Abstracts
These are organised according to country in which the project was carried out. The list is incomplete at the moment.
Australian Projects
Examination of mammal abundance & assemblage structure across an altitudinal gradient in the wet tropics bioregion, Australia.
A Lumholtz's tree kangaroo (Dendrolagus lumholtzi) in the Atherton Tablelands rainforest of north-east Queensland. This species is one of the 14 regionally endemic mammals that contributed to the measures of mammalian biodiversity recorded in this project.
Abstract
The rainforests of the Wet Tropics bioregion of north-eastern Queensland, Australia were listed as a World Heritage Area in 1988 because they contain high levels of species richness, endemism and evolutionary significant taxa. Within this region, the Atherton Tablelands have been cited as being one of the focal points of mammalian diversity, being home to 12 of the 14 regionally-endemic mammals. Much research has been done into spatial patterns in the distribution of mammals, but no studies to date have looked at distribution across the altitudinal gradient.
The aim of this study was to examine patterns of non-volant mammal abundance and assemblage structure across an altitudinal gradient on the Atherton Tablelands. Six sites were chosen at 200m intervals from 0m-1000m a.s.l. (above sea level) and a combination of live trapping of small mammals and spotlighting of arboreal folivores was undertaken on three occasions in June-July 2003. The results of this study showed that the abundance of all species observed varied in a curvilinear fashion with altitude, with the exception of Antechinus adustus, the abundance of which was not correlated with altitude. The murid rodents (Rattus fuscipes, Rattus leucopus, Melomys cervinipes, and Uromys caudimaculatus) were most abundant at the lower-mid altitude ranges (200-400m) while all the marsupials, except Pseudochirops archeri, were restricted to altitudes above 600m.
The overall mammal assemblage structure was strongly influenced by altitude and appeared to become more complex at higher elevations, peaking at 800m. This was largely due to the absence of marsupials from lowland sites. There were more mammal guilds at higher elevations with a corresponding increase in the mean number of species per guild. Further investigation showed that 54% of the variation in the pattern of species richness could be explained by one guild - the large arboreal folivores. Evidence suggests that this guild is the most extinction-prone and that it has poor recolonisation abilities.
B1OCLIM modelling suggested that large areas of upland forests in the Wet Tropics will shrink and become more fragmented with increasing temperatures as a result of global warming. This will have disastrous consequences for the marsupials observed in this study, particularly the arboreal folivores which appear to face increased thermoregulatory costs in lowland forests. Conservation action is urgently needed to ensure that the resilience of the current rainforests is maintained and the regionally-endemic fauna protected.
