Decline in species richness and cover of exotic plants with increasing altitude

Jane Mallen-Cooper and Catherine Marina Pickering

Abstract
Increasing altitude can result in reduced diversity of exotic plants while disturbance usually benefits exotics. Species richness and cover of exotics was examined in paired 120 m2 roadside and adjacent natural vegetation plots at 10 sites along a 1000 m altitudinal gradient from montane to the alpine zone in the Snowy Mountains. Species richness and cover of exotics decreased linearly with increasing altitude in both habitats. The effect of altitude was partly off set by disturbance, with more species and greater cover of exotics on roadside plots. There was high diversity of annual/biennial forbs particularly at low altitude, and few exotic annuals/biennials above 1510 m. The decline in diversity with altitude may be due to differences in disturbance history, with the highest plots having lower levels of use, but the decline in diversity is most likely due to differences in environmental conditions with increasing altitude that limit exotics, particularly annuals/biennials.
(The Victorian Naturalist 125 (3), 2008, 64-75)

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Contribution

Killer Whale Orcinus orca sightings in coastal Victoria

Simon Mustoe

Abstract
The web-based casual sightings network ‘Auscetnet’ receives an average 13 records of Killer Whales per year, mainly from coastal locations of southeast Australia. These data combined with data from the Atlas of Victorian Wildlife are presented to illustrate the pattern of monthly sightings. Sightings peak in late June/early July and again between September and November. There is a distinct decline in sightings between late July and the end August. One individual Killer Whale has been seen twice off the central coast of Victoria and twice off southern New South Wales since 2002, suggesting some Victorian Killer Whales occupy home ranges that extend into NSW waters, although the vast majority of sightings are from south of about 36ºS. Sighting frequency is unlikely to reflect the species’ true abundance and despite frequent records off Victoria and southern NSW, they may be uncommon. There is no evidence to characterise movement patterns but Killer Whales are likely to respond to changes in prey availability, influenced partly by the East Australian Current. Killer Whales have been observed feeding on sharks, sunfish, Humpback Whales and Australian Fur Seals in the region.
(The Victorian Naturalist 125 (3), 2008, 76-81)

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