Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
Malar J ; 17(1): 431, 2018 11 19.
Article in English | MEDLINE | ID: mdl-30453973

ABSTRACT

Following publication of the original article [1], one of the authors flagged that the images for Figs. 2 and 3 were swapped in the published article-Fig. 2 had the image meant for Fig. 3 and vice versa.

2.
Malar J ; 17(1): 381, 2018 Oct 22.
Article in English | MEDLINE | ID: mdl-30348161

ABSTRACT

BACKGROUND: Malaria remains a challenge in Solomon Islands, despite government efforts to implement a coordinated control programme. This programme resulted in a dramatic decrease in the number of cases and mortality however, malaria incidence remains high in the three most populated provinces. Anopheles farauti is the primary malaria vector and a better understanding of the spatial patterns parasite transmission is required in order to implement effective control measures. Previous entomological studies provide information on the ecological preferences of An. farauti but this information has never before been gathered and "translated" in useful tools as maps that provide information at both the national level and at the scale of villages, thus enabling local targeted control measures. METHODS: A literature review and consultation with entomology experts were used to determine and select environmental preferences of An. farauti. Remote sensing images were processed to translate these preferences into geolocated information to allow them to be used as the basis for a Transmission Suitability Index (TSI). Validation was developed from independent previous entomological studies with georeferenced locations of An. farauti. Then, TSI was autoscaled to ten classes for mapping. RESULTS: Key environmental preferences for the An. farauti were: distance to coastline, elevation, and availability of water sources. Based on these variables, a model was developed to provide a TSI. This TSI was developed using GIS and remote sensing image processing, resulting in maps and GIS raster layer for all the eight provinces and Honiara City at a 250 m spatial resolution. For a TSI ranging from 0 as not suitable to 13 as most suitable, all the previous collections of An. farauti had mean TSI value between 9 and 11 and were significantly higher than where the vector was searched for and absent. Resulting maps were provided after autoscaling the TSI into ten classes from 0 to 9 for visual clarity. CONCLUSIONS: The TSI model developed here provides useful predictions of likely malaria transmission larval sources based on the environmental preferences of the mosquito, An. farauti. These predictions can provide sufficient lead-time for agencies to target malaria prevention and control measures and can assist with effective deployment of limited resources. As the model is built on the known environmental preferences of An. farauti, the model should be completed and updated as soon as new information is available. Because the model did not include any other malaria transmission factors such as care availability, diagnostic time, treatment, prevention, and entomological parameters other than the ecological preferences neither, our suitability mapping represents the upper bound of transmission areas. The results of this study can now being used as the basis of a malaria monitoring system which has been jointly implemented by the Solomon Islands National Vector Borne Disease Control Programme, the Solomon Islands Meteorological Services and the Australian Bureau of Meteorology. The TSI model development method can be applied to other regions of the world where this mosquito occurs and could be adapted for other species.


Subject(s)
Animal Distribution , Anopheles/physiology , Communicable Disease Control/methods , Malaria/transmission , Mosquito Control/methods , Mosquito Vectors/physiology , Plasmodium/physiology , Animals , Anopheles/growth & development , Geographic Information Systems , Geographic Mapping , Humans , Larva/physiology , Melanesia , Mosquito Vectors/growth & development
3.
Int J Biometeorol ; 58(6): 1147-62, 2014 Aug.
Article in English | MEDLINE | ID: mdl-23900579

ABSTRACT

There is substantial evidence of climate-related shifts to the timing of avian migration. Although spring arrival has generally advanced, variable species responses and geographical biases in data collection make it difficult to generalise patterns. We advance previous studies by using novel multivariate statistical techniques to explore complex relationships between phenological trends, climate indices and species traits. Using 145 datasets for 52 bird species, we assess trends in first arrival date (FAD), last departure date (LDD) and timing of peak abundance at multiple Australian locations. Strong seasonal patterns were found, i.e. spring phenological events were more likely to significantly advance, while significant advances and delays occurred in other seasons. However, across all significant trends, the magnitude of delays exceeded that of advances, particularly for FAD (+22.3 and -9.6 days/decade, respectively). Geographic variations were found, with greater advances in FAD and LDD, in south-eastern Australia than in the north and west. We identified four species clusters that differed with respect to species traits and climate drivers. Species within bird clusters responded in similar ways to local climate variables, particularly the number of raindays and rainfall. The strength of phenological trends was more strongly related to local climate variables than to broad-scale drivers (Southern Oscillation Index), highlighting the importance of precipitation as a driver of movement in Australian birds.


Subject(s)
Animal Migration , Birds/physiology , Models, Theoretical , Animals , Australia , Climate , Cluster Analysis , Rain , Temperature
4.
Int J Biometeorol ; 58(4): 603-12, 2014 May.
Article in English | MEDLINE | ID: mdl-23934162

ABSTRACT

Seabirds are one of the most threatened groups of birds globally and, overall, their conservation status is deteriorating rapidly. Southern hemisphere countries are over-represented in the number of species of conservation concern yet long-term phenological data on seabirds in the southern hemisphere is limited. A better understanding of the implications of changes in the marine and terrestrial environments to seabird species is required in order to improve their management and conservation status. Here we conducted a meta-analysis of the phenological drivers and trends among southern hemisphere seabirds. Overall there was a general trend towards later phenological events over time (34 % of all data series, N = 47; 67 % of all significant trends), though this varied by taxa and location. The strongest trends towards later events were for seabirds breeding in Australia, the Laridae (gulls, noddies, terns) and migratory southern polar seabirds. In contrast, earlier phenologies were more often observed for the Spheniscidae (penguins) and for other seabirds breeding in the Antarctic and subantarctic. Phenological changes were most often associated with changes in oceanographic conditions, with sea-ice playing an important role for more southerly species. For some species in some locations, such as the Little Penguin Eudyptula minor in south-eastern Australia, warmer oceans projected under various climate change scenarios are expected to correspond to increased seabird productivity, manifested through earlier breeding, heavier chicks, an increased chance of double brooding, at least in the short-term.


Subject(s)
Birds/physiology , Climate Change , Adaptation, Physiological , Animal Migration , Animals , Climate , Molting , Reproduction
5.
PLoS One ; 8(10): e75514, 2013.
Article in English | MEDLINE | ID: mdl-24098389

ABSTRACT

Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported.


Subject(s)
Earth, Planet , Ecological and Environmental Phenomena , Animals , Aquatic Organisms , Classification , Climate , Climate Change , Seasons , Statistics as Topic
6.
Int J Biometeorol ; 54(3): 269-82, 2010 May.
Article in English | MEDLINE | ID: mdl-19937455

ABSTRACT

Numbers of four duck species present within a study area in a tidal embayment (Corner Inlet, south-eastern Australia) were obtained between 1977 and 2002. The species involved were Chestnut (Anas castanea) and Grey (A. gracilis) Teal, Pacific Black Duck (A. superciliosa) and Australian Shelduck (Tadorna tadornoides) and counts are compared with local and distant meteorological data. Chestnut and Grey Teal were most, and Australian Shelduck least, abundant. There was considerable monthly and annual variation; generally, teal and Pacific Black Duck were most numerous in summer and autumn, whereas Shelduck peaked somewhat earlier. Peak abundance corresponded to times of higher inter-annual variation and, apart from Shelduck, abundance had significant, usually weak, negative associations with rainfall though not beyond a one season lag. Pacific Black Duck numbers showed larger, more persistent and positive association with streamflows, particularly in south-eastern Australia, whereas associations for Chestnut Teal were negative and included lags of up to seven seasons. Grey Teal counts showed few significant correlations with streamflow, and Australian Shelduck numbers showed none. Abundance in some species was negatively related to the Southern Oscillation Index in the season of the count, but for Australian Shelduck there was a positive correlation for two seasons previously. Few significant relationships occurred between abundance in Corner Inlet and other Australian waterfowl abundance measures, although annual counts at Corner Inlet were positively correlated with Victorian Summer Waterfowl Counts and negatively with wetland area obtained during East Australia Counts. To an extent, results reflect current views on species' biologies, with birds moving into and out of a saline habitat determined by breeding conditions elsewhere. As found elsewhere, there were some relationships with meteorological variables, though strength and direction varied, perhaps reflecting species' plasticity in responses to rain events at local or distant scale and time.


Subject(s)
Ducks/classification , Ducks/physiology , Meteorological Concepts , Animals , Breeding , Geography , Population Dynamics , Rain , Salinity , Seasons , Species Specificity , Time Factors , Victoria
7.
Int J Biometeorol ; 50(5): 292-304, 2006 May.
Article in English | MEDLINE | ID: mdl-16435107

ABSTRACT

Seasonal and annual movements of Australian waterbirds are generally more complex than those of their Northern Hemisphere counterparts, and long-term data are needed to understand their relationships with climatic variables. This paper explores a long-term (1973-2002) set of waterbird counts from coastal Victoria and relates them to climatic data at local and continental scales. Three species (Black Swan Cygnus atratus, White-faced Heron Egretta novaehollandiae and Grey Teal Anas gracilis) were chosen for this analysis. Black Swans have large local breeding populations near the study region; White-faced Herons have smaller local breeding populations and Grey Teal breed extensively in ephemeral inland floodplains, such as those in the Murray-Darling Basin. All showed significant relationships with streamflow, regional rainfall and the Southern Oscillation Index (SOI) at appropriate scales and time-lags, with streamflow explaining the most variance. Black Swans showed a strong seasonal cycle in abundance and local climate variables had the greatest influence on the counts. Numbers were positively correlated with streamflow in southern Victoria three to six seasons before each count. Broader-scale climatic patterns were more important for the other two species. Numbers of White-faced Herons were positively correlated with streamflow or rainfall over various parts of Australia seven to nine seasons before each count. Numbers of Grey Teal showed weak seasonal cycles, and were negatively correlated with rainfall in Victoria or the Murray-Darling Basin in the seasons before or during each count, and positively with streamflow in the Murray-Darling Basin 15-18 months before each count.


Subject(s)
Breeding , Climate , Meteorological Concepts , Animals , Australia , Birds , Geography , Population Dynamics , Rain , Seasons , Species Specificity , Time Factors , Victoria , Weather
SELECTION OF CITATIONS
SEARCH DETAIL
...