Wet Tropics Bioregion Research Articles

New records and range extensions for liverworts (Marchantiophyta) in the Australian Wet Tropics bioregion

Three species of liverworts are reported as new to Australia, all from the Australian Wet Tropics bioregion: Colura corynophora, Drepanolejeunea serricalyx, and D. tricornua. Significant range extensions within the bioregion are reported for another two species. Cololejeunea kapingaensis, previously reported as ramicolous, is here reported as an epiphyll.

Camera‐trapping density estimates suggest critically low population sizes for the Wet Tropics subspecies of the spotted‐tailed quoll (Dasyurus maculatus gracilis)

AbstractAccurate estimates of distribution and population density are critical for the management of threatened species. This is particularly pertinent for mammalian predators, whose generally low population density, elusive nature, and large home range requirements make it difficult to detect declines. We aimed to refine population estimates of the northern spotted‐tailed quoll (Dasyurus maculatus gracilis) in the Wet Tropics bioregion, to estimate the total number of adults, the likely size of subpopulations across the known distribution of the subspecies, and its associated conservation status. We performed targeted upland camera‐trapping surveys from June 2017 to May 2019. To calculate population densities, we used a combination of the number of individuals identified from each survey and the mean maximum distance moved from three life history stages. We then extrapolated these estimates to modelled suitable habitat areas, refined by the camera‐trapping surveys. Population sizes for the six defined subpopulations were estimated, and ranged from approximately 5 to 105 individuals. The total population was estimated to be 221 individuals. This total population estimate, and the estimates for each of the subpopulations, are lower than previous published estimates and are cause for concern. Given the low population estimates presented here and unresolved threats driving declines in some subpopulations, we suggest elevation of this subspecies to Critically Endangered under the EPBC Act.

<i>Corrigendum to</i>: White-footed dunnarts (<i>Sminthopsis leucopus</i>) in Queensland’s Wet Tropics, with the description of a new subspecies

A population of white-footed dunnarts (<i>Sminthopsis leucopus</i>) occurs in the Wet Tropics bioregion of tropical north Queensland, Australia separated by about 1800 km from conspecifics in temperate New South Wales, Victoria and Tasmania. We conducted targeted surveys for <i>S. leucopus</i> in north-east Queensland and obtained new records, including the first reported capture of the species in Queensland in 18 years. We assessed the genetic and morphological divergence of the north Queensland population against New South Wales, Victorian and Tasmanian <i>S. leucopus</i>, in conjunction with distribution and habitat differences, to assess whether this isolate should be described as a distinct taxon. Sequencing of the mitochondrial Cytochrome <i>b</i> gene revealed genetic divergence estimates of 2.3–2.8% and 4.3–4.8% between the north Queensland population and <i>S. l. ferruginifrons</i> (Victoria) and <i>S. l. leucopus</i> (Tasmania) respectively. Based on genetic divergence, cranial morphology, differences in habitat, and geographical isolation, we describe the north Queensland population as a new subspecies of <i>Sminthopsis leucopus</i>. We suggest a conservation classification of Endangered given its small distribution, apparent low density, tropical upland location and potential threats, especially related to climate change.

Species distribution modelling of the endangered Mahogany Glider (Petaurus gracilis) reveals key areas for targeted survey and conservation

AbstractThe Mahogany Glider (Petaurus gracilis) is one of the most endangered marsupials in Australia. Its known distribution is an approximately 120 km strip of fragmented coastal woodland in north‐east Queensland, from north of Townsville to the Tully area. Records are clustered in a number of well‐surveyed areas, with significant areas of lowland habitat unsurveyed. Around 30% of historic records fall in areas that were subsequently cleared for farmland, and ongoing clearing and fragmentation of lowland sclerophyll forest continues within the potential distribution. Resolving the distribution is an urgent requirement to guide conservation but Mahogany Gliders are difficult to detect in the field. Species distribution modelling offers a technique for estimating the fine‐scale distribution and for targeting further field survey and conservation efforts. We used known occurrence records (N = 481) to predict the distribution of Mahogany Gliders across the Wet Tropics bioregion. We used climatic, topographic and other environmental predictors to generate distribution models using Maxent and Random Forest algorithms, each with two bias correction methods. The predictions revealed that many unknown populations may exist within the currently defined distribution and in important areas beyond this (e.g. Hinchinbrook Island). There was reasonable congruence between models, and we include syntheses of the models to present the most likely current distribution. The most important predictor variables across the models were precipitation seasonality (high seasonality), elevation (generally <100 m), soil type (hydrosols) and vegetation type (including Eucalyptus and Melaleuca woodlands). Our results identify core habitat and reveal key areas that require targeted field surveys. Importantly, the predicted suitable habitat is highly fragmented and ongoing conservation efforts need to improve habitat connectivity and limit further fragmentation.

Xylosma craynii (Salicaceae), a new and restricted species for Queensland's Wet Tropics Bioregion

Xylosma craynii W.E.Cooper is newly described from the Wet Tropics bioregion of north-eastern Queensland. The new species is illustrated and notes on habitat and distribution are provided.

Reinstatement and revision of Kayea Wall. (Calophyllaceae) in Australia, including two new species from Queensland’s Wet Tropics bioregion

Reinstatement and revision of Kayea Wall. (Calophyllaceae) in Australia, including two new species from Queensland’s Wet Tropics bioregion

Climate Change Affects Reproductive Phenology in Lianas of Australia’s Wet Tropics

Lianas are increasing in abundance in many tropical forests. This increase can alter forest structure and decrease both carbon storage and tree diversityviaantagonistic relationships between lianas and their host trees. Climate change is postulated as an underlying driver of increasing liana abundances,viaincreases in dry-season length, forest-disturbance events, and atmospheric CO2concentrations; all factors thought to favour lianas. However, the impact of climate change on liana reproductive phenology, an underlying determinant of liana abundance, has been little studied, particularly outside of Neotropical forests. Over a 15-year period (2000–2014), we examined the phenological patterns of a liana community in intact rainforests of the Wet Tropics bioregion of Australia; a World Heritage Area and hotspot of floral diversity. Specifically, we assessed (1) flowering and fruiting patterns of liana species; (2) potential climate drivers of flowering and fruiting activity; and (3) the influence of El Niño-related climatic disturbances on liana phenology. We found that flowering and fruiting of the studied liana species increased over time. Liana reproduction, moreover, rose in apparent response to higher temperatures and reduced rainfall. Finally, we found flowering and fruiting of the liana species increased following El Niño events. These results suggest that liana reproduction and abundance are likely to increase under predicted future climate regimes, with potentially important impacts on the survival, growth, and reproduction of resident trees and thus the overall health of Australian tropical rainforests.

<i>Corrigendum to</i>: John Dallachy (1804–71): from gardener to botanical collector

The citation ‘Rockingham Bay, J. Dallachy’ is prominent in late nineteenth-century taxonomic publications associated with the flora of tropical Queensland. John Dallachy (1804–71) was employed as a botanical collector by the Melbourne Botanic Garden under the directorship of Baron Ferdinand von Mueller. Between 1864 and 1871, Dallachy resided in the Rockingham Bay area where he collected ~3500 botanical specimens of which ~400 were described as new taxa of flowering plants, ferns, fungi and bryophytes, making him Mueller's most prolific collector of type specimens, apart from Mueller himself. In this, the first of two articles about Dallachy, we outline the origin, and development of this successful botanical collaboration, identifying the experiences and qualities that prompted Dallachy to become a botanical collector, the friendship that formed between Mueller and Dallachy in the face of Dallachy's reversal of fortunes at the Melbourne Botanic Garden, and the circumstances that led to Dallachy and Mueller's shared project to investigate the botanical riches of the floristically diverse Wet Tropics Bioregion.

White-footed dunnarts (

A population of white-footed dunnarts (Sminthopsis leucopus) occurs in the Wet Tropics bioregion of tropical north Queensland, Australia separated by about 1800 km from conspecifics in temperate New South Wales, Victoria and Tasmania. We conducted targeted surveys for S. leucopus in north-east Queensland and obtained new records, including the first reported capture of the species in Queensland in 18 years. We assessed the genetic and morphological divergence of the north Queensland population against New South Wales, Victorian and Tasmanian S. leucopus, in conjunction with distribution and habitat differences, to assess whether this isolate should be described as a distinct taxon. Sequencing of the mitochondrial Cytochrome b gene revealed genetic divergence estimates of 2.3–2.8% and 4.3–4.8% between the north Queensland population and S. l. ferruginifrons (Victoria) and S. l. leucopus (Tasmania) respectively. Based on genetic divergence, cranial morphology, differences in habitat, and geographical isolation, we describe the north Queensland population as a new subspecies of Sminthopsis leucopus. We suggest a conservation classification of Endangered given its small distribution, apparent low density, tropical upland location and potential threats, especially related to climate change.

Long-term changes in populations of rainforest birds in the Australia Wet Tropics bioregion: A climate-driven biodiversity emergency.

Many authors have suggested that the vulnerability of montane biodiversity to climate change worldwide is significantly higher than in most other ecosystems. Despite the extensive variety of studies predicting severe impacts of climate change globally, few studies have empirically validated the predicted changes in distribution and population density. Here, we used 17 years (2000–2016) of standardised bird monitoring across latitudinal/elevational gradients in the rainforest of the Australian Wet Tropics World Heritage Area to assess changes in local abundance and elevational distribution. We used relative abundance in 1977 surveys across 114 sites ranging from 0-1500m above sea level and utilised a trend analysis approach (TRIM) to investigate elevational shifts in abundance of 42 species. The local abundance of most mid and high elevation species has declined at the lower edges of their distribution by >40% while lowland species increased by up to 190% into higher elevation areas. Upland-specialised species and regional endemics have undergone dramatic population declines of almost 50%. The “Outstanding Universal Value” of the Australian Wet Tropics World Heritage Area, one of the most irreplaceable biodiversity hotspots on Earth, is rapidly degrading. These observed impacts are likely to be similar in many tropical montane ecosystems globally.

Arboreality drives heat tolerance while elevation drives cold tolerance in tropical rainforest ants.

Determining how species thermal limits correlate with climate is important for understanding biogeographic patterns and assessing vulnerability to climate change. Such analyses need to consider thermal gradients at multiple spatial scales. Here we relate thermal traits of rainforest ants to microclimate conditions from ground to canopy (microgeographic scale) along an elevation gradient (mesogeographic scale) and calculate warming tolerance to assess climate change vulnerability in the Australian Wet Tropics Bioregion. We test the thermal adaptation and thermal niche asymmetry hypotheses to explain interspecific patterns of thermal tolerance at these two spatial scales. We tested cold tolerance (CTmin ), heat tolerance (CTmax ), and calculated thermal tolerance range (CTrange ), using ramping assays for 74 colonies of 40 ant species collected from terrestrial and arboreal habitats at lowland and upland elevation sites and recorded microclimatic conditions for one year. Within sites, arboreal ants were exposed to hotter microclimates and on average had a 4.2°C (95% CI: 2.7-5.6°C) higher CTmax and 5.3°C (95% CI: 3.5-7°C) broader CTrange than ground-dwelling ants. This pattern was consistent across the elevation gradient, whether it be the hotter lowlands or the cooler uplands. Across elevation, upland ants could tolerate significantly colder temperatures than lowland ants, whereas the change in CTmax was less pronounced, and CTrange did not change over elevation. Differential exposure to microclimates, due to localized niche preferences, drives divergence in CTmax , while environmental temperatures along the elevation gradient drive divergence in CTmin . Our results suggest that both processes of thermal adaptation and thermal niche asymmetry are at play, depending on the spatial scale of observation, and we discuss potential mechanisms underlying these patterns. Despite the broad thermal tolerance range of arboreal rainforest ants, lowland arboreal ants had the lowest warming tolerance and may be most vulnerable to climate change.

Floral attraction and flower visitors of a subcanopy, tropical rainforest tree, Fontainea picrosperma.

Flowering plants in tropical rainforests rely heavily on pollen vectors for successful reproduction. Research into pollination systems in tropical rainforests is dominated by canopy species, while subcanopy plant–pollinator interactions remain under‐represented. The microclimate beneath the rainforest canopy is characterized by low light levels and is markedly different from the canopy environment that receives more light energy.We studied the floral attractants and floral visitors of a dioecious, subcanopy tree, Fontainea picrosperma (Euphorbiaceae), in the Wet Tropics bioregion of northern Queensland, Australia.We found that wind pollination is rare and male and female flowers do not produce nectar. Female flowers are likely pollinated due to their perceptual similarity to pollen‐offering male flowers. Female flowers had the same scent profile as male flowers, and floral scent was an important floral attractant that acted to regulate pollinator behavior. The two most abundant scent compounds present in the floral bouquet were benzyl alcohol and 4‐oxoisophorone. These compounds are ubiquitous in nature and are known to attract a wide variety of insects. Both day‐time and night‐time pollinators contributed to successful pollen deposition on the stigma, and diurnal flower visitors were identified from several orders of insects including beetles, flies, predatory wasps, and thrips. Fontainea picrosperma is therefore likely to be pollinated by a diverse array of small insects.Synthesis. Our data indicate that F. picrosperma has a generalist, entomophilous pollination syndrome. The rainforest subcanopy is a distinctive environment characterized by low light levels, low or turbulent wind speeds, and relatively high humidity. Female flowers of F. picrosperma exhibit cost‐saving strategies by not producing nectar and mimicking the smell of reward‐offering male flowers. Insects opportunistically forage on or inhabit flowers, and pollination occurs from a pool of small insects with low energy requirements that are found beneath the rainforest canopy.

Camptochaete monolina sp. nov. and Camptochaete subporotrichoides (Bryophyta: Lembophyllaceae) from the Australian Wet Tropics

Camptochaete monolina sp. nov. is described from three collections in the Australian Wet Tropics bioregion. Camptochaete subporotrichoides (Broth. & Geh.) Broth. (Bryophyta: Lembophyllaceae), previously known from Indonesia, Papua New Guinea, Vanuatu, Solomon Islands and Fiji, is reported as new to Australia from several collections in the same bioregion.

Diversity and Distribution of the Dominant Ant Genus Anonychomyrma (Hymenoptera: Formicidae) in the Australian Wet Tropics

Anonychomyrma is a dolichoderine ant genus of cool-temperate Gondwanan origin with a current distribution that extends from the north of southern Australia into the Australasian tropics. Despite its abundance and ecological dominance, little is known of its species diversity and distribution throughout its range. Here, we describe the diversity and distribution of Anonychomyrma in the Australian Wet Tropics bioregion, where only two of the many putative species are described. We hypothesise that the genus in tropical Australia retains a preference for cool wet rainforests reminiscent of the Gondwanan forests that once dominated Australia, but now only exist in upland habitats of the Wet Tropics. Our study was based on extensive recent surveys across five subregions and along elevation and vertical (arboreal) gradients. We integrated genetic (CO1) data with morphology to recognise 22 species among our samples, 20 of which appeared to be undescribed. As predicted, diversity and endemism were concentrated in uplands above 900 m a.s.l. Distribution modelling of the nine commonest species identified maximum temperature of the warmest month, rainfall seasonality, and rainfall of the wettest month as correlates of distributional patterns across subregions. Our study supported the notion that Anonychomyrma radiated from a southern temperate origin into the tropical zone, with a preference for areas of montane rainforest that were stably cool and wet over the late quaternary.

Integrating freshwater wetland science into planning for Great Barrier Reef sustainability

Abstract The paper ‘Biodiversity values of remnant freshwater floodplain lagoons in agricultural catchments: evidence for fish of the Wet Tropics bioregion, northern Australia’, published in Aquatic Conservation: Marine and Freshwater Ecosystems in 2015, has contributed in several ways to the integration of freshwater wetland science within new catchment management policies and practices for Great Barrier Reef (GBR) sustainability. The Tully–Murray biodiversity study developed novel protocols to sample larval, juvenile, and adult fish life‐history stages in floodplain lagoons using a combination of boat‐based backpack electrofishing and fyke netting. In addition, hydrological and hydrodynamic models were applied in a completely new way to quantify the timing, extent, and duration of water connectivity across floodplain streams, cane drains, and wetlands. Combining the two novel approaches enabled an analysis of lagoon fish assemblage patterns in relation to environmental gradients, especially floodplain hydrology, connectivity patterns, and measures related to agricultural land use. In demonstrating the importance of different levels of connectivity for different biodiversity outcomes in freshwater floodplain lagoons of the Tully–Murray catchment, the subject paper established that floodplain connectivity needs to be taken into consideration in wetland management practices. The timing of the subject publication was fortuitous. It coincided with the preparation of the evidence‐based 2017 Scientific Consensus Statement on land‐based water quality impacts on the GBR. As one of the few freshwater wetland ecology publications for the catchments of the GBR at that time, this paper played an important role in demonstrating freshwater wetland values, fish conservation options, and management imperatives to sustain wetland ecological health and services in GBR catchments. By advancing the understanding of factors driving biodiversity patterns, and the importance of connectivity and ecohydrological processes in freshwater floodplain wetlands of the GBR catchment, the Tully–Murray study helped to drive new policy directives for the protection and restoration of catchment, floodplain, and estuary functions, and connectivity, now embedded in the Reef 2050 Long‐Term Sustainability Plan 2018, an overarching strategy for managing the GBR over the next 35 years, and complementary Queensland environmental legislation.

Stemmatostoma cribbi n. sp. (Digenea: Cryptogonimidae) from Freshwater Fishes in the Wet Tropics Bioregion of Queensland, Australia.

A survey of the parasite fauna of freshwater fishes from the Wet Tropics Bioregion in Queensland, Australia, revealed the presence of a new species of Stemmatostoma Cribb, 1986 (Digenea: Cryptogonimidae). Stemmatostoma cribbi n. sp. is described from the intestine and pyloric caeca of 2 species of grunter (Terapontidae), Hephaestus fuliginosus (Macleay) and Hephaestus tulliensis (De Vis), and the Jungle perch (Kuhliidae), Kuhlia rupestris (Lacepède), collected from the Barron and Mulgrave-Russell River drainage divisions in tropical north Queensland, Australia. Stemmatostoma cribbi is primarily distinguished morphologically from the type and only other species in the genus, Stemmatostoma pearsoni Cribb, 1986, in having consistently fewer oral spines (14 in S. cribbi vs. 16 in S. pearsoni). Alignment of novel molecular data for S. cribbi and S. pearsoni revealed that they differ genetically by 26 nucleotides (2.1%) over the 1,258 bp partial large subunit (LSU) region, 1 nucleotide (0.8%) over the 121 bp partial 5.8S region, and 23 nucleotides (7.2%) over the entire 318 bp ITS2 rDNA region. Bayesian inference and maximum likelihood phylogenetic analyses of the partial LSU region for the species of Stemmatostoma sequenced here were used to explore the relationships of these species to other cryptogonimid species reported from freshwater ecosystems.

Distribution and diet of feral cats (Felis catus) in the Wet Tropics of north-eastern Australia, with a focus on the upland rainforest

Abstract ContextFeral cats have been identified as a key threat to Australia’s biodiversity, particularly in arid areas and tropical woodlands. Their presence, abundance and potential impacts in rainforest have received less attention. AimsTo investigate the distribution and diet of feral cats (Felis catus) in upland rainforest of the Wet Tropics. MethodsWe collated available occurrence records from the Wet Tropics, and data from upland camera-trapping surveys over an 8-year period, to assess geographic and elevational distribution of feral cats in the bioregion. We also assessed the diet of feral cats from scats collected at upland sites. Key resultsFeral cats are widespread through the Wet Tropics bioregion, from the lowlands to the peaks of the highest mountains (>1600m), and in all vegetation types. Abundance appears to vary greatly across the region. Cats were readily detected during camera-trap surveys in some upland rainforest areas (particularly in the southern Atherton Tablelands and Bellenden Ker Range), but were never recorded in some areas (Thornton Peak, the upland rainforest of Windsor Tableland and Danbulla National Park) despite numerous repeated camera-trap surveys over the past 8 years at some of these sites. Scat analysis suggested that small mammals comprise ~70% of the diet of feral cats at an upland rainforest site. Multivariate analysis could not detect a difference in mammal community at sites where cats were detected or not. ConclusionsFeral cats are widespread in the Wet Tropics and appear to be common in some upland areas. However, their presence and abundance are variable across the region, and the drivers of this variability are not resolved. Small mammals appear to be the primary prey in the rainforest, although the impacts of cats on the endemic and threatened fauna of the Wet Tropics is unknown. ImplicationsGiven their documented impact in some ecosystems, research is required to examine the potential impact of cats on Wet Tropics fauna, particularly the many upland endemic vertebrates. Studies are needed on (1) habitat and prey selection, (2) population dynamics, and (3) landscape source–sink dynamics of feral cats in the Wet Tropics.

John Dallachy (1804–71): from gardener to botanical collector

The citation ‘Rockingham Bay, J. Dallachy’ is prominent in late nineteenth-century taxonomic publications associated with the flora of tropical Queensland. John Dallachy (1804–71) was employed as a botanical collector by the Melbourne Botanic Garden under the directorship of Baron Ferdinand von Mueller. Between 1864 and 1871, Dallachy resided in the Rockingham Bay area where he collected ~3500 botanical specimens of which ~400 were described as new taxa of flowering plants, ferns, fungi and bryophytes, making him Mueller’s most prolific collector of type specimens, apart from Mueller himself. In this, the first of two articles about Dallachy, we outline the origin, and development of this successful botanical collaboration, identifying the experiences and qualities that prompted Dallachy to become a botanical collector, the friendship that formed between Mueller and Dallachy in the face of Dallachy’s reversal of fortunes at the Melbourne Botanic Garden, and the circumstances that led to Dallachy and Mueller’s shared project to investigate the botanical riches of the floristically diverse Wet Tropics Bioregion.

A Revised Checklist of the Moss Flora of the Australian Wet Tropics

The Australian Wet Tropics bioregion is a hotspot for bryophyte diversity. In 2004, 397 moss taxa were known from the bioregion, since when extensive field work and taxonomic studies have added many taxa to the Wet Tropics bryophyte flora, while revisions and nomenclatural changes have reduced the number previously published. In this paper we summarise the additions to our knowledge of Wet Tropics bryophytes, and accept 410 moss taxa from the bioregion, including 170 genera in 60 families. We add 55 taxa to the flora, and 24 are rejected on the basis of false records or misidentifications, or because the records were found to be outside the Wet Tropics bioregion. Records of 14 taxa from the bioregion are considered uncertain, and 6 taxa previously considered doubtful for the bioregion are confirmed. A number of records including Holomitrium cylindraceum and Taxithelium lindbergii are reported as new to Australia.

A review of Austrocallerya and Pongamia (Leguminosae subfamily Papilionoideae) in Australia, and the description of a new monotypic genus, Ibatiria

A review of Austrocallerya J.Compton & Schrire and Pongamia Adans. (Leguminosae subfamily Papilionoideae) in Australia, and the description of a new monotypic genus, Ibatiria W.E.Cooper, is presented with the support of fresh, dried, spirit-preserved specimens, molecular phylogenetic analysis of plastid and nuclear data, and illustrations. Three Austrocallerya species are confirmed, described and distinguished for Australia. Two varieties of Pongamia pinnata (L.) Pierre are recognised; P. pinnata var. minor (Benth.) Domin is reinstated and is distinguished from var. pinnata by habitat, leaflet number and width, floral bract length and bracteole length. The new genus, Ibatiria, includes a single species, Ibatiria furfuracea W.E.Cooper, from Queensland’s Wet Tropics Bioregion. A second-step lectotype is designated for Pterocarpus australis Endl., and lectotypes are designated for Wisteria megasperma F.Muell. and Pongamia glabra var. minor Benth.