Hierarchical scales of spatial variation in the smaller surface and near-surface macrobenthos of a subtropical intertidal seagrass system in Moreton Bay, Queensland

Barnes, R. S. K.; Barnes, Morvan K.

doi:10.1007/s10750-011-0770-9

Cited by 18 publications

(8 citation statements)

References 43 publications

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“…(e.g. Lavery & Vanderklift 2002, Balata et al 2007, nektonic crustaceans and fish associated with Posidonia and Zosterella capricorni (McNeill & Fairweather 1993), and the benthic macrofauna of intertidal expanses of various Zosterella species (Barnes & Barnes 2011, Barnes & Ellwood 2011a, 2012a. Similarly to studies on faunal assemblages in other benthic marine habitats, e.g.…”

Section: Introductionmentioning

confidence: 97%

Spatial stability of macrobenthic seagrass biodiversity

Barnes¹

2013

Mar. Ecol. Prog. Ser.

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The magnitude and patchiness of macrobenthic biodiversity were compared across spatial scales spanning 5 orders of areal magnitude (ca. 2 m 2 to ca. 1.5 ha) in an intertidal seagrass bed in the warm-temperate Knysna estuarine bay, South Africa. The 75 component species and their populations were highly variably distributed across the site, abundances of the individual dominant animals being significantly patchy and composition of the macrofaunal assemblage being significantly non-uniform. Nevertheless, emergent assemblage attributes exhibited spatial constancy: values of assemblage metrics (faunal abundance, species richness, species density and species diversity) did not differ across the site or across spatial scales, and neither did the patterns of dispersion of species diversity, species richness or observed species density. Distribution of the 2 latter through space was even significantly uniform. Ecological arguments developed for temporal constancy of biodiversity seem broadly applicable to the spatial dimension at Knysna, suggesting that although apparently paradoxical, it may be the varying assemblage composition that permits this spatial stability. There is no evidence, however, that the Knysna seagrass macrobenthos is a competitively-structured assemblage with rigid niche-partitioning, a condition suggested to be necessary for temporal constancy; rather, it is more likely to be open, non-equilibrium and below carrying capacity.

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Section: Introductionmentioning

confidence: 97%

Spatial stability of macrobenthic seagrass biodiversity

Barnes¹

2013

Mar. Ecol. Prog. Ser.

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“…Studies of N. capensis beds at Knysna (Barnes, ; and the present paper) and those of equivalent intertidal Nanozostera systems in Moreton Bay, Australia (Barnes and Barnes, ), and in the North Sea, UK (Barnes and Ellwood, ), are beginning to reveal a consistent picture. Within a given bed general ecological features such as benthic faunal density and species richness and species diversity are relatively uniform across space (at least over distances <5 km) whereas the actual assemblages yielding these uniform values are highly variable in both species composition and relative abundances of shared species.…”

Section: Discussionmentioning

confidence: 51%

“…At somewhat larger spatial scales, however, assemblage organization changes from random to deterministic. In the 1 km long, fully marine Steenbok Channel at Knysna, this change in structure occurs in association with clear environmental gradients, both that along the creek axis and that down the shore across the seagrass bed, although no such obvious environmental gradients were evident at sites in Moreton Bay (Barnes and Barnes, ) or the North Sea (Barnes and Ellwood, ). What specific (small‐scale) spatial scales are critical to such changes in assemblage variance and structure are as yet unknown.…”

Section: Discussionmentioning

confidence: 99%

The significance of shore height in intertidal macrobenthic seagrass ecology and conservation

Barnes

Ellwood

2011

Aquatic Conservation

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ABSTRACT1. Benthic faunal assemblages of an intertidal seagrass bed were sampled at three shore heights (LWN, MLW, LWS) at the mouth, mid-point and head of the Steenbok Channel in South Africa's premier seagrass site, the warm-temperate Knysna estuarine bay, Garden Route National Park.2. Faunal abundance, species richness, species diversity, and proportion of rare species were relatively uniform along the Channel, as were faunal abundance, species diversity and proportion of rare species down the shore. Overall species richness per station, however, was significantly lower at LWN than at either MLW or LWS, although the distribution of species richness over the shore did not depart from random at one of the three sites. Overall faunal abundance and those of individual component species were dispersed patchily through the bed.3. The nature of the faunal assemblages present, however, varied significantly throughout the bed, both along the Channel at each shore-height horizon, and down the shore at each site. LWN assemblages formed a unit distinct from those at MLW and LWS. Overall, the shore-height axis accounted for 47% and the along-shore axis 28% of total assemblage variation.4. Faunal assemblages were randomly structured at each nodal intersection point of the down-shore and along-shore axes, but were significantly non-randomly assembled down the shore at each site and along the Channel at each shore-height horizon except at the LWN level.5. Components of total assemblage variance were largest at the smallest scale investigated (1 m). 6. Higher seagrass horizons are not just progressively more impoverished versions of lower ones and although macrofaunal assemblage composition is heavily influenced by shore height much of the ecological structure of faunal assemblages seems little affected by tidal horizon. These findings are discussed in relation to conservation of the vulnerable seagrass Nanozostera capensis at Knysna, a system affected by subsistence exploitation of its intertidal benthic invertebrates.

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“…This was undertaken by investigation of 2 further localities contrasting in their nature to that of Knysna and supporting expanses of unvegetated sand as well as seagrass beds. The first was a highdiversity but low-abundance subtropical South Paci fic locality, at which earlier studies had produced results suggestive of spatially uniform levels of bio diversity (Barnes & Barnes 2011; the second was a lowdiversity but very high-abundance cool-temperate locality in the northeast Atlantic. Further, unlike the system at Knysna, which was dominated mainly by a suite of infaunal polychaetes, strikingly different faunal and/or ecological groups were known to be dominant at the new localities investigated: an epifaunal clade-G truncatelloid micro gastropod (sensu Criscione & Ponder 2013) in both the cool-temperate habitat types, an infaunal urohaustoriid amphipod in the subtropical sandflat, and a range of species (epi-and infaunal clade-I truncatelloids, a macrophthalmid crab, and a phoxocephalid amphipod) with no single overall dominant in the subtropical seagrass (Barnes & Barnes 2011, Barnes & Ellwood 2011b.…”

Section: Introductionmentioning

confidence: 94%

Is spatial uniformity of soft-sediment biodiversity widespread and, if so, over what scales?

Barnes¹

2014

Mar. Ecol. Prog. Ser.

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Spatial variation in the components of faunal assemblages, but spatial uni formity of their biodiversity metrics, as described in 2013 for a seagrass bed in an estuarine bay in the warmtemperate Indian Ocean, is probably widespread in marine environments, and not restricted to seagrass habitats. Here, it is shown to occur across unvegetated siliceous sandflats as well as seagrass beds on a high-diversity but low-abundance subtropical island (North Stradbroke Island, Australia) in the South Pacific, and on a low-diversity but high-abundance cool-temperate island (Scolt Head Island, UK) in the North Atlantic. At the Australian locality, this uniform biodiversity but non-uniform faunal assemblage composistion were observed to extend over distances of at least 6.5 km in both habitat types. Unit areas as small as 0.0275 m 2 in each system supported a statistically invariant percentage of the total species pool of that system (i.e. the system's overall mean percentage constancy index at the spatial scale concerned). Further, assemblages in all localities showed very similar ranked species-constancy curves, even though the proportions of the total numbers comprised by the various species varied widely. It is therefore suggested that the factors structuring the macrofaunal assemblages in such soft-sediment habitats must be capable of promoting comparable systems of relative frequency of occurrence, regardless of local levels of faunal abundance and biodiversity.

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Hierarchical scales of spatial variation in the smaller surface and near-surface macrobenthos of a subtropical intertidal seagrass system in Moreton Bay, Queensland

Cited by 18 publications

References 43 publications

Spatial stability of macrobenthic seagrass biodiversity

Spatial stability of macrobenthic seagrass biodiversity

The significance of shore height in intertidal macrobenthic seagrass ecology and conservation

Is spatial uniformity of soft-sediment biodiversity widespread and, if so, over what scales?

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