Thinking honeyeater: nectar maps for the Northern Territory, Australia

2000 ◽  
Vol 6 (1) ◽  
pp. 61 ◽  
Author(s):  
John C. Z. Woinarski ◽  
Greg Connors ◽  
Don C. Franklin
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Spatial And Temporal Variation ◽  
Wet Season ◽  
Nectar Production ◽  
The World ◽  
Eucalypt Forests ◽  
The Times ◽  
Species Specific ◽  
Nectar Availability

We create monthly maps of nectar availability for the 1.4 x 106 km2 jurisdiction of the Northern Territory, Australia. These are based on a combination of vegetation mapping and a series of indices of plant species specific nectar scoring. The maps reveal complex spatial and temporal variation in nectar availability, but most notably a greater nectar resource in the monsoon-influenced north than in the arid south, and a peak in nectar availability in the dry season. The latter is associated with the extensive tropical eucalypt forests (especially those co-dominated by Eucalyptus miniata and E. tetrodonta). In contrast, wet season nectar availability in these forests is limited, but riparian and swampland forests, typically dominated by Melaleuca species, provide rich but spatially restricted nectar resources. The extensive and rich nectar resources available in eucalypt forests in the dry season supplement the diets of many species which are not primarily nectarivorous. This resource helps shape the singularity of northern Australian eucalypt forests relative to other extensive forests elsewhere in the world. Nectarivores remain in the system through a combination of movements across a number of scales, habitat shifting, and diet shifting. The latter is aided by the peaking of invertebrate and fruit resources at the times of minimum nectar production; a shuffling in resource availability brought about by the extreme climatic seasonality.

Observations on the Larval Diapause of the Pink Bollworm, Platyedra gossypiella, Saund.

1940 ◽  
Vol 30 (4) ◽  
pp. 475-481 ◽  
Author(s):  
F. A. Squire
Keyword(s):  
West Indies ◽  
Dry Season ◽  
Pink Bollworm ◽  
Wet Season ◽  
The West ◽  
Long Cycle ◽  
Larval Diapause ◽  
The World

As cotton crops in many parts of the world end either with the onset of winter or of the dry season, it is natural that the larval diapause which becomes more and more conspicuous as the crop ripens should have come to be regarded as an instance of either hibernation or aestivation; yet in the West Indies where the following observations were made, there is no winter, nor does the ripe boll phase of the crop necessarily fall in the dry season. The latter moreover is not one of complete drought but rather dry only by comparison. Indeed in some islands, such as Montserrat and St. Kitts, the crop is harvested in the wet season. Yet long-cycle or resting larvae are regularly found in all of these islands.

scholarly journals Effects of Effluents on the Quality of River Rido, Kaduna- State, Nigeria

2020 ◽  
Vol 12 (1) ◽  
pp. 159-170
Author(s):  
Louis Buggu ◽  
Funmilayo Yusufu - Alfa ◽  
Abigail Abenu
Keyword(s):  
Heavy Metals ◽  
Treatment Plant ◽  
World Health Organisation ◽  
Dry Season ◽  
World Health ◽  
Wet Season ◽  
Mean Values ◽  
The World ◽  
Effluent Discharge

This study examines the effect of discharged effluents on the quality of river Rido in Kaduna. Ten water samples were collected and tested for Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Manganese (Mn), Mercury (Hg), Nickel (Ni) and Zinc (Zn). The results revealed that in  the dry season,  six heavy metals, namely As, Cd, Cu, Mn, Ni and Zn, presented mean values that were  higher  after the point of effluent discharge; while Cr, Fe and Pb  had lower values and Hg was not detected. In the wet season all the heavy metals tested, except Hg, increased in values after the point of effluent discharge. The values of As, Cd,  Fe, Mn, Ni and Pb after the discharge point, in dry and wet seasons, were greater than the maximum tolerable limits set by the Standard Organisation of Nigeria (SON) and the World Health Organisation (WHO).  The values recorded for Zn and Cu at both dry and wet seasons were below the limit set by the Standard Organisation of Nigeria (SON) and the World Health Organisation (WHO), but the value of Cr was lower than the maximum tolerable limit only in the dry season.  The contamination of the river with heavy metals poses a grave danger to human health, as its water is used for diverse purposes. The wastewater treatment plant of KRPC should be rehabilitated and the wastewater can be pre-treated before it is discharged into the river.

scholarly journals Origin of water-soluble organic aerosols at the Maïdo high-altitude observatory, Réunion Island in the tropical Indian Ocean

2021 ◽  
Author(s):  
Sharmine Akter Simu ◽  
Yuzo Miyazaki ◽  
Eri Tachibana ◽  
Henning Finkenzeller ◽  
Jérôme Brioude ◽  
...  
Keyword(s):  
Indian Ocean ◽  
High Altitude ◽  
Radiative Forcing ◽  
Numerical Models ◽  
Stable Carbon Isotope ◽  
Organic Aerosols ◽  
Dry Season ◽  
Water Soluble ◽  
Spatial And Temporal Variation ◽  
Wet Season

Abstract. The tropical and subtropical Indian Ocean (IO) is expected to be a significant source of water-soluble organic aerosols (WSOAs), which are important factors relevant to cloud condensation nuclei and ice nuclei of aerosol particles. Current atmospheric numerical models significantly underestimate the budget of organic aerosols and their precursors, especially over tropical oceans. This is primarily due to poor knowledge of sources and the paucity of observations of these parameters considering spatial and temporal variation over the tropical open ocean. To evaluate the contribution of sources to WSOA as well as their formation processes, submicrometer aerosol sampling was conducted at the high-altitude Maïdo observatory (21.1° S, 55.4° E, 2,160 m a.s.l), located on the remote island of La Réunion in the southwest IO. The aerosol samples were continuously collected during local daytime and nighttime, which corresponded to the ambient conditions of the marine boundary layer (MBL) and free troposphere (FT), respectively, from March 15 to May 24, 2018. Chemical analysis showed that organic matter was the dominant component of submicrometer water-soluble aerosol (~45 ± 17 %) during the wet season (March 15–April 23), whereas sulfate dominated (~77 ± 17 %) during the dry season (April 24–May 24). Measurements of the stable carbon isotope ratio of water-soluble organic carbon (WSOC) suggested that marine sources contributed significantly to the observed WSOC mass in both the MBL and the FT in the wet season, whereas a mixture of marine and terrestrial sources contributed to WSOC in the dry season. The distinct seasonal changes in the dominant source of WSOC were also supported by Lagrangian trajectory analysis. Positive matrix factorization analysis suggested that marine secondary OA dominantly contributed to the observed WSOC mass (~70 %) during the wet season, whereas mixtures of marine and terrestrial sources contributed during the dry season in both MBL and FT. Overall, this study demonstrates that the effect of marine secondary sources is likely important up to the FT in the wet season, which may be responsible for cloud formation as well as direct radiative forcing over oceanic regions.

Distribution and Abundance of Ducks in the Alligator Rivers Region, Northern Territory

1990 ◽  
Vol 17 (6) ◽  
pp. 573 ◽  
Author(s):  
SR Morton ◽  
KG Brennan ◽  
MD Armstrong
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Correction Factors ◽  
The South ◽  
Wet Season ◽  
Aerial Surveys ◽  
Black Duck

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of wandering whistling-duck Dendrocygna arcuata, plumed whistling-duck D. eytoni, radjah shelduck Tadorna radjah, Pacific black duck Anas superciliosa, and grey teal A. gibberifrons on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal north of the Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela plain, to provide more detailed information. The Magela floodplain was inhabited by few ducks during the wet season (November to March), but numbers then increased to dramatic peaks in the late dry season. The Nourlangie floodplain and Boggy Plain (a large backswamp of the South Alligator floodplain) showed similar patterns, but the numbers of ducks were usually fewer. Ducks were uncommon on the shallower East Alligator and Cooper floodplains except for relatively brief periods in the wet season. The ground surveys suggested that ducks sought out the persistent swamps that characterise the Magela floodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities; on the basis of correction factors calculated from the ground surveys, peak numbers on the five floodplains were roughly estimated to be 400 000 wandering whistling-ducks, 70 000 plumed whistling-ducks, 20 000 radjah shelducks, 50 000 Pacific black ducks, and 50 000 grey teal. Pink-eared ducks Malacorhynchus membranaceus and hardhead Aythya australis were recorded sporadically in low numbers. The Alligator Rivers region acted as a dry season refuge for large concentrations of ducks because of the atypical persistence of freshwaters on the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain. The large aggregations appear to be unique in Australia.

scholarly journals New reports of Australian cutaneous leishmaniasis in Northern Australian macropods

2009 ◽  
Vol 137 (10) ◽  
pp. 1516-1520 ◽  
Author(s):  
A. DOUGALL ◽  
C. SHILTON ◽  
J. LOW CHOY ◽  
B. ALEXANDER ◽  
S. WALTON
Keyword(s):  
Life Cycle ◽  
Cutaneous Leishmaniasis ◽  
Real Time ◽  
Real Time Pcr ◽  
Clinical Findings ◽  
Northern Territory ◽  
Causative Organism ◽  
The World ◽  
Species Specific ◽  
Unique Species

SUMMARYCutaneous leishmaniasis caused by various species of Leishmania is a significant zoonotic disease in many parts of the world. We describe the first cases of Australian cutaneous leishmaniasis in eight northern wallaroos, one black wallaroo and two agile wallabies from the Northern Territory of Australia. Diagnosis was made through a combination of gross appearance of lesions, cytology, histology, direct culture, serology and a species-specific real-time PCR. The causative organism was found to be the same unique species of Leishmania previously identified in red kangaroos. These clinical findings provide further evidence for the continuous transmission of the Australian Leishmania species and its presence highlights the importance of continued monitoring and research into the life-cycle of this parasite.

Seasonal use of savanna landscapes by the Gouldian finch, Erythrura gouldiae, in the Yinberrie Hills area, Northern Territory

2001 ◽  
Vol 28 (4) ◽  
pp. 445 ◽  
Author(s):  
P. L. Dostine ◽  
G. C. Johnson ◽  
D. C. Franklin ◽  
Y. Zhang ◽  
C. Hempel
Keyword(s):  
Full Range ◽  
Northern Territory ◽  
Dry Season ◽  
Perennial Grasses ◽  
Grass Species ◽  
Wet Season ◽  
Themeda Triandra ◽  
Annual Grasses ◽  
Gouldian Finch ◽  
Hills Area

The diet, attributes of feeding sites and patterns of seasonal movements of a population of the Gouldian finch, Erythrura gouldiae, were studied in the Yinberrie Hills area north of Katherine in the Northern Territory. In the dry season (April–November) Gouldian finches foraged mostly on burnt ground and fed on exposed seed of annual grasses, especially seed of spear-grass, Sorghum spp. In the wet season (December–March) Gouldian finches fed on seed of a sequence of perennial grass species, including Themeda triandra, Alloteropsis semialata, Chrysopogon fallax and Heteropogon triticeus. Gouldian finches undertake regular seasonal shifts in habitat, from breeding areas in hill woodland in the dry season to adjacent lowlands throughout much of the wet season, in response to seasonal changes in food availability. There is an annual pulse in abundance of fallen seed in the early dry season that is depleted to near zero levels by germination of annual grasses early in the wet season. Thereafter, finches depend on seed from other sources, principally ripe and ripening seed of perennial grasses. Observations over three successive wet seasons suggest that Gouldian finches track seed resources provided by seeding perennial grasses over an extensive area of lowland grassy woodland adjacent to the breeding area, favouring small patches of grassy woodland for brief periods until seed fall. There were subtle differences between years in the types of resources used. Management of Gouldian finch populations will entail protection and management of the full range of grassland habitats used throughout the annual cycle, and will require predictive knowledge of the causes of patterning of seed resources and probably an ability to exert control over the timing and extent of fires in fire-prone seasonal savanna landscapes.

Germination and establishment of the weeds Sida acuta and Pennisetum pedicellatum in the Northern Territory

1980 ◽  
Vol 20 (105) ◽  
pp. 463 ◽  
Author(s):  
JJ Mott
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Dormant Seed ◽  
Weed Species ◽  
Wet Season ◽  
Perennial Weed ◽  
Hard Seed ◽  
Sida Acuta ◽  
Seed Fall ◽  
Almost All

Two serious weed species in the Northern Territory are Sida acuta, a perennial weed of improved pastures, and Pennisetum pedicellatum, an annual grass that infests grain sorghum crops. In P. pedicellatum the customary successive ploughing carried out to kill seedlings in the early wet season may not give satisfactory control of the weed, while with S. acuta there appears to be a long-term dormant seed pool which can give rise to new generations of seedlings, Investigation into the germination requirements of the 2 species showed that both are dormant at seed fall and require high alternating temperatures to remove an after-ripening requirement. In addition S. acuta needs a further period at high temperature to fracture its impermeable seed coat. Almost all P. pedicellatum seed is non-dormant at the end of the dry season, but that of S. acuta still retains 30% hard seed after one dry season. In the field P. pedicellatum germinated faster than S. acuta, with 80% of the total wet season germination occurring with the first rain. In S. acuta germination was spread over the first 2 months of the season. Ploughing immediately after the break of the wet season killed seedlings of P. pedicellatum, but could bury viable dormant seed. Once buried, this store of dormant seed could remain viable and germinate when disturbed at crop planting. At the end of the wet season no viable seed of P. pedicellatum remained in the soil, but there could be a considerable amount of hard S. acuta seed. The results suggest that control of P. pedicellatum could be best accomplished by the use of minimum tillage procedures, with little ground disturbance to bury the seed, while oversowing with a vigorous perennial pasture species such as calopo (Calopognium mucunoides) could lead to suppression of S. acuta.

Seasonal variations in the macroinvertebrate fauna of billabongs along Magela Creek, Northern Territory

1982 ◽  
Vol 33 (2) ◽  
pp. 329 ◽  
Author(s):  
R Marchant
Keyword(s):  
Seasonal Variations ◽  
Littoral Zone ◽  
Northern Territory ◽  
Dry Season ◽  
Wet Season ◽  
The Mean ◽  
Macroinvertebrate Fauna

The littoral zone of five permanent billabongs along Magela Creek was sampled monthly over 1 year for macroinvertebrates. In three shallow billabongs, greatest numbers of taxa (about 45) and of individuals (about 1000 individuals per minute) were caught in the late wet season and early dry season (April-July); by the end of the dry season (December) these values had decreased to about 18 taxa and about 200 individuals per minute. Fluctuations were not so marked in two deep (or channel) billabongs: rarely were there fewer than 30 taxa and 400 individuals per minute present, and maximal values were similar to those in the shallow billabongs. These changes appeared to be associated with the growth of macrophytes, which occurred during the wet season in all billabongs. There was little variation between billabongs in the mean composition of the fauna.

scholarly journals Environmental Impact of Agrochemical uses on the Island’s Agricultural Production Area in Maranhão, Brazil

2020 ◽  
pp. 75-85
Author(s):  
Sérgio Henrique Pinto Silva ◽  
Mélanie Martins Gonçalves ◽  
Fábio Henrique Ramos Braga ◽  
Neuriane Silva Lima ◽  
Wallace Ribeiro Nunes Neto ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Agricultural Production ◽  
Agricultural Land ◽  
Dry Season ◽  
Soil Samples ◽  
Wet Season ◽  
The World ◽  
Production Area ◽  
Food Needs

Agriculture is the foundation of society, has provided humanity with its food needs for over ten thousand years. The use of pesticides in Brazil and the world has grown exponentially in recent decades. The objective of this study was assessment the use of agrochemicals and their environmental impact on agricultural production of the Island of Maranhão. The study area is located in Paço do Lumiar, Maranhão, Brazil. Soil samples were collected from agricultural land during the wet season (between the months of February and May) and dry season (between the months of September and October) seasons of 2018.

Distribution and abundance of herons, egrets, ibises and spoonbills in the Alligator Rivers Region, Northern Territory

1993 ◽  
Vol 20 (1) ◽  
pp. 23 ◽  
Author(s):  
SR Morton ◽  
KG Brennan ◽  
MD Armstrong
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Correction Factors ◽  
The South ◽  
Wet Season ◽  
Fresh Waters ◽  
Aerial Surveys ◽  
Sacred Ibis ◽  
Egretta Garzetta

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of Pacific herons (Ardea pacifica), pied herons (Ardea picata), cattle egrets (Ardeola ibis), great egrets (Egretta alba), little egrets (Egretta garzetta), intermediate egrets (Egretta intermedia), glossy ibis (Plegadis falcinellus), sacred ibis (Threskiornis aethiopica), straw-necked ibis (Threskiornis spinicollis) and royal spoonbills (Platalea regia) on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela. The aerial surveys indicated that the Magela floodplain was inhabited by few of these birds during the wet season (November-March), but that numbers then increased substantially in the dry season. The Nourlangie floodplain and Boggy Plain (a large backswamp of the South Alligator floodplain) showed similar patterns, but the numbers of birds tended to be lower. Birds were generally uncommon on the shallower East Alligator and Cooper floodplains, except for egrets in the wet season. Ground surveys suggested that the birds sought out the persistent swamps that characterise the Magela foodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities. On the basis of correction factors calculated from ground surveys, peak numbers on the five floodplains were roughly estimated to be about 4000 pacific herons, 50 000 pied herons, 300 000 egrets (primarily intermediate egrets), 60 000 glossy ibis, 16 000 sacred ibis, 80 000 straw-necked ibis and 35 000 royal spoonbills. Great-billed herons (Ardea sumatrana), white-faced herons (Ardea novaehollandiae), striated herons (Butorides striata), rufous night herons (Nycticorax caledonicus), black bitterns (Dupetor flavicollis) and yellow-billed spoonbills (Platalea flavipes) were recorded sporadically in low numbers. The Alligator Rivers region acted as a dry-season refuge for herons, egrets, ibises and spoonbills because of the unusually persistent fresh waters of the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain.

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