Literatura científica selecionada sobre o tema "Vegetation surveys South Australia Fleurieu Peninsula"

This paper describes the South Australian distribution of the southern brown bandicoot (Isoodon obesulus obesulus) on the basis of records of its past occurrence and field surveys undertaken to determine its present distribution. Since European settlement I. o. obesulus has been recorded from four separate regions of the state: the Mount Lofty Ranges, the South East, Kangaroo Island and Eyre Peninsula. Subfossil remains show that I. o. obesulus also once occurred on Yorke Peninsula but there is no evidence that it has existed there in modem times. Field surveys conducted between 1986 and 1993 confirmed that I. o. obesulus still exists in the Mount Lofty Ranges, the South East and on Kangaroo Island. Its status on Eyre Peninsula is uncertain. Isoodon o. obesulus is vulnerable in the South East and Mount Lofty Ranges because of habitat fragmentation and predation by feral carnivores. The Kangaroo Island population is less threatened as large areas of habitat have been preserved and the fox (Vulpes vulpes) has not been introduced. The area of potential bandicoot habitat remaining in these three regions totals approximately 190 000 ha, most of which is already managed for nature conservation. This habitat is highly fragmented, occurring as small remnant patches of native vegetation separated by extensive tracts of cleared and modified land cover. The implications of this habitat configuration for the long-term survival of I. o. obesulus are discussed.

Two conical snail species introduced to Australia from the Mediterranean region during the 20th century are major pests of pastures and grain crops. In 2000, a parasitoid fly, Sarcophaga villeneuveana, was introduced into South Australia for biocontrol of the conical snail, Cochlicella acuta. The fly successfully established in the region but assessments of its impact in different snail aestivation microhabitats were limited. Twenty years on, field surveys were conducted to assess the geographic distribution and parasitism rates of S. villeneuveana on conical snails in the Yorke Peninsula region. Nineteen sites were sampled on four occasions in January and April of both 2019 and 2020. In total, >85,600 C. acuta and >2400 C. barbara were collected from cryptic (ground or plant refuge) and exposed (open ground or elevated substrate) aestivation habitats and assessed for parasitism. The fly was detected at 13 of 19 sampled sites up to 34 km from nursery release sites. Total parasitism rates of suitably sized snails (≥5 mm shell height) were 2.9% for C. acuta and 3.4% for C. barbara. Maximum parasitism rates of 48% for C. acuta and 29% for C. barbara were found at sites adjacent to spring- and summer-flowering native vegetation. Across 13 sites, parasitism rates were higher for C. acuta (5.4%) and C. barbara (15.2%) in exposed habitats above ground level. However, only 34% of C. acuta and 14% of C. barbara were found in elevated habitats as most snails were found in cryptic refuges. There was a seasonal decline in abundance of C. acuta (66%) and C. barbara (45%) between January and April, suggesting natural mortality. Although the overall impact of the fly is limited, high parasitism rates in local environments with flowering resources indicates the potential to enhance biocontrol of both invasive conical snail species.

ABSTRACT The Pygmy Copperhead Austrelaps labialis is South Australia’s only endemic snake, being native to the Adelaide Mount Lofty Ranges and Fleurieu Peninsula; with an additional allopatric population on Kangaroo Island. Within the AMLR, it inhabits stringybark forests and adjacent dense vegetation, occupying a total area of ~150 km2. Here, we document a newly discovered and seemingly isolated population at the north-eastern extent of its known mainland distribution. We visited Lobethal Bushland Park from 2013–2018 and observed snakes of varying age and size, while documenting their ecology and behaviour. In late 2019, the site was decimated by catastrophic wildfire and its persistence here remains unknown. Alongside descriptions of our observations, we suggest measures for the conservation of this vulnerable population in its remnant habitat if it has survived the impacts of wildfire.