State mutability and ethnic civil society: the Palestinian Arab minority in Israel

This article identifies the phenomenon of ethnic civil society activism as mobilization that seeks to empower an ethnic community and challenges the institutional order. The case of the Palestinian Arab minority in Israel is discussed and is used to reveal the conditions under which disaffected minorities pursue the path of ethnic civil society. The study finds that an analytical framework that stresses the mutability of state structures and changes in broader state-society relations provides a better explanation than existing theories of ethnic conflict. State-society characteristics conducive to this type of mobilization are a well-institutionalized state that can prevent deviation from the state's foundational rules and a counterbalanced dispersion of authority that limits regime capacity to control society.     

Competition and succession among coral endosymbionts

Host species often support a genetically diverse guild of symbionts, the identity and performance of which can determine holobiont fitness under particular environmental conditions. These symbiont communities are structured by a complex set of potential interactions, both positive and negative, between the host and symbionts and among symbionts. In reef‐building corals, stable associations with specific symbiont species are common, and we hypothesize that this is partly due to ecological mechanisms, such as succession and competition, which drive patterns of symbiont winnowing in the initial colonization of new generations of coral recruits. We tested this hypothesis using the experimental framework of the de Wit replacement series and found that competitive interactions occurred among symbionts which were characterized by unique ecological strategies. Aposymbiotic octocoral recruits within high‐ and low‐light environments were inoculated with one of three Symbiodiniaceae species as monocultures or with cross‐paired mixtures, and we tracked symbiont uptake using quantitative genetic assays. Priority effects, in which early colonizers excluded competitive dominants, were evidenced under low light, but these early opportunistic species were later succeeded by competitive dominants. Under high light, a more consistent competitive hierarchy was established in which competitive dominants outgrew and limited the abundance of others. These findings provide insight into mechanisms of microbial community organization and symbiosis breakdown and recovery. Furthermore, transitions in competitive outcomes across spatial and temporal environmental variation may improve lifetime host fitness.     

Testing the assumptions of chronosequences in succession

Many introductory ecology textbooks illustrate succession, at least in part, by using certain classic studies (e.g. sand dunes, ponds/bogs, glacial till, and old fields) that substituted space for time (chronosequence) in determining the sequences of the succession. Despite past criticisms of this method, there is continued, often uncritical, use of chronosequences in current research on topics besides succession, including temporal changes in biodiversity, productivity, nutrient cycling, etc. To show the problem with chronosequence-based studies in general, we review evidence from studies that used non-chronosequence methods (such as long-term study of permanent plots, palynology, and stand reconstruction) to test the space-for-time substitution in four classic succession studies. In several cases, the tests have used the same locations and, in one case, the same plots as those in the original studies. We show that empirical evidence invalidates the chronosequence-based sequences inferred in these classic studies.     

江苏省海滩植被演替的研究

江苏省海滩植被可分为滨海盐土植被、盐沼植被及海滩沙生植被三个基本类型。本文论述了这些植被类型的演替规律。滨海盐土植被与盐沼植被的演替,外因于土壤盐分含量递减与有机质含量的递增;海滩沙生植被的演替,外因于土壤沙颗粒大小及其相应的土壤含水量的变化,所以海滩植被演替为外因动态演替。     

Fire and succession in the ultramafic maquis of New Caledonia

Aim This study investigates the role of fire and post fire succession in determining the structure and composition of vegetation on ultramafic iron crust soils. Location The study was conducted in the Plaines des Lacs region of southern New Caledonia. Methods A survey was made of eighty-eight sites, recording floristic composition, trunk size-class distributions, regeneration after fire, growth ring counts of Dacrydium araucarioides (Podocarpaceae) and historical information on past fires. Floristic data was ordinated using multidimensional scaling and an index of succession based on structural and historical information. A transition matrix model was developed to predict the effect of fire frequency on vegetation composition. Results The vegetation is undergoing postfire succession from maquis to forest, after about 75 years, and eventually to rainforest. Gymnostoma deplancheanum has a key role as an early colonist that produces shade, the bulk of the litter, and forms nitrogen fixing nodules with Frankia sp. However, the open canopy of Gymnostoma and slow litter decay creates flammable conditions. Though many species resprout from rootstocks, only thirty-nine persist through fires while 114 others colonize at later successional stages, as the litter layer and shade increase. Some early successional species are later excluded but these can persist locally in swamps and on rocky hill tops. Forest and rainforest are less flammable and the matrix model suggests that ignition frequency has a critical role in determining the abundance of maquis or forest. Main conclusions The vegetation mosaic represents a post fire succession from open maquis to forest. Palynological and charcoal records from late Pleistocene sediments suggest that fire has been a major factor determining the development of maquis vegetation since before the arrival of humans. Recently, frequent fires have converted much of the vegetation to maquis, posing a threat to some forest species and largely eliminating rainforest from iron crust soils.     

The effect of trophic/contaminant interactions on chironomid community structure and succession (Diptera: Chironomidae)

The effects of contaminants and organic pollution on the chironomid communities of two basins in Lac St. Louis, a river-lake on the St. Lawrence River above Montreal, Quebec, were assessed and compared using lake classification theory techniques and morphological deformity indices based on the ligulae and antennae ofProcladius, the dominant surviving component of the south-shore communities. Contaminants from the industrial complex around Beauharnois, Quebec, have seriously degraded communities along the south-shore gradient while the introduction of untreated domestic wastes from Laprairie, Quebec, has seriously affected the communities of the Laprairie basin. The interaction between trophic and contaminant effects constitutes a classic example of the setback or deflection in the trajectory of ecological succession in biological communities hypothesized by ODUM (1981, 1985).     

干扰与生态系统演替的空间分析

演替不光是生态系统在时间序列上的替代过程,而且也是生态系统在空间上的动态演变。演替的空间属性有演替系列的格局、范围、尺度、演替方向和速率、稳定的程度、多样性、以及在自然和人为干扰下的恢复等。干扰破坏了生态系统的稳定性,形成生态系统结构和功能的破损,使生态系统处于一种过渡状态。但是干扰也是生态系统演替的外在驱动力,自然的和人为的干扰引起的生态系统的对称性破缺,推动了系统的进化和演变。外界因素作用于生态系统的干扰因子包含了很多种类,如火、风倒、洪水、病虫害、人类活动等。干扰的属性有范围、频度、季节、强度、损害度、返回时间和循环周期。讨论了这些干扰的类型和生态系统演替所具有空间的特征,并且介绍了干扰和生态系统演替空间分析常用的方法,如空间解绎和辨识、空间统计分析、空间格局分析和地理信息系统的空间分析、以及空间模拟。利用了一些典型的实例来深入阐明空间分析在干扰和生态系统演替中的应用。利用美国加利福尼亚北部火干扰的历史和空间分布的记录,进行了火干扰的空间分析的研究;用Spies等在美国俄勒冈州西部1972～1988年的多时段的变化的实例说明了收获干扰的影响;利用俄勒冈州东部山地的主要两个虫害(山地松树甲虫(Mountain Pine Beetle)和云杉蚜虫(Spruce Budworm))22a的数据分析了病虫害干扰的空间分布格局及其与海拔、温度、降水和植被类型的关系。在生态系统演替的空间分析方面,以美国俄勒冈州西部的历史和现实植被演替格局的分析为例,讨论了如何利用空间分析方法研究区域尺度生态系统的演替,同时比较了历史和现实植被的空间格局指数的变化;用两个实例来说明空间分析在辨识大陆和国家尺度生态系统变迁中的应用,一个是美国原生的老森林(Old～growth)植被从1620年到1920年,300a的空间格局变化,另外一个是加拿大植被从1600年到2000年,大约400a的空间分布变化。最后,对生态系统演替的空间分析的一些重要问题作了探讨,例如：空间分析可否帮助确定地带性顶极群落;如何将外貌与成分结合更好地识别生态系统演替的空间格局与演变趋势;以及如何利用空间分析研究由于人类活动干扰加剧所造成的生态系统自然演化规律的异化。     

宁夏农牧交错带村域景观演替及驱动机制

人类活动与景观格局的关系及其调控,一直是景观生态学研究的核心领域之一。农牧交错带因其环境波动、土地宜农宜牧和政策摇摆,自然生态和地方文化逐渐式微,保护和恢复现有的半自然景观以及由此产生的生物、生态和文化等功能的任务越来越紧迫。本研究以位于农牧交错带的宁夏盐池县皖记沟村为对象,运用遥感资料和访谈调查、地学考察相结合的方法,分析1964—2019年景观变化特征,探讨其景观演替规律及其自然和社会驱动机制,以及景观类型之间的互作机制。结果表明: 研究期间,皖记沟村由草地、耕地、沙地为主的景观结构演变为以草地、灌木林地、沙地、耕地为主的景观结构,由景观功能分离竞争向初步整合转变,形成了草地-耕地-沙地-灌木林地等确定的演替路径。景观演变的主要驱动机制是政策、人类需求和环境的综合作用。政策往往通过大型的、集中的人类活动促进景观发生改变,而环境通过生态系统内在驱动力,促使景观朝着与本底条件相适应的方向演替。景观演替的主要机理是土壤物理结构变化引起的土壤水分变化以及能适应新环境的植被变化。在资源密度较低的农牧交错带,景观功能分离是引起土地沙化的主要原因之一,景观功能的整合、协同大大缓解了生态恶化的局面。将景观分离竞争转化为景观共生,实现景观类型的互补乃至与外来资源的整合,是维持农牧交错带可持续发展的关键途径。     

Dynamics of nitrogen and phosphorus retention during wetland ecosystem succession

We compared the mechanisms of nitrogen (N) and phosphorus (P) removal in four young (<15 years old) constructed estuarine marshes with paired mature natural marshes to determine how nutrient retention changes during wetland ecosystem succession. In constructed wetlands, N retention begins as soon as emergent vegetation becomes established and soil organic matter starts to accumulate, which is usually within the first 1–3 years. Accumulation of organic carbon in the soil sets the stage for denitrification which, after 5–10 years, removes approximately the same amount of N as accumulating organic matter, 5–10 g/m²/yr each, under conditions of low N loadings. Under high N loadings, the amount of N stored in accumulating organic matter doubles while N removal from denitrification may increase by an order of magnitude or more. Both organic N accumulation and denitrification provide for long-term reliable N removal regardless of N loading rates. Phosphorus removal, on the other hand, is greatest during the first 1–3 years of succession when sediment deposition and sorption/precipitation of P are greatest. During this time, constructed marshes may retain from 3 g P/m²/yr under low P loadings to as much as 30 g P/m²/yr under high loadings. However, as sedimentation decreases and sorption sites become saturated, P retention decreases to levels supported by organic P accumulation (1–2 g P/m²/yr) and sorption/precipitation with incoming aqueous and particulate Fe, Al and Ca. Phosphorus cycling in wetlands differs from forest and other terrestrial ecosystems in that conservation of P is greatest during the early years of succession, not during the middle or late stages. Conservation of P by wetlands is largely regulated by geochemical processes (sorption, precipitation) which operate independently of succession. In contrast, the conservation of N is controlled by biological processes (organic matter accumulation, denitrification) that change as succession proceeds.     

论丹霞地貌区生态演替特征及其科学价值

论述了丹霞地貌区生态演替的特征及其科学价值.认为植被演替由于时间漫长、过程复杂而对其研究具极大的难度,时空互代成为演替研究的重要手段,而这需要有完整的空间序列.丹霞地貌区存在着完整的原生演替与次生演替系列.典型丹霞地貌的山顶为原生演替的矮灌木林和乔木林,周围斜坡仍然受季节性降水侵蚀、风化、重力崩塌等作用,原生演替不断从裸露的岩石开始,故形成原生演替早期的苔藓、草本群落,随着岩石的进一步风化和苔藓、地衣等植物的作用,土壤层增厚,将原生演替继续往前推进.特殊的地质地貌过程使之不断有新的崩塌,从裸露的岩石开始的新的原生演替,如此形成不同时间系列的原生演替阶段.丹霞地貌区也存在着完整的次生演替系列,同时存在演替先锋林、演替过渡林和演替基本稳定林.这两个演替系列提供了一个非常难得的理想场所,使得生态学工作者在一个地点就可以观察到一个完整的植被演替系列.其研究可为该区域植被的经营管理和保护措施提供必要的依据.作为生态恢复参照系,对区域的植被生态恢复具有重要的指导意义.＃     

冷季型草坪杂草的季节性发生与演替

对西安地区冷季型草坪杂草的种类、发生时期进行普查,对杂草的发生与季节性演替规律进行了讨论与分析,发现阔叶杂草优势种有酢酱草、蛇莓、紫菀、深绿蒿等,单子叶杂草优势种有狗牙根、马唐、莎草等,并提出了以多度等级确定危害成度及防治建议。     

Diversity and succession of the phytoplankton in a small lake over a two-year period

Phytoplankton in the small central Finnish lake, Vasikkalampi, was studied over a two-year period by weekly sampling simultaneously with monitoring of physical and chemical properties of water, solar radiation energy and zooplankton. In the present paper, the fluctuations in phytoplankton diversity were studied in relation to environmental factors. The special aim for the study was to detect a relation between environmental disturbances and phytoplankton diversity.     

Ecological succession and the rehabilitation of disturbed terrestrial ecosystems

Plant and Soil - Soil and vegetation development on surface-mined coal sites in a mixed grass prairie region were studied as (a) naturally revegetated chronosequences of 1, 7, 17, 30 and 45-year...     

Characteristics and scientific values of ecological succession in Danxia Landform of China

The characteristics and scientific values of ecological succession in Danxia Landform of China were discussed. It was known that research on vegetation succession was quite difficult for its long-term and intricate process. Space-time substitution is an important method to study the succession, while it needs intact spatial succession series. In Danxia Landform, there are such primary and secondary succession series. On the hilltops, there are typical low shrubberies and arboreal forests of primary succession. The surrounding slopes are subjected to seasonal rainfall erosion, weathering action, gravitational collapse and so on. The primary succession constantly starts from bare rocks, and then moss and herbal communities of early primary succession are formed. With further weathering of rocks and effects of moss and lichen, soil layers are getting thicker and thicker, which pushes primary succession ahead. New collapses are ceaselessly induced by the special geological geomorphological process, and then a new primary succession starts from bare rocks. Thus, different stages of primary succession are formed in Danxia Landform. In addition, the secondary succession series exist in Danxia Landform, including the pioneer forests, transitional forests and steady forests. Danxia Landform provides ideal sites for vegetation succession study. The relative studies would be helpful for the vegetation management and protection in this area. As ecological restoration reference, it is also meaningful for the vegetation restoration.     

Coastal fore-dune zonation and succession in various parts of the world

A table is presented of the most important species of the fore-dune complex in various parts of the world, representing all continents. The complex is divided into six zones or habitat types, which have proved to be widely applicable for this purpose. The zones are briefly described in terms of floristics, geomorphology, ecology (sand movement, salinity, organic matter) and climate. A major division is indicated between tropical (including subtropical) and temperate (including cold) regions. The former are subdivided into those with humid and those with arid climates, the latter into those with cool to warm-temperate and those with boreal to subarctic climates. The highest, most extensive and most complicated dune areas occur in those regions where the effects of disturbance by wind and fixation by plant growth are about equally strong. A number of species show the retraction phenomenon: a shift from a certain zone towards a more sheltered zone in an area with more harsh conditions (e.g. a shorter vegetation period). The filling of empty niches by introduced species (e.g. in connection with the scarcity of native tidemark species in temperate Australia) is also quite common. Most communities are rich in (sub)cosmopolitan species.Nomenclature: see various regional references.     

典型草原自然恢复演替过程中植物群落动态变化

以内蒙古巴林右旗退化典型草原为研究对象,采用空间序列代替时间序列的方法,探讨了在围封去除干扰条件下,退化典型草原自然恢复演替进程.研究结果表明,物种多样性在典型草原群落自然恢复过程中呈波动状变化,最高值出现在第6年,为3.3,随后又呈现下降趋势.丰富度和均匀度与物种多样性指数呈显著正相关,相关系数分别为0.848和0.912.地上生物量和物种多样性二者之间没有明显的线性关系,其相关系数为0.4813(P＞0.05).在演替的进程中,群落中主要植物种的优势地位发生了明显的替代变化.在恢复演替初期C4植物对地表的覆盖和有机物的输入起关键作用,而C3植物在后期对群落稳定起重要作用.1年生植物在典型草原恢复初期起着非常重要的作用,可覆盖地表,防止水土流失,并为群落输入大量养分,为其他植物定居创造了稳定良好的土壤环境.     

Leaf miner assemblies: effects of plant succession and grazing management

Abstract. 1. Changes in leaf-miner assemblies during 4 years of secondary succession, under different controlled sheep-grazing treatments, are described and compared to the miner fauna of older grazed grassland nearby.
2. Multivariate analyses were used in conjunction with examination of individual common species to assess the independent effects of time, grazing treatment, plant species composition and architecture on the leaf-miner assemblies.
3. Leaf-miner species composition was strongly related to plant species composition, but was modified by plant structure under different grazing treatments. There was a strong successional trend in miner assemblies, even when the effects of changes in plant composition had been taken into account. Conversely, local variation in miner species composition generally reflected foodplant distribution alone.
4. Grazed treatments had fewer mines than controls, but there were also species specializing in grazed areas, despite the abundance of their foodplants elsewhere. There was a weak indication that miner species in grazed treatments were more likely to fluctuate in abundance than those in controls.
5. The results are discussed in relation to the assembly of grassland insect communities during succession, and the use of 'indicator groups' in management for nature conservation.     

有机磷培养下水体浮游植物竞争与群落结构演替

磷是浮游植物生长的必要元素,也是调控水体富营养化的重要因子之一。在无机磷缺乏的水域,能够有效利用有机磷的藻类有可能成为浮游植物群落的优势种。为了研究有机磷对浮游植物群落结构演替的影响,分别从3个水库采集表层水样,西陂水库(硅藻70.3%,甲藻19.1%,绿藻9.3%)、山美水库(硅藻31.3%,甲藻59.2%,绿藻3.5%)、三十六脚湖(硅藻43.1%,甲藻50.5%,绿藻5.0%),选用有机磷单磷酸腺苷(Adenosine monophosphate,AMP)作为磷源进行实验室模拟实验,并与无机磷(NaH_2PO_4·2H_2O)作为磷源实验组做同步对比,探讨有机磷源条件下浮游植物竞争及群落结构演替规律。结果显示:AMP培养20 d后,西陂水库、山美水库和三十六脚湖的浮游植物生物量分别增加了6.5倍,2.1倍和1.9倍,浮游植物群落结构都演替为以甲藻门和绿藻门为优势藻,所占比例分别为81.8%和16.7%、55.2%和33.5%、73.2%和24.3%,其中西陂水库甲藻门拟多甲藻对有机磷AMP的利用能力强,其所占比例达到81.8%。表明有机磷AMP能有效地促进甲藻门拟多甲藻属的增殖,进而改变水体浮游植物群落结构。     

长白山植被类型特征与演替规律的研究

根据多次对长白山植被调查和长期定位观测资料 ,全面系统地总结了长白山植被类型特征和演替规律 ,详细描述了长白山地带性和非地带性植被类型的性质、组成、结构和分布规律 ,探讨了长白山植被演替与火山爆发的关系。提出长白山植被垂直分布基带应是红白松阔叶混交林 ,也是长白山地带性植被类型。但由于长期受人类活动影响 ,削弱了地带性表现 ,形成大面积的天然次生林和耕地。据此不应该认为 ,人类能消灭客观自然规律的植被分布的地带性 ,为了恢复地带性植被和定向改造自然 ,应引进地带性树种 ,营造结构合理、种类多样和稳定性强的森林群落。     

The molecular basis of autosomal recessive diseases among the Arabs and Druze in Israel

The Israeli population mainly includes Jews, Muslim and Christian Arabs, and Druze In the last decade, data on genetic diseases present in the population have been systematically collected and are available online in the Israeli national genetic database (). In the non-Jewish population, up to 1 July 2010, the database included molecular data on six diseases relatively frequent in the whole population: thalassemia, familial Mediterranean fever (FMF), cystic fibrosis, deafness, phenylketonuria and congenital adrenal hyperplasia, as well as data on 195 autosomal recessive diseases among Muslim Israeli Arabs, 11 among the Christian Arabs and 31 among Druze. A single mutation was characterized in 149 out of the 238 rare disorders for which the molecular basis was known. In many diseases, mutation had never been observed in any other population and was present in one family only suggesting that it occurred as a de novo event. In other diseases, the mutation was present in more than one community or even in other populations such as Bedouins from the Arab peninsula or Christians from Lebanon. In the 89 other disorders, more than one mutation was characterized either in the same gene or in more than one gene. While it is probable that most of these cases represent random events in some cases such as Bardet Biedl among the Bedouins, the reason may be a selective advantage to the heterozygotes.