Conservation value of solar salt ponds in coastal tropical eastern Australia to waterbirds and migratory shorebirds.

2012 ◽  
Vol 18 (2) ◽  
pp. 100 ◽  
Author(s):  
Wayne Houston ◽  
Robert Black ◽  
Rod Elder ◽  
Leif Black ◽  
Richard Segal
Keyword(s):  
Seasonal Pattern ◽  
River Estuary ◽  
Conservation Value ◽  
Wet Season ◽  
Salinity Regime ◽  
Solar Salt ◽  
Migratory Shorebirds ◽  
Complementary Resources ◽  
Eastern Australia ◽  
Natural Wetlands

Some human-altered habitats such as saltfields support significant numbers of shorebirds and waterbirds, but their values in tropical eastern Australia are poorly understood. With the continuing loss of shorebird habitats in the East Asian-Australasian Flyway, identification of important habitats and management is important for their conservation. The habitat value of two saltfields associated with the Fitzroy River estuary, Queensland (23.520S, 150.860E) was evaluated by monthly surveys over 33 months and by comparison to previous surveys of nearby natural wetlands. Saltfields supported as many waterbirds and species as freshwater and naturally saline lagoons. Numbers of migratory shorebirds peaked during the southern migration period (September to November), when wetlands in tropical northern Australia are at their lowest extent, thus elevating the conservation value of tropical saltfields to shorebirds. Sharp-tailed Sandpipers were regularly present in numbers exceeding international levels for staging, while Red-necked Stints were just below the staging criterion. Salinity regime was found to influence waterbird communities associated with saltfield pools: piscivores dominating metasaline pools, and shorebirds hypersaline pools. A seasonal pattern of occurrence occurred in some guilds with greatest numbers in the drier months (cormorants, pelicans, ducks and egrets, all significantly negatively correlated with the previous month’s rainfall), most of which bred in nearby natural wetlands during the wet season. Furthermore, cormorants were abundant in the saltfields and fluctuated less compared with natural lagoons during the critical drier months. Overall, saltfields are an integral component of the ecology of the landscape, providing complementary resources to that of the natural wetlands.

Phenological variation in Heteropogon contortus and its relation to climate

1966 ◽  
Vol 14 (1) ◽  
pp. 35 ◽  
Author(s):  
JC Tothill
Keyword(s):  
Seasonal Pattern ◽  
Natural Populations ◽  
Late Summer ◽  
Day Length ◽  
Tropical Region ◽  
Wet Season ◽  
Early Maturity ◽  
Heteropogon Contortus ◽  
Rainfall Season ◽  
Eastern Australia

Heteropogon contortus Beauv. ex Roem. & Schult. (spear grass or tanglehead) exhibits conisiderable: morphological and phenoiogicai variation. Wniie the morphological variation is apparently unrelated to geographic distribution, the phenological variation appears to be closely associated with differences in climate. Flowering is largely governed by day length, but the seasonal pattern of rainfall distribution has selected only those day lengths which promote flowering within the rainfall season. In the tropical region of north-eastern Australia flowering occurs in late summer and short days, since the wet season prevails over the second half of the summer. When northern material is grown in uniform grass gardens south of this tropical region, late maturity still prevails; hence this behavioural pattern is genetically fixed. In the subtropics, on the other hand, adequate rain may fall over the entire potential growing season or any part of it. In the garden great variation of phenology marks the southern material. Furthermore, sampling within local populations may also show great variation from early maturity through to late. It is suggested that in Australia H. contortus is naturally a species of the semi-arid tropics. It has spread into the subtropics through its ability to match the extended but more uncertain rainfall season by producing types of differing day length response. This variation is fixed by the predominantly apomictic mode of reproduction, while the perenniality of the plants ensures survival over periods of unsuitable climate. A long-term equilibrium is therefore established between the flowering behaviour of the population and its climate. A knowledge of the patterns of behaviour within and between populations is likely to be Important for increased pastoral efficiency, firstly, in preventing natural populations from deteriorating towards earlier maturity, and secondly, in lengthening the productive season of pasture growth.

scholarly journals Shifts of Bacterioplankton Metabolic Profiles along the Salinity Gradient in a Subtropical Estuary

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Hidetoshi Urakawa ◽  
Jaffar Ali ◽  
Rheannon D. J. Ketover ◽  
Spencer D. Talmage ◽  
Juan C. Garcia ◽  
...  
Keyword(s):  
Salinity Gradient ◽  
Water Discharge ◽  
River Estuary ◽  
Metabolic Profiles ◽  
Wet Season ◽  
Biolog Ecoplates ◽  
Utilization Patterns ◽  
Subtropical Estuary ◽  
Discharge Patterns ◽  
Bacterioplankton Communities

Understanding the biodegradation potential of river bacterioplankton communities is crucial for watershed management. We investigated the shifts in bacterioplankton metabolic profiles along the salinity gradient of the Caloosahatchee River Estuary, Florida. The carbon source utilization patterns of river bacterioplankton communities were determined by using Biolog EcoPlates. The number of utilized substrates was generally high in the upstream freshwater dominated zone and low in the downstream zone, suggesting a shift in metabolic profiles among bacterioplankton assemblages along the estuarine gradient. The prokaryotic cell numbers also decreased along the estuarine salinity gradient. Seasonal and site-specific differences were found in the numbers of utilized substrates, which were similar in summer and fall (wet season) and winter and spring (dry season). Bacterioplankton assemblages in summer and fall showed more versatile substrate utilization patterns than those of winter and spring communities. Therefore, our data suggest that microbial metabolic patterns in the subtropical estuary are likely influenced by the water discharge patterns created by dry and wet seasons along the salinity gradient.

scholarly journals Response of the Snowy River Estuary to two environmental flows

2015 ◽  
Vol 127 (2) ◽  
pp. 28
Author(s):  
Errol J. McLean ◽  
Jon B. Hinwood
Keyword(s):  
Fresh Water ◽  
Peak Flow ◽  
Environmental Flows ◽  
River Estuary ◽  
Environmental Flow ◽  
River Channel ◽  
Salinity Gradients ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Major River

The Snowy River is a major river in south-eastern Australia, discharging to the Tasman Sea via a barrier estuary, with its entrance constricted by marine sands. Since the construction of the Snowy Mountains Scheme, river flows have not been sufficient to maintain the river channel. A program of environmental flow releases (EFR) is returning water to the river to restore the fluvial reaches and is now trialling flow regimes that may also benefit the estuarine reaches. This paper documents the response of the estuarine segments of the Snowy River to two EFRs; the release in 2010 was designed to scour the upper reaches of the Snowy River while the larger 2011 release was intended to extend the scouring downstream. For each release, the effects on the entrance morphology, tides and salinity through the flow peak and recovery are described. Each EFR caused minor increases in depth and very minor longshore movement of the entrance channel, although each EFR had been preceded by a larger fresh flow that would have scoured the channels. The small increase in fresh water inflow in the 2010 EFR pushed salinity contours seawards and steepened vertical salinity gradients. The larger inflow in the 2011 EFR purged the upper estuary of saltwater. After the peak flow, salinity recovery was rapid in the principal estuarine channels but took weeks where poorly connected wetlands could store fresh flood waters. Critical flows for scouring the entrance and purging salinity are estimated.

scholarly journals SEASONAL AND INTERANNUAL PATTERN OF METEOROLOGICAL VARIABLES IN CUIABÁ, MATO GROSSO STATE, BRAZIL

2015 ◽  
Vol 33 (3) ◽  
pp. 477 ◽  
Author(s):  
Nadja Gomes Machado ◽  
Marcelo Sacardi Biudes ◽  
Carlos Alexandre Santos Querino ◽  
Victor Hugo De Morais Danelichen ◽  
Maísa Caldas Souza Velasque
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Meteorological Data ◽  
Seasonal Pattern ◽  
Global Radiation ◽  
Meteorological Variables ◽  
Maximum Temperature ◽  
Wet Season ◽  
Agricultural Producers ◽  
Mato Grosso

ABSTRACT. Cuiab´a is located on the border of the Pantanal and Cerrado, in Mato Grosso State, which is recognized as one of the biggest agricultural producers of Brazil. The use of natural resources in a sustainable manner requires knowledge of the regional meteorological variables. Thus, the objective of this study was to characterize the seasonal and interannual pattern of meteorological variables in Cuiab´a. The meteorological data from 1961 to 2011 were provided by the Instituto Nacional de Meteorologia (INMET – National Institute of Meteorology). The results have shown interannual and seasonal variations of precipitation, solar radiation, air temperature and relative humidity, and wind speed and direction, establishing two main distinct seasons (rainy and dry). On average, 89% of the rainfall occurred in the wet season. The annual average values of daily global radiation, mean, minimum and maximum temperature and relative humidity were 15.6 MJ m–2 y–1, 27.9◦C, 23.0◦C, 30.0◦C and 71.6%, respectively. Themaximum temperature and the wind speed had no seasonal pattern. The wind speed average decreased in the NWdirectionand increased in the S direction.Keywords: meteorological variables, climatology, ENSO. RESUMO. Cuiabá está localizado na fronteira do Pantanal com o Cerrado, no Mato Grosso, que é reconhecido como um dos maiores produtores agrícolas do Brasil. A utilização dos recursos naturais de forma sustentável requer o conhecimento das variáveis meteorológicas em escala regional. Assim, o objetivo deste estudo foi caracterizar o padrão sazonal e interanual das variáveis meteorológicas em Cuiabá. Os dados meteorológicos de 1961 a 2011 foram fornecidos pelo Instituto Nacional de Meteorologia (INMET). Os resultados mostraram variações interanuais e sazonais de precipitação, radiação solar, temperatura e umidade relativa do ar e velocidade e direção do vento, estabelecendo duas principais estações distintas (chuvosa e seca). Em média, 89% da precipitação ocorreu na estação chuvosa. Os valores médios anuais de radiação diária global, temperatura do ar média, mínima e máxima e umidade relativa do ar foram 15,6 MJ m–2 y–1, 27,9◦C, 23,0◦C, 30,0◦C e 71,6%, respectivamente. A temperatura máxima e a velocidade do vento não tiveram padrão sazonal. A velocidade média do vento diminuiu na direção NW e aumentou na direção S.Palavras-chave: variáveis meteorológicas, climatologia, ENOS.

scholarly journals Major Stressors Favoring Cholera Trigger and Dissemination in Guinea-Bissau (West Africa)

2021 ◽  
Vol 18 (21) ◽  
pp. 11296
Author(s):  
Ana Machado ◽  
Eva Amorim ◽  
Adriano A. Bordalo
Keyword(s):  
Seasonal Pattern ◽  
Mitigation Strategies ◽  
Wash Water ◽  
Wet Season ◽  
African Countries ◽  
Guinea Bissau ◽  
Sanitation And Hygiene ◽  
Heavy Burden ◽  
Sub Saharan ◽  
Key Indicators

Cholera remains a heavy burden worldwide, especially in Sub-Saharan African countries, which account for the majority of the reported cases on the continent. In this study, a 27-year retrospective analysis of cholera epidemics in Guinea-Bissau was performed in order to highlight major stressors fueling the trigger and dissemination of the disease. Although the role of environmental factors did not always have the same degree of importance for the onset of epidemics, a cholera seasonal pattern was clearly perceived, with most of the reported cases occurring during the wet season. The generated theoretical hypothesis indicated rainfall above climatological average, associated with a lack of WASH (water, sanitation and hygiene) infrastructure, and the occurrence of concomitant epidemics in neighboring countries as the key indicators for optimal conditions for cholera to thrive in Guinea-Bissau. Warmer air temperature, the increase in sea surface temperature, and the decrease in salinity in the coastal areas may also contribute to the emergence and/or aggravation of cholera events. Prediction of the conditions favorable for cholera growth and identification of risk pathways will allow the timely allocation of resources, and support the development of alert tools and mitigation strategies.

scholarly journals The significance and vulnerability of Australian saltmarshes: implications for management in a changing climate

2013 ◽  
Vol 64 (1) ◽  
pp. 66 ◽  
Author(s):  
Neil Saintilan ◽  
Kerrylee Rogers
Keyword(s):  
Sea Level ◽  
Atmospheric Carbon Dioxide ◽  
Services Research ◽  
Goods And Services ◽  
Migratory Shorebirds ◽  
Sporobolus Virginicus ◽  
Past Half Century ◽  
Eastern Australia ◽  
Hard Structures ◽  
Flexible Management

We review the distribution, status and ecology of Australian saltmarshes and the mechanisms whereby enhanced atmospheric carbon dioxide and associated climate change have influenced and will influence the provision of ecosystem goods and services. Research in temperate and subtropical saltmarsh has demonstrated important trophic contributions to estuarine fisheries, mediated by the synchronised mass-spawning of crabs, which feed predominantly on the C4 saltmarsh grass Sporobolus virginicus and microphytobenthos. Saltmarshes also provide unique feeding and habitat opportunities for several species of threatened microbats and birds, including migratory shorebirds. Saltmarshes increased in extent relative to mangrove in Australia in both tide- and wave-dominated geomorphic settings through the latter Holocene, although historic trends have seen a reversal of this trend. Australian saltmarshes have some capacity to maintain elevation with respect to rising sea level, although in south-eastern Australia, the encroachment of mangrove and, in Tasmania, conversion of shrubland to herbfield in the past half-century are consistent with changes in relative sea level. Modelling of the impacts of projected sea-level rise, incorporating sedimentation and other surface-elevation drivers, suggests that the survival of saltmarsh in developed estuaries will depend on the flexible management of hard structures and other impediments to wetland retreat.

Aspects of the reproductive biology of Pseudotolithus typus (Bleeker, 1863) from qua Iboe River Estuary, Nigeria

2020 ◽  
Vol 35 (1) ◽  
pp. 57-66
Author(s):  
A.I. Nta ◽  
A.W. Akpan ◽  
A.O. Okon ◽  
I.K. Esenowo
Keyword(s):  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
River Estuary ◽  
Condition Index ◽  
Mean Value ◽  
Female Dominance ◽  
Wet Season ◽  
Female Ratio ◽  
Average Fecundity ◽  
Spawning Periods

The study was conducted to assess the reproductive biology and condition index of Pseudotolithus typus in Qua Iboe Estuary using standard methods. A total of 580 fish specimen were sampled over a period of 8 months (January – August, 2018). Condition index was generally low with the highest value of 1.03 recorded in the month of April. The overall mean condition index significantly deviated (p<0.05) from the expected value of 1.0. Male-female ratio of the species showed female dominance. Significant variation (p<0.05) were observed in condition and gonadosomatic indices with peak values in the months of March and July for females. Male fish showed no seasonality in gonadosomatic index. The average fecundity ranged from 2140 eggs to 8560 eggs with mean value of 4891±641 eggs. Positive correlation was observed between fecundity and total length, body weight, standard length and gonad weight of the fish. Thus, it could be concluded that P. typus is a dual seasonal spawner having spawning periods early in the year (March) and in the peak of wet season (July). Keywords: Pseudotolithus typus, condition index, gonadosomatic index, fecundity, estuary.

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