V and C Semeniuk Research Group

Warwick, Australia

V and C Semeniuk Research Group

Warwick, Australia
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Unno J.,Edith Cowan University | Unno J.,V and C Semeniuk Research Group | Semeniuk V.,V and C Semeniuk Research Group
Crustaceana | Year: 2011

The previously undescribed population dynamics of the Western Australian soldier crab, Mictyris occidentalis Unno, 2008, in King Bay, north-western Australia are elucidated, with annual observations and sampling over a 30-year period from 1980 to 2010. This is the longest recorded study of a single inter-tidal brachyuran population and shows long-term persistence of soldier crab populations in stable, sheltered habitats. The life cycle of M. occidentalis follows a cryptic subsurface juvenile and immature adult (= adolescent) phase and an emergent adult phase. Population densities were generally 500 crabs/m2 for the early 1980s, late 1980s, and during the early 2000s. Maximum population densities were high in the mid 1980s (800 crabs/m2). The spatial and temporal variability in the distribution of the population was consistent over the study period. Juvenile recruitment extends for up to 7 months of a given year between May and November with the main influx of juveniles usually in June and occasional minor influxes in August or October. Juvenile recruitment is followed by incremental growth of individuals at a rate of 1 mm/month reaching sexual maturity in the first year at 6.0-6.9 mm carapace length (CL). Adult males are larger than females with a maximum size of 15.0 mm CL compared to 12.0 mm CL, respectively. Ovigerous females are low in numbers throughout most of the year but reach a peak in February. During swarming, M. occidentalis populations partition not only by size class, with surface crabs being adults only and subsurface crabs mainly adult females and juveniles, but also by sex in that swarms are male-dominated in varying ratios. © 2011 Koninklijke Brill NV, Leiden.


Semeniuk V.,V and C Semeniuk Research Group | Cresswell I.D.,CSIRO
Diversity | Year: 2013

The current measures of diversity for vegetation, namely alpha, beta, and gamma diversity are not logically consistent, which reduces their effectiveness as a framework for comparative vegetation analysis. The current terms mix concepts: specifically, while alpha diversity measures floristic diversity at a site, and gamma diversity measures floristic diversity regionally, beta diversity is a measure of diversity between two sites and measures a different phenomenon. We seek to rationalise measures of diversity providing a scalar set of measures. Our approach recognises vegetation diversity extends beyond species diversity and should include the various ways plants express themselves phenotypically. We propose four types of diversity, with a new set of prefixes: Type 1 diversity = the largest scale-the regional species pool; Type 2 diversity = the large habitat scale-where species in a habitat have been selected from the regional species pool; Type 3 diversity = intra-habitat expression of floristics, structure, and physiognomy; and Type 4 diversity = the finest scale of expression of vegetation diversity reflecting site selection of floristics, physiography, and phenotypic expression and reproductive strategy. This proposed framework adds significant new power to measures of diversity by extending the existing components to cover floristics, structure, physiognomy, and other forms of phenotypic expression. © 2013 by the authors; licensee MDPI, Basel, Switzerland.


Semeniuk V.,V and C Semeniuk Research Group | Unno J.,V and C Semeniuk Research Group
Ichnos:an International Journal of Plant and Animal | Year: 2014

The Western Australian soldier crab, Mictyris occidentalis Unno 2008, presents an unusual association between crab and ichnological features. As the crab progresses through life, its behavior becomes more complex and its ichnological products more varied: from small, sandy clots and pustules, progressing to various types of shallow, pellet-roofed feeding tunnels and then, when emergent and swarming, eruption structures (exit holes), discard feeding pellets, and re-entry rosettes. The size of tunnels, exit holes, pellets, and re-entry rosettes are commensurate with the size of the crabs. The link between crab ichnological product, life stage, and behavior is so direct that its ichnological features can be used as a surrogate to reconstruct population age structure and age-related behavior. In effect, as it progresses through life from being wholly infaunal to alternating infaunal and epifaunal with swarming behavior, autoecologically and palaeoecologically, the ichnology of the Western Australian soldier crab is a "Rosetta Stone" (used metaphorically, for a series of inscriptions on the tidal flat surface) that can be interpreted to determine species occurrence and population age structure, unravel age-related behavior, and, if preserved as ichnofossils, interpret fossil crab sizes, population structures, behavior and palaeoenvironment. © 2014 Copyright Taylor & Francis Group, LLC.


Brocx M.,Murdoch University | Semeniuk V.,V and C Semeniuk Research Group
Proceedings of the Linnean Society of New South Wales | Year: 2011

To further the disciplines of geoheritage and geoconservation, a Geoheritage "tool-kit" has been developed to systematically compile an inventory at various scales of geological and geomorphological features in a given area, assess their levels of significance, and address whether geoheritage features are treated in isolation or as inter-related suites that should be conserved as an ensemble. The Leschenault Peninsula, a retrograding Holocene dune barrier in south-western Australia, and its leeward estuarine lagoon, provide a case study of the application of this tool-kit. The barrier-and-lagoon is unique in Western Australia and comprises a wide variety of geological and geomorphological features, from large to fine scale, and varying in significance from International to State-wide to Regional. Some key features include: active parabolic dunes; an interface between dunes and estuary that is the most complex sedimentologically, hydrologically, and ecologically in Western Australia; a stratigraphy recording a complex Holocene sea level history; barrier retreat marked by parallel bands of submerged beach rock; and a sheet of calcrete above the water table. In terms of geoconservation, addressing the various features of geoheritage value in this area is best achieved by viewing the system as an integrated geopark of interactive processes, geology, and geomorphology.


Semeniuk V.,V and C Semeniuk Research Group
Proceedings of the Linnean Society of New South Wales | Year: 2011

Accumulation of the Ordovician Daylesford Limestone at Bowan Park, west of Orange, NSW, has been repetitively interrupted by subaerial disconformities. There are distinct diagenetic and pedogenetic suites of products within diverse fossiliferous carbonate lithologies associated with the disconformities as expressed in grains and minerals, fabrics and structures, and lithologies. These include: lithoclasts, calcrete-coated and peripherally-altered lithoclasts, remanié fossils, diagenetic (internal) sediments, terrigenous mud and silica; fossil molds, enlarged fossil molds, cavities, mottles, fissures and irregular surfaces, patches of cryptocrystalline and microcrystalline calcite, bleached zones; and various lithologies such as vugular limestone, mottled limestone, massive light grey limestone, lithoclast grainstone, calcrete-ooid grainstone, calcrete-ooid packstone and wackestone, pellet packstone and wackestone, (terrigenous) mudstone, and palaeosols. Lithoclasts (of vugular limestone with diagenetic sediment) above disconformities, and the restriction of vugular limestone with variable diagenetic sediment-filled cavities beneath disconformities, indicate leaching and internal sedimentation was early and associated with subaerial exposure. The most important factor affecting profile variation is the type of host rock, i.e. grainstone versus muddy limestone. Palaeosols are mostly developed on muddy limestone, and leaching is most common within the altered muddy limestone, whereas for grainstones, palaeosols are generally absent, and cryptocrystalline (and microcrystalline) calcite (calcrete) patches are probably the most important diagenetic product. Beneath the disconformities, ten types of subaerially developed profiles are recognised: erosionally truncated vugular limestone with coralline encrustation on the disconformity, erosionally truncated vugular limestone without palaeosol cover, erosionally truncated vugular limestone with thin palaeosol cover, muddy limestone with thin palaeosol cover with calcrete ooids and remanié fossils, muddy limestone with thick palaeosol cover with calcrete ooids and remanié fossils, muddy limestone with marine-reworked lithoclastic and calcrete ooid grainstone and remanié fossils, solution-altered grainstone with overlying lithoclastic and calcrete ooid grainstone, thick calcrete developed on grainstone, wackestone/lime-mudstone (marl) with overlying sheet of (terrigenous) mudstone, and silicified limestone. Of the range of products and profiles, the vugular limestones stand as the most important indicators of subaerial exposure. The information in this study provides insights into the types of subaerial diagenesis and pedogenesis operating during the Ordovician, and also into landscape setting, palaeo-hydrology and depth of the vadose zone, climate, and groundwater/rainwater alkalinity.


Errami E.,Chouaïb Doukkali University | Ennih N.,Chouaïb Doukkali University | Brocx M.,Murdoch University | Semeniuk V.,V and C Semeniuk Research Group | Otmane K.,Chouaïb Doukkali University
Rendiconti Online Societa Geologica Italiana | Year: 2013

Morocco presents a varied and globally important geology reflecting its successive continental-scale geological settings through geological time. Central, Southern and Western Morocco exhibits a rich geological history of crustal, magmatic, tectonic, metamorphic, sedimentary, and palaeontological features from Archaean to Quaternary, from large- to small-scale and varying in significance from international to local. The geostrategic position of Morocco renders it a land where many civilizations met through time leaving archaeological evidence of outstanding values - as such, its geodiversity is even more attractive as is related to historical, archaeological, architectural, cultural and traditional frames which vary with its geology. In this context, we focus on the central Anti-Atlas that consists of numerous Precambrian inliers amongst a matrix? of Palaeozoic strata, and each inlier has the merit to be transformed into thematic geoparks. Zenaga Inlier is a good example of an ensemble of geological features that have a regionally important geological story and geodiversity that can be transformed into a geopark. In this paper, we present geological information on potential geosites in the Zenaga region of the Central Anti-Atlas which could form the bases for future geoparks. © Società Geologica Italiana, Roma 2013.


Brocx M.,Murdoch University | Semeniuk V.,Murdoch University | Semeniuk V.,V and C Semeniuk Research Group
Geological Society Special Publication | Year: 2015

The Pilbara Coast, in NW Australia, stands unique as the most geologically/geomorphologically diverse arid coast globally and, as such, it is a coastline of Global Significance. Ideally, it should have been listed as a site of World Heritage. While there are a variety of coastal forms along the Pilbara Coast, a ubiquitous feature of the region is the development of extensive salt flats landward of mangrove-fringed coastlines, and leeward of barrier limestone ridges and barrier dunes. The aridity of the Pilbara Coast and the occurrence of extensive salt flats lend themselves to exploitation for development of solar salt production ponds but this has resulted in the destruction of unique coastal geomorphology, salt flat habitats, 'sand island ecology' and the natural diagenesis of arid-zone coastal geology. This contribution explores the significance of solar salt pond development along a globally unique coastline, and highlights that there needs to be a component of geoethics in government decision-making that considers all the values of a site. © 2015 The Author(s).


Semeniuk V.,V and C Semeniuk Research Group
Hydrobiologia | Year: 2013

A review of the Western Australian coast systems shows a range of models of how coastal wetlands could respond to climate change because it spans climates from tropical humid, tropical arid, to near-temperate humid, faces various oceans that drive coastal processes and maintain coastal landforms and habitats, and adjoins a range of hinterland types that develop variable coastal habitats, runoff and rainfall. It thus provides a plethora of settings that latitudinally will respond differentially to any changes in air temperatures, evaporation, rainfall patterns, freshwater influx, wind regimes and storm activity, and derivative responses such as changes in sediment supply, maintenance of coastal forms, coastal groundwater and biota. A review and examples of coastal wetland response to climate changes are provided from Walpole-Nornalup Inlet Estuary, Leschenault Inlet Estuary, the Point Becher area and King Sound. © Springer Science+Business Media B.V. 2012.


Semeniuk C.A.,V and C Semeniuk Research Group | Semeniuk V.,V and C Semeniuk Research Group
Hydrobiologia | Year: 2013

A review of stratigraphic, radiocarbon, pollen, and aerial photographic data on the Swan Coastal Plain, south-western Australia, allows interpretation of long-term changes in climate and its effects on wetlands during the Holocene, whereas monitoring wetland hydrology and vegetation provides a measure of shorter-term changes. The information provides models for basin wetland response to changing climate. Drying climates shift wetlands to drier conditions, turning lakes into seasonally inundated or waterlogged basins, or resulting in an overall loss of wetlands, and favours more saline conditions, and development of carbonate deposits. Wetter conditions results in more frequent inundation, shifting damplands to sumplands or lakes, and resulting in fresher water conditions, and development of peat and/ or organic matter enriched deposits. Examples of wetland basin responses to climate change across the Swan Coastal Plain show differential responses depending on setting, spatial distribution, hydrology, hydrochemistry and geochemistry, different temporal frameworks, and biological resilience. © Springer Science+Business Media B.V. 2012.

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