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Warwick, Australia

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. Source


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. Source


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). Source


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. Source


Errami E.,Chouaib Doukkali University | Ennih N.,Chouaib Doukkali University | Brocx M.,Murdoch University | Semeniuk V.,V and C Semeniuk Research Group | Otmane K.,Chouaib 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. Source

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