scholarly journals Larval Ecology of Anopheles Mosquitoes in Kudat, Sabah

2021 ◽  
Author(s):  
Wilfredo Escalante Aure ◽  
Nelia Palaria Salazar ◽  
Tock Hing Chua
Keyword(s):  
Land Use ◽  
Plasmodium Knowlesi ◽  
Land Use Changes ◽  
Rubber Tree ◽  
Tree Plantation ◽  
Breeding Sites ◽  
Larval Habitats ◽  
Anopheles Mosquitoes ◽  
Land Use Types ◽  
Average Maximum

The emergence of human Plasmodium knowlesi malaria appeared to have been precipitated by the displacement of the natural environment of macaques and Anopheles mosquitoes resulting from deforestation and land-use changes in Malaysia. A longitudinal survey of larval habitats was conducted from May 2015 to April 2016 in the District of Kudat, Sabah to better understand how these changes have affected mosquitoes across six land use categories. Larvae were collected by dipping and reared in the laboratory for the identification of adults. Five anopheline and three culicine species were present: Anopheles balabacensis, An. barbirostris, An. lesteri, An. borneensis, An. umbrosus, Aedes albopictus, Culex gelidus, and Toxorhynchites sp. An. balabacensis was found in all six land-use types. Biodiversity by genera was high in all land-use types. The relative importance of land use types and larval habitats as sources of potential vectors was analyzed by the Kruskal-Wallis H test by ranks. In decreasing order Anopheles larvae were found in rubber tree plantation > coconut plantation > clearing site > palm oil plantation > forest > settlement area. Important larval habitats were intermittent stream > ditch > pond > artificial container > puddle > river > slow-flowing stream. Eighteen breeding sites of An. balabacensis were within (500 m) the average maximum flight range of the species and houses at risk for malaria. Knowledge gained from the study can be used to assess the need for vector control in preventing the spread of P. knowlesi in vulnerable areas.  

scholarly journals Environmental and spatial risk factors for the larval habitats of Plasmodium knowlesi vectors in Sabah, Malaysian Borneo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isabel Byrne ◽  
Wilfredo Aure ◽  
Benny O. Manin ◽  
Indra Vythilingam ◽  
Heather M. Ferguson ◽  
...  
Keyword(s):  
Risk Factors ◽  
Remote Sensing ◽  
Land Use ◽  
Plasmodium Knowlesi ◽  
Spatial Scales ◽  
Land Use Changes ◽  
Remote Sensing Data ◽  
Larval Habitats ◽  
Sensing Data ◽  
Malaysian Borneo

AbstractLand-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission. These land-use changes have been linked to increased incidence in human cases of the zoonotic malaria Plasmodium knowlesi in Sabah, Malaysian Borneo. This study investigates whether these associations are partially driven by fine-scale land-use changes creating more favourable aquatic breeding habitats for P. knowlesi anopheline vectors. Using aerial remote sensing data, we developed a sampling frame representative of all land use types within a major focus of P. knowlesi transmission. From 2015 to 2016 monthly longitudinal surveys of larval habitats were collected in randomly selected areas stratified by land use type. Additional remote sensing data on environmental variables, land cover and landscape configuration were assembled for the study site. Risk factor analyses were performed over multiple spatial scales to determine associations between environmental and spatial variables and anopheline larval presence. Habitat fragmentation (300 m), aspect (350 m), distance to rubber plantations (100 m) and Culex larval presence were identified as risk factors for Anopheles breeding. Additionally, models were fit to determine the presence of potential larval habitats within the areas surveyed and used to generate a time-series of monthly predictive maps. These results indicate that land-use change and topography influence the suitability of larval habitats, and may partially explain the link between P. knowlesi incidence and deforestation. The predictive maps, and identification of the spatial scales at which risk factors are most influential may aid spatio-temporally targeted vector control interventions.

scholarly journals Effects of Climate and Land Use changes on Vegetation Dynamics in the Yangtze River Delta, China Based on Abrupt Change Analysis

2020 ◽  
Vol 12 (5) ◽  
pp. 1955
Author(s):  
Lei Wan ◽  
Huiyu Liu ◽  
Haibo Gong ◽  
Yujia Ren
Keyword(s):  
Land Use ◽  
Vegetation Dynamics ◽  
Abrupt Change ◽  
Land Use Changes ◽  
Yangtze River Delta ◽  
Change Analysis ◽  
Land Use Types ◽  
Natural Land ◽  
Abrupt Change Analysis ◽  
Relationship Of

Vegetation dynamics is thought to be affected by climate and land use changes. However, how the effects vary after abrupt vegetation changes remains unclear. Based on the Mann-Kendall trend and abrupt change analysis, we monitored vegetation dynamics and its abrupt change in the Yangtze River delta during 1982–2016. With the correlation analysis, we revealed the relationship of vegetation dynamics with climate changes (temperature and precipitation) pixel-by-pixel and then with land use changes analysis we studied the effects of land use changes (unchanged or changed land use) on their relationship. Results showed that: (1) the Normalized Vegetation Index (NDVI) during growing season that is represented as GSN (growing season NDVI) showed an overall increasing trend and had an abrupt change in 2000. After then, the area percentages with decreasing GSN trend increased in cropland and built-up land, mainly located in the eastern, while those with increasing GSN trend increased in woodland and grassland, mainly located in the southern. Changed land use, except the land conversions from/to built-up land, is more favor for vegetation greening than unchanged land use (2) after abrupt change, the significant positive correlation between precipitation and GSN increased in all unchanged land use types, especially for woodland and grassland (natural land use) and changed land use except built-up land conversion. Meanwhile, the insignificant positive correlation between temperature and GSN increased in woodland, while decreased in the cropland and built-up land in the northwest (3) after abrupt change, precipitation became more important and favor, especially for natural land use. However, temperature became less important and favor for all land use types, especially for built-up land. This research indicates that abrupt change analysis will help to effectively monitor vegetation trend and to accurately assess the relationship of vegetation dynamics with climate and land use changes.

scholarly journals Using Landsat Thematic Mapper (TM) sensor to detect change in land surface temperature in relation to land use change in Yazd, Iran

Solid Earth ◽  
2016 ◽  
Vol 7 (6) ◽  
pp. 1551-1564 ◽  
Author(s):  
Sajad Zareie ◽  
Hassan Khosravi ◽  
Abouzar Nasiri ◽  
Mostafa Dastorani
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Land Use Changes ◽  
Thermal Conditions ◽  
Kappa Coefficient ◽  
Thematic Mapper ◽  
Landsat Thematic Mapper ◽  
Land Use Types

Abstract. Land surface temperature (LST) is one of the key parameters in the physics of land surface processes from local to global scales, and it is one of the indicators of environmental quality. Evaluation of the surface temperature distribution and its relation to existing land use types are very important to the investigation of the urban microclimate. In arid and semi-arid regions, understanding the role of land use changes in the formation of urban heat islands is necessary for urban planning to control or reduce surface temperature. The internal factors and environmental conditions of Yazd city have important roles in the formation of special thermal conditions in Iran. In this paper, we used the temperature–emissivity separation (TES) algorithm for LST retrieving from the TIRS (Thermal Infrared Sensor) data of the Landsat Thematic Mapper (TM). The root mean square error (RMSE) and coefficient of determination (R2) were used for validation of retrieved LST values. The RMSE of 0.9 and 0.87 °C and R2 of 0.98 and 0.99 were obtained for the 1998 and 2009 images, respectively. Land use types for the city of Yazd were identified and relationships between land use types, land surface temperature and normalized difference vegetation index (NDVI) were analyzed. The Kappa coefficient and overall accuracy were calculated for accuracy assessment of land use classification. The Kappa coefficient values are 0.96 and 0.95 and the overall accuracy values are 0.97 and 0.95 for the 1998 and 2009 classified images, respectively. The results showed an increase of 1.45 °C in the average surface temperature. The results of this study showed that optical and thermal remote sensing methodologies can be used to research urban environmental parameters. Finally, it was found that special thermal conditions in Yazd were formed by land use changes. Increasing the area of asphalt roads, residential, commercial and industrial land use types and decreasing the area of the parks, green spaces and fallow lands in Yazd caused a rise in surface temperature during the 11-year period.

Influences of land use changes on the dynamics of water quantity and quality in the German lowland catchment of the Stör

2021 ◽  
Author(s):  
Chaogui Lei ◽  
Paul Wagner ◽  
Nicola Fohrer
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Arable Land ◽  
Hydrologic Model ◽  
Water Quantity ◽  
Water Yield ◽  
Near Surface ◽  
Daily Streamflow ◽  
Land Use Types ◽  
Water Quantity And Quality

<p>Understanding the impacts of land use changes (LUCC) on the dynamics of water quantity and quality is necessary to identify suitable mitigation measures that are needed for sustainable watershed management. Lowland catchments are characterized by a strong interaction of streamflow and near-surface groundwater that intensifies the risk of nutrient pollution. In this study, a hydrologic model (Soil and Water Assessment Tool, SWAT) and partial least squares regression (PLSR) were used to quantify the impacts of different land use types on the variations in actual evapotranspiration (ET), surface runoff (SQ), base flow (BF), and water yield (WYLD) as well as on sediment (SED), total phosphorus (TP), and total nitrogen (TN). To this end, the model was calibrated and validated with daily streamflow data (30 years) and daily sediment and nutrient data from measurement campaigns (3 years in total). Three model runs over thirty years were performed using the different land use maps of 1987, 2010, and 2019, respectively. Land use changes between those years were used to explain the modelled changes in water quantity and quality on the subbasin scale applying PLSR. SWAT achieved a good performance for streamflow (calibration: NSE=0.8, PBIAS=5.5%; validation: NSE=0.78, PBIAS=5.1%) and for TN (calibration: NSE=0.65, PBIAS= -11.3%; validation: NSE=0.87, PBIAS=2.7%) and an acceptable performance for sediment and TP (calibration: NSE=0.49-0.53, PBIAS=25.8% -29.7%; validation: 0.51-0.7, PBIAS= -23.9% - -8.7%) in Stör catchment. The variations in ET, SQ, BF, WYLD, SED, TP, and TN could be explained to an extent of 67%-88% by changes in the area, shape, dominance, and aggregation of individual land use types. They were largely correlated with the major LUCC in the study area i.e. a decrease of arable land, and a respective increase of pasture and settlement. The change in the percentage of arable land affected the dynamics of SED, TP, TN and BF, indicated by a Variable Influence on Projection (VIP) > 1.2 and largest absolute regression coefficients (RCs: 0.45-0.72 for SED, TP, TN; -0.84 for BF). The change in pasture area affected ET, SED, TP, and TN, as indicated by VIPs >1.  The change in settlement percentage had VIP up to 1.62 for SQ and was positively and significantly influenced it (RC: 1.28). PLSR helped to identify the key contributions from individual land use changes on water quantity and quality dynamics. These provide a quantitative basis for targeting most influential land use changes to mitigate impacts on water quality in the future.</p>

scholarly journals Land-use changes influence soil bacterial communities in a meadow grassland in Northeast China

Solid Earth ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. 1119-1129 ◽  
Author(s):  
Chengyou Cao ◽  
Ying Zhang ◽  
Wei Qian ◽  
Caiping Liang ◽  
Congmin Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Land Use Changes ◽  
Chemical Properties ◽  
Soil Bacterial Communities ◽  
Land Use Types ◽  
Soil Bacterial ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract. The conversion of natural grassland into agricultural fields is an intensive anthropogenic perturbation commonly occurring in semiarid regions, and this perturbation strongly affects soil microbiota. In this study, the influences of land-use conversion on the soil properties and bacterial communities in the Horqin Grasslands in Northeast China were assessed. This study aimed to investigate (1) how the abundances of soil bacteria changed across land-use types, (2) how the structure of the soil bacterial community was altered in each land-use type, and (3) how these variations were correlated with soil physical and chemical properties. Variations in the diversities and compositions of bacterial communities and the relative abundances of dominant taxa were detected in four distinct land-use systems, namely, natural meadow grassland, paddy field, upland field, and poplar plantation, through the high-throughput Illumina MiSeq sequencing technique. The results indicated that land-use changes primarily affected the soil physical and chemical properties and bacterial community structure. Soil properties, namely, organic matter, pH, total N, total P, available N and P, and microbial biomass C, N, and P, influenced the bacterial community structure. The dominant phyla and genera were almost the same among the land-use types, but their relative abundances were significantly different. The effects of land-use changes on the structure of soil bacterial communities were more quantitative than qualitative.

scholarly journals Soil Organic Carbon Shapes AMF Communities in Soils and Roots of Cynodon dactylon under Anti-Seasonal Drying-Wetting Cycles

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 197 ◽  
Author(s):  
Xie Luo ◽  
Xinhua He ◽  
Xiumei Luo ◽  
Yining Liu ◽  
Junqi Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Community Composition ◽  
Cynodon Dactylon ◽  
Land Use Changes ◽  
Soil Microbial Communities ◽  
Rhizosphere Soils ◽  
Land Use Types ◽  
Amf Communities

Anti-seasonal drying-wetting cycles since 2010 have substantially altered its soil and vegetation status in the drawdown zone of China’s Three Gorges Reservoir (TGR). Such alternations may thus affect the composition and functioning of soil microbial communities, including the beneficial arbuscular mycorrhizal fungi (AMF), which enhance plant performance. Moreover, limited information is available if AMF communities are different in soils and roots, particularly under contrasting land-use changes. By combining the Illumina Miseq sequencing with bioinformatics analyses, AMF communities in both rhizosphere soils and roots of a stoloniferous and rhizomatous C4 perennial of Cynodon dactylon were characterized under three land-use types: (1) crop cultivated, (2) non-cultivated non-disturbed, and (3) disturbed non-cultivated land. A total of 35 and 26 AMF taxa were respectively detected from C. dactylon rhizosphere soils and roots from these three land-use types, which had endured four anti-seasonal drying/summer-wetting/winter cycles. Contrasting differentiations in the AMF community composition and structure were displayed in the C. dactylon rhizosphere soils and roots, and between land-use types. Nonmetric multidimensional scaling analyses revealed that AMF communities significantly correlated to soil organic carbon in the rhizosphere soils and roots of C. dactylon, to land-use types only in rhizosphere soils, whereas to soil moisture only in roots. Our results highlight the effects of soil nutrients and land-use changes on AMF community composition and diversity under the canopy of C. dactylon in TGR. The identified dominant AMF taxa can be employed to vegetation restoration in such degraded habitats globally.

scholarly journals Recent Land Use Changes on an Urban Watershed in Moncton, New Brunswick, Canada

2016 ◽  
Vol 9 ◽  
Author(s):  
Mélanie LeBlanc ◽  
Guillaume Fortin
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
Land Use Changes ◽  
Land Uses ◽  
Urban Watershed ◽  
Surface Areas ◽  
Run Off ◽  
Land Use Types ◽  
Natural Land ◽  
The City

Changes in land use, which threaten ecosystems and habitats, have an impact on run-off and water quality on urban areas. Using a GIS program we have classified the land use of the Humphreys Brook watershed and quantified the changes that have occurred using landscape metrics. A rapid growth of the city emerges from our results. All land use types of urban nature have seen an increase in surface areas to the detriment of natural land uses. Moreover the landscape indices are showing signs of rectangularity, where humans have introduced straight edges, and other common processes of transformation to the landscape.

scholarly journals Land-Use Changes at Nest Sites of the Little Owl (Athene noctua) in the South-Moravian Region of the Czech Republic

2018 ◽  
Vol 11 (1) ◽  
pp. 19-34
Author(s):  
Karel Poprach ◽  
Libor Opluštil ◽  
František Krause ◽  
Ivo Machar
Keyword(s):  
Land Use ◽  
Czech Republic ◽  
Land Use Changes ◽  
Arable Land ◽  
Bird Species ◽  
Land Use Type ◽  
The South ◽  
Nest Sites ◽  
Land Use Types ◽  
Little Owl

Abstract The Little Owl is currently endangered bird species of agricultural lowland areas in Central Europe. Nesting sites of the Little Owl are often old trees as well as buildings and quarries with suitable nesting cavities. The Little Owl has severely declined in a major part of Europe during the past decades. Information on habitat requirements of the Little Owl and data related to land-use changes at nest sites (covering both the breeding and foraging habitats) are needed for conservation programmes aimed at this bird species. Land-use changes in farmland rank among frequently discussed negative factors causing the population decline of the Little Owl. The aim of this study is to analyse land-use changes at nest sites of the Little Owl in the South-Moravian region (Czech Republic) between the years 1976/1977 and 2014. In both studied periods (1976/1977 and 2014), the most important land-use type within 500 m from the nest sites of the Little Owl was arable land (66.94 % – 62.25 %), followed by built-up areas (19.97 % –22.41 %), while the other land-use types made up less than 5 %. The proportion of the particular land-use type did not change significantly between the years 1976/1977 and 2014. The most important change in comparison with the period 1976/1977 was the decrease in the area of arable land by 4.69 % and that of orchards and gardens by 1.99 %, while the surface of built-up areas increased slightly by 2.45 % and that of meadows and pastures by 1.5 %. The analysis shows that at the known nest sites of the Little Owl in the South-Moravian region (Czech Republic), there were no significant changes in the proportion of the particular land-use types within 500 m from the nests between the years 1976/1977 and 2014. Based on these results, we can conclude that in comparison with the availability of nest sites, which seems to be the important limiting factor for the occurrence and population density of the Little Owl, land-use changes in study area were not very important factor influencing decline of the Little Owl.

scholarly journals Land-use changes influence soil bacterial communities in a meadow grassland in Northeast China

2017 ◽  
Author(s):  
Chengyou Cao ◽  
Ying Zhang ◽  
Wei Qian ◽  
Caiping Liang ◽  
Congmin Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Land Use Changes ◽  
Chemical Properties ◽  
Soil Bacterial Communities ◽  
Land Use Types ◽  
Soil Bacterial ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract. The conversion of natural grassland into agricultural fields is an intensive anthropogenic perturbation commonly occurring in semi-arid regions, and this perturbation strongly affects soil microbiota. In this study, the influences of land-use conversion on the soil properties and bacterial communities in Horqin Grasslands in Northeast China were assessed. This study aimed to investigate (1) how the abundances of soil bacteria changed across land-use types; (2) how the structure of soil bacterial community was altered in each land-use type; and (3) how these variations were correlated with soil physical and chemical properties. The variations in diversities and compositions of bacterial communities and relative abundance of dominant taxa were detected in four distinct land-use systems, namely, natural meadow grassland, paddy field, upland field, and poplar plantation, through high-throughput Illumina MiSeq sequencing technique. Results indicated that land-use changes primarily affected soil physical and chemical properties and bacterial community structure. Soil properties, namely, organic matter, pH, total N, total P, available N and P, and microbial biomass C, N, and P, influenced the bacterial community structure. The dominant phyla and genera were almost the same among the land-use types, but their relative abundances were significantly different. The effects of land-use changes on the structure of soil bacterial communities were more quantitative than qualitative.

scholarly journals The Impact of Land Use Change on Ecosystem Service Value in the Upstream of Xiong’an New Area

2020 ◽  
Vol 12 (14) ◽  
pp. 5707
Author(s):  
Zhiyin Wang ◽  
Jiansheng Cao ◽  
Chunyu Zhu ◽  
Hui Yang
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Ecosystem Service ◽  
Land Use Changes ◽  
Contribution Rate ◽  
Ecosystem Service Value ◽  
Construction Land ◽  
Service Value ◽  
Land Use Types ◽  
The Impact

The development of the Xiong’an New Area is a crucial strategy for the next millennium in China. The ecosystem upstream of the Xiong’an New Area, serving for the development of the Xiong’an New Area, changed with land use changes. To analyze the contribution rate of the land use change to the ecosystem service value, we analyzed the land use changes of three small watersheds (7318.56 km2) upstream of the Xiong’an New Area based on a total of six phases of land use data from 1980 to 2015. Then, the ecosystem service value (ESV) was calculated using the equivalent factor method. The results showed that the construction land and arable land were the largest land use types that increased and decreased in the area of the study area, respectively. The grassland and construction land were the land use types with the largest transfer-out area and transfer-in area, respectively. The regulating services accounted for the largest proportion of total ESV among different ecosystem service functions, and the grassland and woodland accounted for the largest proportion of total ESV among different land use types. ESV in the study area fluctuated slightly from 1980 to 2015. The decrease of ESV mainly occurred in the surrounding areas of mountain towns, and the conversion of cultivated land to construction land was the main reason for the decrease of ESV in this area. The conversion of grassland to construction land had the largest contribution rate to the decrease of ESV in the study area, while the conversion of grassland to waters had the largest contribution rate to the increase of ESV. In conclusion, controlling the development of construction land and strengthening water resources’ protection may improve the ecosystem service value in the upstream Xiong’an New Area in the future.

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