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
Macroinvertebrate communities in Phragmites australis (Cav.) Trin. ex Steud. reed beds and open bank habitats in central Victorian streams in Australia
- Authors: Jayawardana, Chandamali , Westbrooke, Martin , Wilson, Michael , Hurst, Cameron
- Date: 2006
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 568, no. 1 (2006), p. 169-185
- Full Text: false
- Reviewed:
- Description: Reed invasion is a common phenomenon of open streams with disturbed riparian vegetation in river catchments. Knowledge of the effects of such vegetation change on aquatic communities is fundamental to river management. Macroinvertebrate fauna in Phragmites australis (Cav.) Trin. ex Steud. and open bank habitats were examined in three rivers in central Victoria in order to understand the effect of such littoral habitat on macroinvertebrates. Data were analysed using Partially Nested Factorial ANOVA with season, river and habitats as main effects. Habitat structure had a significant effect (p < 0.05) on macroinvertebrate species richness, however this was not seasonally consistent across the three rivers. There was a significant increase (p < 0.05) in macroinvertebrate taxa richness in Phragmites habitats during winter and spring seasons. Total abundance of taxa showed no consistent significant differences in the two habitats. Results of Canonical Analysis of Principle Coordinates indicated significant differences (p < 0.05) in macroinvertebrate assemblages between Phragmites and bare bank habitats in all seasons. Habitat selection by taxa could be related to the microphysical environment of the habitats. This study suggests that reed beds create important littoral habitat structures which support diverse macroinvertebrate assemblages. © Springer 2006.
- Description: C1
- Description: 2003001589
Macroinvertebrate communities in willow (Salix spp.) and reed beds (Phragmites australis) in central Victorian streams in Australia
- Authors: Jayawardana, Chandamali , Westbrooke, Martin , Wilson, Michael , Hurst, Cameron
- Date: 2006
- Type: Text , Journal article
- Relation: Marine and Freshwater Research Vol. 57, no. 4 (2006), p. 429-439
- Full Text: false
- Reviewed:
- Description: Exotic willows (Salix spp.) are widespread riparian tree species of rivers in temperate Australia and New Zealand. Despite being considered as a weed of national significance, little is known about the habitat value of willows and the impact on aquatic biota of vegetation change following willow management programmes. Macroinvertebrate fauna in root habitats of willows and Phragmites australis habitats were examined in three central Victorian rivers to understand the effect of such littoral habitat changes on macroinvertebrates. Data were analysed using Partially Nested Factorial ANOVA with season, river and habitat as main effects. Habitat structure had a significant effect (P < 0.05) on macroinvertebrate community assemblage. However, effect of habitat was not consistent among seasons. The greatest community differences among habitats were observed during winter and least separation during autumn. Taxa responsible for community differences among habitats were also identified. Species richness and abundance did not show consistent variation among habitats over different rivers or seasons. This study provided some indication of the macroinvertebrate community changes that would take place in situations where riparian vegetation changes takes place from willows to P. australis. © CSIRO 2006.
- Description: C1
- Description: 2003001620
Quantification of intermarket influence based on the global optimization and its application for stock market prediction
- Authors: Tilakaratne, Chandima , Mammadov, Musa , Hurst, Cameron
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at Integrating AI and Data Mining, 1st International Workshop Proceedings, Hobart, Tasmania : 4th - 5th December, 2006
- Full Text: false
- Reviewed:
- Description: This study investigates how intermarket influences can be used to help the prediction of the direction (up or down) of the next day's close price of the Australian All Ordinary Index (AORD). First, intermarket influences from the potential influential markets on the AORD are quantified by assigning weights for all influential markets. The weights were defined as a solution to an optimization problem which aims to maximise rank correlation between the current day's relative return of the AORD and the weighted sum of lagged relative returns of the potential influential markets. Then, the next day's relative return of the AORD is predicted by applying the neural networks as a classifier. Two different scenarios were compared: 1) using the current day's relative returns of different sets of influential markets as separate inputs; and, 2) using only the weighted sum of these relative returns as a "combined market". The results revealed that the second approach provides better predictions in all cases. This shows the effectiveness of the proposed approach for quantifying intermarket influences and the potential of using the "weighted combined markets" for the prediction
- Description: E1
- Description: 2003001609
Simulated power of the discrete Cramer-von Mises goodness-of-fit tests
- Authors: Steele, Mike , Chaseling, Janet , Hurst, Cameron
- Date: 2005
- Type: Text , Conference paper
- Relation: Paper presented at MODSIM 2005: International Congress of Modelling and Simulation, Advances and Applications for Management and Decision Making, Melbourne : 12th -15th December, 2005 p. 1300-1304
- Full Text: false
- Reviewed:
- Description: The use of goodness-of-fit test statistics for discrete or categorical data is widespread throughout the research community with the Chi- Square the most popular when a researcher aims to determine if observed categorical data differs from a hypothesized multinomial distribution. Even for ordinal categorical data, the use of empirical distribution function (EDF) test statistics such as the Kolmogorov-Smirnov, the three Cramér-von Mises (A2, W2 and U2 as defined below) and various modifications of these are limited in the literature. Power studies of the EDF type test statistics are even more limited. This paper compares the simulated power of the three Cramér-von Mises test statistics with that of the Chi-Square test statistic for a uniform null hypothesis against a variety of alternative distributions which are summarized in Figure 1. Recommendations are made on which is the most powerful test statistic for the predefined alternative distributions.
- Description: E1
- Description: 2003001375
Asymmetrical dependence test for intermarket influence analysis
- Authors: Pan, Heping , Tilakaratne, Chandima , Yearwood, John , Hurst, Cameron
- Date: 2004
- Type: Text , Conference paper
- Relation: Paper presented at ICOTA6: 6th International Conference on Optimization - Techniques and Applications, Ballarat, Victoria : 9th December, 2004
- Full Text: false
- Reviewed:
- Description: E1
- Description: 2003000915
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