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Effects of windthrow on a Eucalyptus delegatensis (Myrtaceae) stand and early understorey succession at Snowy River National Park, Victoria

  • Authors: Florentine, Singarayer , Westbrooke, Martin
  • Date: 2003
  • Type: Text , Report
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  • Description: The June 1998 a severe windstorm at Snowy River National Park near Mt. Gelantipy caused severe damage to a stand of Eucalyptus delegatensis. Little is known about the impact of windthrow on E. delegatensis and subsequent seedling recruitment. This study was undertaken 4.5 years later to examine (i) the windthrow damage on E. delegatensis and the understorey Acacia dealbata (type of damage, diameter class distribution), (ii) the influence of tree size (diameter at breast height, 1.3m) on pattern of tree damage (snapped/uprooted/ snapped and resprouting) (iii) undergrowth in the windthrow area compared with control plots, (iv) species composition of soil stored seed bank in windthrow damaged plots and control plots. Eleven (25 x 25 m2) plots within damaged areas and five plots within undamaged (control) were selected for study. Tree diameter at 1.3 from the rooting point and type of damage (snapped, uprooted, snapped resprouted, snapped dead) were recorded. To examine seedling recruitment, each 25 x 25 m2 plot was further divided into 1 x 1 m2 sub-plots. Within each sub plot, all E. delegatensis seedlings and their diameters were recorded. Soil seed bank species composition was examined by taking 88 and 40 soil samples from windthrow and control sites respectively. Soil samples were placed in punnets and new recruits were counted and identified. This study showed that, high winds toppled virtually all trees regardless of size and species damaging 99% of E. delegatensis. Seedling recruitment was 49 ha-1 for the canopy species E. delegatensis and 2,210 ha-1 for the sub-canopy species A. dealbata. No E. delegatensis or A. dealbata seedlings were recorded in the control plots. In the soil seed bank study five species were recovered from soil samples collected from the control and six from the windthrow damaged sites. The canopy species E. delegatensis recruited only from the windthrow site. The exotic Rubus fruticosus was found to be colonizing the windthrow site, but was not present in the control site. Results show that E. delegatensis recruitment is very poor in the damaged area and species colonizing within the windthrow damaged area were light-demanding or early succession species. It is proposed that seedling recruitment in the winthrow sites be promoted by burning the site and broadcasting E. delegatensis seed.
  • Description: K1
  • Description: 2003000710

Flowering, fruiting, germination and seed despersal of the newly emerging weed Solanum mauritianum Scop. (solanaceae) in the wet tropics of north Queensland

  • Authors: Florentine, Singarayer , Westbrooke, Martin , Craig, M.
  • Date: 2003
  • Type: Text , Journal article
  • Relation: Plant Protection Quarterly Vol. 18, no. 3 (2003), p. 116-120
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  • Description: Solanum mauritianum (wild tobacco) has recently become a weed of major concern in some agricultural production areas, and tropical rainforest restoration sites, of the Atherton Tablelands, north Queensland. Until recently, little was known about the ecology of this species. A study was conducted to examine: Ii) the flowering, fruiting pattern, (ii) seed germination pattern, (iii) density of soil stored seed bank, and (iv) potential avian seed dispersers of S. mauritianum. Flowering and fruiting patterns were studied on-randomly selected plants within the study site over a period of 35 days. A germination study was performed on green (unripe) and yellow (ripe) fruits with seeds from green fruits germinating faster than seeds collected from yellow fruits. The density of genninable seeds in the soil seed bank was determined from 94 samples collected beneath the canopy of 24 randomly selected S. mauritianum plants. Of seedlings Ihat germinated, 73% were S. mauritianum and seedling density of S. mauritiallum averaged 16 000 seedlings per hectare. To determine the role of birds in the dispersal of S. mauritianum seeds, observations were made of all birds visiting eleven fruit-bearing plants. To examine the bird's excrement, birds were captured in mist-nets, their excrement collected and any seeds present identified. A total of 340 seeds from 15 plant species were obtained. Four tropical rainforest birds (Australian king parrots (
  • Description: C1
  • Description: 2003000548

Heat requirement for germination of the grass, panicum laevinode

  • Authors: Florentine, Singarayer , Graham, R.A. , Fox, John
  • Date: 2002
  • Type: Text , Journal article
  • Relation: International Journal of Ecology and Environmental Sciences Vol. 28, no. (2002), p. 143-145
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  • Description: Annual grasses are important components of vegetation, especially where perennial grasses have declined from overgrazing. Panicum laevinode is an annual grass that occurs in large numbers in grassy Eucalyptus victrix L. Johnson and K. Hill coolibah woodland in Pilbara, Western Australia. Little is known about the seed germination pattern and requirements of this grass. Our aim was to examine the effect of heat pre-treatment on seed germination of P. laevinode. Only 12% germination was observed from seeds pre-treated at 60oC for periods ranging from 1 to 8 weeks. However seed viability study showed that 61.5% and 71.5% of seeds were viable from 3 and 17 months respectively. Germination study did not reflect results of the viability test.
  • Description: 2003000151

Morphological and physiological adaptations to waterlogging by Eucalyptus seedlings from the semi-arid Pilbara, Western Australia

  • Authors: Florentine, Singarayer , Fox, John
  • Date: 2002
  • Type: Text , Journal article
  • Relation: The Journal of the Royal Society of Western Australia Vol. 85, no. (2002), p. 61-70
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  • Description: This study was undertaken to investigate the adaptation to long term waterlogging of semi-arid eucalyptus species. Long-term waterlogging of Eucalyptus victrix seedlings significantly increases seedling stem diameter. Flooding reduces photosynthesis, transpiration and stomatal conductance. Flooding does not increase shoot fresh or dry weight of 4-, 8- or 17- week old seedlings. Leaf emergence may be stimulated for flooded seedlings compared with unflooded seedlings. Root dry weight is not significantly greater for 17- week old flooded plants than 13- week old seedlings. We suggest that maintenance of a high root/shoot ratio is a drought adaptation. Furthermore, a comparative study of flood tolerance in semi-arid eucalypt species suggests that those species intolerant of flooding seldom express morphological adaptations and fail to recover from physiological damage. Flooding significantly reduced the transpiration rate and stomatal conduct of all three species. Diurnal transpiration, stomatal conductance and leaf water potential of E. terminalis and E. leucophloia were significantly different between treatment (flooding) and control seedlings.
  • Description: C1
  • Description: 2003000132

Responses of the weed parthenium hysterophorus (Asteraceae) to the stem Gall-inducing Weevil Conotrachelus albocinereus (Coleoptera: Curculionidae)

  • Authors: Florentine, Singarayer , Westbrooke, Martin , Dhileepan, Kunjithapatham
  • Date: 2002
  • Type: Text , Journal article
  • Relation: Entomologia Generalis Vol. 26, no. 3 (2002), p. 195-206
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  • Description: A slem-galling weevil COT/o/rad,e/us alboeinereus Fiedler 1940 from Argentina is being field released to regulate populations of the weed Parlhenium hysterophorus in Queensland, Australia since 1995. In this paper we report the tissue and metabolic responses in P hyslerophorus in the context of the biology and feeding behaviour of the weevil. C albocinereus induces elliptical galls often on the main shoot axes and rarely on the terminal and axillary mcristems of the host plant. From oviposition through gall maturation, the structure and metabolism of the host-plant tissues. especially at the gall region, change continuously to accommodate pressure inflicted by the feeding larva. The host plant shows re-dirtttion of its vital metabolites to the gall, and to the lTlCtaplasitd cells of nutrition in particular. In mature galls. the pith parenchyma elements tum lignified. Larval feeding fractures the vertical continuity of vascular tissues, which affects the host plant's overall metabolism As the larva tunnels the shoot eolulTVl. it places the frass at the fissured vascular sites. That activity initialcs n«rosis and eventual death of the living eells of the vascular tissue complex. Such a development induces water.logging stress in the gall and the evapotranspirauonal system displays contrasting responses. Pennanenl1y closed Siomatal apertures and abnonnally inflated substomatal chambers indicate that P hYSleropltorus suffers moisture-stress with cecidogenesis. The larval performance triggers moisture inundation in the galled shoot and this appears to be an advantage in using this weevil in the control of P hyslerop/rorus.
  • Description: C1
  • Description: 2003004175

Efficiency of gall-inducing insects in the biological control of parthenium weed : Structural, metabolic and physiological changes

Gall-inducing insects and biological control of Parthenium hysterophorus L. (Asteraceae)