Christmas Island Research Articles

Influence of Ocean Topography on Tsunami Propagation in Western Australia

Western Australia is susceptible to tsunamis from seismic sources that originate from distant sources including the Sunda Arc. Many surface and subsurface topographic ocean features are located between the Australian continent and locations where tsunamigenic earthquakes occur. These include the Venin Meinesz Seamounts (including Christmas Island) and Horizon Ridge, Exmouth, Zenith and Cuvier Plateaus. Numerical simulations of idealised tsunamigenic earthquakes along the Sunda Arc revealed that these topographic features have a large influence on the distribution of tsunami heights, propagating speeds and energy distribution. The interaction between tsunami waves and Venin Meinesz Seamounts and Horizon Ridge, located close to the earthquake locations, scatter the tsunami energy into several beams. Exmouth Plateau acts as a focusing feature to increase wave heights between North West Cape and Barrow Island whilst Cuvier Plateau deflects energy towards Shark Bay. Although Zenith Plateau has a local effect, it does not influence tsunami waves along the coast. Southwest Australia is “sheltered” from the direct effect of tsunami waves from Sunda Arc due to the combined effects of the Seamounts and Cuvier Plateau in the scattering and refraction of tsunami waves.

Index to Titles and Authors/Editors of Books Reviewed

Index to Titles and Authors/Editors of Books Reviewed

Predicting the ecosystem-wide impacts of eradication with limited information using a qualitative modelling approach.

Conservation-motivated eradications may cause unexpected perverse effects, and these undesirable consequences can be difficult to predict due to the paucity of information on species interactions. A probabilistic qualitative approach, which does not require extensive model parameterization, is becoming increasingly accepted and applied to conservation scenarios when information is limited. However, recent work has criticized this approach on philosophical grounds and proposed an alternative non-probabilistic Boolean analysis method, which circumvents the philosophical difficulties. There is a need for exploring the ability of this novel approach for informing conservation decisions. To do so, we applied the first real-world test of the non-probabilistic Boolean approach using a case study of management of Felis catus (feral cat) and Rattus rattus (black rat) on Christmas Island. We also applied the probabilistic approach as a contrast. Our modeling results showed that the probabilistic approach generated ambiguous outcomes, making it impractical to draw management recommendations. In contrast, the non-probabilistic Boolean approach revealed interpretable rules governing species responses, suggesting that while cat management alone is a risky strategy, the risk of negative effects of cat management on native species can be reduced by the addition of rat management. Thus, given limited resources, in combination with cat management it is prudent to prioritize rat management efforts in the habitats of potentially impacted native species of high concern and value. We conclude that the Boolean approach can be very useful when little information is available to model an ecological system and that it provides a way of identifying the potential risks and benefits of management strategies, enabling better informed conservation decision-making in the face of limited knowledge.

Effects of Amending Phosphatic Fertilizers with Clinoptilolite Zeolite on Phosphorus Availability and Its Fractionation in an Acid Soil

Soils of the tropics are highly weathered, acidic, and low in phosphorus (P) because of high contents of Al and Fe. Satisfactory P supply is essential to ensure optimum soil and crop productivity. Thus, there is a need for amending soils with zeolite to improve availability of P in acid soils as this mineral can fix Fe and Al instead of P. This study was undertaken to determine the transformations of P fertilizers in acid soils following application of Clinoptilolite zeolite (CZ) in laboratory (incubation) and pot trials. An acid soil was incubated with a recommended fertilization rate and a reduced amount of the existing recommended fertilization by 25% but substituting this reduction with an equivalent amount of CZ. Triple superphosphate (TSP), Egypt Rock phosphate (ERP), and Christmas Island Rock phosphate (CIRP) were used as P sources. Selected soil chemical properties, inorganic P fractions, available P, and total P of the native soil were determined before and after the laboratory and pot trials. Zea mays L. (test crop) plant dry matter production, P concentration, P uptake, and P use efficiency were also determined using standard procedures. Effects of the treatments with CZ compared to the recommended fertilization on P fixation were similar. In the laboratory study, the treatments with TSP showed lower dominance of Fe–P but more pronounced in Al–P, whereas for the RPs, Ca–P was dominant. In the pot study, Al–P, Ca–P, and Fe–P were rather pronounced in the treatments with TSP, ERP, and CIRP, respectively. There was a decrease in exchangeable Al and soil titratable acidity because of the ability of the CZ to increase soil pH. Although the availability of P was not significant with the inclusion of CZ in the incubation study, dry matter production, P concentration, P uptake, and P use efficiency in the pot trial were comparable with that of the existing/recommended fertilization, suggesting that the CZ is beneficial and could be used to reduce the P fertilizer requirement for Zea mays L. cultivation on acid soils. Regardless of type of P fertilizer, prevalence of the moderately labile P fractions (Al–P, Fe–P, and Ca–P) of the incubation and pot studies acted as slow-release P sources to contribute to long-term P release. Further studies on the potential of CZ to reduce fertilization and its effects on soil and crop productivity are essential. It is also important to determine the economic benefits of including CZ in Zea mays L. cultivation.

Effect of Christmas Island rock phosphate and rice straw compost application on soil phosphorus availability and maize (Zea maysL.) growth in a tropical acid soil of Kelantan, Malaysia

AbstractPhosphorus (P) fixation is very common in Malaysian acid soils due to the fixation of soluble inorganic P by Al and Fe under acidic soil pH conditions. Farmers tend to perform lots of liming and apply excess amount of P fertilizers in order to saturate the Al and Fe in the soil so that the plants are able to absorb the remaining P. Excessive liming and application of P fertilizers are not only not economical but also not environmentally friendly. Compost with a large surface area and pool of negative charges could be used to reduce P fixation in acidic soil. Hence, this study was carried out to assess the effect of amending Christmas Island rock phosphate (CIRP) with rice straw (RS) compost in improving soil P availability, nutrient uptake, and dry matter production of maize cultivated on a Malaysian tropical acid soil. A pot experiment was carried out in this study with the use of maize (FI hybrid sweet corn 801) as a test crop. The chemical properties of soils applied with RS compost were significantly improved (P≤ 0.05) compared to treatments without RS compost. As the soil pH increased, there was significant reduction in exchangeable acidity, Al and Fe in soil due to exchangeable Al and Fe were fixed with negatively charged functional groups of RS compost’s surfaces, thus increased the P availability and exchangeable cations in the soil applied with RS compost. There was also significantly higher N, P, and K uptake in leaf, stem, and root of maize in the treatments applied with RS compost. Application of CIRP with RS compost was found to increase the soil P availability, maize nutrient uptake, and dry matter production at the end of the pot experiment. An application rate of 15–20 t ha−1of RS compost together with 130 kg ha−1urea, 200 kg ha−1CIRP, and 67 kg ha−1muriate of potash is recommended to improve the soil NPK contents and growth ofZea maysin acidic soil.

Biogeography and emerging significance of Actinobacteria in Australia and Northern Antarctica soils

Actinobacteria play key roles in terrestrial ecosystem functioning. They contribute to global carbon cycling through the decomposition of soil organic matter, increase plant productivity and are widely known as prolific producers of bioactive compounds essential for human and animal health. The almost century-old search for new members of the Actinobacteria has so far proceeded without systematic investigation of regions where novel, diverse and abundant actinobacterial populations occur. We show that such regions are found in Australia, a dry and warm continent with highly weathered soils. Here, Actinobacteria are highly abundant and evidently well-adapted to the warm, dry soil conditions. Australian continental actinobacterial diversity is associated with physicochemical factors, especially soil pHwater, exchangeable calcium and the regional climate. Patterns of their biogeography suggest that only a small fraction of Actinobacteria have the capability of dispersing throughout the Southern Hemisphere, especially across oceans. We identified a core soil actinobacterial community across mainland Australia of 2211 OTUs which declined to 490 OTUs when Tasmania, King Island, Christmas Island and Northern Antarctica were included. These 490 OTUs mapped to three families, i.e., Gaiellaceae, Micromonosporaceae and Nocardiaceae. Agricultural disturbance reduced actinobacterial diversity, hence undisturbed soils with native vegetation may be reservoirs that enrich the actinobacterial communities in adjacent agricultural soils. Interestingly, high OTU similarities between King Island and areas in Antarctica suggest a shared evolutionary history that persists to this day. In conclusion, the abundance of diverse Actinobacteria taxa in Australian soils suggests an increasingly important function of Actinobacteria as the world's soils become warmer and drier.

Этнические процессы у китайцев и малайцев острова Рождества.

Этнические процессы у китайцев и малайцев острова Рождества.

Redrawing Wallace’s Line based on the fauna of Christmas Island, eastern Indian Ocean

AbstractBased on a comprehensive literature survey, we determined the sources of the terrestrial vertebrate species on Christmas Island, asking where they originated relative to Wallace’s Line (the southern end of the divide lies 1100 km to the east, where the Lombok Strait adjoins the eastern Indian Ocean). The two bats, Pipistrellus murrayi and Pteropus natalis, are from the west. Concerning the endemic and ‘resident’ bird species, one is from the west (Collocalia natalis), four are from the east (Accipiter fasciatus, Egretta novaehollandiae, Falco cenchroides and Ninox natalis) and the other 15 are ambiguous or indeterminate. Most of the land-locked species are also from the east: rodents Rattus macleari and Rattus nativitatis, and squamates Cryptoblepharus egeriae, Emoia nativitatis and Lepidodactylus listeria. Additionally, two have westerly origins (Crocidura trichura and Cyrtodactylus sadleiri), one is ambiguous (Emoia atrocostata) and another is unknown (Ramphotyphlops exocoeti). West-directed surface currents that flow across the eastern Indian Ocean towards Christmas Island would have facilitated most of the land-animal colonizations. We therefore suggest that Wallace’s Line be redrawn such that the landmass is placed on the Australasian side of this fundamental biogeographical boundary.

Distinct patterns of hybridization across a suture zone in a coral reef fish (Dascyllus trimaculatus).

Hybrid zones are natural laboratories for investigating the dynamics of gene flow, reproductive isolation, and speciation. A predominant marine hybrid (or suture) zone encompasses Christmas Island (CHR) and Cocos (Keeling) Islands (CKE), where 15 different instances of interbreeding between closely related species from Indian and Pacific Oceans have been documented. Here, we report a case of hybridization between genetically differentiated Pacific and Indian Ocean lineages of the three‐spot dascyllus, Dascyllus trimaculatus (Rüppell, 1829). Field observations indicate there are subtle color differences between Pacific and Indian Ocean lineages. Most importantly, population densities of color morphs and genetic analyses (mitochondrial DNA and SNPs obtained via RADSeq) suggest that the pattern of hybridization within the suture zone is not homogeneous. At CHR, both color morphs were present, mitochondrial haplotypes of both lineages were observed, and SNP analyses revealed both pure and hybrid genotypes. Meanwhile, in CKE, the Indian Ocean color morphs were prevalent, only Indian Ocean mitochondrial haplotypes were observed, and SNP analysis showed hybrid individuals with a large proportion (~80%) of their genotypes assigning to the Indian Ocean lineage. We conclude that CHR populations are currently receiving an influx of individuals from both ocean basins, with a greater influence from the Pacific Ocean. In contrast, geographically isolated CKE populations appear to be self‐recruiting and with more influx of individuals from the Indian Ocean. Our research highlights how patterns of hybridization can be different at scales of hundreds of kilometers, due to geographic isolation and the history of interbreeding between lineages.

A population genetic study of feral cats on Christmas Island

Feral and stray cats are a major threat for endemic species on Christmas Island and have been contributing to their decline. Cats were introduced to Christmas Island in 1888 and are now distributed across the whole island. We analysed the genetic population structure and diversity of feral and stray cats on Christmas Island to evaluate connectivity across the island and the possibility of discernible populations that could be targeted separately. Results indicate no differentiated population structure across the island, with cats facing no habitat obstacles to reduce their dispersal abilities across the island. We found high kin structure, suggesting individuals breeding successfully on the whole island. With the management of domestic and feral/stray cats since 2010, removal efforts targeting the whole island have successfully reduced the effective population size of feral/stray cats in the last five years. We suggest the use of various management techniques to facilitate future removal efforts, especially in areas on the island that are difficult to access.

Is Australia's Transfer and Detention of Refugees to Camps in Manus and Nauru Legitimate?

Refugee Crisis is one of the global issues over recent years. The continuous increase in the number of refugees is distressfully alarming. According to the Global Trends report of United Nations High Commissioner for Refugees (UNHCR), the world's population of refugees raised to 25.4 million at the end of 2017, out of which19.9 Million comes under the UNHCR mandate. Developing countries, despite economic instability, has hosted 85% of the refugees. Turkey, Pakistan, Uganda and Iran are the top four countries to host refugees, respectively. Whereas, on the contrary, Australia is the only country which is not only sceptical in hosting refugees but also, detain them on the offshore camps of Nauru and Manus and Christmas Island. The detention camps, where Human Rights abuses are at its peak. The objective of this essay is to investigate the reasons for the Australian white supremacy policies on the borders; as well as the legitimacy of transferring and detaining refugees to the offshore detention centres in the name of so-called operation sovereign borders. Also, exploring the mindset of inhuman treatment with the refugees as well as asylum seekers in the off-shore detention where the officials lack evidential justifications for such treatment; focusing mainly on the detention centres of Nauru and Manus.

Новый вид Physarum (Myxomycetes) c острова Рождества (Австралия)

A new species of Physarum (Myxomycetes), described herein as P. australiense, appeared on a sample of aerial litter in a moist chamber culture prepared as part of a survey of the myxomycetes of Christmas Island in the Indian Ocean. The morphology of representative sporocarps was examined by light and scanning electron microscopy, and micrographs of relevant morphological details of sporocarps and spores are provided. The species is characterized by distinct and unique morphological features, including brownish-red lime knobs or large squamae on the surface of the single layered peridium, a limeless brittle, black stalk, a large clavate columella that attains the center of the sporotheca, and a capillitium with large white angular or rod-like nodes. The combination of these characteristics makes P. australiense a well-defined morphospecies when compared to all other species of Physarum. In addition to the morphological description, partial sequences of three genetic markers of this new species (SSU, EF1α, and COI) were obtained and submitted to GenBank. Phylogeny, based on the small ribosomal subunit gene (SSU), indicates an affinity of the new species with P. bogoriense and P. hongkongense.

Redescription of a poorly known insular spider Labahitha gibsonhilli (Araneae: Filistatidae)

An illustrated redescription of Labahitha gibsonhilli (Savory, 1943) known only from two syntype females from Christmas Island, is given. The species is re-diagnosed and the lectotype and paralectotype are designated. Labahitha gibsonhilli differs from L. oonopiformis (Bristowe, 1938), the only other known congener, in having a reversed-cordate sternum, as well as in the shape of the receptacles.

Time of re-emergence of Christmas Island and its biogeographical significance

Christmas Island in the eastern Indian Ocean forms the pinnacle of a once-drowned, coral atoll. Exactly when the seamount re-emerged above the seas is, unfortunately, imprecisely understood. One of the consequences of this uncertainty is that it can hamper studies dealing with its land-locked faunal assemblage. We attempt to address this issue using geological and geophysical information. A first constraint is provided by sub-aerially erupted volcanic rocks that accumulated on a karstified land-surface. Radiometric ages for five associated basalt samples yield a mean of 4.39 ± 0.08 Ma (2σ). These data, together with the geological observations, indicate that the island existed in the mid-Early Pliocene. A second constraint is provided by the seamount's postulated uplift path as it ascended the outer-trench high on its journey towards the subduction zone south of Java. Here, the edifice is estimated to have become sub-aerial between 5.66 and 4.49 Ma (5.03 + 0.63/−0.54 Ma). In terms of biogeography, landmass emergence in the latest Miocene-Early Pliocene is largely concordant with the island's native land-locked reptile and mammal species (eight of the nine extant and recently extirpated forms are endemic) as most show only small to negligible levels of genetic differentiation with respect to their nearest off-island relatives. Significantly, though, molecular-clock data for at least two, possibly three, of the lizard species indicate that they split from their nearest living congeners (incidentally, all from lands to the east of the Wallace Line >1100 km away) prior to Christmas Island's emergence, that is in the Late Miocene or earlier (specifically at c. 7 Ma, c. 13 Ma and c. 26 Ma). Assuming the ages are reliable, these dichotomies could be explained if there are/were intermediate relatives that exist elsewhere/are now-extinct as this would facilitate the ancestors of the Christmas Island species colonizing the landmass sometime in the last five million years or so.

Sekresi Asam-asam Organik oleh Aspergillus niger YD 17 yang Ditumbuhkan dengan Batuan Fosfat

Information on ability of Aspergillus niger to secrete organic acid is important in using A. niger as phosphate rock-solubilizing microorganism. This research was aimed to examine the ability of A. niger YD 17 secreting organic acid when it was grown with phosphate rock. An A. niger YD 17 was obtained from Laboratory of Microbiology, Faculty of Agriculture, GMU. The phosphate rock used was Christmas Island phosphate rock. Organic materials consisted of tapioca waste industry, rice bran, and starch. The study was conducted in Pikovskaya liquid medium and soils that were taken from Jasinga, Banten, West Java (ultisol) and Karang Jati, Ungaran, Central Java (inceptisol). The type and level of organic acid production were determined using high performance liquid chromatography (HPLC). The results indicated that A. niger YD 17 was able to secrete organic acid when it was grown with phosphate rock. The level of organic acid in the Pikovskaya liquid medium reached 255.7 g.ml-1, whereas in the soil reached 2992.5 g.g-1. Malate dominated organic acid in the Pikovskaya liquid medium, while in the soils dominated by oxalate. The type and level of organic acid secreted by A. niger YD 17 were influenced by carbon and phosphorus sources, concentration of inoculums, and characteristic of the soils.

Collaborative conservation planning: Quantifying the contribution of expert engagement to identify spatial conservation priorities

AbstractThe importance of expert input to spatial conservation prioritization outcomes is poorly understood. We quantified the impacts of refinements made during consultation with experts on spatial conservation prioritization of Christmas Island. There was just 0.57 correlation between the spatial conservation priorities before and after consultation, bottom ranked areas being most sensitive to changes. The inclusion of a landscape condition layer was the most significant individual influence. Changes (addition, removal, modification) to biodiversity layers resulted in a combined 0.2 reduction in correlation between initial and final solutions. Representation of rare species in top ranked areas was much greater after expert consultation; representation of widely distributed species changed relatively little. Our results show how different inputs have notably different impacts on the final plan. Understanding these differences helps plan time and resources for expert consultation.

Extinction in the Anthropocene.

Samuel Turvey and Jennifer Crees introduce the effects of humans on biodiversity.

Grappling with the Bomb: Britain’s Pacific H-Bomb Tests, by Nic Maclellan

Some sixty years after Britain conducted a series of thermo-nuclear weapons tests in the British colony of Gilbert and Ellice Islands (today’s Republic of Kiribati), the legacy of these trials, especially their environmental and human health effects, remains a source of controversy. Alluding in its title to the code-name of these nine tests, Operation Grapple, which the British government carried out on Christmas Island and Malden Island in 1957 and 1958, Nic Maclellan’s book offers a fresh look at this important chapter in nuclear history. His study takes an unconventional approach: not only does its author reveal in the introduction his activist motivation behind the project, but he also approaches the topic through a series of historical actors who were, in different capacities, involved in the thermonuclear trials. Alongside members of the local populations affected by, and soldiers or civil servants taking part in, these hydrogen bomb tests, Maclellan tells the story of Operation Grapple through the eyes of the British commander of Operation Grapple (Wilfred Oulten), the (former) British prime ministers Sir Winston Churchill and Harold Macmillan and the United States President John F. Kennedy, who arranged for Christmas Island to be used for United States thermonuclear testing in the early 1960s.

<p><strong>Distribution and ecology of myxomycetes on Christmas Island, Indian Ocean</strong></p>

A survey for myxomycetes was carried out on Christmas Island in May 2017. Specimens included those that had fruited in the field under natural conditions and those appearing in moist chamber cultures prepared with samples of dead plant material collected on the island. Fifty-nine species in 18 genera were recorded. Hemitrichia serpula was the most common species represented among field collections, whereas Arcyria cinerea, Diderma effusum, Lamproderma scintillans, Didymium squamulosum, Diderma hemisphericum and Diachea leucopodia were recorded the most often in moist chamber cultures. These new records bring the total number of species of myxomycetes known from Christmas Island to 68 species in 22 genera. The distribution and ecology of these species in relation to the various substrates available to them are discussed.

Geographic and taxonomic patterns of extinction risk in Australian squamates

Australia is a global hotspot of reptile diversity, hosting ~10% of the world's squamate (snake and lizard) species. Yet the conservation status of the Australian squamate fauna has not been assessed for >25 years; a period during which the described fauna has risen by ~40%. Here we provide the first comprehensive conservation assessment of Australian terrestrial squamates using IUCN Red List Categories and Criteria. Most (86.4%; n = 819/948) Australian squamates were categorised as Least Concern, 4.5% were Data Deficient, and 7.1% (range 6.8%–11.3%, depending on the treatment of Data Deficient species) were threatened (3.0% Vulnerable, 2.7% Endangered, 1.1% Critically Endangered). This level of threat is low relative to the global average (~18%). One species (Emoia nativitatis) was assessed as Extinct, and two species (Lepidodactylus listeri and Cryptoblepharus egeriae) are considered Extinct in the Wild: all three were endemic to Christmas Island. Most (75.1%) threat assessments were based on geographic range attributes, due to limited data on population trends or relevant proxies. Agriculture, fire, and invasive species were the threats that affected the most species, and there was substantial geographic variation in the number of species affected by each threat. Threatened species richness peaked on islands, in the Southern Alps, and across northern Australia. Data deficiency was greatest in northern Australia and in coastal Queensland. Approximately one-in-five threatened species were not represented in a single protected area. Our analyses shed light on the species, regions, and threats in most urgent need of conservation intervention.