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1.
Body weight distributions of the amphipod Paramoera walkeri colonizing litter-bags at different depths (2, 5, and 10 m) in Terra Nova Bay were compared. This species dominated the vagile benthic community and was found nearly alone at the shallow sites. At the deepest site it co-occurred with two smaller benthic species (the gastropod Laevilitorina antarctica and the isopod Munna antarctica) but still accounted for most of the animal biomass (80.2%). The frequency size-class distributions of the three dominant species were sharply distinct in a condition of stable coexistence. The total biomass was inversely related to the abundance of animals and diminished with increasing depth. Both species and size-class diversities were higher in deep water which offered a more diversified and favourable habitat than shallow water. At the shallow sites only the large size classes of P. walkeri were present. Differences in the mean individual ash content between samples support the hypothesis that different size individuals of P. walkeri segregated along the depth gradient on the basis of their metabolic requirements and the related ability to exploit sub-optimal environments. 相似文献
2.
Dietary composition of black drum Pogonias cromis in a hypersaline estuary reflects water quality and prey availability
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Kathryn S. Rubio Matthew Ajemian Gregory W. Stunz Terence A. Palmer Benoit Lebreton Jennifer Beseres Pollack 《Journal of fish biology》2018,93(2):250-262
The Baffin Bay estuary is a hypersaline system in the Gulf of Mexico that supports an important recreational and commercial fishery for black drum Pogonias cromis, a benthic predator. Seasonal measurements of water quality variables, benthic macrofauna densities and biomass, and determination of P. cromis food sources using stomach‐content and stable‐isotope analyses were carried out to determine how P. cromis food sources change with water quality and how this may affect P. cromis diet. Gut‐content analysis indicated P. cromis selectively consumed bivalves Mulinia lateralis and Anomalocardia auberiana. Isotope compositions demonstrated that P. cromis relied on these benthic food resources produced in the Baffin Bay estuary year‐round. Biomass and densities of these bivalves were influenced by changes in water quality variables, particularly salinity and dissolved oxygen. Thus, this paper demonstrates the relationship between water quality variables, benthic macrofauna, and their use as food resources by a carnivorous fish species, and emphasizes the need for integrated assessments when studying the effects of water quality on ecosystem function. Holistic approaches such as these can provide important information for management and conservation of fishery resources and can improve predictions of ecosystem response to climate variability. 相似文献
3.
GENE FLOW VERSUS LOCAL ADAPTATION IN THE NORTHERN ACORN BARNACLE, SEMIBALANUS BALANOIDES: INSIGHTS FROM MITOCHONDRIAL DNA VARIATION 总被引:1,自引:0,他引:1
Alice F. Brown Lisa M. Kann David M. Rand 《Evolution; international journal of organic evolution》2001,55(10):1972-1979
Abstract In reciprocal transplant experiments, Bertness and Gaines (1993) found that Semibalanus balanoides juveniles that had settled in an upper Narragansett Bay estuary survived better in that estuary that did juveniles from coastal localities. The observed pattern of survivorship led to the claim that local adaptation may result from a combination of limited gene flow between and strong selection within these habitats. Here we test the hypothesis that limited gene flow has led to habitat‐specific population differentiation using sequence and restriction fragment length polymorphism analyses of the mitochondrial DNA D‐loop region of S. balanoides. Samples were analyzed from replicated coastal and estuary localities in both Narragansett Bay, Rhode Island, and Damariscotta River, Maine. The patterns of FST indicate that gene flow between coast and estuary is extensive (Nm > 100) and is not lower in the estuary with lower flushing rates (Narragansett Bay). Given the high estimate of genetic exchange, adaptations for unpredictable environments seem more likely than local adaptation in this species because loci that respond to selection in one generation are essentially homogenized by the next seasons' settlement. Nevertheless, these estimates of neutral gene flow can help identify the strength of selection necessary for local adaptation to accumulate in Semibalanus. 相似文献
4.
C. E. Little M. Kieffer G. Wippelhauser G. Zydlewski M. Kinnison L. A. Whitefleet‐Smith J. A. Sulikowski 《Zeitschrift fur angewandte Ichthyologie》2013,29(4):709-712
During sampling efforts to study the more abundant Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus, between May of 2009 and November of 2011, four shortnose sturgeon were captured in gill nets near the mouth of the Saco River, Maine. Two of these individuals were tagged with acoustic transmitters to monitor their movement within the Saco River. Additionally, six shortnose sturgeon that had been tagged with acoustic transmitters in the Merrimack River, Massachusetts were detected on the acoustic array deployed within the Saco River and its estuary over this time period. These incidences represent the first verified documentation of shortnose sturgeon within this estuary. 相似文献
5.
Four hundred and thirty two suprabenthic hauls with a modified Macer-GIROQ sledge were taken over the period 1988–1996. Fifteen sites within the English Channel were sampled from the Roscoff and Plymouth waters to the Dover Strait, including the Bay of Morlaix, Bay of Saint Brieuc, the Bay of Seine and the Seine Estuary. The main characteristics of the Benthic Boundary Layer (BBL) macrofauna in the English Channel were elucidated from these data. BBL macrofauna was found over the whole water column sampled (10–150 m). Firstly, the number of species collected was very high (up to 116 species for five hauls) except in the Seine estuary. Numerically, mysids were the dominant group of organisms collected with the sledge, followed by amphipods, cumaceans, isopods and decapods. Abundance and biomass of the fauna were very high in the Seine estuary, especially in the mesohaline and oligohaline zones (maximum >216000 ind. 100 m-3; >200 g AFDW 100 m-3) where the specialised mysids Neomysis integer and Mesopodopsis slabberi occurred in very high abundance. At other sites, the abundance and biomass were moderate (100–10000 ind. 100 m-3; 15–2000 mg AFDW 100 m-3). Abundance reached its maximum when mysids or swarms of amphipods of the genus Apherusa were collected, and during the reproduction of the amphipods of the genus Ampelisca, as in June in the Bay of Morlaix. The number of species, abundance and biomass showed seasonal changes in all sites with, in general, lowest values in winter or spring, and highest values in autumn. For the open sea sites, two main geographical gradients were identified: i) in spring, a higher number of species in the western part of the Channel compared with the eastern part of the Channel and, in autumn, a higher number of species in the eastern part of the Channel compared with the western part, and ii) an increasing density gradient from west to east at spring and a decreasing gradient from west to east during the autumn. The suprabenthic fauna of the Channel can be considered as a unique community including three kinds of species: (i) good swimmer species which were common at all the time and all sites: e.g. Anchialina agilis, Gastrosaccus spp., Haplostylus spp. and Apherusa spp., (ii) species present at all sites only at night: e.g. Atylus vedlomensis, Megaluropus agilis, Melphipidella macra, Orchomenella nana, Pseudocuma longicornis, Schistomysis ornata and Synchelidium maculatum, and iii) species collected at one or a limited number of sites only at night: e.g. Ampelisca spp. at Pierre Noire and Diastylis spp. at site F. The Seine estuary supports a typical suprabenthic estuarine community. Elements of the suprabenthic fauna also showed significant daily rhythms which took several forms depending on the species under consideration. 相似文献
6.
Exotic ecosystem engineers induce structural and qualitative habitat changes in invaded landscapes, yet studies rarely examine the effects of both of these changes on native taxa. We used a factorial experiment in natural, predator‐containing environments to determine whether performance of amphibian larvae was affected by predators and/or changes in habitat structure or chemistry associated with the invasive shrub Lonicera maackii. Invertebrate predators significantly reduced survival of American toad Anaxyrus americanus larvae, whereas tadpole development was accelerated in pools inoculated with the chemical signature of L. maackii. The significant effect of L. maackii chemistry on A. americanus larvae suggests that invasive species may have non‐intuitive effects even on native taxa with which they share no trophic connection, and may represent cryptic components of the multiple, interactive drivers of biodiversity change. 相似文献
7.
The Australasian burrowing isopod (Sphaeroma quoianum) has been introduced to numerous embayments along the Pacific coast of North America. In some bays, populations of S. quoianum can exceed tens of thousands of individuals m−3 and bioturbation by the isopods can exacerbate shoreline erosion. Within their native range, however, studies recognize S. quoianum primarily as a woodborer. We measured the distribution, prevalence, habitat use, density, and associated fauna of S. quoianum in two bays within the native range [Tamar estuary (Tamar), Tasmania and Port Phillip Bay (PPB), VIC, Australia] and in one
bay where the isopods had been introduced (Coos Bay, OR, USA). Distribution, prevalence, and habitat use were determined from
shoreline surveys. Densities and the associated fauna of S. quoianum were measured in three intertidal substrata (marsh bank, wood, and friable rock). In all embayments, S. quoianum occurred primarily between 5 and 30 salinity and 55−68% of sites harbored isopods. Habitat use varied between embayments.
Distributional patterns suggest salinity is the primary factor that limits the establishment and spread of S. quoianum. Isopod densities in all substrata were greater in Coos Bay than in the Tamar or PPB, although only densities within marsh
banks varied significantly. Similarities in the amount of habitat and food, and the burrow dwelling lifestyle of S. quoianum suggest habitat availability/quality, food levels, predation, and competition are not responsible for the large differences
in density. Lack of parasites or disease in populations of S. quoianum introduced to Coos Bay could be responsible for the prolific densities observed. 相似文献
8.
9.
Spatial Patterns of Benthic Macroinvertebrates in Intertidal Areas of a Southern European Estuary: The Tagus, Portugal 总被引:2,自引:2,他引:0
Ana Maria Rodrigues Sónia Meireles Teresa Pereira Alice Gama Victor Quintino 《Hydrobiologia》2006,555(1):99-113
This study characterizes the composition and spatial distribution patterns of the benthic macrofauna in the intertidal mudflats
of the Tagus estuary, western Portugal. A total of 68 species, more than 226,000 specimens with a total wet weight biomass
of approximately 1170 g were identified in 380 sites. The species Streblospio shrubsolii, Cyathura carinata, Tharyx sp., Hydrobia ulvae and Tubificids were the most common and abundant. Scrobicularia plana strongly dominated the biomass. The invertebrate macrofauna of the Tagus estuary shows similarities to what is known from
other temperate mudflats. The diversity of species, their overall abundance and the ratio of Molluscs plus Crustaceans to
Polychaete species corroborate the distinctiveness between temperate and tropical mudflats and sandflats. The spatial distribution
of the fauna reflects the sediment characteristics but the relationship between the environmental and the biological data
is not as strong as obtained for sublittoral areas. This relationship diminishes from the sublittoral shelf to sublittoral
estuarine areas, showing minimum values in this study, suggesting that such a relationship is less straightforward as natural
disturbance increases. Nevertheless, a mixture of grain-size, elevation (inundation time) and particular habitats (relic oyster
beds) form the best explanatory factors for the spatial distribution patterns of the intertidal benthic macrofauna of the
Tagus estuary. 相似文献
10.
Krzysztof Jazdzewski Claude Broyer Magdalena Pudlarz Dariusz Zielinski 《Polar Biology》2001,24(12):910-917
Quantitative samples of benthos were taken on a stony beach in the maritime Antarctic (Admiralty Bay, King George Island, South Shetland Islands) during a complete annual cycle. The sampled habitat consisted of cobbles lying on sand and gravel in the fringe between the littoral and sublittoral zones; samples were always taken at low tide just below the water line. In this habitat, abundant macroalgal detritus was observed between stones. This stony beach appeared to be very rich in vagile fauna settled between and under stones. Macrobenthos consisted mainly of amphipods (ca. 85% of total number), gastropods (11%) and nemerteans (3%). The abundance of whole macrofauna ranged to over 50,000 ind. m-2 and its biomass over 600 g m-2 (FW). Seven species of Amphipoda and four species of Gastropoda were found. Amphipoda were dominated by Gondogeneia antarctica (over 70% of all amphipods) and Paramoera edouardi (over 20%), whereas among gastropods Laevilitorina antarctica prevailed (over 70%). Unexpectedly high abundance and biomass of Amphipoda were observed in the first half of winter (May/July), surpassing otherwise important summer amphipod abundance. The probable reason for this phenomenon could be high autumn abundance of decaying algae on the beach in the tidal zone, providing detritus that is probably the main food source for Amphipoda. 相似文献
11.
Effect of forest removal on the abundance of the endangered American burying beetle, Nicrophorus americanus (Coleoptera: Silphidae) 总被引:1,自引:0,他引:1
J. Curtis Creighton Robert Bastarache Mark V. Lomolino Mark C. Belk 《Journal of Insect Conservation》2009,13(1):37-43
We test the hypothesis that the decline of the endangered American burying beetle (Nicrophorus americanus) from over 90% of its original range is the result of habitat loss and fragmentation of eastern North America. Forest removal
at a site in southeastern Oklahoma known to have a significant population of N. americanus gave us a unique opportunity to test this hypothesis. At the local scale of this experiment, N. americanus declined significantly after forest removal while beetle numbers at adjacent forested plots did not change. Our results indicate
that local disturbances such as forest removal, if occurring across relatively broad spatial scales, can cause wholesale geographic
range collapse in this species. 相似文献
12.
C. T. Hodgdon C. Tennenhouse W. Y. Koh J. Fox J. A. Sulikowski 《Zeitschrift fur angewandte Ichthyologie》2019,35(1):30-37
The shortnose sturgeon (Acipenser brevirostrum; SNS) is an endangered fish that thrives in large river systems along the U.S. east coast. Despite the endangered status, our understanding of this species’ ecology is limited, especially regarding the importance of smaller river systems to their recovery. In 2010, the first sighting of SNS occurred in the Saco River estuary (SRE), Maine, a proportionately smaller system to other known drainages. To investigate the habitat usage of SNS within the SRE, an on‐going acoustic tagging study was initiated in 2011. In 2016, the collection of SRE abiotic data was coupled with the acoustic tagging study in an effort to establish which environmental parameters were most influential to SNS habitat preferences using Poisson regression. Aggregations of SNS in the SRE were concentrated rkm 6–8 and regression analyses revealed that water temperature, conductivity, acidity, and dissolved oxygen content were influential to these aggregations. Furthermore, SNS prey appears to be present and abundant throughout the estuary, and thus we hypothesize that SNS use the SRE as a foraging ground, but aggregate upriver due to the physiologically preferable and energetically optimal abiotic conditions. 相似文献
13.
Biotic resistance is the ability of native communities to repel the establishment of invasive species. Predation by native
species may confer biotic resistance to communities, but the environmental context under which this form of biotic resistance
occurs is not well understood. We evaluated several factors that influence the distribution of invasive Asian mussels (Musculista senhousia) in Mission Bay, a southern California estuary containing an extensive eelgrass (Zostera marina) habitat. Asian mussels exhibit a distinct spatial pattern of invasion, with extremely high densities towards the back of
Mission Bay (up to 4,000 m−2) in contrast with near-complete absence at sites towards the front of the bay. We established that recruits arrived at sites
where adult mussels were absent and found that dense eelgrass does not appear to preclude Asian mussel growth and survival.
Mussel survival and growth were high in predator-exclusion plots throughout the bay, but mussel survival was low in the front
of the bay when plots were open to predators. Additional experiments revealed that consumption by spiny lobsters (Panulirus interruptus) and a gastropod (Pteropurpura festiva) likely are the primary factors responsible for resistance to Asian mussel invasion. However, biotic resistance was dependent
on location within the estuary (for both species) and also on the availability of a hard substratum (for P. festiva). Our findings indicate that biotic resistance in the form of predation may be conferred by higher order predators, but that
the strength of resistance may strongly vary across estuarine gradients and depend on the nature of the locally available
habitat. 相似文献
14.
2017年以来,广东省惠州市在考洲洋潮间带开展了大规模人工种植红树林生态修复工程,但考洲洋人工种植红树林湿地大型底栖动物群落的环境响应未见报道。根据2018-2019年四个季节在考洲洋盐洲大桥附近红树种植1-2年(X断面)和5-6年(Y断面)的两处湿地的大型底栖动物定量取样数据,分析了人工红树林湿地大型底栖动物的时空格局及其环境响应。方差分析表明,Y断面冬季的大型底栖动物群落的物种数、栖息密度、生物量、多样性指数(H'')和丰富度指数(d),以及夏季的栖息密度均随潮高(海平面高程)降低而增加;而Y断面冬季的均匀度指数(J)、夏季的H''和J则是随潮高降低而减少。聚类(Cluster)和非度量多维尺度(nMDS)分析表明冬季和夏季X断面和Y断面大型底栖动物群落相似性较低,而春季和秋季X断面和Y断面大型底栖动物群落相似性较高。冬季和夏季最大潮高、潮差、大型底栖动物物种数、栖息密度、H''和d较春季和秋季的高。红树种植1-2年的X断面大型底栖动物物种数、H''和J低于种植5-6年的Y断面。上述结果证实潮汐和红树种植年限影响考洲洋红树林湿地大型底栖动物的群落结构,研究结果可为大型底栖动物多样性保护和生态修复提供基础资料。 相似文献
15.
Spread of Exotic Cordgrasses and Hybrids (Spartina sp.) in the Tidal Marshes of San Francisco Bay, California, USA 总被引:3,自引:3,他引:0
Debra R. Ayres Debra L. Smith Katy Zaremba Shannon Klohr Donald R. Strong 《Biological invasions》2004,6(2):221-231
Four species of exotic cordgrass (Spartina sp.) occur in the San Francisco estuary in addition to the California native Spartina foliosa. Our goal was to map the location and extent of all non-native Spartina in the estuary. Hybrids of S. alterniflora and S. foliosa are by far the most numerous exotic and are spreading rapidly. Radiating from sites of deliberate introduction, S. alterniflora and hybrids now cover ca. 190 ha, mainly in the South and Central Bay. Estimates of rate of aerial increase range from a constant value to an accelerating rate of increase. This could be due to the proliferation of hybrid clones capable of rapid expansion and having superior seed set and siring abilities. The total coverage of 195 ha by hybrids and other exotic cordgrass species is slightly less than 1% of the Bay's tidal mudflats and marshes. Spartina anglica has not spread beyond its original 1970s introduction site. Spartina densiflora has spread to cover over 5 ha at 3 sites in the Central Bay. Spartina patens has expanded from 2 plants in 1970 to 42 plants at one site in Suisun Bay. Spartina seed floats on the tide, giving it the potential to export this invasion throughout the San Francisco estuary, and to estuaries outside of the Golden Gate. We found isolated plants of S. alterniflora and S. densiflora in outer coast estuaries north of the Bay suggesting the likelihood for the San Francisco Bay populations to found others on the Pacific coast. 相似文献
16.
Peter B. Pearman 《Oecologia》1995,102(1):1-8
Experimental ponds were used as a model system of habitat patches to study the effect of habitat size on the relative growth performance of tadpoles of Bufo americanus and Pseudacris triseriata, and on colonization by predatory insects. Three pond depths and surface areas were habitat size treatments in a replicated, factorial experiment. Tadpoles of both species were astablished together at a single density and ponds were left open to natural colonization by aquatic insects. Pond area had a significant effect on the multivariate response of P. triseriata larval period, survival, and metamorphic mass. P. triseriata survived better relative to B. americanus in larger ponds. However, increasing pond area led to greater incidence of predacious beetle larvae (Dytiscus, Coleoptera: Dytiscidae). Dytiscus larvae had a significant negative effect on the survival of P. triseriata and led to reduced P. triseriata survival relative to B. americanus in colonized ponds. The results suggest that habitat size can influence community structure by altering the distribution of predation among habitat patches. 相似文献
17.
Bernard Morin Christiane Hudon Frederick G. Whoriskey 《Environmental Biology of Fishes》1992,35(3):219-229
Synopsis The coastal fish assemblages of Wemindji, eastern James Bay, were studied in 1987 and 1988 to describe seasonal utilization of the Maquatua River estuary and the adjacent coastal waters by marine and anadromous fishes. Fish diversity was low (11 sp.) and experimental gill net catches were highly variable between sites in the estuary and coastal waters, and also seasonally at a given site. During summer, the estuarine fishes were numerically dominated by two marine species, the fourhorn sculpin,Myoxocephalus quadricornis, and the slender eelblenny,Lumpenus fabricii, and also by juvenile cisco,Coregonus artedii, and juvenile lake whitefish,C. clupeaformis. In coastal waters, three marine species were abundant: the shorthorn sculpin,M. scorpius, the arctic sculpin,M. scorpioides and the Greenland cod.Gadus ogac. In contrast with the estuary, large (> 270 mm) cisco and lake whitefish were abundant in coastal waters indicating extensive movements of these species in James Bay during the summer. Distribution patterns were influenced by a combination of physical conditions (salinity and temperature) and biological characteristics (habitat choice, migration and reproduction) depending on the season. 相似文献
18.
Edna De la Llata Quiroga Randall Arauz Arturo Tripp Valdez Laura Porras Murillo Manuel Spinola Parallada Ricardo Sánchez-Murillo Elpis J. Chávez 《Journal of fish biology》2023,102(3):669-679
Bull shark (Carcharhinus leucas) is a near-threatened elasmobranch species capable of moving between the fresh and salty waters of tropical and subtropical coastal areas, for which we still lack important ecological information. During their first years of life, bull sharks use estuarine systems as nursery areas, making them highly susceptible to environmental and anthropogenic pressures. We studied the trophic ecology of juveniles found in the Coyote estuary, a potential nursery area in Costa Rica, to understand the potential impact of further bull shark declines and gain knowledge that could aid in their conservation. We analysed the trophic ecology of juvenile bull sharks [81–103 cm total length (TL)] in the Coyote estuary, Costa Rica, using stable isotopes of δ15N and δ13C. Since one problem using this technique in juveniles is the confounding effect of the maternal signature, we sampled different tissues (muscle and plasma), verified the status of the shark's umbilical scar and identified the size at which the isotope signature is a result of the animal's current diet. The isotopic values of the muscle tissue reflected the maternal isotopic signature. In contrast, plasma values reflected the diet of juvenile bull sharks >95 cm TL and with a closed umbilical scar. Juvenile bull sharks fed primarily on teleost fishes of the order Anguilliformes and Siluriformes, and have a high trophic position (≥4.0) in the Coyote estuary. Our findings suggest that this estuary is an important feeding site for juvenile bull sharks of the Pacific of Costa Rica. Thus, the protection of essential habitats such as the Coyote estuary will benefit not only bull shark conservation, but also the conservation of an array of fish species that also use this habitat as a rookery, many of which are of commercial interest. 相似文献
19.
Summary Butterfly species lists were assembled for 18 Great Basin mountain ranges for which distributional data on mammals and birds have been analysed previously by other workers. The ranges represent remnant islands of the boreal habitat that once was continuous across the Great Basin but is now restricted to higher elevations as a result of climatic change at the close of the Pleistocene. The effects of biogeographic factors (area, distance, elevation) and habitat diversity on butterfly species number were examined. The Great Basin boreal butterfly faunas were found to be depauperate overall relative that of the principal mainland source, the Rocky Mountains, and were found to have fewer species than predicted by the mainland species-area data. However, only a weak area effect, and no distance effect, was detected by bivariate and multivariate analysis. Furthermore, the habitat diversity score found to explain virtually all the variation in bird species number in the same ranges in previous studies is only marginally significantly correlated with butterflies. When the butterflies are subdivided according to their vagility, the relative differences in the species-area correlation and slope (z-value) between the vagility categories were consistent with those found previously for mammals and birds, and, as predicted by theory, less vagile taxa exhibit higher species-area correlations and z-values. Overall, differences in the insular biogeography of buttterflies and vertebrates seem to reflect fundamental ecological differences between the taxa. 相似文献
20.
Michael J. Blum Erin Knapke Jason S. McLachlan Sunny B. Snider Colin J. Saunders 《Conservation Genetics》2010,11(5):1885-1898
Hybridization is an evolutionary mechanism capable of enhancing adaptive potential, especially among species in fragmented
or disturbed ecosystems like coastal marshes. In this study, we evaluated whether hybridization might influence adaptive responses
in coastal marshes that are susceptible to the effects of global environmental change. To do so, we examined the extent and
nature of hybridization between Schoenoplectus americanus and S. pungens, two ecologically dominant sedges in low-lying marshes across Chesapeake Bay (USA). Observed patterns of variation at genetically
based morphological traits, cpDNA and nuclear microsatellite markers confirm that introgressive hybridization occurs between
the two species. Comparisons of microsatellite and cpDNA profiles found that hybridization is reciprocal, although a disproportionate
number of hybrids exhibit genomic asymmetries favoring S. americanus. AIC model selection consistently identified latitude as the strongest explanatory variable for the distribution of parental
species, although discriminant analysis indicated that distributions also correspond to variation in environmental conditions.
Discriminant analysis further indicated that ecological correlates of hybrid and S. americanus genotypes are similar, but not uniformly so. These findings indicate that the boundary between S. americanus and S. pungens is porous, and that hybridization could influence responses of one or both species to changing environmental regimes. 相似文献