The role of currents in the dispersal of introduced seashore plants around Australia

The aim of this study was to assess the role of currents in the dispersal of seashore species with buoyant propagules. Four introduced species which have now attained a wide distribution in southern and eastern Australia were used as indicators: Cakile edentula, Cakile maritima (Brassicaceae), Euphorbia paralias (Euphorbiaceae) and Arctotheca populifolia (Asteraceae). None arrived in Australia unaided, as all early collection localities are near ports and early long-distance dispersal within Australia was often due to shipping. Buoyancy and viability of propagules were tested to assess dispersal and colonisation potential. Propagule spread was analysed using information from herbarium specimens and fieldwork. A progression of herbarium specimen collection dates could often be explained by regional current regimes, as revealed by stranding locations of drift bottles and drift cards. The eastward spread of Euphorbia paralias from King George Sound, Western Australia, correlated well with stranding patterns of drift bottles released south of the Sound. The colonisation by Arctotheca populifolia of the southern extremity of the Eyre Peninsula and the south-east of South Australia was achieved through fruits carried from Western Australia by the Leeuwin Current. These and other congruencies between patterns of spread and the results of drifter releases are analysed and discussed

Primary vegetation development on the sand spit of Shallow Inlet, Wilsons Promontory, southern Victoria

The sand spit that separates Shallow Inlet from Waratah Bay (38º52ʹ S, 146º13ʹ E), near Wilsons Promontory in southern Victoria, has developed since the previous spit was washed out in 1901. Initially without vegetation, the spit was colonised in the 1960s by the exotic grasses *Thinopyrum junceiforme and to a lesser extent *Ammophila arenaria. These species are native to the coast of western Europe, where they fulfil a key role in dune establishment. Being able to grow through sand accumulating among the culms, these grasses formed mounds where seeds or rhizome fragments were washed up during king tides. Where somewhat sheltered from the strongest impact of the westerlies, mounds gradually coalesced and formed short ridges at the landward side of the spit, and ‘dune fields’ towards its distal end. Circumstances favourable for dune field formation were enhanced by episodic processes in spit growth due to channel shifting in the tidal delta and the gradual lengthening of the main outlet channel. Austrofestuca littoralis and Spinifex sericeus joined the two foreign grasses in their pioneering role. The herbaceous Actites megalocarpa and the shrub Ozothamnus turbinatus established in the lee of the grasses, but conditions on mounds, dune crests and windward slopes are too severe for other species. Only at more sheltered sites is further development of vegetation possible. In the lee of the dune fields it has progressed into an open shrubland, initially of Ozothamnus turbinatus, Olearia axillaris and Olearia glutinosa, later enriched by Acacia longifolia var. sophorae, Leptospermum laevigatum and Leucopogon parviflorus. Wind-dispersed taxa form the dominant component of the vegetation, but several animal-dispersed species became established as well. The complement of woody species begins to resemble that of the dune scrub found elsewhere along this part of the Victorian coast, but several wind-dispersed species, notably Banksia integrifolia, are still lacking and it would appear that dispersal is still a limiting factor in vegetation development. It is pointed out that dune development on the sand spit was initiated by exotic grasses and that without their presence, it is doubtful whether any vegetation would have established there. Many photos support the text- the narrative will say what words can say but words can never say it all (Love 1999)

Ben Marais (1909-1999): The influences on and heritage of a South African Prophet during two periods of transformation

University of Pretoria / Dissertation / Department of Church History and Church Policy / Advised by Prof J W HofmeyrThis thesis in Church History presents a biographic study on the life of Ben Marais against the political and ecclesiastic background of South Africa of the 20th century. The significance of Ben Marais’ life is approached through his correspondence with the secretaries of the World Council of Churches during the 1960s and 1970s. The letters, pertaining to the World Council of Churches financial and moral support for the organisations fighting against Apartheid, reflect on Ben Marais’ involvement with the World Council and his particular concerns. Through a study on the life of Ben Marais insight can be gained into the thinking of the leadership of the NG Kerk. The study presents Ben Marais as a prophet who challenged the then popular tendencies in the NG Kerk theology on policy justification and on the relation between religion and nationalism. The central question in this study asks, what led an ordinary man, of humble background, to the insights he reflected, and guided him through times of transparent opposition to maintain his belief in what was right and just? What was the essence of his theology and understanding of the South African problem? To what extent could the church leaders of the present, and the future learn from his example and life, in terms of the tribulations faced, different schools of thought, and sentiments, both nationalistic and spiritual? The study then wishes to test the following hypothesis: Ben Marais can be considered as one of the steadfast and humble prophets of the church in Southern Africa during the 20th century, who serves as an example of Christian Brotherhood, regardless of the perplexities, for present and future generations on relations between the affairs of faith, state and society. The thesis presents a broader introduction on Church Historiography. Ben Marais’ own historiographical reflection is considered. The approaches to history are summarised as background to the periodisation model adopted by the study. The study wishes to work with a thematic model set against a chronological framework. Sensitivity to geographical concerns is also expressed. Afrikaner Nationalism is not seen in isolation, but in relation to African, English and Indian Nationalism

Robust and fast schemes in broadband active noise and vibration control

This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods

Zeno machines and hypercomputation

This paper reviews the Church-Turing Thesis (or rather, theses) with reference to their origin and application and considers some models of "hypercomputation", concentrating on perhaps the most straight-forward option: Zeno machines (Turing machines with accelerating clock). The halting problem is briefly discussed in a general context and the suggestion that it is an inevitable companion of any reasonable computational model is emphasised. It is hinted that claims to have "broken the Turing barrier" could be toned down and that the important and well-founded role of Turing computability in the mathematical sciences stands unchallenged.Comment: 11 pages. First submitted in December 2004, substantially revised in July and in November 2005. To appear in Theoretical Computer Scienc

Eksternal dari fungsional

Dalam Tulisan ini dibicarakan tentan ekstremal dan funasional T Cy(x)3 yaitu syarat periu dan cukup untuk fungsional 1 [ y(x) J ekstremal, multiplikator Lagrange dan sya:rat transversal. Juga dibahas transformasi Bolza, Mayer dan La,s4ranv,P, serta bentuk benda solid dengan.gaya penghambat (dra,s,,

Flora of the Stockton and Port Hunter sandy foreshores with comments on fifteen notable introduced species

Between 1993 and 2005 I investigated the introduced plant species on the Newcastle foreshores at Stockton and Macquaries Pier (lat 32º 56’ S, long 151º 47’ E). At North Stockton in a rehabilitated area, cleared of *Chrysanthemoides monilifera subsp. rotundata, and planted with *Ammophila arenaria interspersed with native shrubs, mainly Acacia longifolia subsp. sophorae and Leptospermum laevigatum, is a rich flora of introduced species of which *Panicum racemosum and *Cyperus conglomeratus have gradually become dominant in the groundcover. Notwithstanding continuing maintenance, *Chrysanthemoides monilifera subsp. rotundata has re-established among the native shrubs, and together with Acacia longifolia subsp. sophorae, is important in sand stabilisation along the seaward edge of the dune terrace. The foredune of Little Park Beach, just inside the Northern Breakwater, is dominated by Spinifex sericeus and backed by Acacia longifolia subsp. sophorae-*Chrysanthemoides monilifera subsp. rotundata shrubbery. In places the shrubbery has given way to introduced species such as *Oenothera drummondii, *Tetragonia decumbens and especially *Heterotheca grandiflora. At Macquaries Pier *Chrysanthemoides monilifera subsp. rotundata forms an almost continuous fringe between the rocks that protect the pier against heavy southerlies. However, its presence on adjacent Nobbys Beach is localised and the general aspect of this beach is no different from any other along the coast as it is dominated by Spinifex sericeus. Many foreign plant species occur around the sandy foreshores at Port Hunter. Since the first coal exports in the 1850s the Newcastle wharves and ballast-ground at Stockton became points of entry for foreign species, either directly, or via stopovers at other Australian ports. Some of these, *Panicum racemosum, *Tetragonia decumbens, *Ursinia speciosa, *Hebenstretia dentata and until recently, *Heterotheca grandiflora, remained restricted to the Newcastle region, while others, e.g. *Chrysanthemum monilifera subsp. rotundata, *Hydrocotyle bonariensis, *Gladiolus gueinzii and *Oenothera drummondii, spread further afield, but only colonised their preferred coastal habitat. Many more species spread far and wide, their port of introduction no longer recognisable. Other species were introduced as garden plants, escaped and became naturalised. However, for most foreign, generally widespread, species their mode of entry can no longer be determined. 99 species were recorded in the six areas regularly visited, about 25% native to Australia, and 75% about evenly divided between species from Africa, Asia and Europe. More detailed information on 15 of the more notable introduced species is provided in an appendix. On the dune terrace vegetation of North Stockton, only about 20% of the 50 species are native to Australia, the only one of any prominence being Acacia longifolia subsp. sophorae. Nevertheless, on first impression this ‘multinational’ assemblage looks quite normal, and when one compares the ecological functioning of the 1930s vegetation with that of the present vegetation, it appears that, due to presence of more graminoids, and the fact that *Panicum racemosum produces a denser sward than Spinifex sericeus, the present vegetation is more effective in sand-catching and dune stabilisation than the vegetation in the 1930s would have been. However in view of the increasing influence of climate change, e.g. a rise in sea level and more extreme weather events, there is no indication that the present terrace, notwithstanding the increased density of the rhizomatous species and a sprawling shrubby vegetation along the crest, will endure such attacks any better than in the 1990s