Wet Tropics Bioregion Research Articles

Rediscovered or reconsidered: the presumed extinct ferns and lycophytes of tropical Queensland, Australia

The veracity of records of the 11 presumed Extinct or missing ferns and lycophytes from the Wet Tropics Bioregion of northern Queensland is investigated by examination of original materials and by intensive field searches of their recording sites. Two of the species, namely Hymenophyllum whitei and Oreogrammitis leonardii, were rediscovered. One of the species, Lastreopsis dissecta, is taxonomically problematic. Another taxon, Lindsaea pulchella var. blanda, is excluded as an erroneous record. The remaining seven species, namely Didymoglossum exiguum, Haplopteris dareicarpa, Huperzia serrata, Hymenophyllum lobbii, Lemmaphyllum accedens, Pseudodiphasium volubile and Tmesipteris lanceolata, all having been recorded by Karel Domin, appear to be questionable records and their presence in Australia requires ongoing consideration unless they are relocated or can be otherwise excluded.

A synopsis of the genus Bazzania (Marchantiophyta: Lepidoziaceae) in Australia

Thirty-five species of the liverwort genus Bazzania are recognised from Australia, including eleven endemics. The greatest diversity is in the Australian Wet Tropics bioregion in northern Queensland, where 28 species are known to exist. Keys to northern and southern Australian species are provided, and each species is described and illustrated. Bazzania uncigera (Reinw., Blume & Nees) Trevis. is newly reported for Australia.

Trade-offs for butterfly alpha and beta diversity in human-modified landscapes and tropical rainforests.

The accelerating expansion of human populations and associated economic activity across the globe have made maintaining large, intact natural areas increasingly challenging. The difficulty of preserving large intact landscapes in the presence of growing human populations has led to a growing emphasis on landscape approaches to biodiversity conservation with a complementary strategy focused on improving conservation in human‐modified landscapes. This, in turn, is leading to intense debate about the effectiveness of biodiversity conservation in human‐modified landscapes and approaches to better support biodiversity in those landscapes. Here, we compared butterfly abundance, alpha richness, and beta diversity in human‐modified landscapes (urban, sugarcane) and natural, forested areas to assess the conservation value of human‐modified landscapes within the Wet Tropics bioregion of Australia. We used fruit‐baited traps to sample butterflies and analyzed abundance and species richness in respective land uses over a one‐year period. We also evaluated turnover and spatial variance components of beta diversity to determine the extent of change in temporal and spatial variation in community composition. Forests supported the largest numbers of butterflies, but were lowest in each, alpha species richness, beta turnover, and the spatial beta diversity. Sugarcane supported higher species richness, demonstrating the potential for conservation at local scales in human‐modified landscapes. In contrast, beta diversity was highest in urban areas, likely driven by spatial and temporal variation in plant composition within the urban landscapes. Thus, while improving conservation on human‐modified landscapes may improve local alpha richness, conserving variation in natural vegetation is critical for maintaining high beta diversity.

A revision of Australian Plagiochila (Lophocoleinae: Jungermanniopsida)

Fifty-five Plagiochila species are recognized for Australia and New Zealand. Nine of these are new, all from Australia eight of which come from the Wet Tropics Bioregion of north east Queensland and one from the south-eastern mesic archipelago. Four of the new species belong in the challenging, and neglected, section Vagae. Three species are new Australian records, P. daviesiana, P. monospiris, and P. streimannii; and one species, P. alta, is a new record for New Zealand. Six species, P. annotina, P. circumdentata, P. colensoi, P. deltoidea, P. gigantea and P. ramosissima, are excluded from Australia as these are all New Zealand endemics reported in error for Australia. One New Zealand species is reported new for Australia (P. baylisii). Four species are excluded from Australia, P. furcata, P. inflata, P. renitens and P. sciophila, as they are based on misidentifications or are not supported by voucher material or both. Another interpretation of the confusion surrounding the name Plagiochila baileyana is presented, wherein Plagiochila baileyana is accepted as a species distinct from P. gigantea, while Plagiochila aculeata is returned to synonymy of P. fasciculata, and Plagiochila subfasciculata Colenso is reinstated. The number of Plagiochila species in Australia increases from 32 to 41, but the number of species in New Zealand decreases from 28 to 27 as a result of this study. New combinations at species level are also proposed for a variety of P. blepharophora from Fiji and two varieties of P. gymnoclada from Sumatra and Java, two species which morphological data suggests are grossly polyphyletic as currently circumscribed.

Extensive range contraction predicted under climate warming for a gliding mammal in north-eastern Australia

We used MaxEnt to model the current distribution of the yellow-bellied glider (Petaurus australis) and to predict the likely shift in the species’ future distribution under climate-warming scenarios in the Wet Tropics (WT) Bioregion in north Queensland and in the South-eastern Queensland (SEQld) Bioregion, which encompasses south-eastern Queensland and north-eastern New South Wales. Bioclimatic layers were used to generate models from 57 independent records in the WT and 428 records in SEQld. The modelled distribution of core habitat under current climate showed a good fit to the data, encompassing 91% and 88% of the records in each area, respectively. Modelling of future warming scenarios suggests that large contractions in distribution could occur in both bioregions. In the WT, 98% of core habitat is predicted to be lost under low warming (1°C increase) and 100% under high warming (2−3°C increase) by 2070. In SEQld, 80% of core habitat is predicted to be lost under low warming and 90% under high warming by 2070. These results suggest that this species is highly vulnerable to climate warming and highlight the importance of focusing conservation efforts at the bioregional scale. There is also a need to identify potential thermal refuges and ensure habitat connectivity.

Tree leaf trade-offs are stronger for sub-canopy trees: leaf traits reveal little about growth rates in canopy trees.

Can morphological plant functional traits predict demographic rates (e.g., growth) within plant communities as diverse as tropical forests? This is one of the most important next-step questions in trait-based ecology and particularly for global reforestation efforts. Due to the diversity of tropical tree species and their longevity, it is difficult to predict their performance prior to reforestation efforts. In this study, we investigate if simple leaf traits are predictors of the more complex ecological process of plant growth in regenerating selectively logged natural forest within the Wet Tropics (WTs) bioregion of Australia. This study used a rich historical data set to quantify tree growth within plots located at Danbulla National Park and State Forest on the Atherton Tableland. Leaf traits were collected from trees that have exhibited fast or slow growth over the last ~50yr of measurement. Leaf traits were found to be poor predictors of tree growth for trees that have entered the canopy; however, for sub-canopy trees, leaf traits had a stronger association with growth rates. Leaf phosphorus concentrations were the strongest predictor of Periodic Annual Increment (PAI) for trees growing within the sub-canopy, with trees with higher leaf phosphorus levels showing a higher PAI. Sub-canopy tree leaves also exhibited stronger trade-offs between leaf traits and adhere to theoretical predictions more so than for canopy trees. We suggest that, in order for leaf traits to be more applicable to reforestation, size dependence of traits and growth relationships need to be more carefully considered, particularly when reforestation practitioners assign mean trait values to tropical tree species from multiple canopy strata.

Revision of the Australian Wet Tropics endemic rainbowfish genus Cairnsichthys (Atheriniformes: Melanotaeniidae), with description of a new species.

The freshwater melanotaeniid genus Cairnsichthys is endemic to a relatively small area of specialised habitat within the Wet Tropics bioregion of north-eastern Queensland, Australia. It was previously considered as monotypic, including only a single species, C. rhombosomoides (Nichols Raven, 1928). The recent discovery of an apparently-isolated population in the Daintree rainforest, approximately 120 km north of the known range extent, prompted a detailed investigation of its taxonomic status using a combined lines of evidence approach. We provide compelling evidence from multiple nuclear genetic markers (52 allozyme loci), mitochondrial DNA sequence data (1141 bp cytochrome b) and morphology (examination of a suite of 38 morphometric and meristic characters) that supports north-south splitting of C. rhombosomoides. Accordingly, we describe the northern population as a distinct species, C. bitaeniatus sp. nov., on the basis of 25 specimens, 34.7-65.6 mm SL. The new species differs morphologically primarily by having a more slender and narrow shape, featuring a flatter, straighter predorsal profile and shorter second dorsal fin base; possession of slightly smaller scales, reflected in higher counts of lateral scales and predorsal scales; typically more vertebrae; and colour differences including a more robust, short black stripe across the upper operculum, a pronounced yellow patch on the anteroventral body and usually a more conspicuous second dark stripe on the lower body, with adult males generally having yellowish compared to reddish fins. We also provide a generic diagnosis for Cairnsichthys and a redescription of C.rhombosomoides. Information on the known distribution, habitats and conservation status of species in the genus is summarised, the new species being of particular concern as a narrow range endemic with specific environmental requirements.

Perceptions of Cyclone Preparedness: Assessing the Role of Individual Adaptive Capacity and Social Capital in the Wet Tropics, Australia

Given projections of future climate-related disasters, understanding the conditions that facilitate disaster preparedness is critical to achieving sustainable development. Here, we studied communities within the Wet Tropics bioregion, Australia to explore whether people’s perceived preparedness for a future cyclone relates to their: (1) perceived individual adaptive capacity (in terms of flexibility and capacity to plan and learn); and (2) structural and cognitive social capital. We found that people’s perceived cyclone preparedness was only related to their perceived individual flexibility in the face of change. Given that people’s perceived cyclone preparedness was related to individualistic factors, it is plausible that individualism-collectivism orientations influence people’s perceptions at an individual level. These results suggest that in the Wet Tropics region, enhancing people’s psychological flexibility may be an important step when preparing for future cyclones. Our study highlights the need to tailor disaster preparedness initiatives to the region in question, and thus our results may inform disaster risk management and sustainable development policies.

Two additional Chiastocaulon species (Marchantiophyta: Plagiochilaceae) from the Wet Tropics Bioregion of north-eastern Queensland

Two additional species of the liverwort genus Chiastocaulon Carl, namely, C. fasciculatum M.A.M.Renner sp. nov. and C. pachycephalum (De Not.) Herzog, are reported from two mountain tops in the north of the Queensland Wet Tropics Bioregion, namely, Mount Finnigan and Thornton Peak. Given the recent completion of a revision for Chiastocaulon in Australia, the new species provides another cogent demonstration that the bryophyte flora of the Wet Tropics Bioregion is incompletely explored and documented. The new species Chiastocaulon fasciculatum is similar to C. dendroides (Nees) Carl, but can be distinguished by leaf shape and dentition, among other characters. The leaves of C. fasciculatum are ovate and bear two or three prominent equally sized teeth, and the ventral leaf margin bears two to eight smaller teeth, whereas the leaves of C. dendroides are elliptic and bear two unequally sized teeth, the postical of which is largest, and the ventral leaf margin is entire. Chiastocaulon fasciculatum, as far as currently known, is endemic to the Wet Tropics Bioregion. Chiastocaulon pachycephalum, of which the type is from Borneo, is reported for Australia for the first time from specimens collected on Mount Finnigan.

Plectranthus laxus and P. wallamanensis (Lamiaceae): new species from tropical Queensland, Australia

Two new species of Plectranthus L’Hér. are described from tropical Queensland. Both Plectranthus laxus T.C.Wilson & P.I.Forst. and P. wallamanensis T.C.Wilson & P.I.Forst. are perennial suffrutescent shrubs found in open, exposed rocky habitats in the Wet Tropics bioregion. Both species are illustrated and notes on habitat, distribution, affinities and conservation status are provided. A revised key for Plectranthus in Queensland and the Australian tropics is presented.

Tecomanthe burungu (Bignoniaceae), a new species from northern Queensland

The new species, Tecomanthe burungu Zich & A.J.Ford (Bignoniaceae) from the Wet Tropics bioregion of north-eastern Queensland is described, illustrated and differentiated from similar and closely related taxa.

Significant range extensions and new records of mosses from tropical Australia.

We report Pleuridium nervosum and Pseudotaxiphyllum pohliaecarpum as new to the Australian Wet Tropics bioregion, and Fabronia brachyphylla and Pleuridium nervosum as new to the adjacent Einasleigh Uplands bioregion. We also report significant range extensions for other species, and new records of several very rare species.

A second species of Oristicta Tillyard (Odonata: Isostictidae)

In order to include an additional species in the genus Oristicta Tillyard, 1913, the lectotype of its sole species Oristicta filicicola Tillyard, 1913 and the holotype of Phasmosticta interposita Lieftinck, 1951, its assumed junior synonym, the original descriptions of both and numerous museum specimens identified as O. filicicola are studied and discussed. In spite of some variability being noted, it is concluded that they all are O. filicicola which is considered a monotypic species. The additional species is described as Oristicta rosendaleorum sp. nov. It is comprehensively illustrated, and its affinities are discussed. Possibly sympatric in places with O. filicicola, Oristicta rosendaleorum sp. nov. has richer black markings, lacks posterolateral processes/horns on the male’s pronotum (present in O. filicicola), and the male anal appendages are of different form. Oristicta filicicola is known from far north-eastern Queensland from Hammond Island (10.5°S) at the tip of Cape York to the Paluma Range (19°S) in the southern Wet Tropics Bioregion. Oristicta rosendaleorum sp. nov. is currently known from only two localities within 20 km of Lakeland (15.9°S) in south-eastern Cape York Peninsula.

Macromitrium erythrocomum (Bryophyta: Orthotrichaceae), a new species from tropical Queensland, Australia

Macromitrium erythrocomum sp. nov. is recorded and described from the Wet Tropics bioregion, Queensland, Australia. A comparison is made with other Macromitrium species in the region.

Intraspecific variation in climate‐relevant traits in a tropical rainforest lizard

AbstractAimThe exceptionally rich biodiversity found in tropical rainforest is under threat from anthropogenic climate change. We recognize the threat, yet we have little knowledge of the capacity of tropical species to adjust their climate sensitivity in response to it. One indicator of a species’ capacity to adjust to different climates is the amount of intraspecific variation observed in its climate‐relevant traits; if a climate‐relevant trait varies, and this variation is correlated with local climates, it suggests the species can adjust the trait to different conditions through either phenotypic plasticity or evolutionary adaptation. Here, we test for intraspecific variation in climate‐relevant traits in a rainforest specialist to shed light on the capacity of such species to adjust to different climates.LocationThe Wet Tropics Bioregion, Australia.MethodsWe studied 12 populations of a lizard that is a tropical rainforest specialist, the rainforest sunskink (Lampropholis coggeri), testing for intraspecific variation in four traits that are potentially important in determining a species’ climate sensitivity. The measured traits were as follows: critical thermal minimum, critical thermal maximum, thermal optimum for sprinting, and desiccation rate.ResultsWe found substantial variation both through time and across space in the measured traits, suggesting both strong plasticity and substantial geographic variation. Moreover, trait variation was correlated with local climate variables, suggesting variation reflects adjustment to local conditions.Main conclusionsIf physiological lability similar to that observed in rainforest sunskinks occurs in tropical rainforest species more generally, these taxa may not be as climatically specialized, and so not as vulnerable to climate change, as previously thought.

Fish larvae and recruitment patterns in floodplain lagoons of the Australian Wet Tropics

Floodplain lagoons in the Queensland Wet Tropics bioregion, Australia, are important and threatened habitats for fish. As part of studies to assess their ecological condition and functions, we examined patterns of occurrence of fish larvae, juveniles and adults in 10 permanent lagoons on the Tully–Murray floodplain. Lagoons contained early life-history stages of 15 of the 21 native species present, including 11 species that complete their life cycle in fresh waters and 4 that require access to saline habitats for larval development. Lagoon connectivity to the rivers, distance from the coast and flood dynamics influenced temporal variation in fish abundance, population size structures and recruitment patterns. This study and the literature show that wet, post-wet and dry-season habitats are utilised by small opportunists (e.g. Melanotaenia splendida), an equilibrium species (Glossamia aprion) and larger periodic strategists (neosilurid catfishes). Maintenance of natural seasonal patterns of flow and connectivity, and active protection of permanent floodplain lagoons from riparian and land-use disturbance, will be essential if their roles in fish recruitment are to be sustained.

Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

Ecosystem services capacity across heterogeneous forest types: understanding the interactions and suggesting pathways for sustaining multiple ecosystem services

As ecosystem services supply from tropical forests is declining due to deforestation and forest degradation, much effort is essential to sustain ecosystem services supply from tropical forested landscapes, because tropical forests provide the largest flow of multiple ecosystem services among the terrestrial ecosystems. In order to sustain multiple ecosystem services, understanding ecosystem services capacity across heterogeneous forest types and identifying certain ecosystem services that could be managed to leverage positive effects across the wider bundle of ecosystem services are required. We sampled three forest types, tropical rainforests, sclerophyll forests, and rehabilitated plantation forests, over an area of 32,000m2 from Wet Tropics bioregion, Australia, aiming to compare supply and evaluate interactions and patterns of eight ecosystem services (global climate regulation, air quality regulation, erosion regulation, nutrient regulation, cyclone protection, habitat provision, energy provision, and timber provision). On average, multiple ecosystem services were highest in the rainforests, lowest in sclerophyll forests, and intermediate in rehabilitated plantation forests. However, a wide variation was apparent among the plots across the three forest types. Global climate regulation service had a synergistic impact on the supply of multiple ecosystem services, while nutrient regulation service was found to have a trade-off impact. Considering multiple ecosystem services, most of the rehabilitated plantation forest plots shared the same ordination space with rainforest plots in the ordination analysis, indicating that rehabilitated plantation forests may supply certain ecosystem services nearly equivalent to rainforests. Two synergy groups and one trade-off group were identified. Apart from conserving rainforests and sclerophyll forests, our findings suggest two additional integrated pathways to sustain the supply of multiple ecosystem services from a heterogeneous tropical forest landscape: (i) rehabilitation of degraded forests aiming to provide global climate regulation and habitat provision ecosystem services and (ii) management intervention to sustain global climate regulation and habitat provision ecosystem services.

Building a Plant DNA Barcode Reference Library for a Diverse Tropical Flora: An Example from Queensland, Australia

A foundation for a DNA barcode reference library for the tropical plants of Australia is presented here. A total of 1572 DNA barcode sequences are compiled from 848 tropical Queensland species. The dataset represents 35% of the total flora of Queensland’s Wet Tropics Bioregion, 57% of its tree species and 28% of the shrub species. For approximately half of the sampled species, we investigated the occurrence of infraspecific molecular variation in DNA barcode loci rbcLa, matK, and the trnH-psbA intergenic spacer region across previously recognized biogeographic barriers. We found preliminary support for the notion that DNA barcode reference libraries can be used as a tool for inferring biogeographic patterns at regional scales. It is expected that this dataset will find applications in taxonomic, ecological, and applied conservation research.

Ecology of streams in a biogeographic isolate—the Queensland Wet Tropics, Australia

AbstractGlobal studies of streams are needed to develop general ecosystem and management models. We reviewed research that tested ecological models in streams of the Queensland Wet Tropics bioregion (QWT), which makes up 0.26% of Australia but supports distinctive and high biodiversity, most of which is of Gondwanan or marine origin. QWT streams have seasonal but perennial flow, high insolation, and higher diversity of riparian vegetation, invertebrates, and fish than temperate streams. Consistent physical conditions sustain biological processes through the year, and predictable wet seasons, but unpredictable floods, have shaped a resilient and opportunistic biota. Stream food webs are dominated by predators, and prey turnover is rapid. Small streams are heterotrophic and become autotrophic as canopies open in larger streams. Predation and competition influence assemblage composition most in the dry season, when habitats contract and densities increase. Riparian clearing, weed invasion, and agricultural c...