Wyniki wyszukiwania - BazTech

1

Assessing Potential Distributions of Bird Endemic Species: Case Studies of Macrocephalon maleo and Rhyticeros cassidix and Their Threats

Aldiansyah Septianto, Risna Risna, Saputra Randi Adrian

Geomatics and Environmental Engineering

|

2024

|

Vol. 18, no. 3

45--61

EN

Maleo and knobbed hornbill are bird species that are endemic on the island of Sulawesi, which is highly threatened by forest fires. Fires tend to destroy any affected species; however, it is not possible to survey the entire range of the original distribution of the two endemic bird species that are affected by forest fires due to practical constraints. Species distribution modeling using maximum entropy is considered to be an alternative to understanding the potential distribution area of species against the threat of forest fires. The prediction model from MaxEnt all have AUC values of greater than 0.70, which means that the model is good enough to classify the records of the presence of M. maleo and R. cassidix along with the past forest fires. The environmental variables that affect the distribution of M. maleo are its distance from hot water, rivers, and roads, while the distribution of R. cassidix is strongly influenced by its distance from roads, settlements, and rivers. Forest fire distribution is mostly influenced by soil type, land-use land cover, and rainfall. It is predicted that around 238,690 and 677,070 ha of the potential distribution of M. maleo and R. cassidix, respectively, are potentially disturbed and affected by forest fires. However, this number much greater outside conservation areas. The results of this study can be used by the government of the Republic of Indonesia (especially the Ministry of Environment and Forestry) for determining conservation actions for both species in the future.

2

Potential Distribution of Five Native Grass Species in Northern Mexico and their Dynamics due to Climate Variability

Iracheta-Lara Ireyli Z., Hernández-Quiroz Nathalie S., Pinedo-Alvarez Alfredo, Santellano-Estrada Eduardo, Prieto-Amparán Jesús A., Villarreal-Guerrero Federico, Morales-Nieto Carlos R.

Polish Journal of Ecology

|

2021

|

Vol. 69, nr 2

73--83

EN

Grasslands are recognized as the most threatened communities on the planet due to environmental and anthropogenic disturbances. In the state of Chihuahua, Mexico, native grasslands have a great ecological importance due to their wide distribution; however, studies on the current and future potential distributions of grasslands, as well as their temporal dynamics based on climatic variability, are lacking. Thus, we analysed the potential distribution of five native grasses (Bouteloua curtipendula, Bouteloua gracilis, Leptochloa dubia, Digitaria californica and Setaria macrostachya) based on climatic factors. The present data of these species were consulted at the Global Biodiversity Information Facility (GBIF) and recorded with location information: latitude and longitude. This database was complemented with presence data of the five species from previous studies. To characterize the climate niche, the values of the climatic factors at the locations of the species presence, were obtained from the WorldClim. Then, current and future potential distributions of these native species, were generated based on three climate change scenarios, based on Representative Concentration Pathways - RCP2.6, RCP4.5 and RCP6.0). Under the RCP2.6 scenario, the estimated area of S. macrostachya was 12,525.5 ha, representing 7.4% of the state. For B. gracilis, the potential areas under the RCP4.5 and RCP6.0 scenarios were 20,391.49 and 23,079.08 ha, respectively. B. curtipendula represented the smallest area, with 4.6% under the scenario RCP2.6. The distribution of grassland species in northern Mexico is mainly determined by climatic factors; as it may apply for the rest of the grassland species within this area, so those results could increase our knowledge about their potential distribution.

3

Effects of Sample Size, Sample Accuracy and Environmental Variables on Predictive Performance of MaxEnt Model

Li Y., Ding C.

Polish Journal of Ecology

|

2016

|

Vol. 64, nr 3

303--312

EN

The availability of sample data, together with detailed environmental factors, has fueled a rapid increase in predictive modeling of species geographic distributions and environmental requirements. We founded that MaxEnt model has provided different descriptions of potential distributions based on different sample size, sample accuracy and environmental background. We used six combinations based on three sample data set and two kinds of environmental variables to estimate the potentially suitable areas of Brown Eared Pheasant (Crossoptilon mantchuricum) in MaxEnt model. The results show that the complex variables provided the higher AUC value and accurate potential distribution than simple variables based on the same size of samples. Complicated environmental factors combined with moderate size and accurate sample, can predict better results. The model results were scabrous based on simple environmental factors. Furthermore, big sample size and simple prediction environmental factors will reduce the prediction accuracy, whereas small samples provided a conservative description of ecological niche. Here, we highlighted that considering the big size and high accuracy of sample and many environmental factors of a species to minimize error when attempting to infer potential distributions from current data in MaxEnt model.

4

Species distribution models to estimate the deforested area of Picea crassifolia in arid region recently protected : Qilian Mts. National Natural Reserve (China)

Xu Z., Zhao C., Feng Z.

Polish Journal of Ecology

|

2012

|

Vol. 60, nr 3

515-524

EN

The earth is now facing the land degradation due to human disturbance, natural habitats were converted to rural and agricultural areas in order to fulfill the increasing demand of human population. The deforestation of Picea crassifolia (Qinghai spruce) forest at Qilian Mts is an example of such disturbance. P. crassifolia is an ecologically and hydrologically important plant species in the northwestern arid area of China. However, the forests have been intensively and extensively deforested. In order to restore the human-disturbed ecosystems, the spatial distribution of P. crassifolia needs to be delineated. This study employed Genetic Algorithm for Rule-set Prediction model (GARP) and Maximum entropy model (Maxent) and four environmental variables (mean temperature of the warmest quarter, precipitation of the wettest quarter, annual solar radiation, topographic wetness index) to predict the potential distribution of P. crassifolia in Qilian Mts. Genetic Algorithm for Rule-set Prediction model (GARP) produces a model of species niches in geographic space based on heterogeneous rule-sets. Maximum entropy model (Maxent) focuses on fitting a probability distribution for occurrence based on the idea that the best explanation to unknown phenomena will maximize the entropy of the probability distribution, subject to the appropriate constraints. The environmental variables were spatially interpolated throughout the entire study area. We used sensitivity-specificity sum maximum approach to select the threshold value. The projected niche space for the mean temperature of the warmest quarter is between 8.5 and 18.1[degrees]C; the space for the precipitation of the wettest quarter is between 149 and 245 mm; the space for annual solar radiation is 118-1100 x 10[^3] wh m[^-2] and the space for topographic wetness index is between -0.4 and 5.1. The results show that both GARP and Maxent's models produce acceptable predictions, but the overall comparison shows that GARP prediction is better than Maxent's; the comparison between the observed distribution and the predicted distribution suggests that 61% (2869 km2) of P. crassifolia forests have been deforested.

5

Analiza właściwości uziemień, Część 4. Uziemienia w gruncie niejednorodnym

Kosztaluk R.

Przegląd Elektrotechniczny

|

2005

|

R. 81, nr 4

45-49

PL

Przedstawiono metody analizy właściwości uziemień, usytuowanych w gruncie niejednorodnym. Wyznaczono zależności, charakteryzujące uziom półkolisty o małym promieniu, usytuowany w górnej warstwie gruntu. Dokonano oceny właściwości uziomów pionowych, umieszczonych w górnej lub w obydwu warstwach gruntu. Wyznaczono zależności, pozwalające obliczać rezystancję uziemienia ww. uziomów i oceniać rozkład potencjału w gruncie warstwowym oraz na jego powierzchni.. W analizach zastosowano funkcje cylindryczne (walcowe) Bessela: pierwszego rodzaju, rzędu zerowego J0 (x) oraz rozwiązanie szczególne równań różniczkowych zwyczajnych, drugiego rzędu, podane przez Webera.

EN

The analyzing methods of properties of grounding installations, located in the inhomogeneous soil, is presented. The characteristic of half -sphere groundings with small radius located in the upper soil layer is calculated. The properties of vertical groundings, located in the upper or both soil layers are discussed. The equation for grounding resistances, as well as potential distribution for layered soil and on the surface of such grounding installations are derived. In these analysis the Bessel functions J0(x) as well as the special solutions of the ordinary differential equations of second order made by Weber, are applied.