首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Pollen grains have been a major focus of research mostly in temperate regions due to their effects on human health, especially allergies and asthma. The current study investigates a subtropical region characterized by a Mediterranean climate where Sharav conditions are experienced during the spring and autumn. The aim of the current study was to investigate whether Sharav conditions impacted airborne pollen concentrations of allergenic Amaranthaceae, Poaceae, Morus, Pinus, and Quercus more than standard Warm days during the main pollen seasons in the years 2010–2014 in Tel Aviv and Jerusalem (Israel). Slight variation was observed between the main pollen seasons in Tel Aviv compared to Jerusalem resulting from differences in temperature and relative humidity percentages. Additionally, more Sharav conditions occurred in Jerusalem than in Tel Aviv during the study period. The highest pollen concentrations occurred during Sharav days for Amaranthaceae, Poaceae, and Pinus but not for Morus and Quercus. Therefore, individuals who are allergic to Amaranthaceae, Poaceae, and Pinus pollen, and exposed to high pollen concentrations during Sharav days, might suffer more allergy symptoms than on Warm days.  相似文献   

2.
3.
4.
Dominant majorities often use idealized categories to validate the ‘goodness’ and deservingness of minority citizens. For Palestinian citizens of Israel, this category is the ‘good Arab’. Since its origins in early Jewish settlement of Palestine, it has become a powerful and controversial metaphor in Israeli public discourse. As an experienced condition of limited inclusion, the ‘good Arab’ exemplifies the Palestinian dilemma of accessing socioeconomic opportunities in Jewish Israeli spaces that stigmatize and fend off their ethnonational identity. Combining a historical genealogy of the ‘good Arab’ with ethnographic research among Palestinians in Tel Aviv, this article shows how a historically evolved logic of settler colonial control and indigenous erasure continues to define liberal frameworks of conditional citizenship and inclusion. Theorized through the emerging concept of conditional inclusion, these insights open up new avenues for analysis and comparison in anthropological debates surrounding indigenous struggles, settler colonialism, urban inclusion, and citizenship.  相似文献   

5.
In 1991, the Israeli government responded to severe shortages in the low-wage labour force by developing a Foreign Worker Program. Over the next two decades, hundreds of thousands of labour migrants from the Global South were issued work visas that would allow them to live temporarily in Israel. Migrants have since settled, primarily in Tel Aviv, where some have also overstayed their visas, given birth to children, and established ways of living as undocumented residents of Israel’s largest urban centre. In this article, I describe how undocumented migrant women and their Israeli-born children have had a particularly significant impact on the social and political context in which they live. Specifically, I explore how they have come to constitute a “privileged underclass” within the ethnically, geographically, and socio-economically stratified population of the city. While they share dilapidated public spaces and conditions of poverty with their historically marginalized Mizrahi neighbours in the southern part of the city, undocumented women and their children share special events, interpersonal engagements, and processes of “sentimental civics” with the largely wealthy and politically enfranchised Ashkenazi residents of Tel Aviv’s north who are their employers, financial patrons, and supporters of their campaign for citizenship. The development of a “privileged underclass” has thus exacerbated class conflict in Tel Aviv, bringing to the surface the well-established, but long-ignored Mizrahi struggles for recognition, and sowing the seeds for a sometimes violent, yet politically nuanced, anti-migrant mobilization.  相似文献   

6.
7.
8.
1. Despite the growing number of non‐indigenous crayfish species introduced worldwide, little scientific attention has been given to their effects on the recipient communities. Here, we quantified the impact of adult red swamp crayfish (Procambarus clarkii) on key components of the littoral community of a mesotrophic lake in central Italy. We used two densities of crayfish plus a no‐crayfish control, and two complementary methods –in situ enclosures and a laboratory study. 2. Both experiments showed that P. clarkii strongly affects the community even at a low density (4 m−2), although a high crayfish density (8 m−2) showed a more pronounced impact in a shorter time. 3. In enclosures, P. clarkii quickly consumed the pond snail Haitia acuta, notwithstanding its anti‐predator behaviour, but not the mosquitofish Gambusia affinis. The biomass of the hydrophytes Nymphoides peltata and Potamogeton spp. was strongly reduced by crayfish grazing, coupled with their non‐consumptive plant clipping and uprooting, which were particularly intense in the case of Potamogeton crispus. In contrast, Utricularia australis was avoided by P. clarkii, even when other resources were exhausted. 4. The introduction of P. clarkii could reduce biodiversity and increase biotic homogenisation in a short time.  相似文献   

9.
The urban heat island in a small city in coastal Portugal   总被引:3,自引:0,他引:3  
This project arose from the need to study the phenomenon of the urban heat island, since only by recognising this phenomenon can we moderate it to improve the human and urban environments. Not only big cities develop urban heat islands. This study detected the presence and recorded the characteristics of an urban heat island in the small coastal city of Aveiro, Portugal. The study was developed through the scheduled measurements of air temperature and the analysis of the geographical, meteorological and urban conditions. The form and intensity of Aveiro’s heat island are a response to the interaction of three principal factors: the urban morphology (the hottest zones in the city are those with the tallest and the highest density of buildings, without green spaces and with intense generation of heat from traffic, commerce and services); the meteorological conditions (the intensity of the island is at its maximum when the sky is totally clear and there is no wind, and at its minimum in those situations when there is atmospheric instability, such as wind, cloud and precipitation); and the proximity of the coastal lagoon (which borders the city to the west and northwest and moderates seasonal temperatures. The urban heat island influences the comfort and health of its inhabitants, thus urban planning is very important in the moderation and prevention of this phenomenon. Received: 7 July 1999 / Revised: 24 April 2000 / Accepted: 26 April 2000  相似文献   

10.
北京城市扩展对热岛效应的影响   总被引:5,自引:0,他引:5  
以北京市为例,基于多期土地利用变化(LUCC)数据集,城市和郊区气象观测数据及一期Landsat TM影像,对北京市的城市扩展与地表温度和近地表气温的对应关系及变化过程作了分析。利用混合像元分解技术实现北京市区下垫面的分类,并联立"单窗算法"反演的地表温度数据进行分析,在北京市范围内利用多期LUCC和气象站点观测数据,对北京城市扩展对气候的影响进行时间和空间上的综合评价。结果表明:北京市地表温度的高低主要与不透水层的比例有关,不透水层对地表增温的作用要大于植被层的降温作用;从时间上看,初步证实了城市热岛强度前期随着城市扩展而增加,但在一定条件下,其强度随城市扩展并非一味升高,反而会出现一定程度上的稳定甚至降低现象。  相似文献   

11.
Zoos and zoological parks serve as genetic and demographic reserves for strengthening endangered populations and reestablishing extinct populations in the wild. Knowing the genetic ties within captive populations is a very helpful tool for successful reproductive management. In the present study we addressed kinship relationships and behavior among rhinoceroses (Ceratotherium simum simum) raised at the Zoological Center, Tel Aviv/Ramat Gan, Israel, with the hope of identifying reasons for the declining rate of reproduction within the herd. We used the random amplified polymorphic DNA (RAPD) technique to reveal the paternity of the rhinos born at the park. In this way, we identified the paternity of five out of seven young born in the herd, which are currently in Ramat Gan. One male accounted for three (37.5%) births, and two other males accounted for one each. The paternity of the two other animals is unknown and may be of animals that are no longer in the Zoological Center. The genetic determinations were accompanied by behavioral observations, which enabled us to determine the social dynamics in the herd. This study suggests that there are at least three contributing factors to the reproductive decline in the herd: 1) a surplus of males, 2) exclusion of potentially reproductive males from the breeding stock, and 3) specific behavioral and physiological problems in some members of the herd. Zoo Biol 21:561–571, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   

12.
With global warming forecast to continue into the foreseeable future, heat waves are very likely to increase in both frequency and intensity. In urban regions, these future heat waves will be exacerbated by the urban heat island effect, and will have the potential to negatively influence the health and welfare of urban residents. In order to investigate the health effects of the urban heat island (UHI) in Shanghai, China, 30 years of meteorological records (1975–2004) were examined for 11 first- and second-order weather stations in and around Shanghai. Additionally, automatic weather observation data recorded in recent years as well as daily all-cause summer mortality counts in 11 urban, suburban, and exurban regions (1998–2004) in Shanghai have been used. The results show that different sites (city center or surroundings) have experienced different degrees of warming as a result of increasing urbanization. In turn, this has resulted in a more extensive urban heat island effect, causing additional hot days and heat waves in urban regions compared to rural locales. An examination of summer mortality rates in and around Shanghai yields heightened heat-related mortality in urban regions, and we conclude that the UHI is directly responsible, acting to worsen the adverse health effects from exposure to extreme thermal conditions.  相似文献   

13.
卢宁  李俊英  闫红伟  施拓  李英 《生态学杂志》2014,25(10):2951-2958
公园绿地作为城市重要的自然景观元素,其可达性是体现公园绿地所提供的自然服务能否被市民便捷、公平享用的一个重要指标.对可达性理论进行深入研究,从而更加准确、真实地对公园绿地可达性进行评价是目前亟需解决的问题.本文基于QuickBird卫星影像和GIS平台,以沈阳市铁西区为例,选取步行、非机动车、机动车和公共交通4种方式来定量评价公园绿地的可达性,并对4种交通方式下公园绿地可达区的空间分布、可达面积及可达人口的数量差异进行对比分析.结果表明: 沈阳市铁西区公园绿地数量较少且分布不均衡,表现为西南部及中心区域公园绿地的可达性较好,边缘区域可达性较差,东部和北部边缘可达性最差;各交通方式下公园绿地的可达性存在较大差异,机动车可达性最好,其次为非机动车和公共交通,步行可达性最差:近九成的居民可以采用步行30 min、非机动车和公共交通15 min、机动车10 min的方式到达最近的公园绿地.该研究对城市公园绿地可达性理论的深入、系统研究提供了一种新思路,对基于可达性的绿地空间布局优化具有重要的现实意义.  相似文献   

14.
The Coral Triangle encompasses an extensive region of coral reefs in the western tropical Pacific with marine resources that support millions of people. As in all other reef regions, coral reefs in the Coral Triangle have been impacted by anomalously high ocean temperature. The vast majority of bleaching observations to date have been associated with the 1998 La Niña phase of ENSO. To understand the significance of ENSO and other climatic oscillations to heat stress in the Coral Triangle, we use a 5‐km resolution Regional Ocean Model System for the Coral Triangle (CT‐ROMS) to study ocean temperature thresholds and variability for the 1960–2007 historical period. Heat‐stress events are more frequent during La Niña events, but occur under all climatic conditions, reflecting an overall warming trend since the 1970s. Mean sea surface temperature (SST) in the region increased an average of ~ 0.1 °C per decade over the time period, but with considerable spatial variability. The spatial patterns of SST and heat stress across the Coral Triangle reflect the complex bathymetry and oceanography. The patterns did not change significantly over time or with shifts in ENSO. Several regions experienced little to no heat stress over the entire period. Of particular interest to marine conservation are regions where there are few records of coral bleaching despite the presence of significant heat stress, such as in the Banda Sea. Although this may be due to under‐reporting of bleaching events, it may also be due to physical factors such as mixing and cloudiness, or biological factors that reduce sensitivity to heat stress.  相似文献   

15.
Sea turtles were targeted by fisheries in the Mediterranean from 1920 to 1970 and have undergone severe exploitation. At least 30,000 to 40,000 turtles were caught along the Palestinian coastline during the 1920s to 1930s. Although intentional cap- ture of marine turtles is now illegal, sea turtles are still incidentally caught by the fishing industry, making it a major cause of sea turtle mortality. The present study as- sesses the impact of the Israeli fishery fleet on the turtle population in the Levantine basin based on on-board observations and a fishermen survey. The results show that gillnets and trawlers are the main threats to sea turtles in this area. 21 turtles were caught during 1385.5 hours of trawling observations – a catch rate of 0.015 turtles per hour. We estimate that a total of 1,315 turtles are caught annually by Israeli trawlers. According to the fishermen survey, ~21 turtles are caught each year by a single gillnet vessel, yielding an annual estimate of 1,672 turtles for the whole gillnet fleet. We have also found that only a small fraction of the turtles injured by trawlers is represented in the strandings. The mortality rate through trawling and the stranding density is the highest in the region, emphasizing the urgent need to regulate the Israe- li fishery. This fishery poses a major threat to the whole Levantine sea turtle popula- tion, especially during the vulnerable reproduction stage.  相似文献   

16.
刘畅  唐立娜 《生态学报》2020,40(22):8141-8146
城市生态系统服务和可持续发展是当前城市生态学研究的热点问题。景感生态学作为联系生态系统服务和可持续发展的桥梁,可作为研究城市生态系服务和可持续发展的一种有效途径。随着社会发展所伴随的人们经济生活的生活压力增大,城市居民的亚健康状态日益突出。城市公园作为城市生态系统的重要构成,其设计目的应考虑应对城市居民健康问题和促进人类精神文明建设方面的作用。以城市公园景观设计为例,从园路、建筑、植物、水体景观和小品等方面探讨景感生态学在城市公园景观设计中的应用价值。景感生态学作为探索城市公园景观设计的新思路,以实现生态效益和居民福祉的提升,丰富和提升城市公园的生态系统服务功能,从而有利于促进为人类当代和后代提供可持续的福祉,以期驱使人类行为和言行规律朝着对生态系统有益的方向演化,自觉维护和改善生态系统服务,从而可持续地保障城市生态系统服务。  相似文献   

17.
城市湖泊湿地温湿效应——以武汉市为例   总被引:2,自引:0,他引:2  
朱春阳 《生态学报》2015,35(16):5518-5527
选择武汉城市三环内主城区14块湖泊湿地为研究对象,采用小尺度定量测定的方法,研究城市湖泊湿地与温湿效应间的关系。结果表明:(1)城市湿地温度值与面积指数、距离指数呈显著负相关,与景观形状指数呈显著正相关(P0.05);湿度值与面积指数、距离指数、环境类型指数呈显著正相关,与景观形状指数呈显著负相关(P0.05)。其中面积指数的贡献值最大。(2)14块湖泊湿地的降温增湿效应排序为湖泊11—14湖泊6—10湖泊1—5。当湖泊湿地面积为9.2—12.2 hm2时,其降温增湿效应明显;当湖泊湿地面积为308.4hm2左右时,降温效应显著且趋于稳定,湖泊湿地面积为67.6hm2左右时,增湿效应显著且趋于稳定(P0.05)。当湖泊湿地面积达到临界值之后,多斑块离散型(Dispersive)湖泊湿地布局对整个城市环境的降温增湿效应更为显著。  相似文献   

18.
The overall biology of ectotherms is strongly affected by the thermal quality of the environment. The particular conditions prevailing on islands have a strong effect on numerous features of animal life. In this study we compared mainland and island populations of the lizard Lacerta trilineata and hypothesized that insularity would affect the thermoregulatory strategy. Continental habitats were of lower thermal quality, experiencing more intense fluctuations and had higher values of operative temperatures. Nevertheless mainland lizards selected for higher body temperatures in the lab and showed more effective thermoregulation during summer than their island peers. Lizards achieved similar body temperatures in the field in both types of habitat, underlining the importance of predation as a potential factor to mainland lizards that failed to reach their higher thermal preferences. Both island and mainland populations of L. trilineata have been adapted to their thermal environment, supporting the labile view on the evolution of thermal physiology for this species.  相似文献   

19.
鲁蕾  吴亦潇  张维昊 《生态学报》2017,37(18):5993-6004
城市小型湖泊具有对环境变化的高敏感性,其浮游植物群落特征和演替规律对湖泊生态系统的监测与管理有重要意义。本研究于2015年3—12月,对武汉市沙湖进行了生态和水质监测,共鉴定出藻类10门312种,绿藻、硅藻和蓝藻种类数占优。为探究富营养化城市小型湖泊浮游植物群落时空异质性及其演替驱动力,选取了4个多样性指数(Shannon-Wiener指数、Simpson指数、Pielou均匀度指数和Whittaker指数),并进行了多样性指数与环境因子的相关性分析、主成分分析和聚类分析,计算了优势种在监测时段的3个种间联结性指数和校正χ~2 检验系数。结果表明,夏秋季节浮游植物群落处于演替的稳定状态,环境因子驱动作用明显,其中离子浓度的影响大于温度的影响,钠、镁离子浓度为主要影响因素;蓝藻门和绿藻门优势种联结性较高,硅藻门优势种内部联结性较高而与其他门类相关性较低,从季节上看,夏秋季节的优势种种间联结性较高,春冬季优势种与其他时段优势种相关性低,可能为群落在冬春季不稳定的原因。  相似文献   

20.
李玉凤  刘红玉  郑囡  曹晓 《生态学报》2011,31(4):1021-1028
以西溪国家湿地公园为研究案例,从景观功能分类入手,揭示城市湿地公园景观格局与功能特征。结果表明:(1)西溪湿地公园是以生态保护为主,兼顾合理利用为基本功能特征,其生态保护功能区面积占整个公园的53.7%,旅游休闲区面积占46.3%;(2)西溪湿地公园生态保护功能斑块在整个公园中所占面积为42.08%,且面积大、形状复杂、多样性较低;旅游休闲斑块面积占25.41%,并且表现为斑块面积小、形状规则、多样性高等特点;(3)西溪湿地公园生态保护廊道面积是旅游休闲廊道面积的一半左右,其网络结构比旅游休闲廊道复杂,有利于生态保护功能的发挥;(4)生态保护廊道缓冲区内主要由生态保护斑块组成,旅游休闲廊道的缓冲区内生态功能斑块和旅游休闲斑块所占面积相差不大。基于功能分类的景观格局研究方法有利于识别景观功能的空间特征,能够有效揭示景观生态保护与利用的空间关系。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号