North Stradbroke Island: An island ark for Queensland's koala population?

South East Queensland (SEQ) is experiencing the fastest human population growth in Australia, with attendant challenges for wildlife conservation due to expanding urbanisation. The documented dramatic decline of koalas Phascolarctos cinereus on mainland SEQ has provoked popular suggestions that North Stradbroke Island (NSI) should become an "island ark" for koalas. A multidisciplinary study was undertaken to determine the status of koalas on NSI. Aboriginal and European references to koalas on NSI were collected and analysed. To study koala distribution, direct and indirect visual surveys were conducted, whilst habitat use and home ranges were determined by fitting 33 koalas with VHF collars and radio-tracking them. Population characteristics, including health status, proximate causes of mortality and genetic profile, were gathered from radio-tracked koalas and from hospital databases of the Department of Environment and Resource Management

Dispersers shape fruit diversity in Ficus (Moraceae)

Seed dispersal by vertebrates is one of the most common and important plant–animal mutualisms, involving an enormous diversity of fruiting plants and frugivorous animals. Even though plant reproduction depends largely on seed dispersal, evolutionary ecologists have been unable to link co-occurring traits in fruits with differences in behavior, physiology, and morphology of fruit-eating vertebrates. Hence, the origin and maintenance of fruit diversity remains largely unexplained. Using a multivariate phylogenetic comparative test with unbiased estimates of odor and color in figs, we demonstrate that fruit traits evolve in concert and as predicted by differences in the behavior, physiology (perceptive ability) and morphology of their frugivorous seed dispersers. The correlated evolution of traits results in the convergence of general appearance of fruits in species that share disperser types. Observations at fruiting trees independently confirmed that differences in fig traits predict differences in dispersers. Taken together, these results demonstrate that differences among frugivores have shaped the evolution of fruit traits. More broadly, our results underscore the importance of mutualisms in both generating and maintaining biodiversity

The evolution of fruit colour: phylogeny, abiotic factors and the role of mutualists

Abstract The adaptive significance of fruit colour has been investigated for over a century. While colour can fulfil various functions, the most commonly tested hypothesis is that it has evolved to increase fruit visual conspicuousness and thus promote detection and consumption by seed dispersing animals. However, fruit colour is a complex trait which is subjected to various constraints and selection pressures. As a result, the effect of animal selection on fruit colour are often difficult to identify, and several studies have failed to detect it. Here, we employ an integrative approach to examine what drives variation in fruit colour. We quantified the colour of ripe fruit and mature leaves of 97 tropical plant species from three study sites in Madagascar and Uganda. We used phylogenetically controlled models to estimate the roles of phylogeny, abiotic factors, and dispersal mode on fruit colour variation. Our results show that, independent of phylogeny and leaf coloration, mammal dispersed fruits are greener than bird dispersed fruits, while the latter are redder than the former. In addition, fruit colour does not correlate with leaf colour in the visible spectrum, but fruit reflection in the ultraviolet area of the spectrum is strongly correlated with leaf reflectance, emphasizing the role of abiotic factors in determining fruit colour. These results demonstrate that fruit colour is affected by both animal sensory ecology and abiotic factors and highlight the importance of an integrative approach which controls for the relevant confounding factors