Effects of seasonality on the species–area relationship: a case study with birds in urban parks

Aim To examine how parameters of the species–area curve and factors determining bird species richness are affected by seasonality. Location One hundred and thirty urban parks of the city of Valencia (Spain) ranging between 0.03 and 18.6 ha. Methods Bird censuses were conducted monthly during 1998 and 2004. For each park, 27 variables were recorded as measures of size, structure and isolation. Linear regression was used to test for patterns in species richness relative to independent variables. The results of each season were compared. Results Curves corresponding to the breeding period (spring–summer) had significantly higher intercepts, but slopes did not change across seasons. Turnover rates of resident species were dependent on patch size and isolation considering spring, but not autumn, from different years. Additionally, turnover rates in spring were lower in parks in close proximity to others than in isolated ones. In all seasons, the number of bird species showed a strong relationship with park area, which explained c. 60% of the variation in species numbers. Habitat variables and park isolation explained a small amount of the variation in species numbers. The data did not give support to the random placement hypothesis. Main conclusions The overall conclusions of this study give little support to the possible influence of seasonality on species–area relationship or on the three main hypotheses explaining it. This lack of influence of seasonality could be explained by the seasonal stability of the bird populations of the parks within the study area as a consequence of different factors, mainly the characteristics of the species pool, similarity in the features of the parks irrespective of their size, and stability of resources and conditions across seasons. The question of whether this lack of influence of seasonality on the species–area relationship occurs in those ecological systems that have a larger seasonal variation than the urban parks of the study area remains unresolved. Closer examination of the seasonal patterns reported in this study is likely to be useful in increasing our understanding of the species–area relationship.     

基于高通量测序技术的不同年代公园绿地土壤细菌多样性

【背景】细菌多样性对绿地土壤生态功能有重要作用,但不同年代公园绿地土壤的细菌多样性尚未见相关报道。【目的】研究北京市不同年代公园绿地土壤细菌多样性和群落结构特征。【方法】利用IlluminaMiSeq测序技术,分别对北京市代表性古典公园和现代公园绿地土壤细菌群落多样性进行分析。【结果】北京市公园绿地土壤细菌群落共划分为45个已知的菌门,其中变形菌门、酸杆菌门、绿弯菌门和放线菌门为优势细菌群。土壤细菌群落α多样性分析结果表明,古典公园和现代公园的土壤细菌多样性存在差异,表现为古典公园的丰富度和多样性都高于现代公园。此外,土壤细菌群落相似性分析和主坐标分析都表明古典公园和现代公园的土壤细菌群落结构存在显著差异。冗余分析表明,对土壤微生物群落结构产生显著影响的环境因子分别为土壤含水量、有机质和全氮,其它土壤环境因子无统计学意义。首次引入公园年代作为影响因子进行冗余分析的研究结果表明,公园年代为影响公园细菌群落多样性的重要因子。【结论】不同年代公园绿地土壤细菌群落结构和物种多样性具有显著差异,随着公园年代的增加,土壤肥力和微生物多样性增加,绿地生态系统更稳定,可通过制定不同的绿地管理措施改变公园绿地土壤环境,进而优化土壤细菌群落结构,促进土壤碳氮养分循环,提高土壤肥力。     

A Hollywood drama of butterfly extirpation and persistence over a century of urbanization

Few long-term examples exist of wildlife population trends in urban environments despite the recent recognition of the importance of biodiversity in cities. Founded in 1896, Griffith Park’s over 1,700 ha in Los Angeles adjacent to Hollywood represent the largest municipal park in California. Through the 1920s, biologists studied the natural area with great interest but in the decades that followed, little fieldwork was conducted here as Los Angeles developed into a megacity surrounding the park. We combined thorough examination of Griffith Park historical field notes and specimen records (1900–1960) with recent field surveys (2011–2012) to determine (1) the extent of urbanization impacts on butterfly extirpation and persistence and (2) how butterfly traits and host plant relationships might be contributing to butterfly species status. Here we document multiple local butterfly extinctions in Griffith Park; 10 species or 18 % of the historically reconstructed community. Many of these species were lost early in the twentieth century, highlighting the importance of the historical record in understanding urban biodiversity patterns and trends. An analysis of larval host plant status and relationships suggests that a primary factor determining butterfly presence or extirpation is the abundance of the larval host plant in the park, in addition to host plant specificity. Despite these extirpations, we also found that the majority (over 80 %) of native butterfly species have persisted including species of conservation interest. While urban parks certainly suffer from surrounding anthropogenic pressure and impacts, this study also demonstrates the potentially high and underappreciated conservation and ecological value of urban parks.     

重庆市不同年龄综合公园绿化乔木树种多样性和组成的比较研究

该研究通过对重庆市不同时期(解放前、直辖前、直辖后)建造的15个综合公园的绿化乔木树种进行调查,分析了公园年龄对绿化乔木多样性和组成的影响以及公园之间的同质化情况。结果表明:(1)共调查到乔木59种,隶属于28科48属。其中,乡土树种占81.36%,外来树种占18.64%。(2)不同年龄公园乔木物种丰富度之间虽无显著差异,但解放后和直辖后公园乔木多度明显高于解放前;不同年龄公园外来树种的比例无显著差异;黄葛树、雅榕、复羽叶栾树在公园中的应用呈减少趋势,而日本晚樱、荷花玉兰、木犀、黄兰在绿化中的应用却呈增加趋势。(3)不同年龄公园之间同质化程度较低,解放前公园植物群落间Jaccard相似性指数明显高于其他两个阶段,且公园之间的Jaccard相似性指数与公园年龄差距无显著相关关系。综上结果发现,我国历史因素、园林文化和近代城市绿化相关规定可能是外来物种使用的限制因子,并可能导致了小尺度植物群落同质化程度偏低的现象。     

Can human disturbance promote nestedness? A case study with breeding birds in urban habitat fragments

Several factors, singly or in combination, have proven relevant in promoting nestedness in animal communities (area, isolation, habitat structure, etc.); however, little empirical evidence exists about the role of human disturbance. The goal of this paper was to assess whether human disturbance (pedestrians) may affect bird species composition in such a way as to generate a nested distributional pattern. The study was conducted in an urban fragmented landscape, the city of Madrid, where wooded parks were suitable fragments for many bird species, and had different levels of human visitation. At the community level, the distribution of species was significantly nested in two consecutive breeding seasons. Using two different procedures ("temperature" and "departures" methods) to analyse causality in nestedness, I found that pedestrian rate, fragment size and the diversity of stems were significantly correlated to the nested pattern. When analysed simultaneously, and controlling for their independent effects, these factors still accounted for nestedness. Pedestrian rate was the only factor significantly associated with changes in species composition between years. At the individual species level, 74 and 41% of species were significantly nested in relation to pedestrian rate in 1997 and 1998, respectively; however, these percentages were independent of foraging substrate and body size. Besides the classic area and habitat diversity effects, human disturbance can also promote nestedness: locally, by restraining the time and space of foraging and breeding opportunities, thus reducing fragment suitability, and regionally, by increasing extinction and decreasing colonization probabilities in highly disturbed fragments.     

Effect of park age,size, shape and isolation on ant assemblages in two cities of Southern Spain

In the context of conservation biology, we have searched for the most influential characteristics of urban parks on ecological diversity. In this study, therefore, we studied the ant community of 24 parks in two cities of Southern Spain (Cordoba and Seville). In total, 46 species were found. Abundant and widely distributed species were synanthropic ones, such as Lasius grandis, Pheidole pallidula or Tapinoma nigerrimum, and exotic species such as Cardiocondyla mauritanica. However some parks also harbored natural habitat‐preferring species. Park size, shape and distance to city outskirts were the most important predictors of species richness and diversity. Likewise, park age influenced the composition of the ant fauna.     

Patterns of association, nestedness, and species co-occurrence of helminth parasites in the greater kudu, Tragelaphus strepsiceros, in the Kruger National Park, South Africa, and the Etosha National Park, Namibia

The helminth parasites of the greater kudu from the Kruger National Park (KNP), South Africa, and the Etosha National Park (ENP), Namibia, were examined to determine the major patterns of spatial and demographic variation in community structure and to evaluate nonrandomness in parasite community assembly. Nonmetric multidimensional scaling ordination procedures were used to test for differences in parasite community composition between hosts of the 2 parks and between hosts of different demographic groups within KNP. Infracommunities within KNP were also examined for patterns of nonrandomness using 2 null models, i.e., nestedness and species co-occurrence. Infracommunities of KNP and ENP were significantly different from each other, as were infracommunities of different host demographic groups within KNP. Parasite species in the greater kudu from KNP displayed significant levels of nestedness and were found to co-occur less frequently than expected by chance; however, this lack of co-occurrence was significant only when all demographic groups were considered. When restricted to any particular age class, co-occurrence patterns could not be distinguished from random. Overall, these data suggest that biogeography and host demographics are important factors in determining community organization of helminth parasites in the greater kudu.     

基于物种落差分析的公园鸟类多样性提升设计——以湖南常德螺湾湿地公园为例

随着城市化发展,许多公园鸟类栖息环境遭受破坏,导致当前的鸟类多样性与历史上的和周边的都存在较大差异,为此,我们从项目区域的当前-周边-历史三者间在鸟类物种及其栖息地上的落差分析入手,以此确定目标物种及其栖息地,并加以归类,从而有针对性地进行相关设计。2016年5月至2017年3月在湖南常德柳叶湖螺湾湿地公园开展的鸟类多样性提升设计中,通过实地调查并结合文献查阅,记录到项目区域16种,周边79种,历史上146种鸟类,运用三者间的物种落差分析法确定主要的21种可恢复目标物种和4种栖息地类型,结合项目区域及周边空间特点,将项目区域划分为4个区域,在各区域内设计并营建相应的栖息地,再配套采用多种鸟类招引措施。至2017年3月,项目区鸟类已可实地观察到39种,并于2017年12月吸引到超过2000只的野鸭群来此越冬。以上实际效果表明,设计有效地提升了湿地公园鸟类多样性且增加了景观要素,可充分发挥生物保护功能。     

Plant species composition in relation to green cover configuration and function of urban parks in Beijing, China

Parks, as one specific type of urban open space, play important roles in the conservation of urban biodiversity and provision of recreational services for local residents. As there is a lack of specific insight into park plant species composition in relation to park features, 24 sample parks within the inner city of Beijing, the capital of China, were studied by stratified random plot sampling of their tree, shrub, and herbaceous communities, respectively, in order to investigate how human activities have influenced park green cover configuration and floristic characteristics. The quantitative correlation of species richness and the park green cover indices (patch size, shape, etc.) were studied. The importance value index for plant species (trees, shrubs, and herbaceous species) of each park was calculated. The two-way indicator species analysis approach (TWINSPAN) was applied to classify the 24 parks into different groups based on their species assemblages. Two-hundred and eighty-eight species were recorded within the 24 study parks, belonging to 184 genera and 72 families dominated by Gramineae, Compositae, and Leguminosae. Among all the recorded species, 41% are exotic. The species occurrence, abundance and diversity vary significantly among different parks. Besides the positive correlation (R=0.505, P<0.05) between herbaceous species abundance and the park green cover size, no other significant relations were found between the species abundance and other indices of park green cover configuration. Remarkably, the TWINSPAN classification resulted in a good discrimination between park functional types and the variation in their species assemblage. For the parks of similar age (development history) or landscape design, their species assemblages show more similarity. The methodology adopted and results can be employed to improve baseline information on urban plant ecology and support the setting of priorities for future park management and vegetation protection.     

北京城区公园的植物种类构成及空间结构

对植物种类构成及空间结构的研究,可为公园植物多样性保护及公园的科学管理提供重要依据.采用分层随机抽样调查法,调查了北京市五环以内的53处公园,共记录维管束植物96科283属492种.基于研究区乔、灌、草共21个调查项目的大量数据及相关统计分析,对北京城区公园绿地各层植物的常见结构型式进行了阐述.结果表明：北京城区公园植物中,本地种占5386%,植物属的区系地理分布很广泛,优势植物的优势性明显;研究区大部分公园的草本植物种类较为丰富、盖度较高,而灌木盖度偏低、树冠下的灌木也偏少,乔灌植物种类丰富度和密度不高,乔木冠幅、胸径、灌幅及乔灌高度基本在2级水平,但乔木冠层结构比较丰满、受光良好、生长状况良好,灌木叶层缺失不明显.通过相关分析和北京市园林绿化史调研结果推测,北京城区公园植物种类构成及其空间结构主要受园林设计、植物引种、种植管理的影响.     

公园绿地可达性的客观影响因素

公园绿地可达性是衡量城市现代化发展水平、和谐人地关系的一个重要指标.了解公园绿地可达性客观影响因素及作用程度,对有效提高公园绿地可达性、充分发挥公园绿地的服务功能、促进城市健康发展具有重要意义.本文基于ArcGIS 9.3软件平台,运用网络分析法评价了沈阳市三环以内公园绿地服务面积及其服务效率,并分析了公园绿地服务面积及其服务效率随公园绿地面积、公园绿地形状、路网密度的变化规律.结果表明: 公园绿地面积与其服务面积呈显著正相关,与其服务效率呈显著负相关;公园绿地形状与其服务面积及服务效率呈显著正相关;路网密度与公园绿地服务面积呈显著负相关,与其服务效率没有显著相关关系;3个影响因子中,对公园绿地服务面积的影响程度依次为:公园绿地面积>路网密度>公园绿地形状,对公园绿地服务效率的影响程度依次为:公园绿地面积>公园绿地形状>路网密度;公园绿地面积是其服务面积及服务效率的最重要影响因子.     

Conservation of aquatic insect species across a protected area network: null model reveals shortfalls of biogeographical knowledge

The effective conservation of species requires some understanding of where populations occur in a landscape. Gaps in this knowledge base (the “Wallacean Shortfall” of some authors) may coincide with hotspots of diversity for different plant and animal species, requiring the cooperation of a number of different federal, state, local and non-governmental agencies for effective conservation. In this example, the distribution and abundance of benthic macroinvertebrates are widely used as metrics for water quality monitoring, but far less is known about these organisms qua species (taxonomic orders EPT—Ephemeroptera, Plecoptera and Trichoptera). In this study, we inventoried a network of individual US National Park units for species in these orders. These parks are located in geological, ecological and historical places of interest across the states of Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee and Virginia. We sampled these parks in a multi-year intensive inventory in order to determine the composition of the aquatic insect fauna in each park. Since there are no comprehensive accounts of the geographic ranges of these species, we compiled published accounts of species occurrences in these and adjacent states (Arkansas, Florida, Louisiana, Mississippi, West Virginia) to construct a potential species pool for each state. This pool comprised our best estimate of the EPT species that might potentially occur in each state. We used these source pools to test null hypotheses on whether parks disproportionately under- or over-protect species in different categories of risk of imperilment. We find that parks have fewer rare (G1) species than expected from a null model, and parks over-protect some of the most common (G5) species in the network. This pattern would be expected if the actual landscape distributions of the most imperiled (G1) species are small and/or disjunct and tend to occur outside of the national parks in the region. Interactions between park shape (and size) and individual species geographic ranges are likely to influence the precision of estimates of the potential species pool within a protected area. More research is needed on the distribution of imperiled species across the entire geographic range of species, and the traditional practice of compilation and reporting of occurrence records by state is not sufficient for informed conservation practice. State natural heritage programs and biodiversity conservation database efforts (e.g. NatureServe) implicitly recognize the importance of species ranges, but our analysis demonstrates the need to assess these patterns at a finer spatial grain in order for these state lists to serve as meaningful expectations of the composition of species assemblages. Our analysis considers only a tiny fraction of the protected lands in the region, and an enormous additional area of protected lands exists where many of these rare species occur. More precise and accurate reporting of EPT species occurrences in this region will allow resource managers to target the conservation of particular species within single parks, or across protected area networks.     

北京城市公园湿地的休憩吸引力评价

以北京地区20个城市公园湿地为研究对象,从公园湿地的景观质量、区位条件、可达性3方面构建了城市公园湿地休憩吸引力评价指标体系,并基于层次分析法赋权的综合指数评价方法,对公园湿地的休憩吸引力进行评价,最后通过实地问卷调查数据对休憩吸引力评价结果进行验证,结果表明:具有高休憩吸引力的公园湿地依次为颐和园、奥林匹克公园、青龙湖公园、北海公园、圆明园、玉渊潭公园、十渡、金海湖风景区、陶然亭公园、野鸭湖湿地,稻香湖湿地和珍珠湖风景区的休憩吸引力最低,其余8个公园湿地休憩吸引力一般.休憩吸引力评价结果与实际调查数据相符,说明所建立的评价指标体系与评价方法是可行的.20个公园湿地按照其休憩吸引力可聚为4类,据此可制定不同的管理对策.通过城市公园湿地休憩吸引力评价,分析城市公园湿地景观在休闲游憩方面所发挥的作用,可以为城市湿地公园的优化与配置、提高人居环境质量、改善城市景观布局提供依据.     

Influence of urbanization on ant distribution in parks of Tokyo and Chiba City,Japan I. Analysis of ant species richness

To investigate how progressive urbanization influences the distribution of ant species in cities, I compared the ant species richness in urban parks of different areas and ages of Tokyo, the most intensively developed urban region in Japan, and its developing neighbor, Chiba City. A total of 43 ant species were found from 98 parks. Multiple regression analysis revealed that park area and age had a positive effect on the number of ant species in the parks and that the parks in Tokyo contained fewer species than did comparable parks in Chiba. Thus, the progression of urbanization reduces ant species richness in urban parks, most likely because it isolates the parks from the surrounding area. Next, in order to examine the relationships between the types of landform modification and the ant distribution in urban areas, I compared the ant species richness in urban parks of Chiba City among different landform types (upland + terraces, lowlands, cut and fill, banking, and reclamation). This study showed that the parks in the reclaimed lands and lowlands contained fewer ant species than did parks in other areas. The reason for this decline of ant fauna is discussed.     

上海闵行区园林鸟类群落嵌套结构

城市中的园林绿地呈现斑块状分布,其栖息地特征与岛屿栖息地相似。2008年11月至2009年10月,对上海市闵行区内的7块城市绿地进行调查,记录雀形目鸟类的分布情况,并运用Nestedness temperature calculator软件,检验其群落结构是否符合嵌套结构。运用Arc GIS软件分析该地区的卫星图片,收集7块样地的面积、绿地盖度、水源距离和人为干扰程度等数据,结合实地调查所得到的数据,分析这一嵌套结构的形成原因和影响因素。结果显示：上海市闵行区城市绿地中的雀形目鸟类分布是显著的嵌套结构,园林面积、绿地面积和水源情况都对其嵌套结构有显著影响。但是与真正岛屿上存在的群落分布嵌套结构不同,人为干扰程度对这一结构也有非常明显的影响。基于上述结果可以看出,影响上海市园林鸟类的群落嵌套结构的主要原因是栖息地的结构和人为干扰程度。因此,建议在规划和建设城市公园和绿地时,应该偏重于面积较大,植被盖度和丰富度高,结构合理的园林,并且尽量减少人为干扰。     

Old park trees as habitat for saproxylic beetle species

Very old trees harbour a diverse fauna of saproxylic insects, many of which are classified as threatened due to the scarcity of this kind of habitat. Parks, which often contain many old trees, are therefore considered to be important sites for this fauna. However parks are intensively managed and dead wood is often removed. Therefore this study compares if the saproxylic beetle fauna in parks is as diverse as it is in more natural stands. Eight ‘Park’ sites at manor houses around lake Mälaren, Sweden were compared with trees in wooded meadows: eight grazed sites, here termed ‘Open’, and 11 sites regrown with younger trees, termed ‘Re-grown’. The comparison was made on lime trees (Tilia spp.): one of the most frequent tree species in old parks which host a diverse beetle fauna. Beetles were sampled with window traps, which in total caught 14,460 saproxylic beetles belonging to 323 species, of which 50 were red-listed. When comparing all saproxylic species, ‘Park’ sites had significantly fewer species than ‘Open’ sites. However, for beetles in hollow trees and for red-listed species there was no significant difference, the number in ‘Park’ being intermediate between ‘Open’ and ‘Re-grown’. Species composition differed between sites, but only marginally so. Therefore, the conclusion is that old park trees on average are as valuable for faunal diversity as trees in more natural sites. Large conservation benefits can be obtained by combining cultural and conservational values in the management of park habitats.     

基于Landsat-8影像的沿海城市公园冷岛效应——以厦门为例

城市公园主要由水体和绿色植被等景观构成,其形成的公园冷岛（Park cool island,PCI）已成为减缓城市热岛效应的重要途径之一。采用景感生态学中的景感营造理念规划设计城市公园或优化公园空间结构有助于增强公园冷岛效应,进一步改善局地城市热环境。选择沿海城市——厦门市为研究对象,基于2013年8月的Landsat-8 OLI/TIRS遥感影像和Google Earth高分影像数据,首先提取了研究区15个公园的土地利用信息,采用改进的地表温度单通道算法,获取了城市公园地表温度数据,并采用缓冲区分析、景观格局指数和多元统计等方法定量分析公园内部平均地表温度、城市公园冷岛强度（即降温幅度）、公园冷岛影响距离（即对周边区域的降温范围）三者的主要影响因子,并利用景感生态学原理初步剖析了城市公园景感营造的原则。结果显示：（1）公园面积和公园建设用地面积是影响公园平均温度的关键因子（R²=0.915）,这两个因子与公园平均温度均呈显著非线性相关;公园面积存在阈值55 hm²左右;（2）公园冷岛PCI强度由公园绿地面积、公园建筑面积和面积-周长形状指数（P/A）三个因子决定（R²=0.911）;公园冷岛PCI强度与公园绿地面积呈显著非线性正相关,与公园建筑面积呈显著非线性负相关,与面积-周长形状指数（P/A）呈显著线性负相关;在确保公园绿地面积达到一定阈值时,应该尽量降低公园建筑面积,增加公园形状复杂度,有利于其PCI强度的增加,缓解城市热岛效应;（3）公园冷岛影响距离由公园面积和公园水体面积比例决定（R²=0.719）,公园冷岛影响距离与两者呈显著正相关;绿地公园中提高公园水体的面积比例,有助于增大公园冷岛的影响距离;（4）城市公园的规划与设计,需要运用景感生态学的原理,从缓解城市热岛效应的角度,充分考虑公园大小、形状、土地利用类型组成比例及空间配置等因素。     

基于步行指数的深圳市福田区公园绿地社会服务功能研究

城市公园绿地是当代城市的重要组成部分,居民能否方便地享用公园绿地所提供的各项服务与功能,是衡量一个城市人地关系和谐状况、现代化发展水平和居民生活质量的重要指标,也是城市公园绿地社会服务功能的体现。选取深圳市福田区为研究对象,计算单点绿地步行指数,衡量均质区域的公园绿地步行可达性;基于土地利用类型法实现人口数据空间化;基于面域绿地步行指数耦合绿地空间分布与人口格局,评估深圳市福田区居民通过步行方式到达城市公园绿地的便利程度,即城市公园绿地的社会服务功能水平。结果表明:深圳市福田区在区域均质假设下,公园绿地步行可达性整体较好,区域差异较大,呈现出东优西劣的趋势,梅林公园周边、莲花山公园南部、荔枝公园周边及皇岗公园周边是四个公园绿地步行可达性最好的区域,福田区西北部和西南部公园绿地步行可达性差;供需平衡视角下,70%街道的居民可以便捷、公平地享用城市公园绿地所提供的服务,华强北街道、莲花街道、园岭街道和华富街道公园绿地设施建设非常完善,且绿地格局与人口格局配置合理,香蜜湖街道与沙头街道开放性公园绿地建设状况有待改进。将步行指数应用于公园绿地建设状况评估,为步行城市建设、公园绿地空间布局优化提供参考依据。     

Isolation drives taxonomic and functional nestedness in tropical reef fish faunas

Taxonomic nestedness, the degree to which the taxonomic composition of species‐poor assemblages represents a subset of richer sites, commonly occurs in habitat fragments and islands differing in size and isolation from a source pool. However, species are not ecologically equivalent and the extent to which nestedness is observed in terms of functional trait composition of assemblages still remains poorly known. Here, using an extensive database on the functional traits and the distributions of 6316 tropical reef fish species across 169 sites, we assessed the levels of taxonomical vs functional nestedness of reef fish assemblages at the global scale. Functional nestedness was considerably more common than taxonomic nestedness, and generally associated with geographical isolation, where nested subsets are gradually more isolated from surrounding reef areas and from the center of biodiversity. Because a nested pattern in functional composition implies that certain combinations of traits may be represented by few species, we identified these groups of low redundancy that include large herbivore‐detritivores and omnivores, small piscivores, and macro‐algal herbivores. The identified patterns of nestedness may be an outcome of the interaction between species dispersal capabilities, resource requirements, and gradients of isolation among habitats. The importance of isolation in generating the observed pattern of functional nestedness within biogeographic regions may indicate that disturbance in depauperate and isolated sites can have disproportionate effects on the functional structure of their reef fish assemblages.     

转型中工业城市的公园绿地社会公平性研究——以东莞市东城街道为例

作为城市重要的生态空间,公园绿地为城市提供环境基础及景观保障,其资源的合理分配是社会公平的重要体现。提出公园绿地社会公平性新的内涵,即无论个体所处的人居环境条件如何,其获得的城市公园绿地质量应该平等。工业城市向服务型、创新型城市的转变是中国城镇发展的典型趋势,研究其公园绿地的社会公平性为城市更新改造与公共资源分配提供重要的科学依据。以东莞市东城街道为例,构建社会-经济-自然复合人居指标体系与公园质量评价体系,基于可达性模型与Pearson相关性系数对公平性进行测度。结果表明：由于区域更新强度及顺序不同,研究区的绿地布局存在不公平现象,居民享受的公园质量与小区的自然、经济要素具有一定的关联。转型中的工业城市高质量公园聚集于风景资源优越的高端居住区,其他公园质量普遍不佳。工业园区以及旧城区为公园服务盲区的主要聚集地。