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1.
Alberto Bosino Paolo Giordani Geraldine Quénéhervé Michael Maerker 《地球表面变化过程与地形》2020,45(12):3025-3041
Soil erosion is one of the most important environmental problems distributed worldwide. In the last decades, numerous studies have been published on the assessment of soil erosion and the related processes and forms using empirical, conceptual and physically based models. For the prediction of the spatial distribution, more and more sophisticated stochastic modelling approaches have been proposed – especially on smaller spatial scales such as river basins. In this work, we apply a maximum entropy model (MaxEnt) to evaluate badlands (calanchi) and rill–interrill (sheet erosion) areas in the Oltrepo Pavese (Northern Apennines, Italy). The aim of the work is to assess the important environmental predictors that influence calanchi and rill–interrill erosion at the regional scale. We used 13 topographic parameters derived from a 12 m digital elevation model (TanDEM-X) and data on the lithology and land use. Additional information about the vegetation is introduced through the normalized difference vegetation index based on remotely sensed data (ASTER images). The results are presented in the form of susceptibility maps showing the spatial distribution of the occurrence probability for calanchi and rill–interrill erosion. For the validation of the MaxEnt model results, a support vector machine approach was applied. The models show reliable results and highlight several locations of the study area that are potentially prone to future soil erosion. Thus, coping and mitigation strategies may be developed to prevent or fight the soil erosion phenomenon under consideration. © 2020 John Wiley & Sons, Ltd. 相似文献
2.
The Asian elephant (Elephas maximus) and Hoolock gibbon (Hoolock hoolock) are two globally endangered wildlife species limited to only tropical Asian forests. In Bangladesh both species are critically endangered and distributed mainly in the northeast and southeast hilly regions bordering neighboring India and Myanmar. Using existing distribution data, land-use/land cover, elevation and bio-climatic variables, we modeled the likely distribution of Asian elephant and Hoolock gibbon in Bangladesh for 2050 and 2070. We used the IPCC's Representative Concentration Pathways (RCPs) – RCP6.0 and RCP8.5 and Maximum Entropy algorithm for our modelling. Our study indicated that the Asian elephant will be more resilient to climate change compared with the Hoolock gibbon. Habitat loss for the Asian elephant is also expected to remain constant (i.e. 38%) throughout the period, whilst Hoolock gibbon habitat will be more sensitive to climatic variations, with the species predicted to be extirpated from the country by 2070. Being highly exposed to climate change with ever increasing land use pressures, we believe our study in Bangladesh can be used to enhance our understanding of future vulnerabilities of wildlife in a rapidly changing climate. A trans-boundary conservation program with greater attention to the species that are less resilient to climate change is also essential. 相似文献
3.
Myanmar is a country with an economy based on agriculture. It has rich agricultural resources and great potential for development. The development of agriculture in Myanmar is becoming increasingly important to international food security. Assessments of agricultural land resources in Myanmar are the basis for the country’s agricultural development and for food security evaluations. In this paper we used the MaxEnt model to analyze the relationship between the suitability of land for agricultural reclamation and the main environmental variables in Myanmar, and then constructed a model to comprehensively evaluate the suitability of land for agriculture in Myanmar. The results show that: 1) the overall accuracy of the MaxEnt model is high (AUC>0.8), which means there is a high correlation between the database of selected environmental indicators and the true distribution of cultivated land in Myanmar. 2) Soil depth is the most important factor affecting the suitability of land for agriculture in Myanmar. When the thickness of soil layer is less than 100 cm, the suitability of land for agriculture is low. With respect to topographic conditions, slope is the main factor affecting suitability. When the slope is greater than 20 degrees, the suitability of land for agriculture is low. With respect to climate conditions, precipitation is the main influencing factor. There is a positive correlation between river network density and land suitability. 3) Currently, 400 000 km² of the land resources in Myanmar are suitable for agriculture, and of this amount 290 000 km² are highly suitable, accounting for nearly 40% of the country's land area. The highly suitable land is distributed mainly in Magway, Sagaing, Ayeyarwady and Yangon provinces. The provinces are also important grain production areas in Myanmar, and this serves to validate the effectiveness of the method used in this paper. 相似文献
4.
万山群岛海域生态环境日益恶化、渔业资源持续衰退,因此建设万山群岛海洋牧场,修复海域生态环境、实现渔业资源可持续利用迫在眉睫。针对现阶段基于海洋生物资源的海洋牧场适宜性评估的研究较少,本研究利用渔业资源调查和全球物种数据库记录数据及13个环境因素数据,采用物种分布模型MaxEnt对选择的白姑鱼、日本金线鱼、红星梭子蟹和浅缝骨螺潜在分布区进行预测,探讨海洋生物地理分布与海洋环境因素之间的关系进而进行万山海洋牧场生境适宜性评估,结果表明:(1)各模型AUC值均大于0.9,说明构建的模型对这些物种潜在分布的模拟效果较好,后续可采用MaxEnt模型对4种生物的栖息地分布区进行预测;(2)海底浮游植物密度、海底温度以及海底硅酸盐浓度是影响这4种海洋生物栖息地分布的关键环境因子;(3)基于该4种海洋物种MaxEnt模型的HSI分布区所存在重叠区域来看,海洋牧场拟建设区域应为纬度21.85°N~22.15°N,经度113.6°E~114.2°E。研究结果可为万山海洋牧场规划和建设提供科学依据。 相似文献
5.
Lukáš Gábor Vojtěch Barták Vincent Lecours 《International journal of geographical information science》2020,34(8):1567-1584
ABSTRACT Species distribution models (SDMs) are widely used in ecology and conservation. However, their performance is known to be affected by a variety of factors related to species occurrence characteristics. In this study, we used a virtual species approach to overcome the difficulties associated with testing of combined effects of those factors on performance of presence-only SDMs when using real data. We focused on the individual and combined roles of factors related to response variable (i.e. sample size, sampling bias, environmental filtering, species prevalence, and species response to environmental gradients). Results suggest that environmental filtering is not necessarily helpful and should not be performed blindly, without evidence of bias in species occurrences. The more gradual the species response to environmental gradients is, the greater is the model sensitivity to an inappropriate use of environmental filtering, although this sensitivity decreases with higher species prevalence. Results show that SDMs are affected to the greatest degree by the species response to environmental gradients, species prevalence, and sample size. Models’ accuracy decreased with sample size below 300 presences. Furthermore, a high level of interactions among individual factors was observed. Ignoring the combined effects of factors may lead to misleading outcomes and conclusions. 相似文献
6.
David T. Y. Wong William S. Osborne Stephen D. Sarre Bernd Gruber 《International journal of geographical information science》2018,32(5):1006-1025
The geographical distribution of a species is limited by factors such as climate, resources, disturbances and species interactions. Environmental niche models attempt to encapsulate these limits and represent them spatially but do not always incorporate disturbance factors. We constructed MaxEnt models derived from a remotely sensed vegetation classification with, and without, an agricultural modification variable. Including agricultural modification improved model performance and led to more sites with native vegetation and fewer sites with exotic or degraded native vegetation being predicted suitable for A. parapulchella. Analysis of a relatively well-surveyed sub-area indicated that including agricultural modification led to slightly higher omission rates but markedly fewer likely false positives. Expert assessment of the model based on mapped habitat also suggested that including agricultural modification improved predictions. We estimate that agricultural modification has led to the destruction or decline of approximately 30–35% of the most suitable habitat in the sub-area studied and approximately 20–25% of suitable habitat across the entire study area, located in the Australian Capital Territory, Australia. Environmental niche models for a range of species, particularly habitat specialists, are likely to benefit from incorporating agricultural modification. Our findings are therefore relevant to threatened species planning and management, particularly at finer spatial scales. 相似文献
7.
基于最大熵模型（MaxEnt）和地理信息系统,结合中国假木贼属（Anabasis）7个种的地理分布记录及19个环境因子,预测这7个种的潜在分布区及该属的分布中心,并分析其主导环境因子。采用受试者工作特征曲线下面积作为模型预测准确度的衡量指标,刀切法用于评估各环境因子在决定潜在分布区时的贡献量。结果显示：（1）白垩假木贼（A.cretacea）、高枝假木贼（A.elatior）、毛足假木贼（A.eriopoda）、无叶假木贼（A.aphylla）、盐生假木贼（A.salsa）和展枝假木贼（A.truncata）的潜在适生区集中在新疆北部、天山南麓及塔里木盆地西侧,短叶假木贼（A.brevifolia）的潜在适生区在新疆、甘肃、宁夏和内蒙古的部分地区。（2）中国假木贼属的分布中心在新疆准噶尔盆地、天山南麓、塔里木盆地西侧及甘肃西北部的河西走廊。（3）在19个环境因子中,对中国假木贼属这7个种分布区预测贡献量较大的生态因子是年平均气温、最湿月降水量、最干季度平均温度、平均降水量、最冷季度降水量、年均温变化范围和最湿季度降水量。 相似文献
8.
中国富士苹果种植的气候适宜性研究 总被引：4，自引：0，他引：4
基于中国1981-2010年2084个气象台站资料和203个富士苹果种植区分布的地理数据,利用最大熵(MaxEnt)模型和ArcGIS平台,从物种分布机理与品质两方面研究了影响富士苹果在中国分布的主导气候因子及适宜范围,并对其气候适宜性进行区域划分和评价。结果表明,影响富士苹果在中国分布的主导气候因子有8个,富士苹果地理分布的气候适宜范围分别为年日照时数2000-2500 h、年平均气温7-14℃、≥10℃积温3000-4800℃·d、最冷月平均气温-7-0℃、夏季气温平均日较差8-12℃、年降水量400-800 mm、夏季平均气温20-26℃、夏季平均空气相对湿度60%-78%。中国富士苹果的气候适宜区主要分布在黄土高原、环渤海湾和黄河古道,其中,黄土高原区的陕西、山西和甘肃气候适宜度最高,而山东和河北两省富士苹果规模化种植还有较大发展空间。 相似文献
9.
The Africanized honeybee (AHB; Apis mellifera scutellata) is an invasive species which poses a threat to the United States' agricultural industry because of potential decline in pollination services. Previous research has confirmed that the AHB may still expand its range farther north and that limiting environmental factors for AHB distribution vary across the country. This study examines similarities and differences in AHB distribution and the relative importance of environmental factors between two regions of the southwestern United States: southern Utah and southern California. The Maximum Entropy (MaxEnt) modeling approach was used to create two species distribution models of the AHB. First a model was created based on AHB presence data in Utah. This model was used to estimate the Utah distribution and also to project the California distribution based on Utah environmental preferences. The second model was created to predict distribution in California and to project distribution in Utah based on AHB environmental preferences in California. The level of influence of each variable was measured through percent contribution and permutation importance. Model performance was assessed through the area under the receiver operating characteristic curve (AUC). Models estimated AHB presence with high accuracy (AUC > 0.95) in original environments, but were less accurate (AUC < 0.8) in novel environments. Minimum temperature was the primary controlling factor of AHB distribution in each model, and other variables followed similar ranking of importance between the two models. Species response curves varied substantially between the two models. Models did not transfer well from one region to the other because of local differences in response curves and the relative importance of environmental variables, suggesting that AHB in these regions may not have realized their potential geographic range. 相似文献
10.
Isaiah Gwitira Amon Murwira Mhosisi Masocha Fadzai M. Zengeya Munyaradzi Davis Shekede Joconiah Chirenda 《国际地球制图》2013,28(11):1163-1176
AbstractMalaria burden has considerably declined in the last 15 years mainly due to large-scale vector control. The continued decline can be sustained through malaria risk stratification. Malaria stratification is the classification of geographical areas according to malaria risk. In this study, ecological niche modelling using the maximum entropy algorithm was applied to predict malaria vector habitat suitability in terms of bioclimatic and topographic variables. The output vector suitability map was integrated with malaria prevalence data in a GIS to stratify Zimbabwe into different malaria risk zones. Five improved and validated malaria risk zones were successfully delimited for Zimbabwe based on the World Health Organization classification scheme. These results suggest that the probability of occurrence of major vectors of malaria is a key determinant of malaria prevalence. The delimited malaria risk zones could be used by National Malaria Control programmes to plan and implement targeted malaria interventions based on vector control. 相似文献