South Sister St. Marys, Tasmania
|Part of McQuillan's moth collection from South Sister, January 2005
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Peter B. McQuillan
Centre for Environmental Studies
University of Tasmania
The north east of Tasmania is a known biodiversity hotspot, but there is poor documentation of the distribution of local species and limited understanding of their association into functional ecological communities.
Better knowledge of the regional biodiversity of Tasmania is essential as a guide to sustainable management of resources, since maintenance of biodiversity is a key indicator of sustainability.
I briefly surveyed natural habitats on South Sister at the invitation of Mr Frank Giles and Ms Julia Weston, with particular emphasis on invertebrates. There is no doubt that that the area requires a more comprehensive assessment of its biological values given the imminent threat from timber harvesting.
The South Sister forests serve the important and inter-related purposes of safeguarding an important array of native fauna and flora, and providing the foundation of a superb ecotourism experience.
I walked several transects to the summit of South Sister, making notes on species and interactions between species, that I observed. Overnight I operated two 12 volt ultraviolet light traps and a 160watt mercury vapour lamp from a generator in order to attract nocturnal insects.
Specimens were identified by reference to synoptic collections held in my laboratory at the University of Tasmania and the taxonomic literature.
Table 1 is a list of the insect species which have been identified so far. It is noteworthy that several species are not so far known to occur inside any National Park in Tasmania.
Table 1. List of insects, mostly moths, which were collected or observed on South Sister, and which have been identified to at least genus level so far.
Those annotated NNP are not recorded from a National Park in Tasmania.
This readily accessible site features many highlights that, with proper interpretation, would provide a memorable experience for tourists.
Examples of these include:
The dawn chorus of native birds in this forest is exceptional, suggesting the area is an important feeding and activity site for native birds. This may reflect the diversity of food resources present in the area, such as nectar and insects. The chorus iself is a major ecotourism asset. The area does not yet appear to be invaded by aggressive introduced birds such as starlings and blackbirds which tend to become more common as the habitat opens up and introduced weeds such as Cotoneaster and blackberries become more widespread.
Much of the fauna and flora of the area is poorly documented, but this lack of knowledge should not be used as an excuse to claim the area has reduced natural values.
The area is part of a continuum of natural habitats from the summit of South Sister (831m) to the coast, allowing animals and plants to migrate along the full altitudinal range in search of food and enabling for ecological communities of plants and animals to adjust their range in response to climate change.
Steep environmental gradients have played an important role in the redistribution of plants and animals in the recent Ice Ages and the imprint of this movement is still to be seen in the fauna. For example, the areas nearby are well known for parapatric boundaries between species of ground dwelling invertebrates such as velvetworms. These phenomena deserve protection in their own right.
High points in the landscape can be important for some butterfly species as they are used by males displaying 'hilltopping' behaviour during the breeding season. This is essential to their breeding success.
A high diversity of native bees, important to the local flora for pollination, is present in the area. Many native bees depend on the availability of woody debris, as found in a natural forest, for their nesting sites. Rare plant species such as Euphrasia collina ssp. deflexifolia depend on native bees for pollination.
Although the invertebrate list from a single collection period is relatively modest, more thorough collecting of South Sister over a longer time period would probably yield a list several thousand species in total. Even the list available so far includes species not yet recorded from any National Park in Tasmania and hence South Sister can be argued to be an important site for their conservation.
50419-9084 (3, 7, 46, 175)