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 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 Distribution Pattern of Gymnosperms’ Richness in Nepal: Effect of Environmental Constrains along Elevational Gradients

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 625
Author(s):  
Bikram Pandey ◽  
Nirdesh Nepal ◽  
Salina Tripathi ◽  
Kaiwen Pan ◽  
Mohammed A. Dakhil ◽  
...  
Keyword(s):  
Species Richness ◽  
Distribution Pattern ◽  
Species Distribution ◽  
Environmental Variables ◽  
Environmental Indicators ◽  
Climatic Variables ◽  
Elevation Gradients ◽  
Hypothesis Model ◽  
Richness Pattern ◽  
Richness Patterns

Understanding the pattern of species distribution and the underlying mechanism is essential for conservation planning. Several climatic variables determine the species diversity, and the dependency of species on climate motivates ecologists and bio-geographers to explain the richness patterns along with elevation and environmental correlates. We used interpolated elevational distribution data to examine the relative importance of climatic variables in determining the species richness pattern of 26 species of gymnosperms in the longest elevation gradients in the world. Thirteen environmental variables were divided into three predictors set representing each hypothesis model (energy-water, physical-tolerance, and climatic-seasonality); to explain the species richness pattern of gymnosperms along the elevational gradient. We performed generalized linear models and variation partitioning to evaluate the relevant role of environmental variables on species richness patterns. Our findings showed that the gymnosperms’ richness formed a hump-shaped distribution pattern. The individual effect of energy-water predictor set was identified as the primary determinant of species richness. While, the joint effects of energy-water and physical-tolerance predictors have explained highest variations in gymnosperm distribution. The multiple environmental indicators are essential drivers of species distribution and have direct implications in understanding the effect of climate change on the species richness pattern.

scholarly journals Assessing geographic and climatic variables to predict the potential distribution of the visceral leishmaniasis vector Lutzomyia longipalpis in the state of Espírito Santo, Brazil

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0238198
Author(s):  
Karina Bertazo Del Carro ◽  
Gustavo Rocha Leite ◽  
Amandio Gonçalves de Oliveira Filho ◽  
Claudiney Biral dos Santos ◽  
Israel de Souza Pinto ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Potential Distribution ◽  
The State ◽  
Climatic Variables ◽  
Lutzomyia Longipalpis ◽  
Espírito Santo ◽  
Espirito Santo

scholarly journals The jacoona assemblage of the genus Dundubia Amyot & Serville (Homoptera: Cicadidae): a taxonomic study of its species and a discussion of its phylogenetic relationships

1996 ◽  
Vol 66 (3) ◽  
pp. 129-184
Author(s):  
Paul L.Th. Beuk
Keyword(s):  
Related Species ◽  
Phylogenetic Relationships ◽  
Monophyletic Group ◽  
Taxonomic Study ◽  
China And India ◽  
Eleven Species

The species of Orientopsaltria with unicolorous opercula and three related species of Platylomia are transferred to the genus Dundubia and allocated in the ‘Dundubia jacoona assemblage’ pending further investigation. The assemblage comprises eleven species in total; all are found in the Indo-Malaysian Archipelago, Indo-China, and the adjoining parts of China and India. The four species which were until now placed in Orientopsaltria are D. feae (Distant, 1892), D. jacoona (Distant, 1888), D. nigripes (Moulton, 1923), and D. oopaga (Distant, 1881). The three species transferred from Platylomia are D. hainanensis (Distant, 1901), D. nagarasingna Distant, 1881, and D. spiculata Noualhier, 1896. These seven species are all redescribed. Four species are described as new: D. ayutthaya, D. laterocurvata, D. myitkyinensis and D. sinbyudaw. Seven species are synonymized: O. andersoni (Distant, 1883) with D. oopaga, D. bifasciata Liu, 1940 with D. hainanensis, O. hastata (Moulton, 1923) and D. siamensis Haupt, 1918 with D. spiculata, O. fratercula (Distant, 1912) and D. helena Distant, 1912 with D. nagarasingna, and D. longina Distant, 1917 with D. feae. Lectotypes are designated for the following species: Cosmopsaltria andersoni, C.feae, C. fratercula, C. hastata, C. nagarasingna, C. nigripes, C. oopaga, D. helena, D. longina, and D. spiculata. A key to the males is presented and the distributions of the species are discussed. The relationships of the D. jacoona assemblage with Dundubia, Platylomia, and the remaining species of Orientopsaltria are discussed. The species of the D. jacoona assemblage most likely do not form a monophyletic group on their own but rather with Dundubia s. str.

Numerical Changes and Resource Utilization in Orchard Populations of Drosophila.

1985 ◽  
Vol 33 (6) ◽  
pp. 875 ◽  
Author(s):  
KM Nielsen ◽  
AA Hoffmann
Keyword(s):  
Resource Utilization ◽  
Endemic Species ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
Laboratory Experiments ◽  
Climatic Variables ◽  
Partial Agreement ◽  
Larval Stages

Drosophila were collected monthly at a south-east Australian orchard site over 30 months. D, melanogaster was predominant in spring-summer, D. simulans in autumn, and D. immigrans in winter. These seasonal changes are consistent with trends described in an earlier study by McKenzie and Parsons (1974). Numbers of the endemic species D. lativittata tended to follow those of D. melanogaster. Comparisons of numbers of each species with environmental variables indicate that D. melanogaster is positively correlated, and D. immigrans negatively correlated, with temperature parameters. D. simulans and D. lativittata numbers were independent of all climatic variables tested. These associations are consistent with collections by McKenzie and Parsons (1974) from an orchard site, but not from their suburban sites. The associations of numbers of adults of each species with climatic variables are only in partial agreement with results from laboratory experiments on stress in adults. Sampling within the orchard indicates that D. melanogaster and D. simulans are differentially associated with fruit resources at both adult and larval stages, with D. melanogaster predominating on peach resources.

scholarly journals Dominant Height Model for Site Classification ofEucalyptus grandisIncorporating Climatic Variables

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
José Roberto Soares Scolforo ◽  
Romualdo Maestri ◽  
Antonio Carlos Ferraz Filho ◽  
José Márcio de Mello ◽  
Antônio Donizette de Oliveira ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Eucalyptus Grandis ◽  
Site Index ◽  
Climatic Variables ◽  
Site Classification ◽  
Monthly Precipitation ◽  
Annual Increment ◽  
Dominant Height ◽  
Mean Annual Increment ◽  
Height Model

This study tested the effects of inserting climatic variables inEucalyptus grandisas covariables of a dominant height model, which for site index classification is usually related to age alone. Dominant height values ranging from 1 to 12 years of age located in the Southeast region of Brazil were used, as well as data from 19 automatic meteorological stations from the area. The Chapman-Richards model was chosen to represent dominant height as a function of age. To include the environmental variables a modifier was included in the asymptote of the model. The asymptote was chosen since this parameter is responsible for the maximum value which the dominant height can reach. Of the four environmental variables most responsible for database variation, the two with the highest correlation to the mean annual increment in dominant height (mean monthly precipitation and temperature) were selected to compose the asymptote modifier. Model validation showed a gain in precision of 33% (reduction of the standard error of estimate) when climatic variables were inserted in the model. Possible applications of the method include the estimation of site capacity in regions lacking any planting history, as well as updating forest inventory data based on past climate regimes.

scholarly journals Environmental Gradient Favours Functionally Diverse Macrobenthic Community in a Placer Rich Tropical Bay

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
S. K. Sivadas ◽  
B. S. Ingole ◽  
C. E. G. Fernandes
Keyword(s):  
Functional Diversity ◽  
Environmental Variables ◽  
Environmental Gradient ◽  
Geographic Location ◽  
Environmental Parameters ◽  
Coastal Habitat ◽  
Diversity Pattern ◽  
Deposit Feeders ◽  
Biodiversity Pattern ◽  
Tropical Bay

The present paper examines the functional diversity-environment relation in a placer rich tropical bay. Understanding the environmental variables that determine the biodiversity pattern will help in the effective conservation plans of coastal habitat. However, few studies have been carried out on the biodiversity-environment relation from the diverse tropical coastal ecosystem. The geographic location of Kalbadevi Bay along the west coast of India provides an opportunity to study the functional diversity pattern of macrofauna along an environmental gradient. Additionally, the area is also a potential placer mining site. Seasonal sampling was carried out for macrofauna and environmental variables. Macrofaunal functional diversity showed significant temporal variation related to the environmental parameters. The most important environmental variables were organic matter and sediment texture. Filter feeders dominated during postmonsoon which is a period when the water column is enriched with sinking detritus. The deposit feeders which rapidly ingest the settled detritus and also transport it to deeper sediment for the subsurface deposit feeders dominated during premonsoon. Abundance of carnivores was high during premonsoon, a response to increase in food in terms of deposit feeders. The result thus indicates that the temporal environmental variation influenced the macrofaunal functional diversity pattern in the Kalbadevi Bay.

scholarly journals Cladocera distribution along an environmental gradient on the Cerrado-Amazon ecotone: a preliminary study

2019 ◽  
Vol 31 ◽  
Author(s):  
Leandro Schlemmer Brasil ◽  
Ana Luiza-Andrade ◽  
Tiago Borges Kisaka ◽  
Paulo Ilha ◽  
Francisco Diogo Rocha Sousa
Keyword(s):  
Land Use ◽  
Species Distribution ◽  
Environmental Variables ◽  
Redundancy Analysis ◽  
Environmental Gradient ◽  
Canopy Cover ◽  
Knowledge Gap ◽  
Stream Communities ◽  
Preliminary Study

Abstract: Aim Our objective in this study is to understand Cladocera species distribution along an environmental gradient in forest and cropland landscapes in the southern Amazon. Methods We collected Cladocera communities and environmental variables from five streams and verified their associations with a Redundancy Analysis. Results Acroperus tupinamba, Alonella dadayi e Kisakiellus aweti were mostly associated to sites with higher canopy cover. Anthalona neotropica, Anthalona verrucose and Flavalona iheringula occurred exclusively in site with more thalweg depth. Conclusions If these results are confirmed Cladocera stream communities are affected by changes in land use. Further studies in this line are extremely necessary to reduce this knowledge gap.

scholarly journals Climatic constraints and the distribution of Patagonian mice

2019 ◽  
Author(s):  
Trinidad Ruiz Barlett ◽  
Gabriel M Martin ◽  
María Fabiana Laguna ◽  
Guillermo Abramson ◽  
Adrián Monjeau
Keyword(s):  
Potential Distribution ◽  
Vegetation Index ◽  
Habitat Characteristics ◽  
Climatic Variables ◽  
Rodent Species ◽  
Forest Steppe ◽  
Distribution Models ◽  
Humid Climate ◽  
Local Conditions ◽  
Bioclimatic Variables

Abstract We generated potential distribution models for 14 sigmodontine rodent species that inhabit the Andean–Patagonian forest region and adjacent areas, and retrieved the main climatic variables responsible for these models. Our main objective was to compare these climatic variables and the distribution patterns generated for each species, and explore the effects of the physical environment in shaping the composition of rodent communities in the area. We retrieved a total of 1,215 records of species presence from 580 sites. Maxent was used to generate potential distribution models for the 14 rodent species studied. We used a total of 20 variables obtained from the WorldClim database, including elevation and 19 bioclimatic variables, in addition to normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Our results showed a clear discrimination between two groups of rodents, one concentrated in the western part of our study area, with more humid climate and a rugged mountainous and discontinuous habitat, and another inhabiting the eastern, drier part of our study area, which appears to be more uniform in habitat characteristics. These groups showed a mosaic of phylogenetically non-related species from different tribes, that probably arrived or expanded into Patagonia during the last millennia. The overlap of all models showed the forest-steppe ecotone east of Nahuel Huapi Lake and south to −43° latitude as the area with the highest species richness (8–11 species). All species showed a high correspondence with temperature and precipitation that define patterns at a landscape scale, with little to very little information contained in the typical vegetation variables that would define local conditions. En este trabajo generamos modelos de distribución potencial para cada especie de roedor sigmodontino que habita la región de los bosques andino-patagónicos y áreas adyacentes, identificando las principales variables climáticas que influyen en dichas distribuciones. Nuestro principal objetivo fue comparar las variables climáticas y los patrones de distribución generados para cada especie, y explorar los efectos del entorno físico en la composición de los ensambles de especies. Recopilamos un total de 1215 registros de presencia de especies de 580 sitios. Se utilizó MaxEnt para generar los modelos de distribución potencial de las 14 especies de roedores estudiadas, con 20 variables obtenidas de la base de datos WorldClim, incluida la elevación, 19 variables bioclimáticas, además del NDVI y EVI. Nuestros resultados muestran una clara discriminación entre dos grupos de roedores, uno concentrado en el área occidental, con un clima más húmedo y montañoso, y otro que habita en el área más seca del este. Curiosamente, estos grupos muestran un mosaico de especies, filogenéticamente no relacionadas y de diferentes tribus, que probablemente llegaron o se expandieron en la Patagonia durante los últimos milenios. La superposición de todos los modelos muestra el ecotono bosque-estepa, al este del lago Nahuel Huapi y hacia el sur hasta los -43°, como la zona más rica en especies (8 a 11 especies). Todas las especies muestran una alta correspondencia con las variables ambientales (temperatura y precipitación) que definen patrones a escala del paisaje, con muy poca información contenida en las variables típicas de la vegetación que definirían las condiciones locales.

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