Epiphytic bryophytes of Dicksonia antarctica Labill. from selected pockets of cool temperate rainforest, Central Highlands, Victoria

Epiphytic bryophytes of the Soft Tree-fern Dicksonia antarctica Labill. were examined in four Cool Temperate Rainforest pockets of the Central Highlands of Victoria. Thirty-two species, 17 mosses and 15 liverworts, were noted. There was no distinction in species assemblage between the north and south side of tree-ferns although bryophytes occurred on the south side of more tree-ferns than they did on the north side.

Epiphytes on Nothofagus cunninghamii and Eucalyptus regnans in a Victorian cool temperate rainforest

This study investigated the epiphytic communities on Myrtle Beech Nothofagus cunninghamii (Hook.) Oerst. and Mountain Ash Eucalyptus regnans F.Muell. trees in a pocket of Cool Temperate Rainforest in the Yarra Ranges National Park, Victoria, Australia. Twenty species were identified growing on N. cunninghamii, with nine species found on E. regnans. The dominant epiphytes were the moss Dicranoloma menziesii on N. cunninghamii, and the liverwort Bazzania adnexa var. adnexa on E. regnans.

Cool temperate rainforest Lichens of Victoria, Australia: floristics and distribution

Lichen floristics and distribution were examined in cool temperate rainforests of Victoria, Australia. Forty sites were sampled, ten from each of the Otways, Yarra Ranges, Baw Baw, and Errinundra regions. A total of 165 lichen species were recorded, representing 38 fam- ilies. Seventeen species are new for Victoria. Non-metric Multidimensional Scaling showed three lichen groups that corresponded with the rainforest types in which they occurred. A sub-group of lichen species were considered widespread and represented the core of Victoria's rainforest lichen flora.

Observations of the ecological impacts of Sambar Cervus unicolor in East Gippsland, Victoria, with reference to destruction of rainforest communities

Damage caused by Sambar, particularly browsing, antler rubbing and physical removal of particular plant species, is resulting in serious ecological consequences. Threatening processes instigated or maintained by Sambar include: loss of individual taxa, altered vegetation structure and massive
widespread removal and prevention of regeneration, which is now resulting in the loss of plant communities in some areas. These observations are particularly disturbing, as it is apparent that Sambar are yet to reach their full ecological and population potential in south-eastern Australia. The destruction documented ill this article is now so widespread and so severe that in places it represents an ecological disaster for specific plant and animal species, ecological vegetation classes and floristic communities. We strongly recommend that Sambar in particular, and feral deer in general. should no longer be protected under the Wildlife Act 1975 so that control methods can be devised and implemented. It now appears that such measures will he essential for the long-term survival of some fragile plant species and communities in Victoria. (Title: Victorian Naturalist 122(4) 2005, 189-200

Do green and golden bell frogs (Litoria aurea) occupy habitats with fungicidal properties?

The Green and Golden Bell frog Litoria aureo is in major decline in Australia, where its distribution is now confined mainly to the east coast of New South Wales (NSW). Infection by the newly emerged amphibian fungal pathogen Batrachochytrium dendrobatidis has been identified as one of the main threats affecting L. aurea. Surprisingly, some of the sites in NSW sustaining the largest populations of this species are industrial and urban habitats that are often disturbed and polluted, which could protect L. aurea from chytrid infection if pollution had fungicidal capacity.The aim of this study was to characterise the trace metal concentration of several L. aurea breeding sites in the Sydney and IIlawarra regions of NSW and to evaluate the fungicidal efficacy of the main "'ace metals identified. Selected L. aurea sites were sampled throughout the breeding season (September to February) to establish the concentration of trace metals in both surface sediment and waters. Physico-chemical parameters including pH and salinity were also measured. Of the trace metals identified, copper and zinc were consistently elevated across sites. Over 50% of sites exceeded the National Sediment Quality Guideline for both copper and zinc concentration, and over 90% of sites exceeded the National Water Quality Guideline for these metals. Consequently, we evaluated their effect on the growth and survival of a laboratory culture of B. dendrobatidis,These tests were performed in media containing dissolved metal concentrations of 0.02 - 0.65 mgL^-1 Cu and 0.24 - 5.0 mgL^-1 Zn. Growth rates were inferred by total fungal density in liquid culture (based on spectral absorbance measurements), final dry weight, and the density of zoospores in fungal cultures grown for 28 days. Both copper and zinc were found to reduce the growth and proliferation of B. dendrobatidis, but in a non-linear manner. This suggests that L. aurea may be gaining some protection from B. dendrobatidis infection at several of the sites examined.

Movement patterns of southern bell frogs (Litoria raniformis) in response to flooding

Within the semiarid regions of New South Wales, Australia, the endangered southern bell frog (Litoria raniformis) occupies a landscape that is characterised by unpredictable rainfall and periodic flooding. Limited knowledge of the movement and habitat-occupancy patterns of this species in response to flood events has hampered conservation efforts. We used radio-tracking to assess changes in movement patterns and habitat occupancy of L. raniformis (n = 40) over three different periods (November, January and April/May) that coincided with the flooding, full capacity and subsequent drying of waterbodies within an irrigation landscape. We assessed (1) the use of permanent and ephemeral habitats in response to flooding and drying and (2) distances moved, turning angles and dispersion of frogs during wetland flooding, full capacity and drying. Individuals remained in permanent waterbodies in November but had abandoned these areas in favour of flooded ephemeral waterbodies by January. As the ephemeral waterbodies dried, radio-tracked individuals moved back into permanent waterbodies. The movement patterns of radio-tracked individuals were significantly different in the three radio-tracking periods, but did not differ significantly between sexes. Individuals moved significantly greater distances over 24 h, in straighter lines and movements were more dispersed while they occupied ephemeral waterbodies during January than when they occupied permanent waterbodies during November and April/May. Local weather conditions did not influence movement patterns when all three tracking periods were modelled together using a single linear stepwise regression. The dynamic distribution of habitat patches over space and time, combined with changing patterns of resource utilisation and movement of L. raniformis, highlights the importance of incorporating both permanent and ephemeral habitat patches into conservation plans. Reductions in flood frequency and extent of ephemeral wetlands due to modified flooding regimes have the capacity to limit dispersal of this species, even when permanent waterbodies remain unchanged.

Sperm competition and offspring viability at hybridization in Australian tree frogs, Litoria peronii and L. tyleri

Hybridization between closely related species often leads to reduced viability or fertility of offspring. Complete failure of hybrid offspring (post-zygotic hybrid incompatibilities) may have an important role in maintaining the integrity of reproductive barriers between closely related species. We show elsewhere that in Peron's tree frog, Litoria peronii, males more closely related to a female sire more offspring in sperm competition with a less related rival male. Observations of rare 'phenotypic intermediate' males between L. peronii and the closely related L. tyleri made us suggest that these relatedness effects on siring success may be because of selection arising from risks of costly hybridization between the two species. Here, we test this hypothesis in an extensive sperm competition experiment, which shows that there is no effect of species identity on probability of fertilization in sperm competition trials controlling for sperm concentration and sperm viability. Instead, there was a close agreement between a male's siring success in isolation with a female and his siring success with the same female in competition with a rival male regardless of species identity. Offspring viability and survival, however, were strongly influenced by species identity. Over a 14-day period, hybrid offspring suffered increasing mortality and developed more malformations and an obvious inability to swim and right themselves, leading to compromised probability of survival. Thus, hybridization in these sympatric tree frogs does not compromise fertilization but has a strong impact on offspring viability and opportunity for reinforcement selection on mate choice for conspecific partners.

Successional changes in epiphytic rainforest lichens : implications for the management of rainforest communities

We explored lichen species richness and patterns of lichen succession on rough barked Nothofagus cunninghamii trees and on smooth barked Atherosperma moschatum trees in cool temperate rainforests in Victoria, Australia. Nothofagus cunninghamii trees from the Yarra Ranges, and A.moschatum trees from Errinundra were ranked into size classes (small, medium, large and extra-large), and differences in species richness and composition were compared between size classes for each tree species. Nothofagus cunninghamii supported a rich lichen flora (108 trees, 52 lichen species), with the largest trees supporting a significantly higher number of species, including many uncommon species. This success was attributed to varying bark texture, stand characteristics and microhabitat variations as the trees age. Atherosperma moschatum supported a comparable number of species (120 trees, 54 lichen species). Indeed on average, this host supported more lichen species than N. cunninghamii. However, successional patterns with increasing girth were not as clear for A. moschatum, possibly due to the more stable microclimate that this smooth barked host provided. Victorian cool temperate rainforests exist primarily as small, often isolated pockets within a sea of Eucalypt-dominated, fire-prone forest. Many are regenerating from past disturbance. We find that protection of Victoria’s oldest rainforest pockets is crucial, as they represent sources of rare, potentially threatened lichen species, and may be acting as reservoirs for propagules for nearby ageing rainforests. Indeed, even single, large old trees have conservation importance, as they may provide exceptional microhabitats, not found elsewhere in the regenerating rainforest environment.

The apparent paradox of colour variation in aposematic poison frogs

Toxic prey warn their predators about their unprofitability with conspicuous colour patterns that are easily learned and remembered by predators if they are uniform within a population. I studied a variable, warningly-coloured poison frog in the wild and found that such variation in colours may be related to mating advantages, parental duties, microhabitat selection and different behavioural strategies.

Effects of an invasive species on refuge-site selection by native fauna : the impact of cane toads on native frogs in the Australian tropics

Invasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge-site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet-dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non-random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat-site availability for native frogs.

Paradox lost: variable colour-pattern geometry is associated with differences in movement in aposematic frogs

Aposematic signal variation is a paradox: predators are better at learning and retaining the association between conspicuousness and unprofitability when signal variation is low. Movement patterns and variable colour patterns are linked in non-aposematic species: striped patterns generate illusions of altered speed and direction when moving linearly, affecting predators' tracking ability; blotched patterns benefit instead from unpredictable pauses and random movement. We tested whether the extensive colour-pattern variation in an aposematic frog is linked to movement, and found that individuals moving directionally and faster have more elongated patterns than individuals moving randomly and slowly. This may help explain the paradox of polymorphic aposematism: variable warning signals may reduce protection, but predator defence might still be effective if specific behaviours are tuned to specific signals. The interacting effects of behavioural and morphological traits may be a key to the evolution of warning signals. © 2014 The Author(s) Published by the Royal Society. All rights reserved.