Dendrolagus Lumholtzi Research Articles

The use of rope bridges to study the colonisation of restored rainforest habitat by arboreal mammals

This study tested the utility of a rope bridge across a road that traversed restored rainforest habitat (5–8 years old) to assess the use of these new habitats by arboreal mammals. Camera-trapping revealed common brushtail possums (Trichosurus vulpecula), green ringtail possums (Pseudochirops archeri) and Herbert River ringtail possums (Pseudochirulus herbertensis) used the rope bridge regularly while striped possums (Dactylopsila trivirgata), fawn-footed melomys (Melomys cervinipes), long-tailed pygmy-possums (Cercartetus caudatus) and Lumholtz’s tree-kangaroos (Dendrolagus lumholtzi) were recorded at the bridge accesses, but no crossings could be proven. No Lemuroid ringtail possums (Hemibelideus lemuroides) were recorded near the rope bridge. Differences in the use of the restored rainforest habitat and the crossing structure are likely to be caused by differences in the species’ reliance on features in mature forests, and their responses to rainforest edges. The results support the utility of canopy crossing structures to facilitate the use of restored habitat by arboreal mammals.

When ancestry haunts – can evolutionary links to ancestors affect vulnerability of Australian prey to introduced predators? A preliminary study

The high extinction risk of Australian marsupials has been attributed to their failure to recognise novel predators, the application of inappropriate antipredator responses, and advanced hunting strategies of novel predators. This study is a preliminary attempt to explore whether the Lumholtz’ tree-kangaroo (Dendrolagus lumholtzi) (a) is able to recognise odour cues from different predators as threats, and (b) possesses predator-archetype specific antipredator responses. A small number of available captive tree-kangaroos were exposed to faecal odours from two extant predators of different archetypes (python, dingo), a regionally extinct predator which closely matches past terrestrial predators (Tasmanian devil), and a novel predator (domestic dog). Lavender oil was used as non-predator novel odour and water as control. Results suggest that all subjects associated the presented odours with a threat, albeit to different degrees, but did not display predator-archetype specific responses. It appears that this species applies an ancestral antipredator response of flight-on-the ground when encountering predators, including novel predators. Although the results need to be confirmed with more animals, further studies on the vulnerability of Australian prey to novel predators should take the ancestral history of Australian prey species into account.

Terrestrial activity patterns of the Lumholtz’s Tree‐Kangaroo (Dendrolagus lumholtzi) in a restored riparian habitat – Implications for its conservation

SummaryLarge‐scale deforestation and forest fragmentation in the tropical area of the Atherton Tablelands in Far North Queensland, Australia, have placed extensive strains on populations of many endemic species of this area, such as the Lumholtz’s Tree‐Kangaroo (LTK). Despite LTKs predominantly arboreal life and their ability to quickly colonize and adapt to restored forested habitats, little is known about their terrestrial activity patterns within these habitats which put them at risk to predation by canines and to roadkill when crossing nearby roads. Using motion‐sensing cameras, forest floor‐related activities of LTKs were recorded in a restored riparian rainforest habitat in relation to seasons and moon phases. The results show that LTKs exhibit a cathemeral activity pattern of forest floor‐related movements with a tendency towards crepuscular activity at dawn. While there was a significant association between the daytime recordings and the seasons with more activity during the days of the wet season, there was no association between the nighttime recordings and the seasons, as well as the moon phases. These results suggest that seasonal changes in temperature and precipitation, but potentially also in food quality, are likely to affect the frequency at which LTKs access the forest floor. Mitigating threats to LTKs in restored habitats should focus on facilitating terrestrial movements of LTKs, the control of feral dogs, enlarging and connecting available habitat, and educating drivers about peak times of LTK movements on the ground.

Haematological and serum biochemical reference intervals of free-ranging Lumholtz's tree-kangaroos (Dendrolagus lumholtzi).

Reference intervals for haematology and serum biochemistry parameters were developed for free-ranging Lumholtz's tree-kangaroo (Dendrolagus lumholtzi) using 35 samples from 12 female and 15 male free-ranging animals. Captive tree-kangaroos (n = 12) were also sampled for comparison. Differences were found between free-ranging and captive animals in white blood cell and neutrophil counts, and levels of aspartate aminotransferase, alkaline phosphatase, bilirubin, creatine kinase, phosphate, triglycerides and lipase. These differences may be attributed to diet, activity, capture methods or age group. Reference intervals generated may be used for both free-ranging and captive Lumholtz's tree-kangaroos. This study provides a valuable tool for the assessment of health in rescued and captive tree-kangaroos and will aid in investigations into population health and disease in free-ranging Lumholtz's tree-kangaroos. To develop reference intervals (RIs) for haematology and serum biochemistry parameters in Lumholtz's tree-kangaroos. Haematological and serum biochemical RIs were determined using 35 samples from 27 clinically healthy Lumholtz's tree-kangaroos from the Atherton Tablelands region of Queensland examined between 2014 and 2019. Haematology and serum biochemistry parameters were measured from 16 samples from 12 captive animals for comparison. Reference intervals based on 35 samples from free-ranging animals showed higher mean and standard deviation values for white blood cell and neutrophil counts, and levels of aspartate aminotransferase, alkaline phosphatase, bilirubin, creatine kinase, phosphate, triglycerides and lipase than results for 16 samples from captive animals. Captive individuals showed higher mean values than free-ranging individuals for albumin, protein, creatinine as well as Hb, MCV, MCH and MCHC. The haematological and serum biochemistry RIs developed for Lumholtz's tree-kangaroos in this study will provide a valuable tool during clinical examination and investigations into disease and population health by veterinarians and researchers. The differences in parameters between free-ranging and captive animals are consistent with differences in diet, age cohort, activity or capture methods. Reference intervals generated from free-ranging animals should also be valid for captive Lumholtz's tree-kangaroos.

OCULAR ANATOMY AND PATHOLOGY IN LUMHOLTZ'S TREE-KANGAROO (DENDROLAGUS LUMHOLTZI).

Lumholtz's tree-kangaroo (Dendrolagus lumholtzi) is one of two species of tree-kangaroos found in Queensland, Australia. There is little information about ocular anatomy and pathology in any species of tree-kangaroo, and there are claims of blindness from unknown causes in free-ranging Lumholtz's tree-kangaroos. This study investigated ocular anatomy and pathology in 80 individuals, using examination of 31 live animals and histopathologic examination of eyes from 49 carcasses. Tree-kangaroos were found to have a typical vertebrate eye with immuno-histochemical evidence for dichromatic color vision. Only 5.4% of animals had evidence of pathology from traumatic injury, infection, or a variety of nonspecific lesions. Toxoplasmosis was implicated in ocular lesions in three animals. This study did not find evidence of widespread blindness in free-ranging animals nor evidence of toxic optic neuropathy. Examinations of live animals highlighted the need to establish normal ocular examination parameters and vision testing protocols suitable for use in tree-kangaroos and the need for more comprehensive examination and testing of animals thought to have vision loss of unknown origin.

Cost-effectiveness of thermal imaging for monitoring a cryptic arboreal mammal

Context The development of reliable and cost-efficient survey techniques is key to the monitoring of all wildlife. One group of species that presents particular challenges for monitoring is the arboreal mammals. Traditional techniques for detecting these species often yield low detection probabilities (detectability) and are time-consuming, suggesting the potential for novel methods to enhance our understanding of their distribution, abundance and population trajectories. One technique that has been shown to increase detectability in a range of terrestrial species is thermal imaging, although it has rarely been applied to arboreal species. The true conservation status of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is uncertain because of low detectability under typical survey techniques, and a more suitable method is required to enable effective monitoring of the species, making it an ideal candidate for the present study. Aims We aimed to compare the success and cost-effectiveness of surveys utilising thermal imaging with two traditional methods, namely, spotlighting and daytime surveys, so as to optimise monitoring of D. lumholtzi. Methods We conducted surveys at 10 sites in Queensland (Australia) where D. lumholtzi was known to occur, by using each method, and modelled both the detectability of D. lumholtzi and the cost-effectiveness of each technique. Key results Detectability of D. lumholtzi was significantly higher with the use of thermal imaging than it was with the other survey methods, and thermal detection is more cost-effective. In average survey conditions with a trained observer, the single-visit estimated detectability of D. lumholtzi was 0.28 [0.04, 0.79] in a transect through rainforest, by using thermal imaging. Using only spotlights, the detection probability was 0.03 [0, 0.28] under the same conditions. Conclusions These results show that incorporating thermal technology into monitoring surveys will greatly increase detection probability for D. lumholtzi, a cryptic arboreal mammal. Implications Our study highlighted the potential utility of thermal detection in monitoring difficult-to-detect species in complex habitats, including species that exist mainly in dense forest canopy.

Herpesvirus Infection in Lumholtz's Tree-Kangaroo (Dendrolagus lumholtzi).

Herpesvirus infections associated with a range of clinical findings are widespread in free-ranging and captive Australian marsupials. We report on herpesviruses identified by virus neutralization and PCR in free-ranging and captive Lumholtz's tree-kangaroos (Dendrolagus lumholtzi). Herpesvirus has not been confirmed previously by DNA testing in tree kangaroos. Virus neutralization testing for alphaherpesviruses MaHV1 and MaHV2 was positive on 4/10 captive and 0/35 free-ranging tree-kangaroo samples tested. A novel gammaherpesvirus was found on PCR in 17/20 apparently healthy individuals (11/12 free-ranging, 5/6 wild-caught, captive, and 1/2 captive-bred). One captive-bred animal that died following an acute illness was positive on PCR only for MaHV4, an alphaherpesvirus previously identified from an eastern grey kangaroo (Macropus giganteus). The detection of MaHV4, associated with morbidity and mortality in captive tree-kangaroos, raises biosecurity concerns about introducing a non-endemic alphaherpesvirus into naive wild populations through release of captive animals. We propose that: 1) further work on herpesviruses in marsupials be carried out to determine whether herpesviruses from captive individuals represent a potential threat to wild populations, particularly for endangered species in which there are captive breeding and cross-fostering programs; and 2) that captive tree kangaroos be kept in such a way that prevents cross-species transmission of herpesviruses, in particular eliminating close direct or indirect contact with other species of macropods.

Conservation and health of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi)

Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is an iconic species in far north Queensland yet little is known about its health or population status. Studies on this species have been conducted in a limited number of locations and focused primarily on ecology, habitat use and home-range size. The species is relatively common in the Atherton Tablelands but habitat loss, predation by domestic, feral and wild dogs, vehicle strike, low fecundity, and disease have been identified as threats to the population. We review knowledge of population ecology and threats for this species, and include a novel collation of disease reports on all tree-kangaroos with particular reference to Lumholtz’s tree-kangaroo. Health of Lumholtz’s tree-kangaroo appears to be impacted by the increase in humans and domestic animals in their range. There have been reports of melioidosis, toxoplasmosis, tick paralysis and blindness in wild tree-kangaroos. We identify where increased information on health and population viability will improve conservation and management of the species.

Factors affecting the mortality of Lumholtz's tree-kangaroo (Dendrolagus lumholtzi) by vehicle strike

Context Vehicle strike is a major issue where wildlife habitat is intersected by busy roads. Near Threatened Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is a large (5–10 kg) semi-arboreal mammal found in populated rural and forested areas of north-eastern Australia. Warning signs, rope bridges and underpasses have not prevented ~20 animals being killed on the road each year. Aims To identify factors influencing Lumholtz’s tree-kangaroo vehicle strike to help inform mitigation options. Methods Citizen sightings (1998–2000) and 90 road-kills collected over 4.5 years on the Atherton Tablelands, Australia, were examined to determine the causes of vehicle strike in Lumholtz’s tree-kangaroo. The spatial distributions of sightings and road-kills were characterised using nearest-neighbour analysis, and the relationship between them was determined using a Bayesian approach that accounted for spatial autocorrelation. Gender, age, weight, season, rainfall, road and verge characteristics, traffic volumes, speed limits and mitigation measures were recorded to assess their influence on road-kill risk. Adequacy of speed limits to prevent collisions along road sections with more than four road-kills per 8 km (hazard zones) was assessed from visibility and stopping distances. Key results Vehicle strikes mainly affected male tree-kangaroos (2–5 years, 5.5–8 kg), occurred where live animals were most frequently sighted and were most likely on roads with narrow verges, low visibility and medium traffic volumes. Speed limits at hazard zones were inadequate to prevent collisions. Few warning signs corresponded with these zones, and road mortalities persisted where they did. Conclusions Unpredictable dispersal of young males and vehicle speeds unsuited to road conditions drive road mortalities in Lumholtz’s tree-kangaroo. Because tree-kangaroos do not appear to respond to existing mitigation measures, reducing traffic speeds, and increasing visibility, appear to be the most effective mitigation strategies for reducing tree-kangaroo road mortality. Implications Our findings suggest that tree-kangaroo road-kill can be reduced by reducing speed limits in line with government recommendations and increasing visibility by clearing road verges along sections of road with the highest tree-kangaroo mortality. Warning signage should be re-evaluated to determine whether its effectiveness can be improved.

The use of a replanted riparian habitat by the Lumholtz's Tree‐kangaroo (Dendrolagus lumholtzi)

SummaryThis study describes the use of a section of a replanted riparian wildlife corridor by Lumholtz's Tree‐kangaroo (Dendrolagus lumholtzi) (referred to here as LTK) on the Atherton Tablelands in north‐east Queensland, Australia. Selection of plants for replanting had been adjusted to the seasonally inundated clay‐rich and acid soils of the site, and, in some cases, with the aim to establish wind breaks which resulted in a plant composition of this section that differs from known LTK habitats. Through semi‐regular daily observations of individual LTKs over eight years, it was found that LTKs were most commonly recorded on Tallowwood (Eucalyptus microcorys), Rose Gum (E. grandis), Caribbean Pine (Pinus caribaea) and Bunya Pine (Araucaria bidwillii) which were planted as wind breaks in the 1950s and 1980s. On a section planted in 1998, it was found that LTKs used certain tree species more frequently than would have been expected from the relative number in which these species had been planted. This may be associated with certain structural features of the used tree species. The presence of these structural habitat features may allow LTKs to establish home ranges within the restored habitat. Home ranges were calculated for four females, and it was found that they did not differ in size from those reported from other LTK habitats. However, home ranges showed extensive overlaps. The study reveals that LTK will colonise replanted habitat and may be adaptable in its spatial requirements in a restored landscape.

Can incidental sighting data be used to elucidate habitat preferences and areas of suitable habitat for a cryptic species?

The involvement of communities in ecological studies has been shown to augment conservation efforts, especially for cryptic species. However, there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms. This study compares preferences of the Lumholtz's tree kangaroo (Dendrolagus lumholtzi; LTK), a cryptic rainforest folivore in northeastern Australia, for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent. Incidental sighting records suggest that the species uses a wider range of altitudes, annual rainfalls, annual mean temperatures and vegetation types than predicted by scientific studies. Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month. Both data place the species within a comparable range of rainfalls during the driest month, maximum temperatures of the warmest month and soil types. When using identified preferences to assess the extent and distribution of suitable habitat, incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91% between them. The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.

Current knowledge of the behavioural ecology of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi)

Behavioural ecology increasingly contributes to effective species conservation. It provides a better understanding of habitat requirements and landscape use of a species. In this review the current knowledge of the behavioural ecology of the Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is summarised. It describes how the species utilises a structurally diverse environment such as rainforest with respect to its climbing abilities and the consumption of partly toxic rainforest foliage. It presents the latest findings on the use of non-rainforest habitats by this species, how it copes with highly fragmented landscapes within its distribution and the evolutionary bases of its antipredatory behaviours. Available information on home ranges of D. lumholtzi in various habitats is compiled and supplemented by our sparse knowledge of conspecific interactions of this species. The review shows how limited our current knowledge on the behavioural ecology of this species is, and how this knowledge should be integrated into conservation efforts for this species, and aims at encouraging more research in this field.

Exploring the use of a fragmented landscape by a large arboreal marsupial using incidental sighting records from community members

Effective conservation of large mammalian species within a human-modified landscape depends on the knowledge of their ability to utilise available suitable habitat within a matrix of unsuitable habitat. We use incidental sightings of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) in north-eastern Australia that were recorded by community members in a non-standardised way to assess the functional connectivity of the highly fragmented landscape of the Atherton Tablelands for this species. By applying spatial analytical tools to available mapped information on landscape attributes and the reported sightings it was found that the species shows a low matrix resistance. Since most sightings within the matrix were found within 150 m of a patch with suitable habitat and the average distance between these patches was 77 m it can be concluded that Lumholtz’s tree-kangaroos are able to reach most fragmented suitable habitat given certain limitations of the accuracy of the used maps and sighting locations. Based on distances between suitable habitat patches and their predominant size of up to 2 ha we expect that the species can include several fragments into its home range. More sightings of Lumholtz’s tree-kangaroos than expected by chance within the matrix during dry seasons combined with shorter than expected distances into the matrix suggests the existence of seasonal resource-driven movements of this species. Due to the non-standardised nature of the data the derived conclusions need to be tested in rigorous scientific projects before they can be integrated into the development of conservation strategies for Lumholtz’s tree-kangaroos on the Atherton Tablelands.

Studying food preferences in captive cryptic folivores can assist in conservation planning: the case of the Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi)

Food preferences of the arboreal Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi), endemic to the tropical rainforests of north-eastern Australia, are largely unknown, but are likely to affect the movements of this mammal within its home range and across a fragmented landscape. Food selection was investigated by applying a consumption ranking system to 35 browse species provided to six captive animals throughout different years. Animals consumed foliage from a wide range of rainforest tree species, but at different intensities, suggesting that Lumholtz’s tree-kangaroo is a selective folivore. All studied animals showed a general preference for the foliage of the northern olive (Chionanthus ramiflorus) and the umbrella tree (Schefflera actinophylla) throughout the year while foliage from acacias (Acacia spp.), milky pine (Alstonia scholaris) and pink ash (Alphitonia petriei) was less frequently consumed. Foliage from figs (Ficus spp.) and the northern tamarind (Diploglottis diphyllostegia) was consumed at higher rates only at certain times of the year, suggesting the existence of seasonal preferences. The knowledge of general and seasonal food preferences of this large arboreal mammal may allow a better prediction of animal movements and therefore can assist in conservation efforts. Recommendations for the integration of these findings in restoration projects are given.

Improving reliability of scat counts for abundance and distribution estimations of Lumholtz’s Tree-kangaroo (Dendrolagus lumholtzi) in its rainforest habitats.

arboreal folivores, such as Lumholtz’s Tree-kangaroo (Dendrolagus lumholtzi) in Far North Queensland, Australia, scat counts seem to be the most promising ecological technique. However, the occurrence of Lumholtz’s Tree-kangaroos in seasonal rainforests with dense understory, a high diversity of coprophagous invertebrates and with sympatric folivores increases the probability of invalidating results based on scat surveys. This study investigates scat production and scat decomposition patterns to select diagnostic traits of Lumholtz’s Tree-kangaroo scats that can, under varying environmental conditions, assist in distinguishing between fresh and old scats to reduce false positive and false negative errors in species presence due to non- or/and misidentification of scats. Scat production rates of six captive Lumholtz’s Tree-kangaroos were highly variable resulting in different scat numbers and masses. Changes in scat size (mass and circumference), pH and the appearance of mould were monitored under different laboratory conditions and in forest trials. Under wet conditions scats gained mass until they reached an apparent plateau of 130% of their original mass. Scats under dry conditions lost up to 90% of their original mass. Changes in mass were accompanied by changes in circumference of scats. By Day 3 scats had developed signs of mould under laboratory conditions and showed an acidic pH. Field trials revealed a high loss of scats due primarily to their consumption by dung beetles (Scarabaeoidea). For studying Lumholtz’s Tree-kangaroos in their rainforest environment, scat surveys should be confined to dry periods to reduce the probability of false negative errors due to activity of coprophagous invertebrates. Additionally, only fresh scats of average size and with an acidic pH should be used to minimize the risk of misidentifying small sized scats from Red-legged Pademelons (Thylogale stigmatica) as tree-kangaroo scats. More studies on species-specific diagnostic traits of Lumholtz’s Tree-kangaroo scats are necessary to validate false negative and false positive errors in scat counts for this species.

Anatomical adaptations of the hind limb musculature of tree-kangaroos for arboreal locomotion (Marsupialia : Macropodinae)

Tree-kangaroos (Dendrolagini) are Australasian marsupials that inhabit tropical forests of far north-eastern Queensland and New Guinea. The secondary adaptation of tree-kangaroos to an arboreal lifestyle from a terrestrial heritage offers an excellent opportunity to study the adaptation of the musculoskeletal system for arboreal locomotion, particularly from a template well adapted to terrestrial bipedal saltation. We present a detailed descriptive study of the hind limb musculature of Lumholtz’s tree-kangaroo (D. lumholtzi) in comparison to other macropodines to test whether the hind limb musculature of tree-kangaroos is functionally adapted to the different mechanical demands of locomotion in the uneven three-dimensional arboreal environment. The hind limb musculature of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi), the western brush wallaby (Macropus irma), the western grey kangaroo (Macropus fuliginosus) and the quokka (Setonix brachyurus) are described. The hind limb anatomy of D. lumholtzi differed from that of the terrestrial macropodines in that the muscles had a greater degree of internal differentiation, relatively longer fleshy bellies and very short, stout tendons of insertion. There was also a modified arrangement of muscle origins and insertions that enhance mechanical advantage. Differences in the relative proportions of the hind limb muscle mass between tree-kangaroos and terrestrial macropodines reflect adaptation of the limb musculature of tree-kangaroos for arboreal locomotion. The hind limb musculature of Setonix was different to that of both Dendrolagus and Macropus, possibly reflecting its more basal phylogenetic position within the Macropodinae.

Functional morphology of the forelimb of living and extinct tree‐kangaroos (Marsupialia: Macropodidae)

Tree-kangaroos are a unique group of arboreal marsupials that evolved from terrestrial ancestors. The recent discovery of well-preserved specimens of extinct tree-kangaroo species (genus Bohra) within Pleistocene cave deposits of south-central Australia provides a unique opportunity to examine adaptive evolution of tree-kangaroos. Here, we provide the first detailed description of the functional anatomy of the forelimb, a central component of the locomotor complex, in the extant Dendrolagus lumholtzi, and compare its structure and function with representatives of other extant marsupial families. Several features were interpreted as adaptations for coping with a discontinuous, uneven and three-dimensional arboreal substrate through enhanced muscular strength and dexterity for propulsion, grasping, and gripping with the forelimbs. The forelimb musculoskeletal anatomy of Dendrolagus differed from terrestrial kangaroos in the following principal ways: a stronger emphasis on the development of muscles groups responsible for adduction, grasping, and gripping; the enlargement of muscles that retract the humerus; and modified shape of the scapula and bony articulations of the forelimb bones to allow improved mobility. Many of these attributes are convergent with other arboreal marsupials. Tree-kangaroos, however, still retain the characteristic bauplan of their terrestrial ancestors, particularly with regard to skeletal morphology, and the muscular anatomy of the forelimb highlights a basic conservatism within the group. In many instances, the skeletal remains of Bohra have similar features to Dendrolagus that suggest adaptations to an arboreal habit. Despite the irony of their retrieval from deposits of the Nullarbor "Treeless" Plain, forelimb morphology clearly shows that the species of Bohra were well adapted to an arboreal habitat.

Conservation of a rare arboreal mammal: habitat preferences of the Lumholtz's tree-kangaroo, Dendrolagus lumholtzi

Success of conservation efforts of large and cryptic mammals is often limited due to a lack of knowledge of their habitat preferences. This study investigates factors that affect the habitat selection of the rare Lumholtz’s tree-kangaroo, Dendrolagus lumholtzi, using signs of its activity. The presence and absence of scratch marks on tree trunks and faecal pellets within a 100-cm radius around them were surveyed on 23 ha within a 65-ha large fragment of rainforest on the Atherton Tablelands, north-eastern Australia in order to classify trees as ‘actively used’ or ‘inactive’. Structural features of the 315 surveyed tree trunks were also recorded. Using discriminant function analysis, ‘actively used’ trees were found to have no epiphytes on the main trunk, less obstruction by neighbouring trees, shrubs or lianas within a 0.5-m radius of the trunk (particularly in the eastern direction), and a smaller diameter at breast height than ‘inactive’ trees. Smaller tree trunks and less obstruction may facilitate a more rapid movement into the canopy as well as provide potential escape routes from predators. More specific knowledge on factors that affect habitat selection of the Lumholtz’ tree-kangaroo will help in a reclassification of the threatened status of this species and assist in more effective conservation efforts.

Long‐Term Dynamics of a Fragmented Rainforest Mammal Assemblage

Habitat fragmentation is a severe threat to tropical biotas, but its long-term effects are poorly understood. We evaluated longer-term changes in the abundance of larger (>1 kg) mammals in fragmented and intact rainforest and in riparian "corridors" in tropical Queensland, with data from 190 spotlighting surveys conducted in 1986-1987 and 2006-2007. In 1986-1987 when most fragments were already 20-50 years old, mammal assemblages differed markedly between fragmented and intact forest. Most vulnerable were lemuroid ringtail possums (Hemibelideus lemuroides), followed by Lumholtz's tree-kangaroos (Dendrolagus lumholtzi) and Herbert River ringtail possums (Pseudocheirus herbertensis). Further changes were evident 20 years later. Mammal species richness fell significantly in fragments, and the abundances of 4 species, coppery brushtail possums (Trichosurus vulpecula johnstoni), green ringtail possums (Pseudochirops archeri), red-legged pademelons (Thylogale stigmatica), and tree-kangaroos, declined significantly. The most surprising finding was that the lemuroid ringtail, a strict rainforest specialist, apparently recolonized one fragment, despite a 99.98% decrease in abundance in fragments and corridors. A combination of factors, including long-term fragmentation effects, shifts in the surrounding matrix vegetation, and recurring cyclone disturbances, appear to underlie these dynamic changes in mammal assemblages.

Impacts of Cyclone Larry on arboreal folivorous marsupials endemic to upland rainforests of the Atherton Tableland, Australia

Abstract Intense cyclones might be expected to adversely affect populations of arboreal mammals, either directly or as a consequence of the destruction of food resources and other key habitat elements. However, such impacts have rarely been quantified. The present study examined the response of five species of arboreal folivorous marsupials to Severe Cyclone Larry at nine sites in upland rainforests of the Atherton Tableland, north‐east Australia. Sites were originally surveyed for folivores in 1995–1997, and then resurveyed in 2006, 6–8 months after Cyclone Larry had traversed the region. All sites showed evidence of structural damage to vegetation, but overall damage levels (assessed in terms of canopy cover, damage to trees, basal area of dead trees and volume of woody debris) decreased from east to west across the study region. The detectability of rainforest possums increased after the cyclone. For the most commonly observed species, the proportion of individuals observed >5 m from survey transects was correlated with the amount of structural damage to vegetation. To avoid confounding changes in detectability with changes in abundance, only observations close (<5 m) to transects were used to estimate folivore abundance before and after the cyclone. On this basis, there were no significant differences between pre‐ and post‐cyclone abundance estimates for any folivore species. Further, changes in folivore abundance after the cyclone were not correlated with damage to vegetation across sites. Cyclone Larry does not appear to have caused a catastrophic loss of key habitat resources for marsupial folivores at the sites surveyed. The high degree of folivory practiced by marsupial folivores may help make them resilient to cyclone impacts. These conclusions are more robust for three commonly observed folivore species (Hemibelideus lemuroides, Pseudochirulus herbertensis and Trichosurus vulpecula johnstonii) than for two less frequently encountered species (Pseudochirops archeri and Dendrolagus lumholtzi).