25 research outputs found

    Synchronous diversification of Sulawesi's iconic artiodactyls driven by recent geological events

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    The high degree of endemism on Sulawesi has previously been suggested to have vicariant origins, dating back to 40 Ma. Recent studies, however, suggest that much of Sulawesi’s fauna assembled over the last 15 Myr. Here, we test the hypothesis that more recent uplift of previously submerged portions of land on Sulawesi promoted diversification and that much of its faunal assemblage is much younger than the island itself. To do so, we combined palaeogeographical reconstructionswithgenetic andmorphometric datasets derived from Sulawesi’s three largest mammals: the babirusa, anoa and Sulawesi warty pig. Our results indicate that although these species most likely colonized the area that is now Sulawesi at different times (14 Ma to 2-3 Ma), they experienced an almost synchronous expansion from the central part of the island. Geological reconstructions indicate that this area was above sea level for most of the last 4 Myr, unlike most parts of the island. We conclude that emergence of land on Sulawesi (approx. 1-2 Myr) may have allowed species to expand synchronously. Altogether, our results indicate that the establishment of the highly endemic faunal assemblage on Sulawesiwas driven by geological events over the last few million years

    Eroding abodes and vanished bridges: historical biogeography of the substrate specialist pebble-mound mice (Pseudomys).

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    Aim: To determine whether the pronounced ecological importance of pebble mounds to pebble-mound mice (Pseudomys) is manifest in their continental biogeography.\ud \ud Location: Northern Australia.\ud \ud Methods: A GIS-based comparison was made between the habitats contained within the potential climatic distributions of mice, representing a null hypothesis of no habitat selection, and their actual distributions based on all known location records.\ud \ud Results: All species had a clear preference for hilly, rocky landscapes with a surficial cover dominated by bedrock. Simple vegetation communities with relatively open eucalypt overstorey and grassy understorey were preferred. Highly degraded rocks and aggradational surfaces and plains were avoided. The extent of the summer monsoon may be important in determining the southern limits of the group's distribution. Major disjunctions between species were attributable to the presence of clay plains and sand sheets.\ud The behavioural requirement of pebble-mound mice for mounds determines their population distribution pattern and the distribution of the different species within the genus.\ud \ud Main conclusions: The behavioural need for pebble mounds drives the distributional pattern of populations and species of pebble-mound mice. The initial spread of pebble-mound mice probably occurred during the late Pliocene or earliest Pleistocene. There has predominantly been degradation of the potential distribution of the group since that time due to the stability of Australian landscapes and Pleistocene planation and sand sheet development over large areas of northern Australia. This process is ongoing, and past regions of rocky contact between current distributions have disappeared, while the distributional limits of several species are steadily being reduced by erosion of hills and the spread of dune fields

    The biology of the northern brown bandicoot, Isoodon macrourus (Marsupialia: Peramelidae) at Mitchell Plateau, Western Australia

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    Breeding, population dynamics and seasonal changes in physical and physiological parameters were examined in Isoodon macrourus at the Mitchell Plateau between September 1981 and November 1982. Females gave birth to litters of 2.5 ± 1.0 (16) young between September and April. They produced up to three litters in a breeding season with an average interval between successive litters of 89.5 (51-108) days. Adult testosterone levels and scrota1 size began to increase in July and peaked in September 1982. The overall ratio of adult males to adult females was 1:0.54; it was 1:0.80 for pouch young. Females were more frequently trapped on sequential trips than were males. Density on the grids increased towards the end of the dry season (July and September 1982)-mostly as a result of increased numbers of females. Adult males and females moving onto the grids during the dry season tended to select different habitats. Adult males moved significantly more in the wet season (September 1981, January and April) than they did in the dry season (July and September 1982); they also moved significantly more than adult females in the wet season. Seasonal variations were recorded for most physical and physiological parameters. During the wet period from September 1981 to January 1982, body weight, haemoglobin, haematocrit and total plasma albumin declined, while total white blood cells and proportion of lymphocytes to granular leucocytes rose. This indicated that this period was one of change in condition for this species. Compared to adult females, adult males were larger and heavier, had higher values of haematocrit and lymphocytes, and lower values of granular leucocytes, free steroids, CBGBd and albumin bound corticosteroid. There was considerable between-year variability in condition of individuals and both sexes differed significantly in September 1981 and 1982 in their weight, haematocrit, total white blood cells, granular leucocytes, MCBC and testosterone. Individuals at disparate localities at the Mitchell Plateau showed similar seasonal physiological and physical responses, except for one grid where they were heavier.C. Kemper, D. J. Kitchener, W. F. Humphreys, R. A. How, L. H. Schmitt and A. Bradle

    Freedom to do what you are told : senior management team autonomy in an NHS Acute Trust

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    Arguably, the government's aim of using the reward of ‘earned autonomy’ and Foundation Trust status as an incentive to improve performance in the NHS will only be effective if Trust managers view greater autonomy as both desirable and realistic. This article examines this issue by investigating the extent to which members of an NHS Trust's senior management team perceive themselves as autonomous, the factors most likely to hinder their ability to operate autonomously, and the extent to which managers want greater autonomy. In the event, autonomy was largely restricted by extensive centrally dictated targets. Entrenched professional interests and a lack of managerial skills on the part of clinician managers suggested limitations on the extent to which autonomy can be realistically devolved. Additionally, there was little belief among managers that greater autonomy would enable healthcare services to be delivered more effectively
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