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.

Letter to the editors on termite stone lines

To the Editors,Termite activity is ubiquitous in Australia's seasonally wet tropics, and some degree of termite disturbance is inevitable in archaeological sites across this region. Our paper specifically focused on developing guidelines for identifying situations where termite activity has been sufficient to create a stone line that mimics an archaeological horizon (Smith et al., 2020). In a critique, Williams et al. (2020) arbitrarily discount the criteria we propose for discriminating between these phenomena. Here, we respond to their comments and discuss the role of luminescence dating in identifying bioturbation by termites

Nitrate Removal Performance of Denitrifying Woodchip Bioreactors in Tropical Climates

In Australia, declining water quality in the Great Barrier Reef (GBR) is a threat to its marine ecosystems and nitrate (NO3−) from sugar cane-dominated agricultural areas in the coastal catchments of North Queensland is a key pollutant of concern. Woodchip bioreactors have been identified as a potential low-cost remediation technology to reduce the NO3− runoff from sugar cane farms. This study aimed to trial different designs of bioreactors (denitrification walls and beds) to quantify their NO3− removal performance in the distinct tropical climates and hydrological regimes that characterize sugarcane farms in North Queensland. One denitrification wall and two denitrification beds were installed to treat groundwater and subsurface tile-drainage water in wet tropics catchments, where sugar cane farming relies only on rainfall for crop growth. Two denitrification beds were installed in the dry tropics to assess their performance in treating irrigation tailwater from sugarcane. All trialled bioreactors were effective at removing NO3−, with the beds exhibiting a higher NO3− removal rate (NRR, from 2.5 to 7.1 g N m−3 d−1) compared to the wall (0.15 g N m−3 d−1). The NRR depended on the influent NO3− concentration, as low influent concentrations triggered NO3− limitation. The highest NRR was observed in a bed installed in the dry tropics, with relatively high and consistent NO3− influent concentrations due to the use of groundwater, with elevated NO3−, for irrigation. This study demonstrates that bioreactors can be a useful edge-of-field technology for reducing NO3− in runoff to the GBR, when sited and designed to maximise NO3− removal performance.

Description of the female, nymph and larva and mitochondrial genome, and redescription of the male, of Ixodes barkeri Barker, 2019 (Acari: Ixodidae) from the short-beaked echidna, Tachyglossus aculeatus, with a consideration of the most suitable subgenus for this tick

Background Ixodes barkeri, a tick with a distinctive ventrolateral horn-like projection on palpal segment 1, was described in 2019 from two male ticks from the Wet Tropics of Far North Queensland, Australia. However, females lie at the core of the taxonomy and subgenus classification of Ixodes, hence we sought specimens of female ticks, successfully recovering females, plus nymphs and larvae. Mitochondrial genomes are also desirable additions to the descriptions of species of ticks particularly with regard to subgenus systematics. So, we sequenced the mt genomes of I. barkeri Barker, 2019 and the possible relatives of I. barkeri that were available to us (I. australiensis Neumann, 1904, I. fecialis Warburton & Nuttall, 1909, and I. woyliei Ash et al. 2017) with a view to discovering which if any of the subgenera of Ixodes would be most suitable for I. barkeri Barker, 2019. Results The female, nymph, larva, and mitochondrial genome of Ixodes barkeri Barker, 2019 are described for the first time and the male of I. barkeri is redescribed in greater detail than previously. So far, I. barkeri is known only from a monotreme, the short-beaked echidna, Tachyglossus aculeatus (Shaw, 1792), from the highland-rainforests of Far North Queensland, Australia. Conclusions Our phylogeny from entire mitochondrial genomes indicated that I. barkeri, and indeed I. woyliei Ash et al. 2017, another tick that was described recently, are best placed in the subgenus Endopalpiger Schulze, 1935.

Moth species richness in an upland tropical rainforest: A citizen scientist assisted study

Diversity studies on moths in Australia are rare, presenting various shortfalls in knowledge that impedes and understanding of their biodiversity values and their conservation. In particular, the Wet Tropics of Australia deserves attention, given the paucity of systematic moth surveys in the region and its World Heritage Area status. To fill this knowledge gap, we conducted a study to observe moths on 191 nights over a main one-year survey period at an upland rainforest locality, and uploaded all observations on iNaturalist. We also compiled other incidental observations in the general locality by other observers and observations outside the survey period. In total, we document 4,434 observations of moths represented by 1041 distinct moth morphospecies. Of these, 703 are formally named species of moths, 146 to genus and 255 to higher taxonomic designations above genus level. Despite the rather intensive main survey effort, our results suggest that we have yet to reach a plateau in documenting the moth species richness of the locality. Using this study as a model, we show that the iNaturalist platform serves as an effective means to document and digitally curate biodiversity values at a locality, whilst providing complete data transparency and enabling broader community engagement of citizen scientists. We recommend the use of iNaturalist for future moth inventories, and as a resource for follow up meta-analyses of regional moth diversity and distributions.

Effectiveness and recommendation of NPK-compound fertilization on maize

The development of maize plants in the wet tropics was experiencing problems due to a lack of nutrients, especially N, P, and K, so that to get optimal yield, additional nutrients are needed through NPK fertilization. This study aims to determine the effectiveness of fertilizers and provide recommendations for the appropriate dose of compound NPK fertilization (formulation 15:15:15, 20:10,10, and 15:8:10) to increase production, farming efficiency, and income of maize farmers. This research was conducted at the Experimental Farm of Indonesian cereal Research Institute, Maros from June until October 2020. This research was arranged in randomized block design with three replication. The treatment consists of five NPK- compound fertilizers with two doses of NPK+ urea combination. The comparisons were Urea (control) and Urea + SP36+KCl (standard). The results of this research were all formulations of NPK compound fertilizers (15:15:15, 20:10:10, and 15:8:10) deserve to be recommended for maize. Recommendations for applying NPK 15:15:15 compound fertilizer to maize plants are 450 kg/ha combined with 250 kg urea/ha with a yield probability of 12 t/ha. The recommendation for applying 20:10:10 NPK compound fertilizer to maize was 350 kg/ha + 200 kg urea with a yield probability of ±11 t/ha. The recommendation for giving NPK 15:8:10 compound fertilizer for maize was 450 kg/ha combined with 250 kg urea/ha with a yield probability of 11 t/ha.

The adaptive challenge of extreme conditions shapes evolutionary diversity of plant assemblages at continental scales

The tropical conservatism hypothesis (TCH) posits that the latitudinal gradient in biological diversity arises because most extant clades of animals and plants originated when tropical environments were more widespread and because the colonization of colder and more seasonal temperate environments is limited by the phylogenetically conserved environmental tolerances of these tropical clades. Recent studies have claimed support of the TCH, indicating that temperate plant diversity stems from a few more recently derived lineages that are nested within tropical clades, with the colonization of the temperate zone being associated with key adaptations to survive colder temperatures and regular freezing. Drought, however, is an additional physiological stress that could shape diversity gradients. Here, we evaluate patterns of evolutionary diversity in plant assemblages spanning the full extent of climatic gradients in North and South America. We find that in both hemispheres, extratropical dry biomes house the lowest evolutionary diversity, while tropical moist forests and many temperate mixed forests harbor the highest. Together, our results support a more nuanced view of the TCH, with environments that are radically different from the ancestral niche of angiosperms having limited, phylogenetically clustered diversity relative to environments that show lower levels of deviation from this niche. Thus, we argue that ongoing expansion of arid environments is likely to entail higher loss of evolutionary diversity not just in the wet tropics but in many extratropical moist regions as well.

Adaptive Heritage: Is This Creative Thinking or Abandoning Our Values?

Protected areas, such as natural World Heritage sites, RAMSAR wetlands and Biosphere Reserves, are ecosystems within landscapes. Each site meets certain criteria that allow it to qualify as a heritage or protected area. Both climate change and human influence (e.g., incursion, increased tourist visitation) are altering biophysical conditions at many such sites. As a result, conditions at many sites are falling outside the criteria for their original designation. The alternatives are to change the criteria, remove protection from the site, change site boundaries such that the larger or smaller landscape meets the criteria, or manage the existing landscape in some way that reduces the threat. This paper argues for adaptive heritage, an approach that explicitly recognizes changing conditions and societal value. We discuss the need to view heritage areas as parts of a larger landscape, and to take an adaptive approach to the management of that landscape. We offer five themes of adaptive heritage: (1) treat sites as living heritage, (2) employ innovative governance, (3) embrace transparency and accountability, (4) invest in monitoring and evaluation, and (5) manage adaptively. We offer the Australian Wet Tropics as an example where aspects of adaptive heritage currently are practiced, highlighting the tools being used. This paper offers guidance supporting decisions about natural heritage in the face of climate change and non-climatic pressures. Rather than delisting or lowering standards, we argue for adaptive approaches.

Cloud cooling effects of afforestation and reforestation at midlatitudes

Because of the large carbon sequestration potential, reforestation and afforestation (R&A) are among the most prominent natural climate solutions. However, while their effectiveness is well established for wet tropics, it is often argued that R&A are less advantageous or even detrimental at higher latitudes, where the reduction of forest albedo (the amount of reflected solar radiation by a surface) tends to nullify or even overcome the carbon benefits. Here, we carefully analyze the situation for R&A at midlatitudes, where the warming effects due to vegetation albedo are regarded to be almost balanced by the cooling effects from an increased carbon storage. Using both satellite data and atmospheric boundary-layer models, we show that by including cloud–albedo effects due to land–atmosphere interactions, the R&A cooling at midlatitudes becomes prevalent. This points to a much greater potential of R&A for wet temperate regions than previously considered.