Fossils reveal late Holocene diversity and post-European decline of the terrestrial mammals of the Murray–Darling Depression

2017 ◽  
Vol 44 (1) ◽  
pp. 60 ◽  
Author(s):  
Diana A. Fusco ◽  
Matthew C. McDowell ◽  
Graham Medlin ◽  
Gavin J. Prideaux

Context Establishing appropriate faunal baselines is critical for understanding and abating biodiversity declines. However, baselines can be highly reliant on historical records that come from already disturbed ecosystems. This is exemplified in the Murray–Darling Depression bioregion of Australia, where European settlement (and accompanying marked land-management changes and the introduction of many species) triggered rapid declines and losses of native species, often before their documentation. Aims We aim to establish the mammal fauna present when Europeans settled the Murray Mallee and Murray–Darling Depression bioregion and determine the extent of mammal loss since European settlement. Methods We describe a dated vertebrate assemblage from Light’s Roost in the lower Murray Mallee region of South Australia. We compare our data with those of modern fauna surveys and historical records to document the extent of change in the mammal fauna since European settlement. Key results Radiocarbon ages showed that the assemblage was accumulating, at a minimum, within an interval from 1900 to 1300 years ago. Since this time, the Murray–Darling Depression has lost half of its flightless terrestrial mammals. Species lost include the mulgara (Dasycercus blythi/cristicauda), which places this taxon within only 40km of Lake Alexandrina, the hitherto-disputed type locality for D. cristicauda. Fossils provided the principal evidence for nearly half of the Murray Mallee fauna and over three-quarters of the fauna are represented in the fossil record. Conclusions Late Holocene assemblages provide important archives of species biogeography and diversity. Our revised faunal baseline indicated that the pre-European fauna of the Murray–Darling Depression was more diverse than hitherto understood and its reduction appears largely caused by the impacts of European settlement. Implications Baselines for species distributions derived from historical records and modern faunal surveys are likely to be incomplete and warrant revision, particularly for smaller and more cryptic species. Deficiencies in regional records mask the extent of mammal declines caused by European colonisation and associated agricultural practices, and thus vulnerability to anthropogenic disturbance.

2012 ◽  
Vol 34 (2) ◽  
pp. 202 ◽  
Author(s):  
Barbara A. Wilson ◽  
Leonie E. Valentine ◽  
Alice Reaveley ◽  
Joanne Isaac ◽  
Kristen M. Wolfe

Over the last 30 years declining rainfall and increased aquifer abstraction have heavily impacted water availability and ecosystems on the Gnangara Groundwater System (GGS). The mammal fauna of the area is considered to have been rich, with up to 28 terrestrial and 5 volant native species recorded since European settlement. This study investigated previous and current distribution of mammals on the GGS, and assessed potential impacts of predicted rainfall and groundwater declines on mammals. A general survey was conducted at 40 sites, and targeted trapping was undertaken for Hydromys chrysogaster and Isoodon obesulus fusciventer at wetlands. Nine native and seven introduced terrestrial mammal species were recorded during the general survey and capture rates were very low (1.05%). The most commonly captured native species was Tarsipes rostratus. There is evidence that only 11 (9 recorded and 2 considered to be extant) of the 28 historically recorded terrestrial native mammals still persist in the area. The species predicted to be most susceptible to rainfall and groundwater level declines include H. chrysogaster, I. obesulus fusciventer, and T. rostratus. Management and recovery actions required to protect mammals under predicted climatic changes include identification and maintenance of refugia and ecological linkages, supplementation of lakes, development of ecologically appropriate fire regimes, and control of predators.


2016 ◽  
Vol 12 (1) ◽  
pp. 20150774 ◽  
Author(s):  
Heidi K. Alleway ◽  
Bronwyn M. Gillanders ◽  
Sean D. Connell

The antiquity of human impact on ecosystems is increasingly understood, though the arrival of settlers to new lands remains a defining period. Colonization of the ‘neo-Europes’, a reference from the discipline of history, precipitated changes in aquatic ecosystems through modification of waterways and introductions of non-native species. We considered historical fisheries and fish market records from South Australia (1900–1946) against contemporary production statistics (1987–2011). Native inland species historically contributed large quantities to the market but have deteriorated such that fishing is now limited, and conservation regulations exist. This pattern mirrors the demand-driven transition from freshwater to marine fisheries in Europe; hence, we propose that this pattern was predicated on societal expectations and that European settlement and introduction of non-native fishes led to systematic overexploitation and degradation of native inland fisheries species in Australia, representing a further consequence of neo-European colonization to ecology. Accurate interpretation of ecological change can ensure more appropriate management intervention. Concepts, such as neo-Europe, from alternative disciplines can inform the recognition and evaluation of patterns at regional and global scales.


2013 ◽  
Vol 35 (1) ◽  
pp. 54 ◽  
Author(s):  
A. N. Start ◽  
A. A. Burbidge ◽  
P. G. Kendrick ◽  
N. L. McKenzie

The mammal fauna of the south-western Little Sandy Desert was systematically surveyed during three visits to each of five sites at three locations representing the array of surfaces in the biogeomorphic landscape of the study area. A fourth, less systematic, expedition revisited one location and sampled two new ones. Nineteen extant, native species and seven exotic species were recorded. Fourteen extant species were below the Critical Weight Range (CWR), two (both large macropods) were above it and three (a monotreme, a rodent and a dasyurid) were within it. Another five CWR species may persist but were not recorded. An additional 19 species, all within the CWR, are thought to have occurred in the area but are now presumed extinct or locally extinct; we recorded evidence for the former presence of four of them. Surface type was an important determinant of habitat and spatially minor surfaces were disproportionately diverse but differed in their relevance to indigenous and exotic species respectively. Sandstone ranges had the richest indigenous faunas and six extant species were restricted to that habitat. Loam and clay surfaces had the richest exotic faunas.


1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.


1994 ◽  
Vol 17 (1) ◽  
pp. 19
Author(s):  
J. Barker ◽  
D. Lunney ◽  
T. Bubela

Mammal surveys were carried out on the Carrai Plateau and Richmond Range in north-east New South Wales between March 1988 and November 1989. The emphasis was placed on rainforest mammals, following the recognition by Adam ( 1987) that the species lists of mammals in the state's rainforests were incomplete and that more research was needed. The mammals were surveyed primarily by analysis of prey remains in Dog and Fox scats, collected from roads throughout the forests, and from bat trapping. The bat fauna at both the Carrai Plateau and Richmond Range is rich (1 0 species and nine species respectively, including the rare Golden-tipped Bat, Kerivoula papuensis, in the Richmond Range). Scat analysis revealed the presence of 24 native species on the Carrai Plateau, and on the Richmond Range there were 17 species, including high numbers of two pademelon species. Feral prey species are almost completely absent, although the Fox is an established predator in both areas. A sharp division was identified between the mammal faunas of closed and open forests. Differences were found also between the mammal fauna composition of the two rainforest sites, and with those of nearby eucalypt forests. The mammal fauna of New South Wales rainforests is distinct from open forests and future mammal surveys are needed to ensure an adequate level of knowledge to identify and conserve these areas.


2003 ◽  
Vol 51 (1) ◽  
pp. 1 ◽  
Author(s):  
B. M. Potts ◽  
R. C. Barbour ◽  
A. B. Hingston ◽  
R. E. Vaillancourt

The contamination of native-eucalypt gene pools via exotic pollen is of concern as (i) pollen dispersal is believed to be much more widespread than seed dispersal, (ii) reproductive barriers are often weak between closely related species, (iii) European settlement has already had a major impact on Australia's eucalypt woodlands and mallee, (iv) there has been a rapid expansion of eucalypt plantations and restoration plantings in Australia and (v) Australia is the custodian of an internationally important genetic resource. Pollen flow between plantation and native eucalypt species has already been reported and implementation of strategies to minimise the risk and consequences of genetic pollution is important if Australian forestry is to be considered sustainable. The risks associated with the introduction of non-native species, provenances and hybrids include direct effects on the gene pool through genetic pollution as well as indirect effects on dependent biodiversity. In many cases, the risk of genetic pollution will be small due to strong barriers to hybridisation between distantly related species, differences in flowering time or poor fitness of hybrids. There is no risk of hybridisation between species from the different major eucalypt genera and/or subgenera (e.g. symphyomyrts, monocalypts, eudesmids, bloodwoods and angophora). The main plantation species are symphyomyrts and within this subgenus, the probability of successful hybridisation generally decreases with increasing taxonomic distance between species. The planting of non-local provenances or improved material within the range of native populations has the potential to have an impact on local gene pools to varying degrees, indicating the requirement for the adoption of management strategies to reduce this risk. Naturally small or remnant populations are at particular risk. A framework for assessment of the risk of genetic pollution is developed herein.


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