitat quality. In two widely separated ecoregions with very different fish faunas, degradation and loss of submerged aquatic vegetation (SAV) habitat has lead to declines in fish standing stock and species richness. The abundance, biomass, and species richness of the fish assemblage were significantly higher at sites that have high levels of eelgrass habitat complexity (biomass >100 wet g m?2; density <100 shotts m?2) compared to sites that have reduced eelgrass (biomass <100 wet g m?2; density <100 shoots m?2) or that have completely lost eelgrass. Abundance, biomass, and species richness at reduced eelgrass complexity sites also were more variable than at high eelgrass complexity habitats. Low SAV complexity sites had higher proportions of pelagic species that are not dependent on benthic habitat structure for feeding or refuge. Most species had greater abundance and were found more frequently at sites that have eelgrass. The replacement of SAV habitats by benthic macroalgae, which occurred in Buzzards Bay but not Chesapeake Bay, did not provide an equivalent habitat to seagrass. Nutrient enrichment-related degradation of eelgrass habitat has diminished the overall capacity of estuaries to support fish populations. 相似文献
16.
Aaron Bartholomew 《Estuaries and Coasts》2002,25(5):1045-1052
An index of structural habitat complexity was devised: the average inter-structural space size within a habitat/the width of the prey organism of concern (Sp/Py). Prey survivorship should be low at Sp/Py<1 as the prey will be effectively excluded from using the habitat as refuge (they cannot maneuver through the spaces). At Sp/Py near to 1, survivorship should be high, as the spaces within the habitat are ideal for the prey and their predators are excluded (assuming they are larger than the prey). As Sp/Py increases, prey survivorship should drop rapidly until reaching a lower plateau where no predators are excluded by the structure. Sp/Py is dimensionless, and is potentially applicable across different scales and habitat types. Some of the predictions of this model were tested using artificial seagrass plots deployed in a seagrass bed in the York River, Virginia. The plots had 5 different structural treatments: control (a base with no ribbon), low, medium and high densities, as well as a heterogeneous treatment (composed of 1/3 low, medium and high density in a single treatment). The abundance of 2 mobile fauna size classes (<3.5 mm width and 3.5 to 9.5 mm width) and total species richness were compared among the different density treatments. The abundance of the smaller fauna increased with increasing density, and this response was proportional to the total surface area of the plots. The small fauna apparently did not respond to the smaller, ideal space sizes associated with the higher density plots. The larger fauna responded to the treatments as well, with the highest abundances occurring in the heterogeneous and high density treatments. The larger fauna did not respond to the structure proportional to the surface area within the plots, and its is possible that they responded to the inter-structural space sizes appropriate to their body sizes, although the results do not clearly support this conclusion. The different treatments did not affect species richness when the effect of total abundance on richness was controlled. 相似文献
17.
Michael Drexler Melanie L. Parker Stephen P. Geiger William S. Arnold Pamela Hallock 《Estuaries and Coasts》2014,37(4):962-972
The eastern oyster, Crassostrea virginica, plays an essential functional role in many estuarine ecosystems on the east and Gulf coasts of the USA. Oysters form biogenic reefs but also live on alternative intertidal substrates such as artificial surfaces and mangrove prop roots. The hypothesis tested in this study was that non-reef-dwelling oysters (i.e., those inhabiting mangrove, seawall, or restoration substrates) were similar to their reef-dwelling counterparts based upon a suite of biological parameters. The study was carried out at six sites in three zones in Tampa Bay on the west coast of Florida using monthly samples collected from October 2008–September 2009. The timing of gametogenesis and spawning, fecundity, and juvenile recruitment were the same for oysters in all four habitats. Oyster size (measured as shell height), density, and Perkinsus marinus infection intensity and prevalence varied among habitats. This study indicates that oysters on mangroves, seawalls, and oyster restoration substrates contribute larvae, habitats for other species, and likely other ecosystem benefits similar to those of intertidal oyster reefs in Tampa Bay. Oysters from alternative intertidal substrates should be included in any system wide studies of oyster abundance, clearance rates, and the provision of alternate habitats, especially in highly developed estuaries. 相似文献
18.
Fish and invertebrate assemblages in seagrass, mangrove, saltmarsh, and nonvegetated habitats 总被引：1，自引：0，他引：1
Many studies compare utilization of different marine habitats by fish and decapod crustaceans; few compare multiple vegetated
habitats, especially using the same sampling equipment. Fish and invertebrates in seagrass, mangrove, saltmarsh, and nonvegetated
habitats were sampled during May–August (Austral winter) and December–January (Austral summer) in the Barker Inlet-Port River
estuary, South Australia. Sampling was undertaken using pop nets in all habitats and seine nets in seagrass and nonvegetated
areas. A total of 7,895 fish and invertebrates spanning 3 classes, 9 orders, and at least 23 families were collected. Only
one fish species,Atherinosoma microstoma, was collected in all 4 habitats, 11 species were found in 3 habitats (mangroves, seagrass, and nonvegetated), and 13 species
were only caught in seagrass and nonvegetated habitats. Seagrass generally supported the highest numbers of fish and invertebrates
and had the greatest species richness. Saltmarsh was at the other extreme with 29 individuals caught from two species. Mangroves
and nonvegetated habitats generally had more fish, invertebrates, and species than saltmarsh, but less than seagrass. Analyses
of abundances of individual species generally showed an interaction between habitat and month indicating that the same patterns
were not found through time in all habitats. All habitats supported distinct assemlages although seagrass and nonvegetated
assemblages were similar in some months. The generality of these patterns requires further investigation at other estuaries.
Loss of vegetated habitats, particularly seagrass, could result in loss of species richness and abundance, especially for
organisms that were not found in other habitats. Although low abundances were found in saltmarsh and mangroves, species may
use these habitats for varying reasons, such as spawning, and such use should not be ignored. 相似文献
19.
This study investigates the influence ofPhragmites australis (common reed) invasion on the habitat of the resident marsh fish,Fundulus heteroclitus (mummichog) in the Hackensack Meadowlands, New Jersey. These abundant fish play an important role in the transfer of energy
from the marsh surface to adjacent subtidal waters and thus estuarine food webs. The objectives of this 2-yr study (1999 and
2000) were to compare the distribution and abundance of the eggs, larvae, juveniles, and adults of mummichog and their invertebrate
prey inhabitingSpartina alterniflora-dominated marshes withPhragmites-dominated marshes, and to experimentally investigate the influence of marsh surface microtoprography on larval fish abundance
withinPhragmites-dominated marshes. In 2000, we verified that egg deposition does occur inPhragmites-dominated marshes. In both years, the abundance of larvae and small juveniles (4–20 mm TL) inS. alterniflora was significantly greater than inPhragmites-dominated marshes, while larger juveniles and adults (>20 mm TL) were similarly abundant in both habitat types. The overall
abundance of larvae and small juveniles was significantly greater in experimentalPhragmites plots in which microtopography was manipulated to resemble that ofSpartina marshes than inPhragmites control plots. Major groups of invertebrate taxa differed between marsh types with potential prey for larval fish being significantly
more abundant inS. alterniflora marshes.Phragmites-dominated marshes may not provide the most suitable habitat for the early life-history stages of the mummichog. The low abundance
of larvae and small juveniles inPhragmites marshes is likely due to inadequate larval habitat and perhaps decreased prey availability for these early life history stages. 相似文献
