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1
Suppiah, R. "The Australian summer monsoon: a review." Progress in Physical Geography: Earth and Environment 16, no. 3 (September 1992): 283–318. http://dx.doi.org/10.1177/030913339201600302.
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The Australian summer monsoon influences the climate of the Australian tropics during the period from December to March. During this period, interannual and intraseasonal variations of rainfall associated with global-scale circulation anomalies strongly effect human life and economic activities in this region. Any changes in the global-scale circulation patterns in relation to changes in the heat balance components under enhanced greenhouse condition could alter monsoonal circulation characteristics and thus could bring serious impacts to human life in the monsoon-dominated region. To provide a basis for looking at changes in monsoonal characteristics under enhanced greenhouse condition, the current understanding of the Australian summer monsoonal circulation characteristics is reviewed here. Detailed information is given on the formation and the steady development of the Pilbara heat low over the northwestern part of Australia and the importance of the location of the monsoon shear line, active and break cycles of the monsoon, influence of South China Sea cold surges on monsoon activity, 40-50 oscillation in monsoon rainfall and winds and their link to El Nino/ Southern Oscillation (ENSO) phenomenon, the influence of the ENSO phenomenon on rainfall on interannual time scales and the link between monsoonal activity and tropical cyclones. The problems related to the above mentioned topics and their research priorities are highlighted.
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Azzali, Simona, Lisa Law, and Anita Lundberg. "Sustainable Tropical Urbanism: Insights from Cities of the Monsoonal Asia-Pacific." eTropic: electronic journal of studies in the tropics 19, no. 2 (December 21, 2020): 1–24. http://dx.doi.org/10.25120/etropic.19.2.2020.3777.
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The Tropics is experiencing the fastest growing urbanisation on the planet and faces serious sustainability issues. This introduction to the eTropic Special Issue on ‘Sustainable Tropical Urbanism’ calls for a notion of plural sustainabilities in order to critique how urban sustainability has mainly been developed in temperate zones and transferred to tropical regions; but also, to recognise shared aspects of the Tropics, including climate change and environmental challenges, as well as histories of colonialism and their continuing postcolonial cultural and socioeconomic effects on peoples of the Tropics and their futures. These threads are drawn together under a conceptual trio of Place, Past, and People in order to further explore these similarities and differences. Narrowing the focus to the monsoonal Asia-Pacific region, this Special Issue presents case studies from Khulna and Chittagong in Bangladesh; Singapore and the Indonesian city of Semarang in Southeast Asia; and the regional city of Cairns in tropical northeast Australia. This Special Issue of eTropic brings together research articles, scoping reviews and viewpoints from multiple disciplines and interdisciplines to explore the dynamics of sustainable tropical urbanism.
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Chiang, J. C. H., W. Kong, C. H. Wu, and D. S. Battisti. "Origins of East Asian Summer Monsoon Seasonality." Journal of Climate 33, no. 18 (September 15, 2020): 7945–65. http://dx.doi.org/10.1175/jcli-d-19-0888.1.
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AbstractThe East Asian summer monsoon is unique among summer monsoon systems in its complex seasonality, exhibiting distinct intraseasonal stages. Previous studies have alluded to the downstream influence of the westerlies flowing around the Tibetan Plateau as key to its existence. We explore this hypothesis using an atmospheric general circulation model that simulates the intraseasonal stages with fidelity. Without a Tibetan Plateau, East Asia exhibits only one primary convective stage typical of other monsoons. As the plateau is introduced, the distinct rainfall stages—spring, pre-mei-yu, mei-yu, and midsummer—emerge, and rainfall becomes more intense overall. This emergence coincides with a pronounced modulation of the westerlies around the plateau and extratropical northerlies penetrating northeastern China. The northerlies meridionally constrain the moist southerly flow originating from the tropics, leading to a band of lower-tropospheric convergence and humidity front that produces the rainband. The northward migration of the westerlies away from the northern edge of the plateau leads to a weakening of the extratropical northerlies, which, coupled with stronger monsoonal southerlies, leads to the northward migration of the rainband. When the peak westerlies migrate north of the plateau during the midsummer stage, the extratropical northerlies disappear, leaving only the monsoon low-level circulation that penetrates northeastern China; the rainband disappears, leaving isolated convective rainfall over northeastern China. In short, East Asian rainfall seasonality results from the interaction of two seasonally evolving circulations—the monsoonal southerlies that strengthen and extend northward, and the midlatitude northerlies that weaken and eventually disappear—as summer progresses.
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Favors, James E., and John T. Abatzoglou. "Regional Surges of Monsoonal Moisture into the Southwestern United States." Monthly Weather Review 141, no. 1 (January 1, 2013): 182–91. http://dx.doi.org/10.1175/mwr-d-12-00037.1.
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Abstract Episodic surges of moisture into the southwestern United States are an important attribute of the North American monsoon. Building upon prior studies that identified mesoscale gulf surges using station-based diagnostics, regional surges in monsoonal moisture are identified using precipitable water and integrated water vapor flux from the North American Regional Reanalysis. These regional surge diagnostics exhibit increased skill over gulf surge diagnostics in capturing widespread significant multiday precipitation over the state of Arizona and are associated with the northward intrusion of moisture and precipitation into the southwestern United States. Both tropical and midlatitude circulation patterns are associated with identified regional surge events. In the tropics, the passage of a tropical easterly wave across the Sierra Madre and through the Gulf of California facilitates a northeastward flux of moisture toward the southwestern United States. In midlatitudes, the breakdown and eastward shift of an upper-level ridge over the western United States ahead of an eastward-propagating trough off the Pacific Northwest coast helps destabilize the middle troposphere ahead of the easterly wave and provides a conduit for subtropical moisture advection into the interior western United States.
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Krishnamurti, T. N., Ruby Krishnamurti, Sweta Das, Vinay Kumar, A. Jayakumar, and Anu Simon. "A Pathway Connecting the Monsoonal Heating to the Rapid Arctic Ice Melt*." Journal of the Atmospheric Sciences 72, no. 1 (January 1, 2015): 5–34. http://dx.doi.org/10.1175/jas-d-14-0004.1.
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Abstract This study provides a monsoonal link to the rapid Arctic ice melt. Each year the planetary-scale African–Asian monsoonal outflow near the tropopause carries a large anticyclonic gyre that has a longitudinal spread that occupies nearly half of the entire tropics. In recent years, the South Asian summer monsoon has experienced increased rainfall over northwestern India and Pakistan and it has also contributed to more intense local anticyclonic outflows from this region. The western lobes of these intense upper-high-pressure areas carry outflows with large heat fluxes from the monsoon belt toward central Asia and eventually to the region of the rapid ice melt of the Canadian Arctic. In this study this spectacular pathway has been defined from airflow trajectories, heat content, and heat flux anomalies. Most of these show slow increasing trends in the last 20 years. The monsoonal connection to the rapid Arctic ice melt is a new contribution of this study. This is shown from the passage of a vertical column of large positive values of the heat content anomaly that can be traced from the Asian monsoon belt to the Canadian Arctic. The heat flux along these episodic and intermittently active pathways is shown to be considerably larger than the atmospheric poleward flux across latitude circles and from the oceans. This study contrasts these thermodynamic wave trains (defining this pathway) for the more conventional dynamic wave trains.
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Andersen, Alan N., François Brassard, and Benjamin D. Hoffmann. "Unrecognized Ant Megadiversity in Monsoonal Australia: Diversity and Its Distribution in the Hyperdiverse Monomorium nigrius Forel Group." Diversity 14, no. 1 (January 11, 2022): 46. http://dx.doi.org/10.3390/d14010046.
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We document diversity and its distribution within the hyperdiverse Monomorium nigrius Forel group of the Australian monsoonal tropics, an unrecognized global centre of ant diversity. The group includes a single described species, but several distinct morphotypes each with multiple clearly recognizable taxa are known. Our analysis is based on 401 CO1-sequenced specimens collected from throughout the Australian mainland but primarily in the monsoonal north and particularly from four bioregions: the Top End (northern third) of the Northern Territory (NT), the Sturt Plateau region of central NT, the Kimberley region of far northern Western Australia, and far North Queensland. Clade structure in the CO1 tree is highly congruent with the general morphotypes, although most morphotypes occur in multiple clades and are therefore shown as polyphyletic. We recognize 97 species among our sequenced specimens, and this is generally consistent (if not somewhat conservative) with PTP analyses of CO1 clustering. Species turnover is extremely high both within and among bioregions in monsoonal Australia, and the monsoonal fauna is highly distinct from that in southern Australia. We estimate that the M. nigrius group contains well over 200 species in monsoonal Australia, and 300 species overall. Our study provides further evidence that monsoonal Australia should be recognized as a global centre of ant diversity.
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Andersen, Alan N., John C. Z. Woinarski, and Ben D. Hoffmann. "Biogeography of the ant fauna of the Tiwi Islands, in northern Australia's monsoonal tropics." Australian Journal of Zoology 52, no. 1 (2004): 97. http://dx.doi.org/10.1071/zo03013.
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This paper describes the biogeography at the species level of ants from the Tiwi Islands, and represents the first such analysis for any region in Australia. The Tiwi Islands are located 20 km off the mainland coast near Darwin in northern Northern Territory, and include Australia's second largest insular landmass after Tasmania. The islands receive the highest mean annual rainfall (up to 2000 mm) in monsoonal northern Australia, and they are the closest part of the Australian landmass to south-east Asia. On the basis of ~1300 species records, we list 154 species (including nine introduced) from 34 genera. The richest genera are Polyrhachis (20 species), Monomorium (15), Camponotus (14), Pheidole (12), and Iridomyrmex (11). In all, 66% of the native Tiwi species belong to Torresian (tropical) species groups, which is considerably higher than the 44% for Australia's monsoonal ant fauna as a whole. Fifteen Tiwi ant species are not known from mainland Australia. These include a species of Anonychomyrma, which is the only record of the genus in monsoonal Australia, Polyrhachis debilis, the only representative of the sub-genus Cyrtomyrma known from north-western Australia, and the only species of the araneoides group of Rhytidoponera known from the Northern Territory. Unfortunately, the Tiwi ant fauna also includes the exotic invasive species Pheidole megacephala, which represents a serious conservation threat.
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Oberprieler, Stefanie, Alan Andersen, and Craig Moritz. "Ants in Australia’s Monsoonal Tropics: CO1 Barcoding Reveals Extensive Unrecognised Diversity." Diversity 10, no. 2 (May 14, 2018): 36. http://dx.doi.org/10.3390/d10020036.
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Attard, S. M., and S. C. Mckillup. "Reproduction and Growth of The Bandicoot Isoodon macrourus At Four Sites in Rockhampton, Queensland." Australian Mammalogy 20, no. 3 (1998): 411. http://dx.doi.org/10.1071/am98411.
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Within Australia the northern short-nosed bandicoot, Isoodon macrourus, occurs in coastal areas from the Kimberleys to the monsoonal tropics of the Northern Territory and from Cape York Peninsula to the Hawkesbury River, New South Wales (Gordon 1983). The reproductive ecology of I. macrourus has been studied in two captive (Hall 1983; Gemmell 1988) and five natural populations (Gordon 1971, 1974; Gemmell 1982; Hall 1983; Friend 1990; Kem- per et al. 1990; Budiawan 1993). Three of the latter (Darwin, the Mitchell Plateau and Townsville) were in the tropics; breeding at these sites occurred dur- ing the wetter months of the year but not during the summer of 1982/3 in Darwin when the monsoon failed (Friend 1990) or during the relatively dry winter/spring of 1991 in Townsville (Budiawan 1993), suggesting a dependence on rainfall (Friend 1990; Budiawan 1993). We report on differences in the reproduction, growth and development of I. macrourus in Rockhampton, Queensland, from March - October 1993 at four adjacent sites which received different amounts of artificial watering.
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PETTIT, MAGEN J., and ALAN N. ANDERSEN. "A new species of Epopostruma (Hymenoptera: Formicidae) from monsoonal Australia." Zootaxa 5048, no. 1 (October 5, 2021): 141–44. http://dx.doi.org/10.11646/zootaxa.5048.1.9.
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Epopostruma is an uncommon genus of myrmicine ants endemic to relatively mesic regions of southern and eastern Australia. Here we describe a new species recently recorded from the ‘Top End’ of Australia’s Northern Territory, E. topendi sp. n. from Melville Island and Nitmiluk National Park. The new species is known from one specimen from each of two sites in the Australian monsoonal tropics, the only records of the genus from this region. This addition brings the number of described species of Epopostruma to twenty.
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Huey, Joel A., Benjamin D. Cook, Peter J. Unmack, and Jane M. Hughes. "Broadscale phylogeographic structure of five freshwater fishes across the Australian Monsoonal Tropics." Freshwater Science 33, no. 1 (March 2014): 273–87. http://dx.doi.org/10.1086/674984.
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Taylor, J. Mary, and John H. Calaby. "Reproductive strategies of Pseudomys nanus and Pseudomys delicatulus (Rodentia : Muridae) from the monsoonal tropics of the Northern Territory." Australian Journal of Zoology 52, no. 3 (2004): 271. http://dx.doi.org/10.1071/zo03011.
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In the highly punctuated monsoonal climate of the Alligator Rivers area of Australia, Pseudomys nanus and Pseudomys delicatulus breed in the latter part of the monsoon season and can extend their breeding activity into spring. P. nanus may reproduce virtually year-round, presumably when environmental conditions are favourable. In both species, the predominance of young non-breeding adults and juveniles in the spring signals a new infusion of animals into the population and a large population turnover at the expense of older members. The young survivors of the seasonal transition from extremely dry to intensely wet conditions then become the primary contributors to the next major breeding episode. This study is based on histological evidence from the reproductive systems of both sexes.
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Sabin, T. P., and Olivier M. Pauluis. "The South Asian Monsoon Circulation in Moist Isentropic Coordinates." Journal of Climate 33, no. 12 (June 15, 2020): 5253–70. http://dx.doi.org/10.1175/jcli-d-19-0637.1.
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AbstractThe atmospheric circulation during the South Asian summer monsoon season is analyzed in moist isentropic coordinates. The horizontal mass transport is sorted in terms of its equivalent potential temperature and is separated into the upper- and lower-tropospheric contributions. This technique makes it possible to trace the transport of air parcels over long distances, identify regions of convective motion in the tropics, and assess the impacts of diabatic processes. The goal here is to assess the thermodynamic characteristics of the atmospheric overturning associated with the South Asian monsoon and to connect this thermodynamic structure to horizontal transport. The monsoon is associated with a low-level inflow of warm and moist air, compensated by an upper-tropospheric outflow at high potential temperature. The South Asian monsoon differs, however, from other monsoonal systems in two important ways. First, the ascending air exhibits an unusually high equivalent potential temperature, which results in global lifting of the tropopause during the boreal summer. Second, on a seasonal basis the main monsoon regions appear to be shielded from dry air intrusion from the extratropical regions.
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Bowman, D. M. J. S., and L. D. Prior. "Why do evergreen trees dominate the Australian seasonal tropics?" Australian Journal of Botany 53, no. 5 (2005): 379. http://dx.doi.org/10.1071/bt05022.
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The northern Australian woody vegetation is predominantly evergreen despite an intensely seasonal climate and a diversity of deciduous species in the regional flora. From a global climatic perspective the dominance of evergreen rather than deciduous trees in the Australian savannas is apparently anomalous when compared with other savannas of the world. However, this pattern is not unexpected in light of existing theory that emphasises photosynthetic return relative to cost of investment between deciduous and evergreen species. (a) Climatically, monsoonal Australia is more extreme in terms of rainfall seasonality and variability and high air temperatures than most other parts of the seasonally dry tropics. Existing theory predicts that extreme variability and high temperatures favour evergreen trees that can maximise the period during which leaves assimilate CO2. (b) Soil infertility is known to favour evergreens, given the physiological cost of leaf construction, and the northern Australian vegetation grows mainly on deeply weathered and infertile Tertiary regoliths. (c) These regoliths also provide stores of ground water that evergreens are able to exploit during seasonal drought, thereby maintaining near constant transpiration throughout the year. (d) Fire disturbance appears to be an important secondary factor in explaining the dominance of evergreens in the monsoon tropics, based on the fact that most deciduous tree species of the region are restricted to small fire-protected sites. (e) Evolutionary history cannot explain the predominance of evergreens, given the existence of a wide range of deciduous species, including deciduous eucalypts, in the regional tree flora.
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Fenker, Jessica, Leonardo G. Tedeschi, Jane Melville, and Craig Moritz. "Predictors of phylogeographic structure among codistributed taxa across the complex Australian monsoonal tropics." Molecular Ecology 30, no. 17 (July 20, 2021): 4276–91. http://dx.doi.org/10.1111/mec.16057.
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Woinarski, J. C. Z. "The conservation status of rodents in the monsoonal tropics of the Northern Territory." Wildlife Research 27, no. 4 (2000): 421. http://dx.doi.org/10.1071/wr97047.
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The rodent fauna of the monsoonal tropics of the Northern Territory comprises 23 native species and two introduced species. Three species (Zyzomys maini, Z. palatalis and Pseudomys calabyi) are endemic to the area, and four species (Pseudomys hermannsburgensis, P. desertor, P. johnsoni and Notomys alexis) enter the area only on its southern (arid) fringe. The rodent fauna is closely related to that of the Kimberley, Western Australia. Distribution maps for all species are given. One species (Z. palatalis) has an extremely restricted range and is regarded as critically endangered. The lack of information on the distribution and abundance of rodents in general in this area is evident in the national classification of five of its species (Xeromys myoides, Mesembriomys macrurus, Notomys aquilo, Pseudomys desertor and Pseudomys johnsoni) as Insufficiently Known. The two introduced rodents (Mus domesticus and Rattus rattus) are virtually restricted to urban and highly modified areas, although R. rattus also occurs on one uninhabited island. In contrast to that of much of the rest of Australia, this rodent fauna has apparently retained its full complement of species since European colonisation. This enduring legacy is attributable largely to the relatively limited modification of its environments. However, three species (Mesembriomys macrurus, Rattus tunneyi and Conilurus penicillatus) appear to be declining. The pattern of decline in these species, and in the mammal fauna generally, is obscured by the very limited historical data. However, declines appear most pronounced in the cattle country of the Victoria River District and Gulf regions. Priorities for the management of this rodent fauna include survey of poorly known areas, survey for poorly known species, monitoring of rodent communities, and landscape-wide management of the three pervasive processes with probably greatest impacts – fire, grazing and feral predators.
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Moritz, C., E. J. Ens, S. Potter, and R. A. Catullo. "The Australian monsoonal tropics: An opportunity to protect unique biodiversity and secure benefits for Aboriginal communities." Pacific Conservation Biology 19, no. 4 (2013): 343. http://dx.doi.org/10.1071/pc130343.
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The Australian monsoonal tropics region contains one of the planet’s largest, relatively intact tropical savannas and has been continually occupied by humans for at least 50,000 years. The region, spanning Cape York Peninsula, the Top End and the Kimberley of northern Australia has long been known to host high biodiversity, but only now is the true extent of locally unique (endemic) species and genetic diversity within each of these areas becoming apparent. Though some critical regions have been included in the national reserve system, including the iconic Kakadu National Park, the ecological and evolutionary dynamics are such that large interconnected swathes of the region need to be actively managed to sustain this unique diversity in the face of escalating anthropogenic impacts and species decline. The growth in Indigenous Protected Areas and Indigenous-owned land where Traditional Owners aspire to “care for their Country” offers an opportunity to contribute to the broader conservation effort in the region. The conservation imperative is also entwined with Aboriginal cultural aspirations. Over the last few decades there has been a resurgence of effort by Aboriginal landowners to maintain their cultural responsibilities and knowledge, pursue socio-economic development opportunities, as well as to protect the bio-cultural values of their ancestral country. In the Australian monsoonal tropics, over 40% of the landscape is under some form of Aboriginal ownership or control and emerging initiatives such as the Indigenous Protected Area programme, representing a partnership of community, government and sometimes NGOs offer one (though not the only) constructive way forward. As the biological uniqueness of the landscape is uncovered, this should bolster the perceived biodiversity value and encourage further investment in protecting it, especially through programmes that promote engagement with, and employment of, Aboriginal communities. For this to be sustainable, the discovery and management of the region’s biodiversity needs to be driven increasingly by Aboriginal land owners with clear cultural and community, as well as biodiversity, benefits. This
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Greenwood, DR. "Eocene monsoon forests in central Australia?" Australian Systematic Botany 9, no. 2 (1996): 95. http://dx.doi.org/10.1071/sb9960095.
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The Australian Tertiary plant fossil record documents rainforests of a tropical to temperate character in south-eastern and south-western Australia for much of the Early Tertiary, and also shows the climatically mediated contraction of these rainforests in the mid to Late Tertiary. The fossil record of Australian monsoon forests, that is semi-evergreen to deciduous vine forests and woodlands of the wet-dry tropics, however, is poorly known. Phytogeographic analyses have suggested an immigrant origin for some floral elements of present day monsoon forests in northern Australia, while other elements appear to have a common history with the tropical rainforests sensu stricto and/or the sclerophyllous flora. Early Tertiary macrofloras in northern South Australia may provide some insight into the origins of Australian tropical monsoon forests. The Middle Eocene macrofloras of the Poole Creek palaeochannel, and the ?Eocene-Oligocene silcrete macrofloras of Stuart Creek, both in the vicinity of modern Lake Eyre South, have foliar physiognomic characteristics which distinguish them from both modern rainforest and Eocene-Oligocene floras from south-eastern Australia. Preliminary systematic work on these floras suggests the presence of: (1) elements not associated today with monsoon forests (principally 'rainforest' elements, e.g. Gymnostoma, cf. Lophostemon, cf. Athertonia, Podocarpaceae, ?Cunoniaceae); (2) elements typical of both monsoon forests and other tropical plant communities (e.g. cf. Eucalyptus, cf. Syzygium, and Elaeocarpaceae); (3) elements likely to be reflecting sclerophyllous communities (e.g. cf. Eucalyptus, Banksieae and other Proteaceae); and (4) elements more typically associated with, but not restricted to, monsoon forests (e.g. Brachychiton). The foliar physiognomic and floristic evidence is interpreted as indicating a mosaic of gallery or riverine rainforests, and interfluve sclerophyllous plant communities near Lake Eyre in the Early Tertiary; deciduous forest components are not clearly indicated. Palaeoclimatic analysis of the Eocene Poole Creek floras suggests that rainfall was seasonal in the Lake Eyre area in the Eocene; however, whether this seasonality reflects a monsoonal airflow is not clear.
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Carthew, K. D., M. P. Taylor, and R. N. Drysdale. "An environmental model of fluvial tufas in the monsoonal tropics, Barkly karst, northern Australia." Geomorphology 73, no. 1-2 (January 2006): 78–100. http://dx.doi.org/10.1016/j.geomorph.2005.07.007.
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Moritz, C., M. K. Fujita, D. Rosauer, R. Agudo, G. Bourke, P. Doughty, R. Palmer, et al. "Multilocus phylogeography reveals nested endemism in a gecko across the monsoonal tropics of Australia." Molecular Ecology 25, no. 6 (February 16, 2016): 1354–66. http://dx.doi.org/10.1111/mec.13511.
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Hancock, G. R., JBC Lowry, and C. Dever. "Surface Disturbance and Erosion by Pigs: A Medium Term Assessment for the Monsoonal Tropics." Land Degradation & Development 28, no. 1 (December 2016): 255–64. http://dx.doi.org/10.1002/ldr.2636.
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Shelley, James J., Tim Dempster, Matthew C. Le Feuvre, Peter J. Unmack, Shawn W. Laffan, and Stephen E. Swearer. "A revision of the bioregionalisation of freshwater fish communities in the Australian Monsoonal Tropics." Ecology and Evolution 9, no. 8 (March 29, 2019): 4568–88. http://dx.doi.org/10.1002/ece3.5059.
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DiNezio, Pedro N., Jessica E. Tierney, Bette L. Otto-Bliesner, Axel Timmermann, Tripti Bhattacharya, Nan Rosenbloom, and Esther Brady. "Glacial changes in tropical climate amplified by the Indian Ocean." Science Advances 4, no. 12 (December 2018): eaat9658. http://dx.doi.org/10.1126/sciadv.aat9658.
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The mechanisms driving glacial-interglacial changes in the climate of the Indo-Pacific warm pool are poorly understood. Here, we address this question by combining paleoclimate proxies with model simulations of the Last Glacial Maximum climate. We find evidence of two mechanisms explaining key patterns of ocean cooling and rainfall change interpreted from proxy data. Exposure of the Sahul shelf excites a positive ocean-atmosphere feedback involving a stronger surface temperature gradient along the equatorial Indian Ocean and a weaker Walker circulation—a response explaining the drier/wetter dipole across the basin. Northern Hemisphere cooling by ice sheet albedo drives a monsoonal retreat across Africa and the Arabian Peninsula—a response that triggers a weakening of the Indian monsoon via cooling of the Arabian Sea and associated reductions in moisture supply. These results demonstrate the importance of air-sea interactions in the Indian Ocean, amplifying externally forced climate changes over a large part of the tropics.
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SAMBASIVARAO, A., and VK VAMADEVAN. "Insolation in monsoonal wet tropics and Transmission / reflection coefficients of Leaves of some plantation crops." MAUSAM 36, no. 3 (April 6, 2022): 347–50. http://dx.doi.org/10.54302/mausam.v36i3.1980.
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Andersen, A. N., M. Houadria, M. Berman, and M. van der Geest. "Rainforest ants of the Tiwi Islands: a remarkable centre of endemism in Australia’s monsoonal tropics." Insectes Sociaux 59, no. 3 (May 29, 2012): 433–41. http://dx.doi.org/10.1007/s00040-012-0238-6.
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Egan, JL, and RJ Williams. "Lifeform distributions of woodland plant species along a moisture availability gradient in Australia's monsoonal tropics." Australian Systematic Botany 9, no. 2 (1996): 205. http://dx.doi.org/10.1071/sb9960205.
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A series of vegetation sites was established in Australia's Northern Territory between Darwin and Tennant Creek, a distance of approximately 1000 km and 7° latitude (12°30'–19°30'S). This region encompasses a strong environmental gradient in mean annual moisture availability (450–1600 mm) whilst remaining within a predominantly summer monsoonal rainfall regime. All sites are within eucalypt-savanna habitats on lighter textured soils (sands–loams). Major changes in family and species representation occur at approximately 16–17° latitude, supporting findings of other workers. Within these eucalypt-savanna communities, the percentage of annual species is consistently around 30% regardless of latitude. However, the distribution of resource allocation strategies used by perennial plants exhibits distinct latitudinal trends. The proportion of deciduous and seasonally perennial species declines with latitude whilst suffrutescent shrub species become increasingly abundant. Species possessing root structures adapted for storage purposes appear to be limited to latitudes north of 15°S.
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Lim, Young-Kwon, and Kwang-Yul Kim. "ENSO Impact on the Space–Time Evolution of the Regional Asian Summer Monsoons." Journal of Climate 20, no. 11 (June 1, 2007): 2397–415. http://dx.doi.org/10.1175/jcli4120.1.
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Abstract This study investigates how ENSO affects the space–time evolution of the Asian summer monsoon (ASM) precipitation and synoptic variables on a 5-day resolution over the entire ASM area. Cyclostationary EOF and regression methods were used to investigate the detailed evolution features associated with ENSO during the prominent life cycle of the ASM (21 May–17 September). This ENSO mode is identified as the third largest component (next to the seasonal cycle and the intraseasonal oscillations with a 40–50-day period) of the ASM rainfall variation. The ENSO mode reveals that the individual regional monsoons over the ASM domain respond to ENSO in a complex manner. 1) Under the El Niño condition, the early monsoon stage over India, the Bay of Bengal, and the Indochina peninsula is characterized by rainfall deficit, along with a delayed monsoon onset by one or two pentads. This is the result of weakened diabatic heating over the Asian continent and meridional pressure gradient over the Indian Ocean, causing a weak low-tropospheric westerly monsoonal flow and the ensuing moisture transport decrease toward the regional monsoon areas. Onsets of the subsequent regional monsoons are delayed successively by this poorly developed ASM system in the early stage. 2) The Walker circulation anomaly persistently induces an enhanced subsidence over the Maritime Continent, resulting in a drought condition over this region for the entire ASM period. 3) The Hadley circulation anomaly linked to the Walker circulation anomaly over the Tropics drives a rising motion over the subtropical western Pacific, resulting in a wetter south China monsoon. The negative sea level pressure anomaly over the subtropical western Pacific associated with this anomalous Hadley circulation provides an unfavorable condition for the moisture transport toward East Asia, causing drier monsoons over north China, Japan, and Korea regions. 4) This negative sea level pressure anomaly intrudes into India, the Bay of Bengal, and the Indochina peninsula during late July and early August, developing a brief wet period over these regions. In contrast, the physical changes including the onset variation and the monsoon strength addressed above are reversed during La Niña events. In reality, the observed ASM rainfall anomaly does not necessarily follow the ENSO-related patterns addressed above because of other impacts contributing to the rainfall variations. Although the impact of ENSO is moderately important, a comparison with other impacts demonstrates that the rainfall variations are controlled more by regional-scale intraseasonal oscillations.
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Bowman, DMJS. "Diversity Patterns of Woody Species on a Latitudinal Transect From the Monsoon Tropics to Desert in the Northern Territory, Australia." Australian Journal of Botany 44, no. 5 (1996): 571. http://dx.doi.org/10.1071/bt9960571.
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A belt transect, made up of 15 contiguous cells (width, 3.5° of longitude; length, 1° of latitude), was established from the monsoon tropics on the central north coast of the Northern Temtory (11°S) to the central Australian desert on the South Australian border (26°S). On this transect, mean annual rainfall was found to have a negative exponential decay with latitude, with arid conditions commencing at around 18"s-the limit of the monsoonal rains. The mean elevation of each cell steadily increased from the north coast to reach a maximum average elevation of 700 m at around 23°S. The mean alphadiversity (quadrat species richness), and mean beta-diversity (turnover of species along an environmental gradient) was determined for each of the 15 cells by sub-sampling a large 20 × 20 m quadrat data set (N > 2000) collected during the course of the Northern Territory 1:106 vegetation mapping program. It was found that there was little within-cell variation of beta-diversity of woody species which occurred in at least five quadrats, as approximated by the first axis of a detrended correspondence analysis (DCA) of these data. The mean first axis DCA scores were strongly correlated with latitude (r = 0.99); thus, there is no evidence for a floristic disjunction in the composition of common woody species between the monsoon tropics and desert. Mean alpha-diversity had a bimodal distribution on the latitudinal transect, with the maximum mean quadrat richness in the monsoon tropics and a second smaller peak occurred in central Australia, with the lowest levels of alpha-diversity to the south of the limit of the monsoon rains. This pattern was mirrored by the mean number and mean Shannon-Wiener diversity of 1:106 vegetation map units on the transect. It was found that 81% of the variance of mean alpha-diversity was explained by mean annual rainfall and mean elevation for the 15 cells. The increase in mean alpha-diversity in central Australia appears to be related to environmental heterogeneity associated with mountainous terrain. It is possible that the central Australian mountains are a refuge for plants that were more widespread during the last ice-age. It is unknown whether the woody species diversity patterns are in equilibrium with the prevailing climate. More data on the palaeo-environments of the Northern Territory are required to answer this question.
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Prokop, Paweł, Łukasz Wiejaczka, Hiambok Jones Syiemlieh, and Rafał Kozłowski. "Response of Water Chemistry to Long-Term Human Activities in the Nested Catchments System of Subtropical Northeast India." Water 11, no. 5 (May 10, 2019): 988. http://dx.doi.org/10.3390/w11050988.
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The subtropics within the monsoonal range are distinguished by intensive human activity, which affects stream water chemistry. This paper aims to determine spatio-temporal variations and flowpaths of stream water chemical elements in a long-term anthropogenically-modified landscape, as well as to verify whether the water chemistry of a subtropical elevated shield has distinct features compared to other headwater areas in the tropics. It was hypothesized that small catchments with homogenous environmental conditions could assist in investigating the changes in ions and trace metals in various populations and land uses. Numerous physico-chemical parameters were measured, including temperature, pH, electrical conductivity (EC), dissolved organic carbon (DOC), major ions, and trace metals. Chemical element concentrations were found to be low, with a total dissolved load (TDS) below 52 mg L−1. Statistical tests indicated an increase with significant differences in the chemical element concentration between sites and seasons along with increases of anthropogenic impact. Human influence was clearly visible in the case of cations (Ca2+, K+, Mg2+, Na+) and anions (Cl−, HCO3−, NO3−, SO42−), compared to trace metals. The order of most abundant metals Fe > Zn > Al > Sr was the same in springs and streams, regardless of population density, land use, and season. Principal component analysis (PCA) demonstrated that major ion concentrations in stream water followed the pattern forest < cultivated land < grassland < built-up area. Surface water chemistry of the subtropical elevated shield has mixed features of tropical and temperate zones. Low concentrations of chemical elements; small seasonal differences in headwater streams; and increased concentrations of NO3−, SO42−, DOC, and Zn in the wet monsoon season are similar to those observed in the tropics. The role of long-term cultivation without chemical fertilizers in ions supply to streams is less than in other headwater areas of the tropical zone. Strong control of water chemistry in densely populated built-up areas is analogous to both tropical and temperate regions. Population density or a built-up area may be used as a proxy for the reconstruction or prediction of the anthropogenic impact on stream water chemistry in similar subtropical elevated shields.
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Liu, Boqi, Congwen Zhu, Yuan Yuan, and Kang Xu. "Two Types of Interannual Variability of South China Sea Summer Monsoon Onset Related to the SST Anomalies before and after 1993/94." Journal of Climate 29, no. 19 (September 14, 2016): 6957–71. http://dx.doi.org/10.1175/jcli-d-16-0065.1.
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Abstract An advance in the timing of the onset of the South China Sea (SCS) summer monsoon (SCSSM) during the period 1980–2014 can be detected after 1993/94. In the present study, the interannual variability of the SCSSM onset is classified into two types for the periods before and after 1993/94, based on their different characteristics of vertical coupling between the upper- and lower-tropospheric circulation and the differences in their related sea surface temperature anomalies (SSTAs). On the interannual time scale, type-I SCSSM onset is characterized by anomalous low-level circulation over the northern SCS during 1980–93, whereas type-II SCSSM onset is associated with anomalies of upper-level circulation in the tropics during 1994–2014. The upper-tropospheric thermodynamic field and circulation structures over the SCS are distinct between the two types of SCSSM onset, and this investigation shows the importance of the role played by the spring SSTAs in the southern Indian Ocean (SIO) and that of ENSO events in type-I and type-II SCSSM onset, respectively. In the early episode, the warming SIO SSTAs can induce an anomalous low-level anticyclone over the northern SCS that affects local monsoonal convection and rainfall over land to its north, demonstrating a high sensitivity of subtropical systems in type-I SCSSM onset. However, in type-II SCSSM onset during the later episode, the winter warm ENSO events and subsequent warming in the tropical Indian Ocean can influence the SCSSM onset by modulating the spring tropical temperature and upper-level pumping effect over the SCS.
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MELVILLE, JANE, KATIE SMITH DATE, PAUL HORNER, and Paul Doughty. "Taxonomic revision of dragon lizards in the genus Diporiphora (Reptilia: Agamidae) from the Australian monsoonal tropics." Memoirs of Museum Victoria 78 (2019): 23–55. http://dx.doi.org/10.24199/j.mmv.2019.78.02.
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Brady, Christopher J., and Richard A. Noske. "Generalised regressions provide good estimates of insect and spider biomass in the monsoonal tropics of Australia." Australian Journal of Entomology 45, no. 3 (August 2006): 187–91. http://dx.doi.org/10.1111/j.1440-6055.2006.00533.x.
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McCosker, TH, PK O'Rourke, AR Eggington, and FW Doyle. "Soil and plant relationships with cattle production on a property scale in the monsoonal tallgrass tropics." Rangeland Journal 10, no. 1 (1988): 18. http://dx.doi.org/10.1071/rj9880018.
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Extreme variability in cattle production between replicate paddocks in a large supplementation experiment on Mount Bundey Station in the Danvin pastoral district of the Northern Territory, led to a search for reasons for the differences. Soil type, land unit and pasture parameters were related to cattle production parameters. Pregnancy rates of lactating heifers were positively related to yields of Themeda triandra, Sorghum plumosum, Eriachne burkittii and Eragrostis spp., the fist three of which declined in yield following heavy grazing pressure. Quantity of pasture was more closely correlated with animal production than was quality due to the wide range in yields and narrow range in quality attributes. Pregnancy rate in lactating heifers was more sensitive to yield of pasture species than was lactating cow pregnancy rate, breeder mortality, calf weight per breeder mated or steer average daily gain. Heifers consumed less supplement relative to their requirements than mature cows and steers and their response was not confounded by previous history. These factors probably account for their greater sensitivity to pasture variations. Pregnancy rate of cows was positively related to the proportion of lowland soil types and negatively to proportion of lithosol (hills). An equation incorporating the percentages of these soils, explained 63%. 42% and 39% of the variation in lactating cow pregnancy rate in 1982, 1983 and 1984 respectively. Variation in pregnancy rate among paddocks was therefore largely attributed to variation in the proportions of "upland" and "lowland" soil types. Sensitivity to grazing pressure of species within the native pasture was indicated by localized damage to T. triandra and S. plumosum and a large reduction in yield of Sintrans after five years of continuous grazing with access to non-protein nitrogen supplements at one breeder to 14ha. Native pastures in the Adelaide River area would not sustain this stocking rate. 18
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Woodcock, Deborah W., and Herbert W. Meyer. "The Piedra Chamana fossil woods and leaves: a record of the vegetation and palaeoenvironment of the Neotropics during the late middle Eocene." Annals of Botany 125, no. 7 (March 12, 2020): 1077–89. http://dx.doi.org/10.1093/aob/mcaa039.
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Abstract Background and Aims The Piedra Chamana fossil forest in northern Peru is an assemblage of angiosperm woods and leaves preserved in volcaniclastic rocks dated to 39 Mya (late Middle Eocene). We analysed the anatomical and morphological features of the fossils to reconstruct the palaeoenvironment during this time of global warmth, taking advantage of the co-occurrence of woods and leaves to compare different proxies and analytical approaches. Methods Wood characters analysed include vessel-related functional traits, traits linked to Baileyan trends, and quantitative features such as vessel diameter and density. Diameter-distribution and diameter and position plots are used to represent vessel diameter and arrangement. Leaf margin and area analysis provides additional climate estimates. Key Results The fossil woods show many similarities with modern tropical-forest woods and tropical fossil-wood assemblages; closest correspondence within the Neotropics is to semi-deciduous lowland tropical forest with moderate precipitation (~1000–1200 mm). Features unusual for the modern South American tropics are mainly vessel-related characters (semi-ring porosity, grouped vessels, helical vessel thickenings, short vessel elements) linked to water stress or seasonal water availability. Leaf analysis indicates mean annual temperature of 31 °C (n = 19, 100 % entire-margined) and mean annual precipitation of 1290 mm (n = 22, predominantly microphylls and notophylls). Conclusions The palaeovegetation was clearly lowland tropical forest with a dry aspect, but anomalous aspects of the wood anatomy are consistent with the high temperatures indicated by the leaves and are probably explained by differences in seasonality and water stress compared to the present-day Neotropics. A close modern analogue may be in very seasonal regions of Asia. Pronounced monsoonal (summer-rain) conditions may relate to a location (palaeolatitude of 13°S) outside the near-equatorial tropics.
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BOURKE, GAYLEEN, RENAE C. PRATT, ERIC VANDERDUYS, and CRAIG MORITZ. "Systematics of a small Gehyra (Squamata: Gekkonidae) from the Einasleigh Uplands, Queensland: description of a new range restricted species." Zootaxa 4231, no. 1 (February 9, 2017): 85. http://dx.doi.org/10.11646/zootaxa.4231.1.5.
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The tropical savannah landscapes of Australia’s north, though previously overshadowed by the biodiverse rainforests of the Wet Tropics, are themselves now attracting interest for their biological significance and uniqueness. The Einasleigh Uplands region of north-east Queensland is home to a diverse group of mammals and reptiles and was previously recognised for its importance in shaping speciation in birds. Here we add a small saxicoline gecko to a growing list of recently described reptiles that are endemic to this region. Phylogenetic analyses including Gehyra species from the arid zone and the monsoonal tropics reveal that small Gehyra geckos in this area, while closely resembling Gehyra nana from the Top End and Kimberley, form a clade that is geographically isolated and phylogenetically distant from the G. nana complex. Instead, the Einasleigh Uplands taxon is sister to a large, arboreal species within the arid zone clade. It is readily distinguished from all lineages within the G. nana complex, its closest relative G. purpurascens, and all other rock-dwelling species from the arid zone by a combination of its very small body size, few subdigital lamellae, and mid tan to golden dorsal coloration with a pattern of scattered pale ocelli and irregular dark-brown blotches on a stippled background. We therefore describe this taxon as a new Australian species of Gehyra, Gehyra einasleighensis sp. nov., based on a combination of phylogenetic separation, morphological characters and discrete geographic distribution.
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Gorman, J., A. B. Cunningham, S. Wei, D. M. Marcsik, and M. D. Hoult. "Factors influencing the growth of the floriculture industry in the monsoonal tropics of the Northern Territory, Australia." Acta Horticulturae, no. 1104 (October 2015): 421–28. http://dx.doi.org/10.17660/actahortic.2015.1104.62.
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Laver, Rebecca J., Paul Doughty, and Paul M. Oliver. "Origins and patterns of endemic diversity in two specialized lizard lineages from the Australian Monsoonal Tropics (Oeduraspp.)." Journal of Biogeography 45, no. 1 (November 13, 2017): 142–53. http://dx.doi.org/10.1111/jbi.13127.
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Stobo-Wilson, A. M., D. Stokeld, L. D. Einoder, H. F. Davies, A. Fisher, B. M. Hill, T. Mahney, et al. "Bottom-up and top-down processes influence contemporary patterns of mammal species richness in Australia's monsoonal tropics." Biological Conservation 247 (July 2020): 108638. http://dx.doi.org/10.1016/j.biocon.2020.108638.
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Fordyce, I. R., G. A. Duff, and D. Eamus. "The Water Relations of Allosyncarpia ternata (Myrtaceae) at Contrasting Sites in the Monsoonal Tropics of Northern Australia." Australian Journal of Botany 45, no. 2 (1997): 259. http://dx.doi.org/10.1071/bt96016.
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Allosyncarpia ternata S.T.Blake (Myrtaceae) is an evergreen tree, restricted largely to rocky habitats on the Arnhem Land Plateau in the wet–dry tropics of northern Australia. Allosyncarpia ternata grows in a wide range of habitats, including sites near permanent springs, where it forms a distinctive closed-canopy forest with an understorey of rainforest plants, and sites on exposed cliffs and hilltops, where it occurs in open forest and woodland. Leaf water relations differ markedly between these contrasting sites. During the dry season, trees at open sites show strong diurnal hysteresis in stomatal conductance (gs); afternoon depressions in gs coincide with regular afternoon increases in vapour pressure deficit. Pressure–volume analyses indicate that A. ternata maintains turgor down to leaf water potential values of about –2.8 MPa, close to the minimum experienced by hilltop leaves late in the dry season. By contrast, trees on the ravine floor, with year-round access to water, exhibit much smaller diurnal and seasonal variation in stomatal conductance and little seasonal variation in leaf water potential. It is concluded that this flexible response in leaf water relations to seasonally dry conditions is partly responsible for the ability of A. ternata to occupy and dominate the vegetation in such a wide variety of habitats. The near confinement of the species to the Arnhem Land Plateau is in part due to the water-holding capacity of the bedrock.
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McCaskill, MR. "An efficient method for generation of full climatological records from daily rainfall." Australian Journal of Agricultural Research 41, no. 3 (1990): 595. http://dx.doi.org/10.1071/ar9900595.
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Three methods were compared for providing data to accompany a daily rainfall record: (i) a seasonal mean calculated from smooth curves; (ii) a seasonal mean modified by rainday effects; and (iii) actual data with missing observations filled in by method (ii). Existing plant growth models developed for the Australian tropics were used to compare the three data generation methods. These models were used to predict the number of growth days (a measure of how much plant growth would be expected in a season), green days (a measure of the duration of weight gain by rangeland cattle), runoff, and germination days. Three stations were used, one each from the monsoonal tropics, the coastal dry tropics, and the coastal subtropics. Comparatively little bias was introduced from methods (i) and (ii). Differences were greater for episodic events such as runoff and germination, than for more continuous events such as growth. There were no significant effects of generation method on calculated growth days or green days. Runoff calculated from method (i) averaged 7% lower than when actual data were used, compared with only a 3% underestimate from method (ii). The number of germination days were underestimated by between 4 and 17% when method (i) was used, compared with between a 3% underestimate and a 6% overestimate with method (ii). It was concluded that method (ii) should be used in preference to the seasonal mean alone, because of the more accurate model predictions from method (ii). A stochastic weather generator would however be required where events such as frosting would be important in risk analyses.
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Heiniger, Jaime, Skye F. Cameron, and Graeme Gillespie. "Evaluation of risks for two native mammal species from feral cat baiting in monsoonal tropical northern Australia." Wildlife Research 45, no. 6 (2018): 518. http://dx.doi.org/10.1071/wr17171.
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Context Feral cats are a significant threat to native wildlife and broad-scale control is required to reduce their impacts. Two toxic baits developed for feral cats, Curiosity® and Hisstory®, have been designed to reduce the risk of baiting to certain non-target species. These baits involve encapsulating the toxin within a hard-shelled delivery vehicle (HSDV) and placing it within a meat attractant. Native animals that chew their food more thoroughly are predicted to avoid poisoning by eating around the HSDV. This prediction has not been tested on wild native mammals in the monsoonal wet–dry tropics of the Northern Territory. Aim The aim of this research was to determine whether northern quolls (Dasyurus hallucatus) and northern brown bandicoots (Isoodon macrourus) would take feral cat baits and ingest the HSDV under natural conditions on Groote Eylandt. Methods We hand-deployed 120 non-toxic baits with a HSDV that contained a biomarker, Rhodamine B, which stains animal whiskers when ingested. The species responsible for bait removal was determined with camera traps, and HSDV ingestion was measured by evaluating Rhodamine B in whiskers removed from animals trapped after baiting. Key results During field trials, 95% of baits were removed within 5 days. Using camera-trap images, we identified the species responsible for taking baits on 65 occasions. All 65 confirmed takes were by native species, with northern quolls taking 42 baits and northern brown bandicoots taking 17. No quolls and only one bandicoot ingested the HSDV. Conclusion The use of the HSDV reduces the potential for quolls and bandicoots to ingest a toxin when they consume feral cat baits. However, high bait uptake by non-target species may reduce the efficacy of cat baiting in some areas. Implications The present study highlighted that in the monsoonal wet–dry tropics, encapsulated baits are likely to minimise poisoning risk to certain native species that would otherwise eat meat baits. However, further research may be required to evaluate risks to other non-target species. Given the threat to biodiversity from feral cats, we see it as critical to continue testing Hisstory® and Curiosity® in live-baiting trials in northern Australia.
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Nott, Jonathan. "The Influence of Deep Weathering on Coastal Landscape and Landform Development in the Monsoonal Tropics of Northern Australia." Journal of Geology 102, no. 5 (September 1994): 509–22. http://dx.doi.org/10.1086/629695.
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Phoutthavong, Kittisack, Akihiro Nakamura, Xiao Cheng, and Min Cao. "Differences in pteridophyte diversity between limestone forests and non-limestone forests in the monsoonal tropics of southwestern China." Plant Ecology 220, no. 10 (July 29, 2019): 917–34. http://dx.doi.org/10.1007/s11258-019-00963-8.
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Anderson, R. Y. "Enhanced climate variability in the tropics: a 200 000 yr annual record of monsoon variability from Pangea's equator." Climate of the Past 7, no. 3 (July 19, 2011): 757–70. http://dx.doi.org/10.5194/cp-7-757-2011.
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Abstract. A continuous series of 209 000 evaporite varves from the equator of arid western Pangea (age = −255 ma), as a proxy for surface temperature, has a complete suite of Milankovitch cycles and harmonics as expected for a rectified reaction to precession-modulated insolation at the equator. Included are modes of precession (23.4 kyr, 18.2 kyr), semi-precession (11.7 kyr, 9.4 kyr), and harmonics at ~7 kyr and 5.4 kyr. An oscillation of ~100 kyr, with 35 % of total variance, originates as an amplitude modulation of precession cycles. An exceptionally strong 2.3 kyr quasi-bi-millennial oscillation (QBMO) appears to have had its own source of forcing, possibly solar, with its amplitude enhanced at Milankovitch frequencies. Seasonal information in varves traces the rectifying process to asymmetrical distribution of Pangea relative to the equator, and its effect on monsoonal circulation and heat flow near the equator during summer solstices in the hemispheres.
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Sangakkara, U., and P. Stamp. "Productivity and nitrogen use of maize as affected by in situ and ex situ green manuring in major and minor seasons of tropical Asia." Acta Agronomica Hungarica 57, no. 3 (September 1, 2009): 285–96. http://dx.doi.org/10.1556/aagr.57.2009.3.4.
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Green manuring is considered an important agronomic practice for smallholder farming systems in the tropics. Different species of legumes and non-legumes are applied either as ex situ or in situ green manures. Thus a field study conducted under rainfed conditions in Sri Lanka compared the effect of in situ and ex situ green manuring using two popular green manures ( Crotolaria juncea — a legume and Tithonia diversifolia — a non-legume) on the growth, seed yield and N use pattern of maize ( Zea mays ), the most popular upland cereal in the Asian tropics, grown with high and low N rates, in the two seasons that correspond to the monsoonal rains. In situ green manuring, especially with crotolaria, increased the growth, seed yield and N use efficiency of maize when compared to the ex situ addition of similar quantities of the green manure. The impact was also greater in the minor season, when the crop was subjected to moisture stress conditions. The benefits of in situ green manuring with tithonia were lower than those due to crotolaria. In situ green manuring with tithonia also led to a greater increase in growth, seed yield and N use efficiency in maize compared to ex situ green manuring with this species. The green manures, especially in situ application, also increased the benefits of enhanced rates of N fertilizer to the crops in both seasons, with greater use efficiency in the major season. The study showed the benefits of green manuring (both in and ex situ ) for obtaining higher yields of maize in the growing seasons of the Asian tropics, especially the in situ application of legume species.
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Kodama, Yasu-Masa, Masaki Katsumata, Shuichi Mori, Sinsuke Satoh, Yuki Hirose, and Hiroaki Ueda. "Climatology of Warm Rain and Associated Latent Heating Derived from TRMM PR Observations." Journal of Climate 22, no. 18 (September 15, 2009): 4908–29. http://dx.doi.org/10.1175/2009jcli2575.1.
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Abstract The large-scale distribution of precipitation and latent heating (LH) profiles in the tropics, subtropics, and part of the midlatitudes was studied using a 9-yr dataset derived from Tropical Rainfall Measuring Mission precipitation radar observations, with emphasis on the contribution of warm rain. The distribution of warm rain showed features unique from those of rain in other categories and those of outgoing longwave radiation. Warm rain was weak over land but widely distributed over oceans, especially along the intertropical convergence zone (ITCZ) and the western part of the subtropical oceans. The observed amount of warm rain depended on the rainfall intensity rather than on the frequency of warm rain events. The amount of warm rain over ocean was positively correlated with sea surface temperature (SST); this dependency was found in the tropics, subtropics, and part of the midlatitudes, whereas dependency of SST on total rain was confined to the tropics. Both total rain and warm rain were concentrated in the ITCZ, which elongated along the local SST maximum. Small amounts of warm rain were found along subtropical convergence zones (the baiu frontal zone and subtropical portions of the South Pacific convergence zone and the South Atlantic convergence zone) with ample total rainfall. However, larger amounts of warm rain were observed at the lower-latitude sides of these zones in the upstream portions of low-level moisture flow toward the zones. Warm rain may cultivate the subtropical convergence zones by deepening the moist boundary layer and increasing moisture flux toward the zones. The statistical relationship between warm rain and low-level cloudiness showed that the warm rain amount was large when low-level cloudiness was 20%–30% and small when low-level cloudiness was greater than 40%. This indicates that intense warm rain is provided by convective clouds, not by stratiform clouds, in conditions of substantial cloudiness. Despite the small contribution to total rain, warm rain maintained positive LH values over most of the tropical and subtropical oceans. The LH by warm rain masked low-level cooling observed in stratiform rain and maintained positive LH in the lower atmosphere below the melting layer. Because warm rain was confined to oceans, a strong LH contrast was maintained along the coast; this contrast reached values of 1–2 K day−1 in certain places and may affect local and monsoonal circulation across continental coasts.
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Chan, Eric K. W., Yixin Zhang, and David Dudgeon. "Arthropod 'rain' into tropical streams: the importance of intact riparian forest and influences on fish diets." Marine and Freshwater Research 59, no. 8 (2008): 653. http://dx.doi.org/10.1071/mf07191.
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Terrestrial arthropods might represent an important energy source for stream predators, but these trophic linkages have seldom been studied in the tropics. Terrestrial arthropod inputs (essentially, arthropod ‘rain’) into four streams with different riparian vegetation (two draining shrublands and two draining forests) were measured over three consecutive seasons (dry, wet, dry) from 2005 to 2007 in monsoonal Hong Kong. Predatory minnows, Parazacco spilurus (Cyprinidae), were collected and their consumption of terrestrial arthropods was estimated. Inputs of arthropods were dominated by Diptera, Collembola, Formicidae and aerial Hymenoptera, accounting for ≥73% of the arthropod abundance. Seasonal variation was marked: numbers in the dry seasons were approximately half (47–57%) those in the wet season, and biomass fell to one-third (33–37%) of the wet-season value. Shrubland streams received 19–43% fewer individuals and 6–34% less biomass than shaded forest streams. An analysis of fish diets in three of the four streams showed that terrestrial insects and spiders were more important prey in the two forest streams, accounting for 35–43% of prey abundance (39–43% by volume) v. 28% (27%) in the shrubland stream. Because riparian vegetation is the source of terrestrial arthropod inputs to streams, degradation of streamside forests that reduce these inputs will have consequences for the diets of stream fishes.
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Firth, Ronald S. C., Elizabeth Jefferys, John C. Z. Woinarski, and Richard A. Noske. "The diet of the brush-tailed rabbit-rat (Conilurus penicillatus) from the monsoonal tropics of the Northern Territory, Australia." Wildlife Research 32, no. 6 (2005): 517. http://dx.doi.org/10.1071/wr04127.
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The diet of the brush-tailed rabbit-rat (Conilurus penicillatus) was assessed by microscopic analysis of faecal samples from 35 individuals collected from three different sites in the Northern Territory (Garig Gunak Barlu National Park (Cobourg Peninsula), Kakadu National Park and Melville Island) at various times of the year during 2000–02. Seed was the most abundant item in the overall diet of C. penicillatus, making up 68% of identifiable particles, with smaller proportions contributed by leaves (21%), plant stems (8%) and insects (2%). ANOSIM tests revealed no difference in diet between the sexes and seasons, but there was a significant difference in the diet between the sites, with seed material present in 74% of the samples from Cobourg and in 62% and 58% of samples from Kakadu and Melville respectively. Leaf matter was present in 19% of samples from Cobourg and in 26% and 24% of samples from Kakadu and Melville respectively. Stem material was present in only 6% of samples from Cobourg and in 8% and 13% of samples from Kakadu and Melville respectively. Insect matter was present in small quantities across all three sites. The high proportion of seed in the diet suggests that C. penicillatus is primarily granivorous.
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Sundaram, Suchithra, and David M. Holland. "A Physical Mechanism for the Indian Summer Monsoon—Arctic Sea-Ice Teleconnection." Atmosphere 13, no. 4 (March 31, 2022): 566. http://dx.doi.org/10.3390/atmos13040566.
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Significant changes in the Arctic climate, particularly a rapid decline of September Arctic sea ice has occurred over the past few decades. Though the exact reason for such drastic changes is still unknown, studies suggest anthropogenic drivers, natural variability of the climate system, and a combination of both as reasons. The present study focus on the influence of one of the natural variabilities of the climate system, the teleconnections associated with the Indian Summer Monsoon (ISM), and its relationship to September Arctic sea ice. Using 50 years (1951–2000) of National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) NCEP/NCAR reanalysis data, APHRODITE precipitation data, Gridded Monthly Sea Ice Extent and Concentration, 1850 Onward, V2, and HadISST sea-ice concentration data, it is shown that during many strong (weak) ISM years, the Arctic sea ice increased (decreased) predominantly over the Chukchi and Beaufort Seas. The ISM plays a significant role in causing a positive (negative) North Atlantic Oscillation (NAO) during strong (weak) ISM years through the monsoon-desert mechanism associated with monsoonal heating. Simultaneously, the NAO during a strong (weak) ISM causes weakening (strengthening) of the Beaufort Sea High (BSH). The strength of the BSH modulates the Arctic atmospheric circulation, advecting cold air and the direction of the transpolar drift stream, both leading to the generation of more (less) sea ice over the Chukchi-Beaufort Sea region during strong (weak) ISM years. The study illustrates a new atmospheric teleconnection between the tropics and the Arctic.
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OLIVER, PAUL M., CHRIS J. JOLLY, PHILLIP L. SKIPWITH, LEONARDO G. TEDESCHI, and GRAEME R. GILLESPIE. "A new velvet gecko (Oedura: Diplodactylidae) from Groote Eylandt, Northern Territory." Zootaxa 4779, no. 3 (May 20, 2020): 438–50. http://dx.doi.org/10.11646/zootaxa.4779.3.10.
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Over the last decade, the combination of biological surveys, genetic diversity assessments and systematic research has revealed a growing number of previously unrecognised vertebrate species endemic to the Australian Monsoonal Tropics. Here we describe a new species of saxicoline velvet gecko in the Oedura marmorata complex from Groote Eylandt, a large island off the eastern edge of the Top End region of the Northern Territory. Oedura nesos sp. nov. differs from all congeners in combination of moderate size, and aspects of tail morphology and colouration. It has not been reported from the nearby mainland regions (eastern Arnhem Land) suggesting it may be an insular endemic, although further survey work is required to confirm this. While Groote Eylandt is recognised as a contemporary ecological refuge for declining mammal species of northern Australia, newly detected endemic species suggest it may also be of significance as an evolutionary refuge for many taxa, especially those associated with sandstone escarpments.