ORCID Profile
0000-0002-5773-5994
Current Organisations
Rhodes University
,
Nelson Mandela University
,
University of Cambridge Saint Catharine's College
,
University of Cambridge
,
University of Queensland
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Publications
Interactions between benthic molluscs in a Sulawesi mangal, indonesia: The cerithiid mud-creeper Cerithium coralium and potamidid mud-whelks, Terebralia spp.
Publisher: Cambridge University Press (CUP)
Date: 09-04-2003
DOI: 10.1017/S0025315403007380H
Abstract: The sediment surface within the Osbornia belt of a mangal on Pulau Hoga, Tukang Besi Islands, Sulawesi, Indonesia, is dominated inter alia by deposit-feeding gastropod molluscs at a mean density of some 230 ind m −2 although, unusually, species of Cerithidea do not occur. Densities of the two most numerous species, the potamidid mud-whelk Terebralia sulcata and the Cerithidea -like cerithiid mud-creeper Cerithium coralium , are inversely correlated, although the species occurred together in 42% of quadrat s les. Within and beyond the normal range of field densities of each species ( C. coralium mean 153 m −2 T. sulcata mean 75 m −2 ) there was no evidence of intraspecific depression of feeding rate, as assessed by the production of faecal pellets, although this was significantly reduced in the occasional very high density aggregations of C. coralium ( m −2 ). The presence of the larger T. sulcata did appear to have a strong inhibitory effect on feeding in C. coralium the converse, however, could not be demonstrated. Abundances of Terebralia palustris and C. coralium were also inversely correlated where the two co-occurred.
The critical scale of small-scale spatial variation in ecological patterns and processes in intertidal macrobenthic seagrass assemblages
Publisher: Elsevier BV
Date: 02-2012
Uniform functional structure across spatial scales in an intertidal benthic assemblage
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.MARENVRES.2015.03.006
Abstract: To investigate the causes of the remarkable similarity of emergent assemblage properties that has been demonstrated across disparate intertidal seagrass sites and assemblages, this study examined whether their emergent functional-group metrics are scale related by testing the null hypothesis that functional ersity and the suite of dominant functional groups in seagrass-associated macrofauna are robust structural features of such assemblages and do not vary spatially across nested scales within a 0.4 ha area. This was carried out via a lattice of 64 spatially referenced stations. Although densities of in idual components were patchily dispersed across the locality, rank orders of importance of the 14 functional groups present, their overall functional ersity and evenness, and the proportions of the total in iduals contained within each showed, in contrast, statistically significant spatial uniformity, even at areal scales <2 m(2). Analysis of the proportional importance of the functional groups in their geospatial context also revealed weaker than expected levels of spatial autocorrelation, and then only at the smaller scales and amongst the most dominant groups, and only a small number of negative correlations occurred between the proportional importances of the in idual groups. In effect, such patterning was a surface veneer overlying remarkable stability of assemblage functional composition across all spatial scales. Although assemblage species composition is known to be homogeneous in some soft-sediment marine systems over equivalent scales, this combination of patchy in idual components yet basically constant functional-group structure seems as yet unreported.
On reproductive strategies in adjacent lagoonal and intertidal-marine populations of the gastropod hydrobia ulvae
Publisher: Cambridge University Press (CUP)
Date: 08-1988
DOI: 10.1017/S0025315400043265
Abstract: The coastal prosobranch Hydrobia ulvae is known to occur in a wide range of marine and brackish habitats and to display great variation in its breeding and life-history characteristics. Several hypotheses have been advanced to account for the latter, including that the variation is environmentally induced and that the species can be ided into ecotypes. Comparison of two adjacent populations in Norfolk, U.K., one from the marine intertidal zone and the other from a non-tidal, landlocked, brackish coastal lagoon, however, disclosed that although shell form differed markedly (including a mean height ratio of 1:1.2), there was no difference in such otherwise variable features as numbers of eggs per capsule, size at hatching and larval type. In both, each capsule contained an average of 21-22 eggs, which hatched at a shell length of 152-154 μn to liberate relatyyively long-lived, free-swimming veligers. The two populations were also interfertile. In no respect had the isolated lagoonal population erged away from the parent marine one towards the contrasting reproductive strategies characterizing the specifically lagoonal species of Hydrobia that occur nearby. The ‘displacement’ of shell size observed in the lagoon in the absence of sympatric hydrobiids is considered to cast further doubt on competitive character displacement in this genus.
Distinguishing ten sympatric species of fiddler crab (Decapoda: Ocypodidae) using a suite of phenotypic characteristics
Publisher: Magnolia Press
Date: 27-08-2021
DOI: 10.11646/ZOOTAXA.5026.4.2
Abstract: Ten species of fiddler crab are reported inhabiting the intertidal zone of a shore on Kaledupa Island, Indonesia. This is one of the highest recorded numbers of fiddler crab species living in sympatry, equating to over two-thirds of those known from the Wallacea biogeographic region and more than half of all those recorded from Indonesia. The descriptions to identify and distinguish these ten species are provided using a suite of characters e.g., carapace, major cheliped, male gonopods, gastric mills, life colouration in males and females, and notes on their ecology and distribution. Specimens were observed and collected in the Wakatobi National Park, near the village of Ambeua on Kaledupa island, Sulawesi Tenggara, Indonesia. Gastric mills are described for the first time for Gelasimus jocelynae, Paraleptuca crassipes, Tubuca coarctata, T. demani and T. dussumieri. A tabulation of anatomical features and colouration for all species in this study is provided as a support for field studies. It identifies features that support the recently proposed taxonomic revision of fiddler crabs by Shih et al. (2016).
Functional uniformity underlies the common spatial structure of macrofaunal assemblages in intertidal seagrass beds
Publisher: Oxford University Press (OUP)
Date: 09-02-2015
DOI: 10.1111/BIJ.12483
Morisita's index of patchiness and edge effects: A response to Butturi-Gomes and Petrere (2020)
Publisher: Elsevier BV
Date: 10-2020
Interspecific competition and rarity in mudsnails: Feeding interactions between and within Hydrobia acuta neglecta and sympatric Hydrobia species
Publisher: Wiley
Date: 2005
DOI: 10.1002/AQC.677
Marine conservation policy in Seychelles: Current constraints and prospects for improvement
Publisher: Elsevier BV
Date: 05-2012
Biodiversity differentials between the numerically-dominant macrobenthos of seagrass and adjacent unvegetated sediment in the absence of sandflat bioturbation
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.MARENVRES.2014.05.013
Abstract: Species composition, abundance and bio ersity of the South African estuarine invertebrate fauna are known to show marked differentials between seagrass beds and adjacent unvegetated sands in enclosed estuarine/marine bays. Such differentials were investigated at four disparate localities in a bay lacking the callianassid bioturbation of other local sites. Here there were no such marked or consistent differences: <50% of differentials were statistically significant, with seagrass showing the lower, not higher, level in half of those. Overall, faunal abundance was lower in seagrass in the ratio of 0.64 : 1, whilst species density was higher but only by 1.13 to 1. Seagrass assemblages at a given locality were more similar to those of the adjacent bare sand than they were to seagrass assemblages at other localities, and likewise in respect of those in the bare sand. This suggests that marked differentials, where they occur, may result not from any supposed favourability of seagrass as a habitat but from the operation of processes within the unvegetated-sediment compartment of the system.
Strengthening the DNA barcode reference library for South African estuarine macrofauna
Publisher: National Inquiry Services Center (NISC)
Date: 02-01-2021
Patterns of seagrass macrobenthic biodiversity in the warm-temperate Knysna estuarine bay, Western Cape: a review
Publisher: Springer Science and Business Media LLC
Date: 11-03-2021
DOI: 10.1007/S10452-021-09848-3
Abstract: Knysna estuarine bay in South Africa's Garden Route National Park is that country's most significant estuarine system for bio ersity and conservation value. One outstanding feature is support of 40% of South Africa's—and maybe 20% of the world's—remaining vulnerable and decreasing dwarf-eelgrass, Zostera capensis , whose associated benthic macrofauna has been studied since 2009. For these invertebrates, Knysna comprises several significantly different compartments: sandy mouth well-flushed marine embayment poorly flushed central sea-water 'lagoon' and two disjunct but faunistically similar peripheral regions–marine backwater channels, and low-salinity upper estuary. Although macrofauna ranges from dilute brackish to fully marine, its abundance, local patchiness, and over considerable stretches, species density remains remarkably constant further, one-third of species occur throughout. Intertidally, all but peripheral compartments are low density and infaunally dominated, while some peripheral areas, and much of the subtidal, are higher density and epifaunally dominated. Overall, seagrass macrobenthos appears maintained below carrying capacity (e.g., by abundant juvenile fish) and of random species composition within a site. Two further characteristics are notable: Unusually, seagrass supports fewer animals than adjacent unvegetated areas, probably because of lack of bioturbatory disturbance in them, and the vegetation cover may ameliorate ambient habitat conditions. Unfortunately, continual heavy and effectively unpreventable exploitation for bait occurs, and chlorophyte blooms have developed because of high nutrient input. Knysna presents a microcosm of problems facing bio erse and high-value habitats set within areas of high unemployment where subsistence fishing provides the main source of protein and seagrass provides the only source of bait.
Spatial structure of a multi-species guild: the dominant biofilm-grazing microgastropods of seagrass
Publisher: Springer Science and Business Media LLC
Date: 06-10-2019
Spatial homogeneity of benthic macrofaunal biodiversity across small spatial scales
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.MARENVRES.2016.10.006
Abstract: Spatial heterogeneity of bio ersity has been extensively researched, but its spatial homogeneity is virtually unstudied. An intertidal seagrass system at Knysna (South Africa) known to display spatially homogeneous macrobenthic species density at scales ≥0.0275 m
Animal abundance and food availability in coastal lagoons and intertidal marine sediments
Publisher: Cambridge University Press (CUP)
Date: 04-2000
DOI: 10.1017/S0025315499001782
Abstract: The relationships between the standing stocks of deposit-feeding benthic invertebrates and benthic chlorophyll- a , phaeopigment and total combustible organic matter were investigated at a series of coastal lagoons and in the type of intertidal soft-sediment sites from which the lagoons originated. Across all the sites, in Norfolk, UK, an inverse relationship occurred between (a) the amounts of chlorophyll -a and of other potential food materials and (b) the degree of coverage by water. The biomass of consumers also decreased with increased water coverage, so that the lagoons supported less biomass than the adjacent high-level intertidal sites. Further, the deposit-feeder biomass supported by unit food decreased with extent of water coverage. There was no evidence of any relationship between deposit-feeder and food biomass within any single site, in spite of the study period being selected to be that in which there was maximum likelihood of competition for microphytobenthic food. Whilst chlorophyll concentrations may set the maximum achievable level of consumer biomass at these sites, including in the deeper lagoons setting very low potential maximum population densities, the seasonal abundance patterns of the deposit feeders appear to be determined by other factor(s).
European estuaries and lagoons: A personal overview of problems and possibilities for conservation and management
Publisher: Wiley
Date: 09-1991
Intertidal sands and interstitial fauna associated with different stages of salt-marsh development
Publisher: Elsevier BV
Date: 09-1976
Do species display characteristic intraspecific levels of patchiness in a given habitat type? The case of intertidal seagrass macrobenthos
Publisher: Springer Science and Business Media LLC
Date: 04-11-2020
DOI: 10.1007/S00227-020-03793-9
Abstract: Intertidal macrobenthic assemblages associated with monospecific stands of Zostera muelleri , Cymodocea serratula , Halodule uninervis and Halophila ovalis seagrasses are known to display uniform spatial patchiness on the Moreton Bay coast of North Stradbroke Island, Queensland, as do those in Z. capensis in the Knysna estuarine bay, South Africa. Thirty-seven historical datasets of these macrobenthic assemblages were re-analysed to assess variation of local patchiness in each of the 18 most common in idual assemblage components at each of these localities in terms of three metrics: overall patchiness (Lloyd's index of patchiness), levels of unoccupancy, and variation in abundance across occupied s les (Lloyd's index of mean crowding). Within-site patchiness was not caused by a restriction of in idual species to specific subareas but by variation in their local density, particularly by the extent of unoccupied ‘interstitial’ spaces within patches. Especially in the more uniform Queensland conditions, the more common species occurred relatively widely across the whole locality in idual s les from which a given species was absent never themselves formed patches, the number of such s les conforming to points on truncated normal curves of the frequency of occurrence. Of the 36 species investigated, the two most abundant and widespread both in Queensland and in South Africa displayed significant or near-significant uniformity of levels of local patchiness, whilst five showed significantly uniform mean crowding and ten significantly uniform unoccupancy. This is the first demonstration that some species may display a characteristic level of patchiness in a given habitat type.
The significance of shore height in intertidal macrobenthic seagrass ecology and conservation
Publisher: Wiley
Date: 20-10-2011
DOI: 10.1002/AQC.1234
On the very edge: Faunal and functional responses to the interface between benthic seagrass and unvegetated sand assemblages
Publisher: Inter-Research Science Center
Date: 14-07-2016
DOI: 10.3354/MEPS11800
Spatial variation in abundance and diversity of the smaller surface and near-surface eelgrass-associated intertidal macrobenthos within a warm-temperate estuarine bay in the Garden Route National Park, RSA
Publisher: Wiley
Date: 21-10-2010
DOI: 10.1002/AQC.1152
A Redescription of Macrophthalmus Latipes Borradaile, 1903: An Ocypodid Crab With Portunid-Like Paddles (Decapoda, Brachyura)
Publisher: Brill
Date: 1973
Shore height and differentials between macrobenthic assemblages in vegetated and unvegetated areas of an intertidal sandflat
Publisher: Elsevier BV
Date: 06-2012
Littoral biodiversity across scales in the Seychelles, Indian Ocean
Publisher: Springer Science and Business Media LLC
Date: 11-03-2009
Seagrass macrobenthic biodiversity does not vary in conformity with a leaky-lagoonal confinement gradient
Publisher: Elsevier BV
Date: 03-2023
Distribution patterns of macrobenthic biodiversity in the intertidal seagrass beds of an estuarine system, and their conservation significance
Publisher: Springer Science and Business Media LLC
Date: 04-01-2013
An experimental study of the pattern and significance of the climbing behaviour of hydrobia ulvae
Publisher: Cambridge University Press (CUP)
Date: 05-1981
DOI: 10.1017/S0025315400046944
Abstract: The climbing behaviour of the gastropod Hydrobia ulvae (Pennant) and its relationship with flotation/dispersal were investigated by field observations and experiments in Norfolk, U.K. and by laboratory experiments. Field experiments of the type used by previous authors were discontinued when it was observed that counts at low tide of snails which had climbed objects the previous high tide did not reflect adequately climbing activity during that period of tidal cover. Both field and laboratory studies yielded five general results: (i) snails climbed only when covered by tidal water (ii) climbing activity was not related to population density (iii) climbing activity, under conditions of constant population density, varied markedly during the cycle of spring tidal cover, reaching a peak after the first few tides and declining rapidly thereafter (iv) maximum numbers of snails were present on submerged structures relatively early in any given period of cover and declined (snails crawled downwards off the structure) as the period of cover continued and (v) rarely were large proportions of climbed Hydrobia floated off their support by the incoming tide this was associated only with conditions of extreme calm.
Reproductive strategies in contrasting populations of the coastal gastropod Hydrobia ulvae. II. Longevity and life-time egg production
Publisher: Elsevier BV
Date: 1990
Regional and latitudinal variation in the diversity, dominance and abundance of microphagous microgastropods and other benthos in intertidal beds of dwarf eelgrass, Nanozostera spp
Publisher: Springer Science and Business Media LLC
Date: 12-02-2010
Little-known and phylogenetically obscure South African estuarine microgastropods (Mollusca: Truncatelloidea) as living animals
Publisher: Informa UK Limited
Date: 14-12-2018
Hierarchical scales of spatial variation in the smaller surface and near-surface macrobenthos of a subtropical intertidal seagrass system in Moreton Bay, Queensland
Publisher: Springer Science and Business Media LLC
Date: 29-05-2011
The occurrence and ecology of a marine hydrobiid mudsnail in the southern hemisphere: The Knysna Estuary, South Africa
Publisher: Wiley
Date: 06-08-2002
Are seaward pneumatophore fringes transitional between mangrove and lower-shore system compartments?
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.MARENVRES.2017.01.008
Abstract: Work in temperate New Zealand has concluded that seaward fringes of Avicennia pneumatophores (P) form an 'important ecological transitional environment' between seagrass (Z) and mangrove (M), supporting intermediate macrofaunal numbers and bio ersity (Alfaro, 2006). This study re-examined that hypothesis in subtropical Moreton Bay, Queensland, and investigated its dependence on the nature of the lower-shore habitat i.e. whether seagrass or sandflat (S). Adjacent macrobenthic assemblages across 45 m deep Z:P:M and S:P:M interfaces were compared uni- and multivariately and via various assemblage metrics. Here, system compartment P was not intermediate. In Z:P:M interfaces it was essentially an extension of the lower-shore assemblage and supported peak bio ersity. In contrast, P in S:P:M interfaces was partly an extension of the upper-shore assemblage with unchanged bio ersity but minimum abundance. Several species spanned the whole interface zone, and assemblage structure and several metrics remained unchanged across it. These findings are discussed in relation to ecotones in general. Like other such zones the characteristics of pneumatophore-fringe ecotones are context dependent.
Abrupt transitions between macrobenthic faunal assemblages across seagrass bed margins
Publisher: Elsevier BV
Date: 10-2013
Macrobenthic assemblage structure in a cool-temperate intertidal dwarf eelgrass bed in comparison with those from lower latitudes
Publisher: Oxford University Press (OUP)
Date: 22-09-2011
The response of the intertidal gastropod Hydrobia ulvae (Pennant) to sediments of differing particle size
Publisher: Elsevier BV
Date: 1978
A remarkable case of fiddler crab, Uca spp., alpha diversity in Wallacea
Publisher: Springer Science and Business Media LLC
Date: 06-12-2010
Biodiversity differentials between seagrass and adjacent bare sediment change along an estuarine gradient
Publisher: Elsevier BV
Date: 09-2022
Ecology of Swanpool, Falmouth. V. Phytoplankton and nutrients
Publisher: Elsevier BV
Date: 08-1979
Seagrass macrofaunal abundance shows both multifractality and scale-invariant patchiness
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.MARENVRES.2018.04.009
Abstract: Spatial patterns of abundance of the whole macrobenthic assemblage and of its 10 most numerous species were examined across hierarchically nested scales within a 0.85 ha area of intertidal seagrass in subtropical Moreton Bay, Queensland. Multifractality characterised the assemblage and all ten dominant species across those scales (c. 33, 130, 530 & 2115 m
Spatial stability of macrobenthic seagrass biodiversity
Publisher: Inter-Research Science Center
Date: 20-11-2013
DOI: 10.3354/MEPS10546
Concluding contribution towards a revision of, and a key to, the genus Macrophthalmus (Crustacea: Brachyura)
Publisher: Wiley
Date: 06-1977
What does measuring species diversity in estuarine seagrass systems actually assess?
Publisher: Elsevier BV
Date: 12-2021
An ecological study of a pool subject to varying salinity (Swanpool, Falmouth). An introductory account of the topography, fauna and flora.
Publisher: JSTOR
Date: 10-1971
DOI: 10.2307/3446
Intraspecific Abundance–Occupancy–Patchiness Relations in the Intertidal Benthic Macrofauna of a Cool-Temperate North Sea Mudflat
Publisher: Springer Science and Business Media LLC
Date: 13-09-2022
DOI: 10.1007/S12237-021-00998-Z
Abstract: The macroecological variable of patchiness (Lloyd’s I p index of patchiness, P ) has recently been shown to be related inter- and intraspecifically to those of abundance (numbers m −2 , A ), and occupancy (% occurrence in s les, O ) in lower latitude seagrass macrofaunas. For the first time in higher latitudes, intraspecific relationships between three spatial variables were investigated in the intertidal mudflat macrobenthos of the Scolt Head barrier island, southern North Sea (53° N, 01° E). S ling was conducted between early July and late September 2009–2013 using 710-µm mesh for s le processing. Strong positive interspecific A - O and negative interspecific P - O and P - A relationships were present. Two of the most numerous and widespread assemblage components, however, occurred with effectively constant occupancy ( Peringia ulvae , 100%, and Tubificoides benedii , 93%) across the whole 20-ha locality and therefore could not show intraspecific relationships of occupancy with other macroecological metrics. These two apart, only one other dominant species failed to show a significant positive intraspecific A - O relationship no species showed significant P - A relations of any form and only two showed the negative P - O ones that have been described elsewhere. The intraspecific A - O patterns appear to contrast with those of an earlier study at another North Sea locality (the Dutch Wadden Sea), although differences are more apparent than real, but the Scolt Head fauna showed fewer intraspecific P - O and P - A relations than those characterising similar circumstances in the two lower-latitude localities previously investigated. Neither developmental mode nor variation in local abundance appears to influence these patterns. A - O - P relations therefore seem widespread but may be subject to latitudinal modification.
An ecological study of the Swanpool, Falmouth. II. Hydrography and its relation to animal distributions
Publisher: Elsevier BV
Date: 04-1973
Variation in feeding rate of the intertidal mudsnail Hydrobia ulvae in relation to the tidal cycle
Publisher: Wiley
Date: 06-2006
Seagrass-associated macrobenthic functional diversity and functional structure along an estuarine gradient
Publisher: Elsevier BV
Date: 10-2015
The coastal lagoons of Britain: An overview and conservation appraisal
Publisher: Elsevier BV
Date: 1989
Factors affecting climbing in the coastal gastropod hydrobia ulvae
Publisher: Cambridge University Press (CUP)
Date: 05-1981
DOI: 10.1017/S0025315400046956
Abstract: In a series of laboratory experiments designed to create conditions under which the dispersal and feeding hypotheses of climbing in Hydrobia ulvae would predict opposing results, significantly larger numbers of snails climbed ( a ) food-bearing sticks than non-food-bearing sticks, ( b ) in 100% sea water than in 41% sea water, and ( c ) in the dark than in the light. The first two of these results are in accordance with the hypothesis that climbing is not a distinct behavioural activity but is merely normal crawling/browsing behaviour carried out in a vertical plane they are in disagreement with the hypothesis that climbing is undertaken in order to facilitate dispersal away from unfavourable conditions. The third result is neutral in respect of the two hypotheses, but is explicable in terms that activity during the night is advantageous because of lowered rates of vertebrate predation.
Do beds of subtidal estuarine seagrass constitute a refuge for macrobenthic biodiversity threatened intertidally?
Publisher: Springer Science and Business Media LLC
Date: 22-07-2020
DOI: 10.1007/S10531-020-02019-0
Abstract: Bio ersity differentials between macrobenthic assemblages associated with adjacent intertidal and subtidal areas of a single seagrass system were investigated for the first time. Assemblage metrics of conservation relevance—faunal abundance and its patchiness, faunal richness, and beta ersity—were examined at four contrasting dwarf-eelgrass localities in the Knysna estuarine bay, part of South Africa's Garden Route National Park but a system whose intertidal areas are heavily impacted anthropogenically. Faunal assemblages were significantly different across all localities and between subtidal and intertidal levels at each locality although their taxonomic distinctness was effectively constant. Although, as would be expected, there were clear trends for increases in overall numbers of species towards the mouth at all levels, few generalities relating to the relative importance of the subtidal seagrass habitat were evident across the whole system—magnitude and direction of differentials were contingent on locality. Shore-height related differences in assemblage metrics were minor in the estuarine and lagoonal zones but major in the marine compartment, although the much greater subtidal faunal abundance there was largely consequent on the superabundance of a single species (the microgastropod Alaba pinnae ), intertidal zones then displaying the greater species ersity due to greater equitability of species densities. Along its axial channel, the Knysna subtidal seagrass does not support richer versions of the intertidal polychaete-dominated assemblages fringing it instead, it supports different and more patchily dispersed gastropod-dominated ones. At Knysna at least, the subtidal hardly constitutes a reservoir of the seagrass bio ersity present intertidally.
The faunas of land-locked lagoons: Chance differences and the problems of dispersal
Publisher: Elsevier BV
Date: 03-1988
What, if anything, is a brackish-water fauna?
Publisher: Cambridge University Press (CUP)
Date: 1989
DOI: 10.1017/S0263593300028674
Abstract: The nature of the fauna of brackish-water environments is reviewed. It is concluded that: (a) a specific brackish-water macrofauna does not exist (b) in salinities of c . 5-8‰ the fauna is one that also occurs in soft sediments under fully marine conditions when circumstances (possibly the absence of competing species) permit (c) in salinities of c . 5‰ the fauna is essentially a freshwater one and (d) inability to cope physiologically with brackish water is not a factor of major importance in limiting species ersity in these habitats, except in the vicinity of 5‰ salinity. Caution is therefore advised in assigning brackish status to past environments on the basis of their preserved fauna.
Gender and Species Differences in Sentinel Crabs (Macrophthalmus) Feeding on an Indonesian Mudflat
Publisher: Oxford University Press (OUP)
Date: 2006
DOI: 10.1651/C-2612.1
A critical appraisal of the application of Guelorget and Perthuisot's concepts of the paralic ecosystem and confinement to macrotidal Europe
Publisher: Elsevier BV
Date: 1994
Daily activity rhythms in the intertidal gastropod Hydrobia ulvae (Pennant)
Publisher: Elsevier BV
Date: 03-1986
Do different sympatric seagrasses support macrobenthic faunas of differing composition, abundance, biodiversity or patchiness?
Publisher: Elsevier BV
Date: 09-2020
Context dependency in the effect of Ulva‐induced loss of seagrass cover on estuarine macrobenthic abundance and biodiversity
Publisher: Wiley
Date: 10-10-2019
DOI: 10.1002/AQC.2977
Abstract: An extensive area of seagrass covering the shore of part of the South African estuary ranked highest in overall national conservation and bio ersity importance (the Knysna estuarine bay) was killed by a series of seasonal green‐tidal blankets of Ulva starting in the late austral summer of 2015, leaving bare muddy sediment. An earlier (2011) survey of then seagrass macrobenthic assemblages at 27 stations along over 1 km of that shore was exactly repeated in 2018 after this event. After loss of seagrass, intertidal macrofauna became significantly less speciose (1:0.61), spatially and systematically more uniform (1:1.30 and 1:1.63), but more (not the usual less) abundant (0.62:1). Assemblage composition also changed, with polychaete numbers (small nereidids, spionids, fabriciids and an endemic paraonid) increasing from % of total macrofaunal in iduals to % (although cirratulids decreased), whereas small malacostracan crustaceans (except the hipod Grandidierella sp.) and microgastropods diminished to insignificant levels—microgastropods for reasons possibly unconnected with the green tide. Comparison with areas not vegetated in 2014, however, indicated that although macrofaunal abundance was greater in the 2018 Ulva ‐induced bare areas, levels of per unit area bio ersity (number of species, species and taxonomic ersity per station) were comparable. This suggests that the effect of local loss of seagrass cover is context dependent, particularly with regard to pre‐existing local seagrass versus adjacent bare‐sediment differentials, and does not necessarily lead to any “degraded” state. Decreased local importance of small malacostracans may severely impact the region's usage by the adult and juvenile fish for which it is an important nursery and feeding ground.
Repeated cycles of immersion and emersion amplify the crawling rhythm of the intertidal gastropod Hydrobia ulvae
Publisher: Cambridge University Press (CUP)
Date: 22-07-2011
DOI: 10.1017/S0025315411000853
Abstract: Hydrobia ulvae displays an endogenous rhythm of crawling behaviour of circatidal periodicity, with higher levels of activity during high water. In the present study we address the effect of repeated cycles of immersion and emersion at tidal periodicity on the level and synchronism of the behaviour, by contrasting these with the effects of continuous immersion and continuous emersion. Snails were recorded in dark conditions under the different immersion regimes for 3 days. The results show that continuously emersed snails displayed very low levels of activity. Average activity levels of continuously immersed snails and of those subjected to tidal cycles of immersion and emersion were similar, had identical periods related to the period of the tidal cycle, and had similar phase relationships to the expected tidal cycle. However, form-estimates for these two categories of snails differed, the snails subjected to cyclic conditions showing a larger litude and greater synchronism of activity. Therefore, it is concluded that recurrent cycles of immersion and emersion should contribute to well defined cycles of activity in the intertidal environment, with greater activity levels during high water.
Spatial variability in the structure of intertidal crab and gastropod assemblages within the Seychelles Archipelago (Indian Ocean)
Publisher: Elsevier BV
Date: 04-2012
Variation in paragnath number in some British populations of the estuarine polychaete Nereis diversicolor
Publisher: Elsevier BV
Date: 11-1977
Interspecific relationship of patchiness to occupancy and abundance, as exemplified by seagrass macrobenthos
Publisher: Elsevier BV
Date: 02-2021
Is spatial uniformity of soft-sediment biodiversity widespread and, if so, over what scales?
Publisher: Inter-Research Science Center
Date: 14-05-2014
DOI: 10.3354/MEPS10770
Spatial uniformity of biodiversity is inevitable if the available species are distributed independently of each other
Publisher: Inter-Research Science Center
Date: 03-12-2014
DOI: 10.3354/MEPS11067
Interspecific abundance-occupancy relations along estuarine gradients
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.MARENVRES.2022.105755
Abstract: Do interspecific abundance-occupancy (A-O) relationships vary systematically along environmental gradients? A-O relationships of macrobenthic assemblages of seagrass and adjacent bare-sediment were compared at series of sites along two types of estuarine gradient the longitudinal one of the main axial channel, and a transverse one from that channel into progressively smaller channels and creeks enclosed within fringing saltmarsh. Three general features emerged: A-O regression slopes were remarkably uniform across all the disparate assemblages and sites (1.04 ± 0.08) values of R
Intrapopulation variation in Hydrobia sediment preferences
Publisher: Elsevier BV
Date: 08-1979
An Introduction to Marine Ecology: Third Edition
Publisher: Wiley
Date: 29-03-2009
Investment in eggs in lagoonal hydrobia ventrosa and life-history strategies in north-west european hydrobia species
Publisher: Cambridge University Press (CUP)
Date: 08-1994
DOI: 10.1017/S0025315400047718
Abstract: Expected lifetime investment in eggs and related parameters are described for a lagoonal population of Hydrobia ventrosa (Mollusca: Gastropoda) in East Anglia, UK, and these are compared with those of East Anglian lagoonal populations of H. neglecta and both lagoonal and intertidal-marine populations of H. ulvae . In contrast to an earlier study on Danish populations, which suggested that H. neglecta and H. ventrosa are at opposite ends of the hydrobiid spectrum of investment in reproduction, the order of increasing relative allocation of resources to egg production runs H. neglecta = H. ventrosa → lagoonal H. ulvae → intertidal-marine H. ulvae . That is, from the two small, short-lived, specialist lagoonal species producing few, large, directly-developing eggs, to the larger, potentially longer-lived H. ulvae that produces many small eggs which develop into veliger larvae. The lagoonal populations of all three Hydrobia species, however, are very similar to each other in terms of reproductive investment. When like cohorts are compared, in each, the annual egg weight is equal to the annual adult growth increment, and the weight of eggs produced per expected lifetime is half the adult growth increment at the time of death. These lagoonal populations are markedly dissimilar to intertidal-marine populations of H. ulvae , which produce an annual weight of eggs some 15 times the annual adult growth increment, and an expected lifetime egg weight some two-and-a-half times the adult growth increment at the time of death.
What determines the distribution of coastal hydrobiid mudsnails within north-western Europe?
Publisher: Wiley
Date: 10-1999
Feeding rates of continually submerged Hydrobia ulvae vary during the daylight hours
Publisher: Cambridge University Press (CUP)
Date: 12-2003
DOI: 10.1017/S0025315403008646
Abstract: Feeding, as estimated by egestion rate, in coastal epibenthic mud snails Hydrobia ulvae living continually submerged in lagoon-like conditions varies significantly with time of day. Both in the field and in the laboratory, egestion rate is maximal around mid-day and minimal at twilight. This variation, here ranging in magnitude from mean lows of some nine faecal pellets h −1 to highs of 34 h −1 , is consonant with likely rhythms of availability and productivity of their microphytobenthic food.
Local patchiness of macrobenthic faunal abundance displays homogeneity across the disparate seagrass systems of an estuarine bay
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.MARENVRES.2019.05.001
Abstract: Spatial variation in the degree of local patchiness of macrobenthic assemblage abundance was assessed across the 16 km
The Macrophthalminae of Australasia; with a review of the evolution and morphological diversity of the type genus Macrophthalmus (Crustacea: Brachyura).
Publisher: Wiley
Date: 10-1967
Isometric scaling of faunal patchiness: Seagrass macrobenthic abundance across small spatial scales
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.MARENVRES.2019.03.011
Abstract: Following earlier studies across 2115 → 33 m
The circatidal rhythm of the estuarine gastropod Hydrobia ulvae (Gastropoda: Hydrobiidae)
Publisher: Oxford University Press (OUP)
Date: 19-05-2010
Dilemmas in the theory and practice of biological conservation as exemplified by British coastal lagoons
Publisher: Elsevier BV
Date: 1991
Spatial variation in the macrobenthic assemblages of intertidal seagrass along the long axis of an estuary
Publisher: Elsevier BV
Date: 10-2012
Uca cryptica Naderloo, Türkay & Chen, 2010 (Crustacea: Brachyura: Ocypodidae) is no longer cryptic
Publisher: Magnolia Press
Date: 03-07-2015
DOI: 10.11646/ZOOTAXA.3981.2.10
Abstract: Uca cryptica Naderloo, Türkay & Chen, 2010, was originally described from four male specimens found in museum collections without any information regarding the site of collection. We present the first recorded field observations of this species and new morphological features. Specimens were observed and collected in the Wakatobi National Park, on the island of Kaledupa, Sulawesi Tenggara, Indonesia. Colouration of both males and females is described and ecology and distribution are noted. Uca cryptica has been seen coexisting with nine other species one of the highest recorded numbers of Uca species living in sympatry.
Abundance/occupancy/patchiness relations in estuarine seagrass macrobenthos
Publisher: Elsevier BV
Date: 11-2019
chapter 11 Macrofaunal Community Structure and Life Histories in Coastal Lagoons
Publisher: Elsevier
Date: 1994
The brackish-water fauna of northwestern Europe
Publisher: Cambridge University Press
Date: 1994
Variation in paragnath number of Nereis diversicolor in relation to sediment type and salinity regime
Publisher: Elsevier BV
Date: 03-1978
Within-species relationship of patchiness to both abundance and occupancy, as exemplified by seagrass macrobenthos
Publisher: Springer Science and Business Media LLC
Date: 09-07-2021
DOI: 10.1007/S00442-021-04985-W
Abstract: For the first time, intraspecific relationships between the macroecological metrics patchiness (P) and both abundance (A) and occupancy (O) were investigated in a faunal assemblage. As a companion study to recent work on interspecific P, A and O patterns at the same localities, intraspecific patterns were documented within each of the more dominant invertebrates forming the seagrass macrobenthos of warm–temperate Knysna estuarine bay (South Africa) and of sub-tropical Moreton Bay (Australia). As displayed interspecifically, in idual species showed strong A–O patterns (mean scaling coefficient − 0.76 and mean R 2 0.8). All P–O relations were negative and most (67%) were statistically significant, although weaker (mean R 2 0.5) than A–O ones most P–A ones were also negative but fewer (43%) achieved significance, and were even weaker (mean R 2 0.4) 33% of species showed no significant interrelations of either O or A with P. No species showed only a significant P–A relationship. Compared with interspecific P–A–O data from the same assemblages, power–law scaling exponents were equivalent, but R 2 values were larger. Larviparous species comprised 70% of the total studied, but 94% of those displaying significant patchiness interrelationships 5 of the 9 showing no P–A or P–O relationships, however, were also larviparous. At Knysna, though not in Moreton Bay, larviparous species also showed higher levels of occupancy than non-larviparous ones, whilst non-larviparous species showed higher levels of patchiness. Dominant Moreton Bay species, but not those at Knysna, exhibited homogeneously sloped P–O relationships.
Where ecologically ‘tis better to go brown than green: enhanced seagrass macrobenthic biodiversity within the canals of a brownfield coastal marina
Publisher: Springer Science and Business Media LLC
Date: 11-08-2022
DOI: 10.1007/S10531-022-02468-9
Abstract: At the start of the 21st century, a coastal residential-estate marina was developed on a previously degraded and polluted brownfield island site within Knysna estuarine bay, Garden Route National Park, South Africa, including the creation of 25 ha of new flow-through tidal canals. Canals near the larger entrance to this system now support permanently submerged beds of seagrass, which in turn support abundant macrobenthic invertebrates. In comparison with equivalent seagrass-associated assemblages present in natural channels around the island, those in the artificial marina canals were similarly structured and dominated by the same species, but the marina assemblages were significantly more species-rich (1.4 x on average) and were more abundant. Indeed, this area of marina supports the richest seagrass-associated macrofaunal bio ersity yet recorded from South Africa. The canals created de novo therefore now form a valuable addition to the bay’s marine habitat, in marked contrast to the generality that marinas developed on greenfield sites represent a net reduction in intertidal and shallow marine area and associated seagrass-associated benthos. If located and constructed appropriately, brownfield marina development and conservation of coastal marine bio ersity clearly need not be antithetical, and brownfield sites may provide opportunity for the location and management of ‘artificial marine micro-reserves’ or for the action of ‘other effective area-based conservation measures’ for soft-sediment faunas.
Related Organisations
University Of Cambridge Saint Catharine's College
Location: United Kingdom of Great Britain and Northern Ireland
University Of Cambridge
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
No related grants have been discovered for Richard Barnes.