Towards a kala azar risk map for Sudan: mapping the potential distribution of Phlebotomus orientalis using digital data of environmental variables

1999 ◽  
Vol 4 (2) ◽  
pp. 105-113 ◽  
Author(s):  
M. C. Thomson ◽  
D. A. Elnaiern ◽  
R. W. Ashford ◽  
S. J. Connor
Keyword(s):  
Environmental Variables ◽  
Potential Distribution ◽  
Digital Data ◽  
Risk Map ◽  
Kala Azar ◽  
Phlebotomus Orientalis

scholarly journals Maxent Data Mining Technique and Its Comparison with a Bivariate Statistical Model for Predicting the Potential Distribution of Astragalus Fasciculifolius Boiss. in Fars, Iran

2019 ◽  
Vol 11 (12) ◽  
pp. 3452 ◽  
Author(s):  
Marjaneh Mousazade ◽  
Gholamabbas Ghanbarian ◽  
Hamid Reza Pourghasemi ◽  
Roja Safaeian ◽  
Artemi Cerdà
Keyword(s):  
Data Mining ◽  
Statistical Model ◽  
Habitat Suitability ◽  
Environmental Variables ◽  
Potential Distribution ◽  
Data Mining Technique ◽  
Mining Technique ◽  
Suitability Map ◽  
Habitat Suitability Map ◽  
Edaphic Variables

The identification of geographical distribution of a plant species is crucial for understanding the importance of environmental variables affecting plant habitat. In the present study, the spatial potential distribution of Astragalus fasciculifolius Boiss. as a key specie was mapped using maximum entropy (Maxent) as data mining technique and bivariate statistical model (FR: frequency ratio) in marl soils of southern Zagros, Iran. The A. fasciculifolius locations were identified and recorded by intensive field campaigns. Then, localities points were randomly split into a 70% training dataset and 30% for validation. Two climatic, four topographic, and eight edaphic variables were used to model the A. fasciculifolius distribution and its habitat potential. Maps of environmental variables were generated using Geographic Information System (GIS). Next, the habitat suitability index (HSI) maps were produced and classified by means of Maxent and FR approaches. Finally, the area under the receiver operating characteristic (AUC-ROC) curve was used to compare the performance of maps produced by Maxent and FR models. The interpretation of environmental variables revealed that the climatic and topographic parameters had less impact compared to edaphic variables in habitat distribution of A. fasciculifolius. The results showed that bulk density, nitrogen, acidity (pH), sand, and electrical conductivity (EC) of soil are the most significant variables that affect distribution of A. fasciculifolius. The validation of results showed that AUC values of Maxent and FR models are 0.83 and 0.76, respectively. The habitat suitability map by the better model (Maxent) showed that areas with high and very high suitable classes cover approximately 22% of the study area. Generally, the habitat suitability map produced using Maxent model could provide important information for conservation planning and a reclamation project of the degraded habitat of intended plant species. The distribution of the plants identifies the water, soil, and nutrient resources and affects the fauna distribution, and this is why it is relevant to research and to understand the plant distribution to properly improve the management and to achieve a sustainable management.

scholarly journals The correspondence between environmental similarity and geographical sympatry in Uromastyx species

2020 ◽  
Vol 41 (2) ◽  
pp. 245-251
Author(s):  
Marwa Kechnebbou ◽  
Jorge M. Lobo ◽  
Mohsen Chammem
Keyword(s):  
Related Species ◽  
Environmental Variables ◽  
Potential Distribution ◽  
Environmental Gradient ◽  
Climatic Variables ◽  
Geographical Isolation ◽  
Speciation Process ◽  
Environmental Similarity ◽  
Eleven Species

Abstract Estimating the realized and potential distribution of species has become a very active field of research with capacity to propose likely speciation mechanisms. Here, environmental variables and point locality data derived from several sources were used to examine the concordance between geographical distributions and environmental niches derived from occurrences for eleven species of the genus Uromastyx (Reptilia, Agamidae). Our results indicate that the degree of geographical overlap is definitively and statistically lower than the degree of environmental similarity. This reinforces the hypothesis that speciation process within the genus Uromastyx will be mainly based on geographical isolation. However, the environmental divergence among some groups of species cannot be excluded; high environmental distances can be obtained for some related species and the environmental gradient represented by two unique climatic variables allows discriminating some species among which an ecological or environmental segregation would be a plausible explanation.

scholarly journals Modelling the Effects of Climate Change on the Distribution of Endangered Cypripedium japonicum in China

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 429
Author(s):  
Yadong Xu ◽  
Yi Huang ◽  
Huiru Zhao ◽  
Meiling Yang ◽  
Yuqi Zhuang ◽  
...  
Keyword(s):  
Climate Change ◽  
Environmental Variables ◽  
Potential Distribution ◽  
Species Distribution Model ◽  
Characteristic Curve ◽  
Climatic Conditions ◽  
Distribution Model ◽  
Suitable Habitat ◽  
Mountainous Area ◽  
The Impact

Cypripedium japonicum is an endangered terrestrial orchid species with high ornamental and medicinal value. As global warming continues to intensify, the survival of C. japonicum will be further challenged. Understanding the impact of climate change on its potential distribution is of great significance to conserve this species. In this study, we established an ensemble species distribution model based on occurrence records of C. japonicum and 13 environmental variables to predict its potential distribution under current and future climatic conditions. The results show that the true skill statistic (TSS), Cohen’s kappa statistic (Kappa), and the area under the receiver operating characteristic curve (AUC) values of the ensemble model were 0.968, 0.906, and 0.995, respectively, providing more robust predictions. The key environmental variables affecting the distribution of C. japonicum were the precipitation in the warmest quarter (Bio18) and the mean temperature in the driest quarter (Bio9). Under future climatic conditions, the total suitable habitat of C. japonicum will increase slightly and tend to migrate northwestward, but the highly suitable areas will be severely lost. By 2070, the loss of its highly suitable habitat area will reach 57.69–72.24% under representative concentration pathway (RCP) 4.5 and 8.5 respectively, and the highly suitable habitats in Zhejiang and Anhui will almost disappear. It is noteworthy that the highly suitable habitat of C. japonicum has never crossed the Qinba mountainous area during the migration process of the suitable habitat to the northwest. Meanwhile, as the best-preserved area of highly suitable habitat for C. japonicum in the future, the Qinba mountainous area is of great significance to protect the wild germplasm resources of C. japonicum. In addition, we found that most of the changes predicted for 2070 will already be seen in 2050; the problem of climate change may be more urgent than it is believed.

scholarly journals Habitat preference and potential distribution of Magnolia officinalis subsp. officinalis and M. o. subsp. biloba in China

2019 ◽  
Vol 36 ◽  
pp. 93-111
Author(s):  
Chuangye Song ◽  
Huiming Liu ◽  
Jixi Gao
Keyword(s):  
Human Disturbance ◽  
Environmental Variables ◽  
Potential Distribution ◽  
Habitat Preferences ◽  
Extreme Temperatures ◽  
Conservation Areas ◽  
Suitable Habitats ◽  
Magnolia Officinalis ◽  
The Relationship ◽  
Selection Of

Magnolia officinalis subsp. officinalis and M. officinalis subsp. biloba are important medicinal plants in China. The bark of these two subspecies is commonly used in the production of a widely-used Chinese traditional medicine named ‘Houpu’. In recent years, M. o. subsp. officinalis and M. o. subsp. biloba have become increasingly threatened owing to the over-harvesting of their bark and the fragmentation of their habitats. In this study, we aimed to support the conservation and cultivation of these two subspecies in China by: (1) assessing the relationship between numerous environmental variables and the geographical distributions of the subspecies; (2) analysing the environmental characteristics of suitable habitats for both subspecies and predicting the spatial distribution of these habitats in China; and (3) identifying conservation areas of both subspecies in China via overlay analysis. We also assessed the degree of human disturbance within suitable habitats. We found that temperature was a major determinant for the distribution of M. o. subsp. officinalis. Conversely, the distribution of M. o. subsp. biloba was primarily dependent on precipitation rather than temperature. Distinct habitat preferences were observed between M. o. subsp. officinalis and M. o. subsp. biloba. Suitable habitats of M. o. subsp. officinalis were primarily distributed in the northern subtropical areas of China, with greater fluctuations in ambient temperature, lower extreme temperatures, less precipitation and greater fluctuations in precipitation. Habitats suitable for M. o. subsp. biloba were highly fragmented and were distributed in the central subtropical areas of China. We found that a large proportion of suitable habitats were not in the protected areas and that they were significantly disturbed by human activity. This analysis could provide useful information for the conservation of both M. o. subsp. officinalis and M. o. subsp. biloba and could aid in the selection of cultivation sites.

scholarly journals Studies on sand fly fauna and ecological analysis of Phlebotomus orientalis in the highland and lowland foci of kala-azar in northwestern Ethiopia

PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0175308 ◽  
Author(s):  
Esayas Aklilu ◽  
Araya Gebresilassie ◽  
Solomon Yared ◽  
Mizan Kindu ◽  
Habte Tekie ◽  
...  
Keyword(s):  
Sand Fly ◽  
Ecological Analysis ◽  
Kala Azar ◽  
Phlebotomus Orientalis

scholarly journals Distribution modeling of Psellogrammus kennedyi (Eigenmann, 1903) and new records in the Lower Paranapanema River, Brazil

Check List ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. 1277-1284
Author(s):  
Lucas Ribeiro Jarduli ◽  
Alan Deivid Pereira ◽  
Diego Azevedo Zoccal Garcia ◽  
João Daniel Ferraz ◽  
Iago Vinicios Geller ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Native Species ◽  
Potential Distribution ◽  
New Records ◽  
Preventive Measure ◽  
Prediction Modeling ◽  
Efficient Tool ◽  
Distribution Modeling ◽  
First Time ◽  
Control And Eradication

Understanding the potential distribution of non-native species can be an important tool in preventing biological invasions. We recorded for the first time Psellogrammus kennedyi, a small non-native characiform, in the Lower Paranapanema River, Brazil. According to environmental variables and prediction modeling, the species presents high potential distribution in the Upper Paraná river basin. The model used herein is an efficient tool to determine where non-native species may be able to establish. This approach can be used as a preventive measure, once the control and eradication measures are often ineffective and uneconomical.

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