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1.
基于广西崇左市2001年和2010年两期遥感影像,在遥感、地理信息技术和统计分析工具支持下,应用分形理论对2001—2010年10 a间该地区土地利用类型形态复杂度与结构稳定度的时空格局进行实证研究。结果表明:（1）崇左市边境4县（市）各土地利用类型的分布都具有分形结构,2001年和2010年各地类斑块总体上形状比较规则,结构相对稳定;（2）10 a间各地类的分形维数逐步增大并向临界值1.5逼近,稳定性指数则不断减小并接近于0,呈现出高复杂性和低稳定性的分形演变趋势;（3）大新县和龙州县的水域、凭祥市和宁明县的林园地的复杂性升高而稳定性下降趋势最为明显,大新县和龙州县的未利用地、凭祥市和宁明县的草地变化幅度最小;（4）崇左市今后发展应加强土地利用的规划引导,采取有效措施来适当控制土地类型整体分形维数的增加,维持土地利用结构的稳定性。 相似文献
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为揭示边境地区土地利用转型对生态服务功能的影响,推动区域生态环境与社会经济高质量发展。基于广西边境地区2000年、2010年、2018年3期土地利用遥感监测数据,识别18年间土地利用转型和生态系统服务价值的动态演变过程,结合改进的交叉敏感性系数探讨了广西边境地区生态系统服务价值对土地利用转型的敏感性程度。结果表明:(1)2000—2018年广西边境地区土地转型前期平缓,后期剧烈,耕地向建设用地、水域的转移是主要的转型驱动因素;(2)2000—2018年ESV呈现出先增后减的态势,地均ESV高值主要集中于防城区、宁明县南部以及那坡县南部生态环境本底优越的一带,地均ESV低值出现在宁明县北部、龙州县、大新县以及靖西市的中心城区生态系统较为薄弱的岩溶地区;(3)耕地、林地、水域与其他地类相互转型对生态系统服务功能影响较为敏感,其中最敏感的是林地与建设用地的转型,草地、未利用地与其他地类的转型缺乏敏感性。(4)生态敏感性空间演化分异特征显著,耕地与建设用地高生态敏感性重点分布在东兴市、宁明县、龙州县、靖西市,林地与建设用地高生态敏感区主要分布在防城区和东兴市主城区、凭祥市以及靖西市北部等重要的贸易出口通道。研究结果可为优化边境国土空间格局,实现生态服务功能的提升提供科学指引。 相似文献
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4.
白头叶猴采食植物的再研究 总被引：1，自引：1，他引：0
2006年使用了较先进的录像设备,结合单筒望远镜对白头叶猴进行了全天候的跟踪观察和录像,使我们有可能更准确地仔细鉴定白头叶猴采食的植物及采食部位,也为动物生态的研究提供一个可重复验证的方法。经统计分析发现:白头叶猴属热带分布的灵长类动物,全以植物的各部分器官为食;被采食的植物大多数为热带分布的物种,是当地植被重要的建群种或优势种;在白头叶猴采食的物种中,有一部分是人类使用的药用植物;其中落叶成分和喜钙植物都较多;初步认为白头叶猴对不同的植物其喜食程度有明显不同。 相似文献
5.
We developed large-scale spatially explicit models to predict the distribution of suitable habitat patches for the Greater rhea (Rhea americana), a near-threatened species, in two areas of central Argentina with different land use: a grassland area (ca. 4943 km2) mainly devoted to cattle grazing and an agro-ecosystem area (ca. 4006 km2) mostly used for crop production. The models were developed using logistic regression and were based on current records of Greater rhea occurrence coupled with remote sensing data, including land cover and human presence variables. The habitat suitability maps generated were used to predict the suitable habitat patch structure for wild rhea populations in each area. Fifty-one percent of the total grassland area was suitable for the species, being represented by a single large patch that included 62% of the individual locations. In the agro-ecosystem, only 28% of the total area was suitable, which was distributed among four patches. Seventy percent of rhea observations were in suitable habitat, with all rheas grouped in the largest patch. Conservation efforts for preserving wild rhea populations should be focused on maintaining habitats similar to grasslands, which are less profitable for landowners at present. Consequently, the protection of the pampas grasslands, a key habitat for this species as well as for others with similar habitat requirements, will demand strong conservation actions through the reconciliation of interests between producers and conservationists, since the proportion of croplands is increasing. 相似文献
6.
David W. Hilbert Matt Bradford Trevor Parker David A. Westcott 《Biological conservation》2004,116(3):367-377
A generalised linear model was used to predict climatically suitable habitat for the golden bowerbird (Prionodura newtonia De Vis), an endemic species of the Wet Tropics of North Queensland. Mean temperature of the coldest quarter and mean precipitation of the wettest quarter were found to be the best habitat predictors. For independent validation data, accuracy was 67% (Kappa statistic, n=30). Past, and future habitats suitable to the golden bowerbird were mapped by altering the temperature and precipitation input to the model. In the current climate, total potential habitat is estimated to be 1564 km2, occurring as a number of separate patches with distinct bowerbird subpopulations. Past habitat was most limiting, 406 km2, during the Holocene climatic optimum (c. 5000-3600 YBP, +2 °C and +50% rainfall relative to today). With future warming, assuming a 10% decrease in rainfall, potential habitat is reduced to 582 km2 (1 °C warming), 163 km2 (2 °C warming) and 37 km2 (3 °C warming). Thus, global warming in the coming decades is likely to be a significant threat to the survival of this and similar upland and highland species in the tropics. 相似文献
7.
Mark Hebblewhite Dale G. Miquelle Andre A. Murzin Vladimir V. Aramilev Dimitri G. Pikunov 《Biological conservation》2011,(10):2403-2413
The Far Eastern Leopard (Panthera pardus orientalis; Schlegel, 1857) is perhaps the world’s most endangered large felid subspecies occurring in a single population of ?30 adults, and faces immediate risk of extinction unless additional populations can be established within its historical range in the Russian Far East. We used locations of leopard tracks (and their ungulate prey) collected from snow track surveys from 1997 to 2007 to develop resource selection functions (RSF) to identify potential habitat for reintroduction. We compared models that include prey versus those based on landscape covariates, and also included covariates related to human-induced mortality. To estimate potential population size, we used a habitat-based population estimate based on the ratio of population size and RSF value of occupied range. Far Eastern leopards selected for areas with high ungulate density, lower-elevation Korean pine forests on southwest facing slopes, and in areas far from human activity. Using this RSF model, we identified a total of 10,648 km2 in eight patches >500 km2 of potential Far Eastern leopard habitat that could harbor a potential population of 105.3 (57.9–147.2) adults. In combination with the existing population, successful reintroductions could result in a total of 139.2 (76.5–194.6) adult leopards, a 3–4-fold increase in population size. Our habitat models assist the reintroduction planning process by identifying factors that predict presence and potential suitable habitat. Identifying the highest quality, most connected patches, in combination with appropriate selection and training of released animals, is recommended for successfully reintroducing Far Eastern leopards, and potentially other endangered carnivores into the wild. 相似文献
8.
以2002年前后的Landsat7ETM+遥感影像为主要数据源,采用人机交互解译的方法,对珠江上游喀斯特地区土地石漠化强度现状进行遥感解译,解译精度高达87%。对遥感解译分析和研究的结果表明:整个珠江上游的土地石漠化已十分严重,石漠化、半石漠化土地面积3万9900 km2,占总面积的16.4%;石漠化、半石漠化比率大于15%的石漠化县有52个,其中贵州省土地石漠化最严重,石漠化、半石漠化比率高达21.9%,有23个石漠化县(区),广西和云南相对较轻,石漠化、半石漠化比率分别为14.7%和14.4%,分别有21和8个石漠化县。珠江上游19个市(州)中就有12个市(州)的石漠化、半石漠化面积超过1000km2,集中分布于贵州黔南州—广西河池市、贵州黔西南州—云南曲靖市和云南文山州—广西百色市3个石漠化条带上。 相似文献
9.
Degradation of tropical forest in Hainan, China, 1991-2008: Conservation implications for Hainan Gibbon (Nomascus hainanus) 总被引：1，自引：0，他引：1
Mingxia Zhang John R. Fellowes Xuelong Jiang Bosco P.L. Chan Jianguo Zhu 《Biological conservation》2010,143(6):1397-73
The Hainan gibbon (Nomascus hainanus) is one of the most endangered primates in the world, confined to mature natural forest in Hainan Island, China. We assessed changes in habitat condition on the island between 1991 and 2008, using vegetation maps generated by remote-sensing images. We defined forest suitable for gibbons based on composition, tree size and canopy cover. During the 17-year period, the area of suitable gibbon forest decreased by 540 km2 (35%) across the whole island, and by 6.3 km2 (7%) in the locality of the sole remaining gibbon population at Bawangling National Nature Reserve. The forest patches large enough (>1 km2) to support a gibbon group decreased from 754 km2 to 316 km2 in total area, and from 92 to 64 in number. Suitable natural forest was mainly replaced by plantations below 760 m, or degraded by logging, grazing and planting of pines above 760 m. Meanwhile, forests in former confirmed gibbon areas became more fragmented: mean area of patches decreased by 53%. We mapped the patches of natural forest in good condition which could potentially support gibbons. We recommend a freeze on further expansion of plantations between core patches at Bawangling, Jiaxi-Houmiling and Yinggeling Nature Reserves in accordance with forest protection regulations; establishment of nature reserves in currently unprotected natural forest patches elsewhere in line with the local government’s nature reserve expansion policy; and active natural-forest restoration between remaining fragments at Bawangling. 相似文献
10.
随着空气质量和畜禽养殖污染问题日益严峻,快速发展的规模化畜禽养殖面临的环境压力不断增大,明确规模化畜禽养殖的氨排放量及其排放特征,可为大气环境管理和畜禽养殖污染防治提供科学依据及对策。本文根据重庆市规模化畜禽养殖业氨排放系数和活动水平数据,估算了重庆市2013年规模化畜禽养殖业氨排放量,分析氨排放特征,并探讨了相应的氨减排措施。结果表明,2013年重庆市规模化畜禽养殖氨排放总量为17 102.92 t,排放强度为0.21 t·km~(-2);合川、丰都和潼南依次是规模化畜禽养殖业氨排放量最大的3个区县,排放份额共占总排放量的30.19%;从空间分布特征来看,璧山区为氨排放强度最大的区县,其排放强度为1.17 t·km~(-2),氨排放强度最小的是城口县,为0.01 t·km~(-2);在全局空间区域上,重庆市规模化畜禽养殖氨排放空间分布存在显著的空间正相关;局部空间区域上有4个区县呈现"高-高"类型区,5个区县呈现"低-低"类型区,没有出现"高-低"或"低-高"类型区。规模化生猪养殖是重庆市畜禽养殖业最大的氨排放贡献源,排放量达9 538.63 t,贡献率为55.80%;其次是蛋鸡,其贡献率为15.87%。畜禽在圈舍、储存管理和后续利用(施肥)3个阶段的氨排放量不同,家禽在圈舍阶段的氨排放贡献率均超过60%,其次是后续利用(施肥)阶段,尿粪储存阶段氨排放量最小;家畜氨排放贡献率最高的是后续利用(施肥)阶段,其次是圈舍内的排放,储存阶段释放的氨量很少。奶牛养殖是减排的重点控制源,规模化畜禽养殖主要减排措施包括低氮饲料喂养、畜舍改造、粪便加盖或密封以及粪肥注施等。 相似文献
11.
基于熵权物元模型的黄芩适宜生境区划 总被引：1，自引：0，他引：1
[目的]黄芩(Scutellaria baicalensis Georgi)是中国3级野生保护药材物种。利用生境适宜性评价模型对黄芩的适宜生境进行区划,并计算各适宜生境面积,为保护和实现黄芩资源的可持续利用提供科学依据。[方法]利用熵权物元模型,建立黄芩标志性药用成分黄芩苷(C21H18O11)含量与15个环境评价因子之间的模糊隶属函数,采用熵值法确定各评价因子权重,结合GIS空间分析模拟中国黄芩生境适宜区地理空间分布。[结果]中国黄芩不适宜生境、低适宜生境、中适宜生境和高适宜生境的面积分别为5.07×106,1.65×106,1.88×106和1.00×106 km2,其中高适宜生境主要集中在秦岭—淮河一线以北,以河南、山东、辽宁、陕西中南部、河北、吉林、黑龙江南部、山西南部等地区为显著代表,此外云南、安徽等省也有少量分布,与实际分布范围极为吻合。[结论]评价因子中平均日较差、降水季节性变化、最湿月降水量以及坡向基本控制了黄芩的地理空间分布。 相似文献
12.
Biotic homogenization, driven by native species losses and invasive species gains was investigated for the flora of California. Data from a variety of available databases were aggregated at the county level to examine patterns in county population density and growth in relation to floristic change. Based on population, California was divided into three zones: high (n = 9; 257-1320 people/km2), medium (n = 25; 28-177 people/km2), and low (n = 24; 1-24 people/km2) density counties. Examining patterns of rare plant occurrences among these counties revealed that high and medium density counties contained, on average, as many or more rare and endemic species than low density counties. The largest pool of these species, 48 percent of the 962 highly threatened taxa in California, is restricted to high and medium density counties. Thus, urban and urbanizing counties play a strategic role in maintaining a part of California’s flora that is both globally significant and threatened with extinction. Examining species losses and noxious weed additions across high density counties, reveals a consistent pattern of low similarity among species that have been extirpated from high density counties and a high similarity among noxious weeds that these counties now share. The consequence is that California’s urban county floras appear to be homogenizing. Examining homogenization using the entire flora for urban counties demonstrates that less similar counties become more similar. The effect of loss of rare species could outweigh the gain in exotics, under an assumption of strong extinction. Finally, a strong negative relationship between population density and the proportion of county land in public ownership suggests that high and medium density counties are in a poor position to protect rare plant populations on a localized basis. 相似文献
13.
基于InVEST模型的未利用地开发前后生境质量评价——以唐县为例 总被引：1，自引：1，他引：0
生境质量评价对生物多样性保护有至关重要的作用,为探究未利用地开发对唐县生境质量的影响,本文运用InVEST模型中的Habitat Quality模块分析2000年、2007年和2016年河北省唐县未利用地开发前后的生境质量变化情况。研究表明:1)2000—2016年,未利用地开发方向主要以草地、林地和耕地为主,未利用地比例从100%(以2000年未利用地面积为基数)减少到33.70%,草地、林地和耕地比例从0分别增加到27.43%、 21.30%和10.46%。2)唐县未利用地斑块所占景观面积比逐年减少,其平均斑块面积由开发前的94.73 hm~2减少到开发后的6.15hm~2;林地、水域和草地所占景观面积比例增加。未利用地开发后均匀度指数和多样性指数都有所增加,各景观组分所占面积比例差异减小,生态系统稳定性提高。3)未利用地开发后,研究区生境质量明显提升,生境质量得分由2000年的0.09上升到2007年的0.28,2016年又上升到0.39。研究结果可以为制定合理的土地规划以及土地开发工作中的生境及生物多样性保护等提供科学依据。 相似文献
14.
2004年1月，在广西南部中越边境地区的宁明县考察时，采到一号翚形目鸟类标本，经鉴定为仓鸮(Tyto alba)，是广西鸟类新纪录。标本保存于广西大学动物科学技术学院动物标本室。 相似文献
15.
Thresholds in landscape parameters: occurrence of the white-browed treecreeper Climacteris affinis in Victoria, Australia 总被引：1，自引：0，他引：1
The concept of critical thresholds of habitat loss has recently received considerable attention in conservation biology and landscape ecology, yet empirical examples of thresholds are scarce. Threatened species management could benefit from recognition of thresholds because conditions under which populations are at risk can be specified. In this study, 56 woodland patches in north-west Victoria were surveyed for the white-browed treecreeper Climacteris affinis, a threatened insectivorous bird of the semi-arid zone of southern Australia. Comparisons with historic records indicate the species’ range is contracting in Victoria. Using logistic regression and hierarchical partitioning, two models of patch occupancy were developed. Tree species composition was an important factor in both models, confirming the treecreepers’ affinity for belah Casuarina pauper and slender cypress-pine Callitris gracilis-buloke Allocasuarina luehmannii woodlands in north-west Victoria. The first model emphasized the importance of demographic isolation: probability of patch occupancy decreased with distance to the nearest occupied patch. A threshold response in demographic isolation was apparent. In agricultural landscapes, most suitable woodland patches within 3 km of an occupied patch were occupied, whereas patches beyond the threshold were vacant. The threshold distance increased to a minimum of 8 km in a matrix of native vegetation, suggesting landscape context affects the response of white-browed treecreepers to habitat fragmentation. Demographic isolation is a quasi-dependent variable and therefore a second model was developed using surrogate variables for demographic isolation. A positive relationship with the proportion of woodland cover in the landscape (100 km2) emerged as the pre-eminent explanatory factor. Depending on woodland quality, a threshold of patch occupancy was apparent at levels of woodland cover between 15 and 25%. However, belah and slender cypress-pine-buloke woodlands now cover only 10% of their original extent in the region. These results highlight the inter-dependence of patch isolation with the amount and quality of habitat in the landscape and the implications this has for maintaining functional connectivity. The retention (or restoration) of suitable habitat is the critical issue for conservation of the white-browed treecreeper, but in landscapes below the threshold of habitat cover, viability of local populations may be influenced by the configuration and quality of remaining habitat. 相似文献
16.
A study in southern Ethiopia of Swayne's hartebeest (Alcelaphus buselaphus swaynei), an endangered species of antelope, showed the animals to be well adapted to their limited habitat. The animals exhibit certain ecological differences from the closely related Coke's hartebeest in that they have a well-defined calving season, select short grass areas for feeding, are independent of free water and are not territorial throughout the year. The population is now less than 1000 and suitable territory has been reduced to 58 km2. 相似文献
17.
European Bison (Bison bonasus) barely escaped extinction in the early 20th century and now only occur in small isolated herds scattered across Central and Eastern Europe. The species’ survival in the wild depends on identifying suitable habitat for establishing bison metapopulations via reintroductions of new herds. We assessed European Bison habitat across the Carpathian Mountains, a stronghold of European Bison and one of the only places where a viable bison metapopulation may be possible. We used maximum entropy models to analyze herd range maps and habitat use data from radio-collared bison to identify key habitat variables and map European Bison habitat across the entire Carpathian ecoregion (210,000 km2). Forest cover (primarily core and perforated forests) and variables linked to human disturbance best predict bison habitat suitability. Bison show no clear preference for particular forest types but prefer managed grasslands over fallow and abandoned fields. Several large, suitable, but currently unoccupied habitat patches exist, particularly in the eastern Carpathians. This available suitable habitat suggests that European Bison have an opportunity to establish a viable Carpathian metapopulation, especially if recent trends of declining human pressure and reforestation of abandoned farmland continue. Our results also confirm the suitability of a proposed Romanian reintroduction site. Establishing the first European Bison metapopulation would be a milestone in efforts to conserve this species in the wild and demonstrate a significant and hopeful step towards conserving large grazers and their ecological roles in human-dominated landscapes across the globe. 相似文献
18.
As part of our ungulate population protection program, the specific causes of ungulate mortality were examined and the effect of single habitat on habitat selection by ungulate analyzed. An integrated occurrence–mortality model for three ungulate species (wild boar Sus scrofa L., red deer Cervus elaphus L. and roe deer Capreolus capreolus Pallas) within the Wanda Mountains of Heilongjiang Province, China was then created. Results showed that steel cable snares and poison, used to kill ungulates, were the primary threats to survival of wild boar (40.07% poison, 27.79% cable snares), red deer (51.35% poison, 40.54% cable snares) and roe deer (29.31% poison, 56.90% cable snares). Furthermore, we found evidence that aspect, slope, elevation and forest type are important factors in determining ungulate habitat preference. The integrated occurrence–mortality model indicated that 46.39% of suitable habitat was associated with mortality risk. This model correctly classified 8.06% (297.49 km2) of the study area as unsuitable habitat, 5.43% (200.44 km2) as first attractive sink-like habitat, 32.76% (1209.85 km2) as second attractive sink-like habitat, 8.20% (302.77 km2) as third attractive sink-like habitat, and 8.91% (329.00 km2), 30.53% (1127.22 km2) and 6.11% (225.29 km2) as first, second and third source-like habitats, respectively. The results indicate that source-like habitats should be preserved to prevent habitat loss and degradation, while attractive sink-like habitats should be managed effectively to mitigate mortality risks. In particular, the various authorities need to be more proactive (increase patrolling, thereby providing employment, educational opportunities and increasing income) to reduce human-caused ungulate mortality. 相似文献
19.
Habitat colonization and abandonment affects the distribution of a species in space and time, ultimately influencing the duration of time habitat is used and the total area of habitat occupied in any given year. Both aspects have important implications to long-term conservation planning. The importance of patch isolation and area to colonization-extinction events is well studied, but little information exists on how changing regional landscape structure and population dynamics influences the variability in the timing of patch colonization and abandonment events. We used 26 years of Kirtland’s Warbler (Dendroica kirtlandii) population data taken during a habitat restoration program (1979-2004) across its historical breeding range to examine the influence of patch attributes and temporal large-scale processes, specifically the rate of habitat turnover and fraction of occupied patches, on the year-to-year timing of patch colonization and abandonment since patch origin. We found the timing of patch colonization and abandonment was influenced by patch and large-scale regional factors. In this system, larger patches were typically colonized earlier (i.e., at a younger age) and abandoned later than smaller patches. Isolated patches (i.e., patches farther from another occupied patch) were generally colonized later and abandoned earlier. Patch habitat type affected colonization and abandonment; colonization occurred at similar patch ages between plantation and wildfire areas (9 and 8.5 years, respectively), but plantations were abandoned at earlier ages (13.9 years) than wildfire areas (16.4 years) resulting in shorter use. As the fraction of occupied patches increased, patches were colonized and abandoned at earlier ages. Patches were abandoned at older ages when the influx of new habitat patches was at low and high rates. Our results provide empirical support for the temporal influence of patch dynamics (i.e., patch destruction, creation, and succession) on local colonization and extinction processes that help explain large-scale patterns of habitat occupancy. Results highlight the need for practitioners to consider the timing of habitat restoration as well as total amount and spatial arrangement of habitat to sustain populations. 相似文献
20.
《国际水土保持研究(英文)》2022,10(3):414-421
Desertification in degraded grasslands is manifested through the development of bare sandy patches, which eventually lead to habitat fragmentation. The ability of these bare sandy patches to regenerate naturally through in-situ soil seed banks is not well understood. To fill this knowledge gap, we randomly selected 24 bare sandy patches with areas ranging from 19 to 898 m2 in a desertified grassland of the Horqin sandy land, Northern China to determine whether soil seed bank can be used for natural regeneration of bare sandy patches. Species composition and density of soil seed bank as well as aboveground vegetation composition, abundance and coverage were investigated. We then determined their relationships with in-situ habitat characteristics. Our observations showed that the studied area had low soil seed bank density and species richness, as well as depauperate soil seed bank communities. Consequently, local soil seed bank was not able to provide sufficient seed source for natural regeneration. This was indicated by the relationships between aboveground vegetation, soil seed bank and the in-situ habitat characteristics. For bare patches with an area between 300 m2 and 900 m2, increase the soil seed bank density and species richness should be the main restoration measures. For bare patches with a small area of less than 50 m2, restoration of vegetation density should be the main measure. Our data highlighted that different extents of desertification, indicated by different bare patches, are requiring distinct restoration measures. 相似文献