Does Geijera parviflora Lindl. (Rutaceae) facilitate understorey species in semi-arid Australia?
- Authors: Warnock, Andrew , Westbrooke, Martin , Florentine, Singarayer , Hurst, Cameron
- Date: 2007
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 29, no. 2 (2007), p. 207-216
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- Reviewed:
- Description: Species composition under tree canopies often differs from that of surrounding micro-environments. In arid and semi-arid zones, trees can be beneficial to understorey vegetation. This study examined zones of vegetation composition and soil physiochemical parameters associated with Geijera parviflora Lindl. The importance of shade, rainfall redistribution, seed bank and soil moisture were examined. Species abundance, soil moisture, seed bank composition, rainfall redistribution and soil nutrient concentration were measured under five randomly selected mature G. parviflora trees in south-western New South Wales, Australia. To complement the findings from this study, artificial shade plots were constructed in a canopy-free area and species abundance measured seven months after shade construction. The study demonstrated that G. parviflora was associated with zonation of understorey vegetation. Two zones of understorey vegetation were found in relation to G. parviflora: (i) under the tree canopy with high species diversity, and (ii) beyond the canopy, this community being dominated by Dissocarpus paradoxus throughout the year with Crassula colorata appearing after rainfall. The zone beyond the canopy also had lower soil nutrient concentrations. Soil moisture, nutrient concentration and the seed bank density were significantly higher under the canopy. However, the canopy reduced precipitation reaching the soil surface. The effects of the canopy on understorey species composition and soil moisture were enhanced after winter rainfall. Artificial shade increased species abundance and richness under a 90%-shading treatment. The results indicated that G. parviflora generated spatial heterogeneity over the broader plant community increasing species richness, abundance and diversity under the canopy. This emphasises the importance of arid zone trees in conserving understorey plant diversity. Shading, soil nutrient concentration and increased seed bank density and soil moisture appeared to be key influences on the plant communities under the canopy. © Australian Rangeland Society 2007.
- Description: C1
- Description: 2003004817
Dry lakes and drifting seed-heads : The ecology of fairy grass Lachnagrostis filiformis
- Authors: Gosney, Kathleen , Florentine, Singarayer , Hurst, Cameron
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at the15th Australian weeds conference, Adelaide : 24th September, 2006
- Full Text: false
- Reviewed:
- Description: Lachnagrostis filiformis (frost) Trin, commonly known as fairly grass, is a native grass that has recently become a major concern for rural communities.
- Description: E1
- Description: 2003001631
Establishment, initial impact and persistence of parthenium summer rust puccinia melampodii in north Queensland
- Authors: Dhileepan, Kunjithapatham , Florentine, Singarayer , Lockett, Catherine
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at the 15th Australian Weeds Conference Papers and Proceedings, Adelaide : 24th September, 2006
- Full Text: false
- Reviewed:
- Description: The partenium sumemr rust (puccinia melampodii dietel & holway, uredinals), native to Mexico, is a host-specific and highly damaging pathogen suited tio warmer weather conditions.
- Description: E1
- Description: 2003001629
Metabolite mobilization in the stem galls of Parthenium hysterophorus induced by Epiblema strenuana inferred from the signatures of isotopic carbon and nitrogen and concentrations of total non-structural carbohydrates
- Authors: Florentine, Singarayer , Raman, Anantanarayanan , Dhileepan, Kunjithapatham , Madhaven, S.
- Date: 2006
- Type: Text , Journal article
- Relation: Entomologia Experimentalis et Applicata Vol. 119, no. (2006), p. 101-107
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- Reviewed:
- Description: Parthenium hysterophorus L. (Asteraceae) is a weed of national significance in Australia. Among the several arthropod agents introduced into Australia to control populations of P. hysterophorus biologically, Epiblema strenuana Walker (Lepidoptera: Tortricidae) is the most widespread and abundant agent. By intercepting the normal transport mechanisms of P. hysterophorus, the larvae of E. strenuana drain nutrients, other metabolic products, and energy, and place the host plant under intense metabolic stress. In this study, determinations of total non-structural carbohydrates (TNC) levels and carbon and nitrogen isotope ratios of fixed products in different parts of the plant tissue, including the gall, have been made to establish the function of gall as a sink for the nutrients Values of
- Description: C1
- Description: 2003001571
The arid land invasive weed Nicotiana glauca R. Graham (Solanaceae) : Population and soil seed bank dynamics, seed germination patterns and seedling response to flood and drought
- Authors: Florentine, Singarayer , Westbrooke, Martin , Gosney, Kathleen , Ambrose, Graeme , O’Keefe, M.
- Date: 2006
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 66, no. (2006), p. 218-230
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- Description: Disturbances in plant communities provide opportunities for weed germination, propagation, spread, and invasion. When the population density of a weed increases, fast-tracked and appropriate control management strategies are required. The objectives of this study were to: (i) examine the population and soil seed bank dynamics of Nicotiana glauca; (ii) compare the germination patterns of invasive N. glauca seeds collected from two states in Australia, and (iii) investigate the impact of a flood in September 1997 and subsequent drought on N. glauca seedlings. The density of N. glauca followed a steep positive increment during the sampling time (September 1999 to October 2004). The increment pattern was similar in flooded fenced and unfenced plots. Plant density increased over much of the observation period, but had declined to 80 and 432 stems ha−1, respectively, by October 2004. Stem density recorded in October 2004 along two transects radiating from the central point of the newly created lake demonstrated that a significant number of stems appeared to be dead. A soil seed bank study revealed that seed density varied significantly (p=0.0001) between flooded fenced (598.75±71) and flooded unfenced (327.5±66) plots. In contrast, no N. glauca seedlings were recruited from the soil collected from the control plots. Germination trials were undertaken on N. glauca seed collected from New South Wales. There was no significance difference detected between treatments light and temperature. Similarly, no interaction was found between light and temperature. A comparative study on seed germination patterns of N. glauca seeds collected from Ivanhoe, New South Wales, and the Flinders Ranges, South Australia, showed that temperature had a significant effect on N. glauca seed germination. The effect varied significantly with main variables (state, length and time) and also with different interactions, except state×light (p=0.3840). N. glauca seedlings exposed to flood were found to withstand partial flooding for at least 58 days. Under waterlogged conditions, the seedlings showed stem hypertrophy and produced adventitious roots. Only one seedling was found dead in the drought treatment. In conclusion, it is clear that N. glauca invaded the area after a rare flood event and began to function as a casual weed. Established seedlings in the field can withstand extreme ecological events such as flood and drought. Understanding the plants’ ecological characteristics through a study such as this at an early rather than late stage in the invasion will help us to take appropriate control measures for this species.
- Description: C1
- Description: 2003001616
Arid land vegetation dynamics after a rare flooding event : influence of fire and grazing
- Authors: Westbrooke, Martin , Florentine, Singarayer , Milberg, Per
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 61, no. 2 (Apr 2005), p. 249-260
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- Description: Arid vegetation is subjected to more or less frequent fire, drought, and sporadic flooding events and grazing. Whilst fire, drought and grazing have been the subject of considerable research, little is known of the impact of flooding in arid environments. In this study we examined opportunistically the effects of a flooding event, and its interaction with fire and grazing on moulding arid vegetation in New South Wales, Australia. We assessed vegetation approximately 2 and 5 years after recession of the water in fenced and unfenced plots subjected to different combinations of flooding and fire. Number of species per area dropped from 11.8 to 5.7 per 625 m(2). Vegetation in plots left open to grazing by vertebrates differed from fenced plots, but the amount of variation explained was small compared with flooding and the change over time. The taxa mostly associated with flooding were Eragrostis spp., Pseudognaphalium luteoalbum and the exotic Nicotiana glauca. Major flooding events not only trigger native species' germination and recruitment but may also create an avenue for exotic species to invade. (C) 2004 Elsevier Ltd. All rights reserved.
- Description: C1
- Description: 2003001050
Ecology of the endangered Southern Shepherd's Purse Ballantinia antipoda (Brassicaceae) and the associated moss mat community on Mount Alexander, Victoria
- Authors: Ambrose, Graeme , Florentine, Singarayer , Seidel, Jessica , Wilson, Michael
- Date: 2005
- Type: Text , Journal article
- Relation: Victorian Naturalist Vol. 122, no. (2005), p. 179-188
- Full Text:
- Reviewed:
- Description: Despite its rarity, conservation status and location within the regional park, there is only limited information on the ecology of B. antipoda. The significance of the micorhabitat provided by the associated moss mat community is unclear.
- Description: 2003001088
Effects of gall induction by Epiblema strenuana on gas exchange, nutrients, and energetics in Parthenium hysterophorus
- Authors: Florentine, Singarayer , Raman, Anantanarayanan , Dhileepan, Kunjithapatham
- Date: 2005
- Type: Text , Journal article
- Relation: Biocontrol Vol. 50, no. 5 (Oct 2005), p. 787-801
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- Reviewed:
- Description: Gall induction by arthropods results in a range of morphological and physiological changes in their host plants. We examined changes in gas exchange, nutrients, and energetics related to the presence of stem galls on Parthenium hysterophorus L. (Asteraceae) induced by the moth, Epiblema strenuana Walker (Lepidoptera: Tortricidae). We compared the effects of galls on P. hysterophorus in the rosette (young), pre-flowering (mature), and flowering (old) stages. Gall induction reduced the leaf-water potential, especially in flowering stage plants. In young and mature stage plants, galling reduced photosynthetic rates considerably. Gall induction reduced the transpiration rate mostly in mature plants, and this also diminished stomatal conductance. Energy levels in most galls and in shoot tissue immediately below the galls were significantly higher than the energy levels in stem tissue immediately above the galls, indicating that the gall acts as a mobilizing sink for the moth. Galling had significant effects on concentrations of minerals such as boron, chloride, magnesium, and zinc. In galled plants, reduced leaf-water potential and reduced rates of photosynthesis, transpiration, and stomatal conductance may have altered mineral element levels. These observed effects demonstrate that E. strenuana has the potential to regulate P. hysterophorus.
- Description: C1
- Description: 2003001078
Exotic plant species invasion in south west New South Wales : Influence of a rare flooding event and grazing
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2005
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 20, no. 2 (2005), p. 42-45
- Full Text: false
- Reviewed:
- Description: The main objectives of this study were to investigate: (i) the distribution of exotic plant species in flooded and control (unflooded) areas in relation to a 1997 episodic flooding event and (ii) the influence of grazing in flooded and unflooded open and fenced plots on wed colonization.
- Description: 2003001069
Fire and hollow formation in box-ironbark eucalypts of the Warby Range State Park
- Authors: Adkins, Matthew , Westbrooke, Martin , Florentine, Singarayer , McDonald, Simon
- Date: 2005
- Type: Text , Journal article
- Relation: Victorian Naturalist Vol. 122, no. 1 (2005), p. 47-56
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- Reviewed:
- Description: Hollows are an important, but rare, resource for several native vertebrate species in the box-ironbark forests of central Victoria. A study assessed the external features of trees from burnt and unburnt areas of forest to determine the influence of fire on hollow formation in these forests. Significantly greater proportions of trees in burnt areas has scars than trees in unburnt areas. Fire had less influence on the number of small, medium, large and very large dead branches/branch stubs than tree diameter. Similarly, tree size rather than fire was a major determinant in the occurrence of hollows. The greater number of scars in burnt trees might eventually lead to a difference in hollow numbers between burnt and unburnt trees (A).
- Description: 2003001062
Invasion of the noxious weed Nicotiana glauca R. Graham after an episodic flooding event in the arid zone of Australia
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 60, no. 4 (Mar 2005), p. 531-545
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- Reviewed:
- Description: During November 1997, an extreme rainfall event caused flooding in the Olary Creek and created a terminal lake within mallee vegetation on Nagaela Station, far western New South Wales. To assess the effect of this rare event on native flora, six 25×25 m2 grazing exclusion plots were established on flooded (4), and un-flooded control (2) areas. We investigated (i) the distribution of Nicotiana glauca in relation to the 1997 flooding event (ii) the variation in density of N. glauca soil-stored seed between soil in control and exclosure plots (iii) the allelopathic effects of N. glauca on germination of Lactuca sativa seeds. Analysis of N. glauca stem sections revealed a maximum of five growth rings, confirming an origin following the 1997 flood event. At a September 1998 assessment, no N. glauca were found across flooded and control plots. In October 2000 N. glauca occurred at densities of 24 and 12 N. glauca seedlings ha−1 in the flooded unfenced and fenced plots respectively. No N. glauca individuals were recorded either from control fenced or unfenced plots. The soil-stored seed study revealed that larger numbers of N. glauca seeds were recovered from the flooded open plot (1936±968) than in flooded fenced plots (856±428.12) but none was found in the control plots. Leachates obtained from dry leaves and twigs had a significantly greater negative impact (p>0.001) on germination of L. sativa seeds than leachates obtained from fresh leaves and bark. This study showed that the density of N. glauca is high in areas where grazing had eliminated competition from native shrubs and grasses. N. glauca is potentially a serious weed along the Olary Creek and ephemeral lake boundaries. Management strategies such as reducing grazing pressure from native and introduced animals and/or effective eradication programs should be adopted, to minimize further infestation.
- Description: C1
- Description: 2003001049
Rainfall-driven Episodic Flood Events : Are they a major factor in moulding New South Wales arid land vegetation patterns?
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2005
- Type: Text , Journal article
- Relation: Australian Geographer Vol. 36, no. 2 (2005), p. 171-181
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- Reviewed:
- Description: Episodic high rainfall has been proposed as an important factor in perennial species recruitment but flooding based on rainfall at a distance from the site has received little attention. Although such flood events in arid Australia are rare, studies of the ephemeral Olary Creek indicate that occasional floods can also have a high impact on the vegetation and landscape. During February 1997, a high-rainfall event caused flooding in the Olary Creek. One branch of the creek created a terminal lake within mallee vegetation on Nagaela Station in far-western New South Wales. The flood path of Olary Creek and this terminal lake allow study of the importance of rainfall-driven flood events in shaping vegetation in arid environments. This paper reports (i) the response of arid land plant species to high-rainfall-driven episodic flood events and (ii) how grazing pressure from native and introduced herbivores can impact on native species response. A systematic study was conducted to understand the botanical composition in flooded and control areas based on 25 m2 fenced and unfenced plots subjected to flooding and nonflooding. For 6 years following flooding, species richness in the flooded area was twice that of unflooded areas. In particular, 27 native species from 13 families were recorded both in the enclosed and open plots located in the flooded area. Over the study period nine species: Brachyscome ciliaris, Helichrysum leucopsidium, Vittadinia cuneata, Casuarina pauper, Maireana sedifolia, Salsola kali, Sclerolaena obliquicuspis, Eremophila sturtii and Eucalyptus foecunda germinated only in the flooded enclosed plots. Further, 11 exotic species from five families were recorded in the flooded (both enclosed and open) plots over the study period. Knowledge gained from this study will contribute to management strategies for arid land vegetation.
- Description: C1
- Description: 2003001067
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: 2004
- Type: Text , Journal article
- Relation: Australian Forestry Vol. 67, no. 1 (2004), p. 54-58
- Full Text: false
- Reviewed:
- Description: During June 1998 a very strong windstorm at the Snowy River National Park ncar 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 y later 10 examine (i) windthrow damage to E. delegatensis and the understorey Acacia dealbata, (ii) the influence of tree size on the pattern of lree damage, (iii) the undergrowth in the windthrow area compared with that in control plots, and (iv) species composition of the soil-stored seed-bank in windthrow and control plots. We found that high winds toppled virtually all trees regardless of size and species, damaging 99% of the E. delegarensis. In windthrow plots there were 49 seedlings ha- I of E. delegarensis and 2210 ha-I of A. dealbata. No E. delegarensis or A. deafbara 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 colonising the windthrow site, but was not present in the control site. Results show that E. defegarensis recruitment is very poor in the damaged area, and species colonising within that area are light demanding or early succession species. It is proposed that seedling recruitment in the windthrow sites be accelerated by burning the site and broadcasting E. delega/ensis seed, or transplanting seedlings.
- Description: C1
- Description: 2003000710
Evaluation of alternative approaches to rainforest restoration on abandoned pasturelands in tropical north Queensland, Australia
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Land Degradation & Development Vol. 15, no. 1 (Jan-Feb 2004), p. 1-13
- Full Text:
- Reviewed:
- Description: The lag time for natural recruitment of tropical rainforest species in abandoned pastureland is very long, therefore artificial restoration techniques have been employed to accelerate natural seedling recruitment. The objectives of this study were to investigate: (1) the success/failure of establishment 502 seedlings belonging to 15 species from 11 families planted approximately ten years ago; and (2) the influence of different restoration techniques on enhancing natural recruitment during this period. The study was conducted in the wet tropical rainforest region of northeast Queensland, Australia as a completely randomized block design involving five treatments with two replicates. In each plot, 63 tropical rainforest seedlings from one or a combination of species were planted randomly. Two control plots were laid out where no seedlings were planted. Survival, height and diameter data were taken on the seedlings ten years after planting. Each 11×17 m2 plot was further divided into 187, 1×1 m2 subplots. Within each subplot all seedlings recruited were located and identified. Canopy cover was estimated using belt transects 1 m apart that ran in an east-west direction across the plots. Within each plot the percentage of grass, and the crown cover were estimated using the Braun-Blanquet cover abundance scale. Survival rate of planted seedlings varied across the treatment plots. The survival rate ranged from 65 to 75 per cent for primary-promoter species, 85 to 100 per cent in middle-phase species and 42 to 57 per cent for mature-phase species. No Pilidiostigma tropicum seedlings survived in any treatment. Fourteen species recruited naturally across the treatment plots. A total of 410 seedlings were naturally recruited from 11 different families in the ten-year-old reforested site. The highest natural recruitment (236 seedlings) occurred in Treatment 3, where Omalanthus novo-guineensis seedlings were planted with eight primary-promoter species, followed by 99 in Treatment 5 where a group of primary-promoters, middle phase species and mature-phase species were planted together, 36 in Treatment 4 (Alphitonia petriei planted with eight primary-promoter species), 10 in Treatment 2 where only Omalanthus novo-guineensis seedlings were planted, and 13 in control plots. Grass cover declined with increasing species diversity and increased canopy cover. The results indicate that the diversity of species used in restoration had a major influence on natural recruitment. Copyright © 2004 John Wiley & Sons, Ltd.
- Description: C1
- Description: 2003000714
Observations on survival and early growth of natural regeneration in floodplain coolibah Eucalyptus victrix (Myrtaceae) in the Pilbara, Western Australia
- Authors: Fox, John , Florentine, Singarayer , Westbrooke, Martin , Hurst, Cameron
- Date: 2004
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 26, no. 2 (2004), p. 150-160
- Full Text: false
- Reviewed:
- Description: Observations are presented on the natural regeneration of Eucalyptus victrix L. Johnson and K. Hill (coolibah), the dominant tree species of grassy woodlands on the floodplain of the Fortescue River, north of Newman in the Pilbara district of Western Australia. The main objectives of this study were to examine: (i) survival of newly recruited E. victrix seedlings on flooded and burnt sites, and (ii) growth and survival of established plants in a gilgaied landscape. Populations of newly-recruited seedlings following flooding or fire were monitored opportunistically at 'Marillana' and 'Ethel Creek' stations, for up to two years from tagging. A population of saplings at 'Roy Hill' station was observed over eight years. Seedling densities of E. victrix in flooded sites were 0.32 and 1.03 plants/m2 in 1995 and 1997 respectively. Locally high densities reached from 1.2 to 17.7 plants/m2 on areas of 28 and 6 m2 respectively. At the burnt site at 'Ethel Creek', 1.30 plants/m2 were observed where 58 seedlings were recorded on an area of 445 m2 a year after a natural fire. Many of these persisted well into their second year, whereas seedlings recruited in the flooded sites generally lasted less than a year (250-376 days). In contrast, persistence of a cohort of 100 established saplings <2 m tall in a gilgaied landscape at 'Roy Hill' was high. During 8 years of observations, only one sapling was lost. Those found at the edges of gilgais had attained greater heights (3.91 ± 1.14 m) than saplings located inside (3.16 ± 0.95 m) or on top (3.12 ± 0.93 m) of the gilgais. This study demonstrates that the seedling stage in E. victrix is critical, in that once newly recruited individuals reach the sapling stage (0.6-1 m), mortality rates are much reduced. Unfortunately, it was not possible during the course of this study to locate a cohort of young seedlings that did survive and so any consideration of the conditions necessary for their survival is speculative.
- Description: C1
- Description: 2003000725
Restoration on abandoned tropical pasturelands - Do we know enough?
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Journal for Nature Conservation Vol. 12, no. (2004), p. 85-94
- Full Text:
- Reviewed:
- Description: Tropical rainforests have been disappearing at an alarming rate. In addition to preserving remaining tropical rainforests, we need to convert degraded and abandoned pasturelands into secondary forests. To accelerate this, human intervention in the recovery process is essential. In this review paper we (i) encapsulate some of the problems, which might surface when converting abandoned land to secondary forest. (ii) Look at some of the restoration techniques used in restoration programs and propose additional techniques for consideration. Major barriers to natural regeneration on abandoned and degraded pasturelands are: weed infestation, lack of indigenous soil seed bank, lack of seed supply/movement, soil compaction, depletion of soil nutrients and unsuitable microclimate and microhabitat. Although several restoration techniques have been recommended, most restoration programs have been carried out using native seedling transplants to accelerate natural recruitment. Most restoration groups in the tropics are still in the initial stages of determining which species or species combination to chose to gain maximum benefit. On the other hand restoration ecologists are struggling to detect which techniques are most appropriate to restore degraded and abandoned pasturelands. Our review shows that there is immediate need for further research and development on restoration techniques by examining the ecological and economic effectiveness of: direct seeding, stem cuttings using native pioneer or climax species and simple manipulation such as displacing branches of pioneer species with mature seeds on abandoned and degraded pasturelands and artificial perching to accelerate natural regeneration. These techniques are essential to successfully heal the wound humans have inflicted on the most spectacular and species-rich ecosystems on earth.
- Description: C1
- Description: 2003000720
The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill Station, Pilbara District, Western Australia
- Authors: Graham, R.A. , Florentine, Singarayer , Fox, John , Luong, T. M.
- Date: 2004
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 26, no. 1 (2004), p. 17-33
- Full Text: false
- Reviewed:
- Description: The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and prior to summer rainfall. From each sample spot, three soil depths (surface, 1-5, and 6-10 cm) were segregated from beneath surface areas of 100 cm(2). Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m(2)), and the annual herbs Calotis multicaulis (Asteraceae; 346/m(2)), and Mimulus gracilis (Scrophulariaceae; 168/m(2)). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C-4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.
- Description: C1
- Description: 2003000711
The impact of deforestation and pasture abandonment on soil properties in the wet tropics of Australia
- Authors: Rasiah, Velu , Florentine, Singarayer , Williams, B. L. , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Geoderma Vol. 120, no. 1-2 (2004), p. 35-45
- Full Text:
- Reviewed:
- Description: Limited information exists on the changes in soil properties, particularly from the wet tropics of Australia, under long-term abandoned pasture, which was previously grazed and was established on deforested tropical rainforest. This information may be help in successful forest reestablishment. The objectives of this study were to assess the cumulative impact deforestation, grazed and abandoned pasture on selected soil physico-chemical properties from (i) an abandoned pastureland and (ii) a recently planted rainforest (PRF), planted in the abandoned pastureland. The experimental site is a field in the Northeast Queensland (NEQ) wet tropical region of Australia. This site was deforested approximately 70 years ago and brought under unfertilized grazed pasture for 30 years. Subsequently the grazed pastureland was abandoned and remains un-grazed for 40 years. A section of the abandoned pastureland was planted, 10 years ago, with native forest species, involving different combinations in five treatments in a completely randomised block design. A nearby undisturbed rainforest is used as the background against which assessment was carried out. Soil samples from 0- to 15-cm depth were collected in July 2000 and analyzed for nitrate-N, ammonium-N, total N, total soil organic C (SOC) and labile-C, pH (in water and CaCl2), electrical conductivity (EC), exchangeable Ca, Mg, Na, K, and Al, and bulk density. Compared to the rainforest, the N and C concentrations of different forms under abandoned pasture and PRF were significantly less, exclusive of the total N under abandoned pasture. More specifically, the SOC under the abandoned pasture was 37,600 mg/kg compared with 74,800 mg/kg under rainforest and 27,000 mg/kg in the PRF. The exchangeable Al under rainforest was 8.5 c molc/kg compared with 42. 4 to 80.2 c molc/kg under abandoned pasture and PRF. In general exchangeable cations (sum of Ca, Mg, K, and Na) under the rainforest were higher than the abandoned pasture. Soil under the abandoned pasture and PRF are more acidic by 0.5 to 1 units than the rainforest. Higher bulk densities under abandoned pasture and PRF led to 0.03% to 0.07% reductions in total porosities. Though we did not anticipate the soil under the abandoned pasture to recover 100% in 30-40 years, the results indicate that 40 years under abandoned pasture or 30 years of abandoned pasture plus 10 years under PRF was not sufficient to bring about substantial improvement in soil properties comparable to the rainforest. This implies the resiliency of tropical soils, in general, to recover from deforestation and cultivation induced degradation is poor. © 2003 Elsevier B.V. All rights reserved.
- Description: C1
- Description: 2003000713
Allelopathic effects of Eucalyptus victrix L. on Eucalyptus species and grasses
- Authors: Florentine, Singarayer , Fox, John
- Date: 2003
- Type: Text , Journal article
- Relation: Allelopathy Journal Vol. 11, no. 1 (2003), p. 77-83
- Full Text: false
- Reviewed:
- Description: C1
- Description: 2003000583
Allelopathic potential of the newly emerging weed solanum mauritianum Scop. (solanaceae) in the wet tropics of north-east Queensland
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2003
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 18, no. 1 (2003), p. 23-25
- Full Text:
- Reviewed:
- Description: Solanum mauritianum
- Description: C1
- Description: 2003004172