Research Reports

The Fish of Kororoit Creek – Stressed Relicts and City Slickers

Paul G Close

Abstract
Kororoit Creek is a metropolitan watershed in which human disturbances may have reduced the health of aquatic fauna populations. Identifying changes in the distribution, diversity and abundance of aquatic fauna is hindered by a paucity of biological information, especially with regard to fish. Intensive surveys conducted during January 2000 quantified the species richness and abundance of fish and decapod crustacea at six sites in Kororoit Creek. A total of nine freshwater and one estuarine fish species was collected, of which five were native species representing approximately 50% of the native taxa expected to occur in the catchment. The relative abundance of exotic species tended to be high in the lower catchment and very low in the mid- to upper catchment. This study identifies a number of anthropogenic factors affecting aquatic fauna populations in Kororoit Creek.
(The Victorian Naturalist 119 (1), 2002, 4-13)
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The Mammal Fauna of Remnant Native Grasslands
of the Western Basalt Plains and Northern Plains of Victoria

Susan A Hadden

Abstract
Twenty-four native grassland remnants in the Western Basalt and Northern Plains of Victoria, Australia, were investigated to determine the composition of the mammal fauna and evaluate their habitat use. These sites included remnants that had differing levels of grazing pressure, structural attributes and floristic diversity. Mammals were assessed by pitfall trapping and systematic searching. Grassland characteristics, representing structure and diversity, that might affect the mammal species richness of the grassland were recorded. Five mammal species were recorded in the Western Basalt Plains and four in the Northern Plains. Sites with light grazing, open ground cover and high native plant richness favoured native mammal species.
(The Victorian Naturalist 119 (1), 2002, 14-20)
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How Do Nectar Foraging Butterflies Select Flowers?

Melissa B Nunn

Abstract
Nectar foraging tendencies of two species of butterfly was experimentally investigated using characteristics of flowers that may influence selection of nectar resources. Potentially influential characteristics of nectar flowers were simulated in various combinations in a controlled laboratory situation. Wild-caught butterflies were captured for use in the experiments. The two species preferred different combinations of factors, potentially reflecting their natural foodplants. Common Grass-blue Zizina labradus visited small white flowers most frequently, a combination of factors displayed by known foodplants. Australian Painted Lady Vanessa kershawi preferred to feed on yellow, medium or large flower combinations that match the flowers of Capeweed Arctotheca calendula and some other observed foodplants. The position of the experimental flower on the ‘stem’ was not a significant contributor to flower selection; however, flower size did contribute. There was a positive relationship between the size of the butterfly and that of the flower chosen. In the wild, this may reflect not only the flower’s ability to support the weight of the butterfly, but also the amount of nectar supplied by the flower.
(The Victorian Naturalist 119 (1), 2002, 21-27)
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Contributions

Invertebrates of Mount McKay – a Brief Survey

EJ Grey

Abstract
This note reports the results of a brief, small-scale survey of terrestrial invertebrates near Mount McKay in north-east Victoria conducted in October 1999. Survey areas, in this sub-alpine zone, included Open Heathland, Tussock Grassland and small Snow Gum Eucalyptus pauciflora patches. The invertebrates were collected in pitfall traps and by hand and the greatest numbers were taken in the more open sites that were exposed to sunshine.
(The Victorian Naturalist 119 (1), 2002, 29-35)
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