Urban Parks In Beijing Research Articles

The value of pocket parks in preserving urban butterfly diversity

Butterflies, valued for their aesthetic and ecological value, are key subjects in urban biodiversity research. Our study focused on the often-overlooked roles of pocket parks, which are micro-greenspaces and small amusement parks open to the public. Despite their limited size, pocket parks are vital in maintaining the diversity of urban butterflies. We contrasted pocket park diversity with urban parks in Beijing, China. Next, using hierarchical clustering, we classified butterflies into exploiters, adapters, and avoiders based on how well they adapted to urban environments. Finally, we used Logistic regression and Poisson regression to build generalised linear models for all species and each of the three groups separately, allowing us to investigate the differences in the effects of variables from food resources and shelters on various butterfly groups in pocket parks. The results showed that although the primary restrictions differ depending on the group, pocket parks can serve as habitats for most species. Management intensity, pocket park area and nectar plants were significant variables for all species. The tourist intensity and host plants were variables that affected the presence of exploiters. Host plants, nectar plants, and management intensity all affected adapter diversity. Pocket parks’ area was only affected avoiders significantly. These results suggest that pocket parks have roles as source and sink habitats for exploiters and adapters and as stepping stones and corridors for most butterfly species inhabiting cities.

Soil microbial responses to multipollutant exposures in megacity's parks of Beijing

Soil life revolves around microorganisms that are crucial for soil ecosystems and health. In megacities, the combined exposure of multiple pollutants exerts a significant impact on the structures and functions of soil microorganisms; however, there is a lack of empirical studies on this topic. Hence, we conducted a study including urban parks in Beijing, China. The results indicate that bacteria were abundant in the soils of Beijing parks, showing the same dominant groups but different rare groups. The dominant groups included Actinobacteria and Proteobacteria. Candidate phyla radiation bacteria, a large evolutionary radiation of bacterial lineages whose members remain mostly uncultivated, were the main specialists. Under the combined exposure of multiple pollutants, the structures of soil microbial communities in different parks were similar. Community change due to pollutants (31%) was greater than that due to natural factors (2.4%). Among multipollutants, organophosphate esters, led by dibutyl phosphate, had the highest influence on microbial abundance and distribution. An increase in dibutyl phosphate concentration decreased the abundance of Firmicutes, while the abundance of Synergistota was increased. The interactions among pollutants affecting the bacteria were different. Bis(2-chloroethyl) phosphate, nickel and benzo[g,h,i]perylene influenced microorganisms by working with organophosphate esters. High-molecular-weight polycyclic aromatic hydrocarbons, such as benzo[a]pyrene and benzo[g,h,i]perylene, mainly acted on the functional genes and thus affected multiple biogeochemical cycles. Benzo[a]anthracene, bis(2-chloroethyl) phosphate, and arsenic were the primary pollutants affecting metabolic pathways. Our research helps to better understand the impacts of urban environmental pollution on soil microorganisms.

Urban park attributes as predictors for the diversity and composition of spontaneous plants − A case in Beijing, China

Urban biodiversity homogenization and native species habitat loss are becoming increasingly severe. The overuse of lawn grasses and cultivars in green spaces is one of the most important drivers. Scholars have asserted that spontaneous vegetation provides various ecological benefits and should be widely incorporated in planting design. Factors influencing spontaneous plant diversity have mainly been studied in specific habitats or at the city scale, and findings surrounding the attributes of urban parks that support the diversity of spontaneous plants are lacking. This study aimed to provide a perspective on conserving spontaneous plants through inferring the urban park attributes associated with plant diversity. Twenty-two urban park samples in Beijing were examined to identify the correlation between various park variables and spontaneous vegetation. This study recorded 199 spontaneous plant species, with large historic parks containing the most number of species. Park size was a remarkable predictive variable for the diversity of spontaneous plants. Species richness and diversity in large parks were significantly higher than in small parks; not only in total richness due to the species–area relationship but also in richness and diversity at the community level independent of plot number. Microhabitat heterogeneity and the percentage of green area had the strongest positive association with the richness of spontaneous plants. In contrast, the maintenance intensity, perimeter–area ratio, and fragmentation of green area, deciduous forest, and open lawn patches had negative associations with spontaneous plant richness. Redundancy analysis demonstrated that park area, maintenance intensity, microhabitat heterogeneity, and deciduous forest patches were the most remarkable variables predicting species composition. The correlations of variables related to water and open lawn patches with spontaneous plant diversity were more evident in summer. The predicted variables were also more significantly correlated with the diversity of exotic species in summer than in spring. Perennial herbs were more sensitive to the evaluated park attributes. This study elucidates how spontaneous plants are associated with the attributes of urban parks in Beijing, with critical implications for other large cities.

Organophosphate esters in soils of Beijing urban parks: Occurrence, potential sources, and probabilistic health risks

Organophosphate esters (OPEs) are an emerging contaminant widely distributed in the soil. OPEs have drawn increasing attention for their biological toxicity and possible threat to human health. This research investigated the pollution characteristics of two typical OPEs, organophosphate triesters (tri-OPEs) and organophosphate diesters (di-OPEs), in soils of 104 urban parks in Beijing. The median concentrations of Σ11tri-OPEs and Σ8di-OPEs were 157 and 17.9 ng/g dw, respectively. Tris(2-chloroisopropyl) phosphate and bis(2-ethylhexyl) phosphate were the dominant tri-OPE and di-OPE, respectively. Consumer materials (such as building insulation and decorative materials), traffic emissions, and reclaimed water irrigation may be critical sources of tri-OPEs in urban park soils. Di-OPEs mainly originated from the degradation of parent compounds and industrial applications. Machine learning models were employed to determine the influencing factors of OPEs and predict changes in their concentrations. The predicted OPEs concentrations in Beijing urban park soils in 2025 and 2030 are three times and five times those in 2018, respectively. According to probabilistic health risk assessment, non-carcinogenic and carcinogenic risks of OPEs can be negligible for children and adults. Our results could inform measures for preventing and controlling OPEs pollution in urban park soils.

Large urban parks summertime cool and wet island intensity and its influencing factors in Beijing, China

Construction of urban parks has long been proved as an effective way to mitigate urban heat island effect, and better arrangement of green spaces in a city is expected to help regulate urban climate. To provide further empirical evidence and guidance for urban green spaces planning and design, field measurement of summertime air temperature and relative humidity was conducted in and out of 10 large urban parks in Beijing, China. Averaged daytime and nighttime park cool and wet island intensity were 1.09 ℃, 1.48 % and 3.63 ℃, 4.25 % respectively. Parks’ influence on local-scale climate extended as far as over 1km during summer nights, and more effective cooling effects were provided within approximately one-park width. Among all influencing factors, park size plays dominant role in regulating nighttime local-scale climate in parks’ adjacent area, while vegetation coverage around sampling points out of urban parks also has significant contributions, indicating that large urban parks and their surrounding urban greenery interact to affect neighborhood climate. Park size was the only factor found correlated with nocturnal park cool and wet island intensity. Results of this study provide additional information on large urban parks’ local-scale climate effect and give insights to future urban green spaces planning and design practice.

Spatial-temporal distribution characteristics and evolution mechanism of urban parks in Beijing, China

Urban parks are vital ecological recreational places, and their spatial evolution has a certain influence on the ecological environment and quality of citizens’ daily life. Taking Beijing as an example, this paper firstly explores the dynamic evolution of urban parks in Beijing by comparing spatial distribution characteristics in three time points of 2005, 2010, and 2017. Besides changes in number and area, the spatial structure and accessibility are examined by the methods of directional distribution, kernel density estimation and network analysis. Then three-factor analysis method is used to explain the evolution mechanism. The results reveal that there exist obvious and continuous growths in urban parks regardless of quantity, area or accessibility. According to the core-periphery spatial distribution pattern, Beijing has gradually formed a systematic green recreational network, and the service area of urban parks by walking within 30 min is 58.6 % of total area. Stability factors, dynamic factors and random factors play important roles during the spatial evolution of urban parks through restraint mechanism, supply-demand mechanism and triggering mechanism respectively. The findings offer both theoretical construct and policy recommendations for the development and sustainability of urban parks in Beijing and other rapidly urbanizing cities with high population densities.

Effect of Space Configurational Attributes on Social Interactions in Urban Parks

Urban parks are one of the most common spaces for social interactions in modern cities. The design of park spaces, especially space configuration, has significant influences on people’s social behaviors in parks. In this study, the associations between space configurational attributes and social interactions were investigated using space syntax theory. An observation analysis of social behaviors was carried out in two urban parks in Beijing, China. Nine space configurational attributes, including depth to the gate, depth to the main road, connectivity, normalized angular integration (NAIN), and normalized angular choice (NACH) with three radii, were calculated using a segment model. The variance analysis and regression analysis reveal the strong joint effect of space type, space scale factors, and space configurational attributes on social interaction behaviors in parks. The personal interaction group contained 23% of the total observed people involved in social interactions. Pathway length, zone area, and NACH-10K (NACH with a radius of 10,000 m) are positively associated with the number of people involved in personal interactions. For the social interaction group (77% of the total observed people), the space scale and depth to main city road were found to have a positive and negative influence on social interaction intensity.

Fine-grained assessment of greenspace satisfaction at regional scale using content analysis of social media and machine learning

Assessing perceptions of green spaces is of considerable interest to developers aiming for sustainable urbanization. However, there are numerous challenges facing the development of a rapid, effective, and fine-grained method to assess large-scale greenspace perception. Survey-based studies of perception yielded detailed assessments of green spaces but lacked regional comparisons. The few big-data-based studies of greenspace perception lacked fine-grained explorations. Therefore, we used content analysis to interpret perception in two ways: perceived frequency and perceived satisfaction, including overall park satisfaction and satisfaction with individual landscape features. We analyzed social media posts about urban parks in Beijing, China. A structured lexicon was developed to capture detailed landscape features, and machine learning was employed to assess satisfaction levels. Both of these techniques performed well in interpreting greenspace satisfaction from volunteered textual comments. A detailed study of 50 parks demonstrated that overall park satisfaction was positive. Additionally, individual landscape features were more influential than frequency of landscape features in affecting satisfaction. Our framework confirmed the potential of online comments as complementary to traditional surveys in assessing greenspace perception, while enhancing our understanding of this perception on a regional scale. Practically, this study can facilitate sustainable policy-making regarding urban green spaces, specifically through offering a structured landscape-feature lexicon, rapid regional comparison of various parks, and an emphasis on quality rather than quantity of landscape features.

Differences in Response of Butterfly Diversity and Species Composition in Urban Parks to Land Cover and Local Habitat Variables

Background and Objectives: As urbanisation is a significant global trend, there is a profound need for biodiversity protection in urban ecosystems. Moreover, the potential of urban green space to support urban biodiversity should be appreciated. Butterflies are environmental indicators that are sensitive to urbanisation. Therefore, it is important to identify butterfly distribution patterns and the factors influencing butterfly diversity and species composition in urban parks within cities. Research Highlights: To our knowledge, ours is the first study evaluating the effects of both land cover and local habitat features on butterfly species composition in urban parks of Beijing, China. Materials and Methods: In this study, we surveyed butterfly richness and abundance in 28 urban parks in Beijing, China. The parks differed in age and location in the urban area. Meanwhile, we investigated the green space in the surroundings of the parks at multi-spatial scales at the landscape level. We also investigated local park characteristics including the age of the park (Age), perimeter/area ratio of the park (SQPRA), area of the park (ha) (Area), green space cover within the park (Greenp), nectar plant species richness (Necpl), abundance of flowering nectar plants (Necabu) and overall plant species richness (Pl). Generalised linear models (GLMs) and redundancy discriminant analysis (RDA) were applied to relate butterfly diversity and butterfly species composition to environmental variables, respectively. Results: We recorded 3617 individuals belonging to 26 species from July to September in 2019. Parks on the city fringe had significantly higher butterfly diversity. Butterfly species richness was mostly related to total plant richness. The abundance of flowering nectar plants was closely linked to butterfly abundance. Land cover had little impact on butterfly diversity and community structure in urban parks. Conclusions: Once a park has sufficient plants and nectar resources, it becomes a useful haven for urban butterflies, regardless of the surrounding land cover. Well-planned urban parks focused on local habitat quality support butterfly conservation.

Outdoor thermal comfort during winter in China's cold regions: A comparative study

Due to limits to standard methods for surveying outdoor thermal comfort (OTC), it is difficult to compare thermal benchmarks and thermal index calibrations among studies and climatic regions. Using uniform standard meteorological measurements and questionnaire surveys, our study conducted an OTC study in urban parks in Beijing, Xi'an and Hami; representative of cities in China's cold regions. The Universal Thermal Climate Index (UTCI) was used as the thermal comfort index, and differences in residents' thermal perceptions and outdoor thermal benchmarks among these cities were compared. Results showed that: 1) air temperature (Ta) and globe temperature (Tg) were two primary factors affecting residents' thermal sensations in the three cities during winter. Residents' thermal sensation in Beijing and Hami was negatively correlated with wind speed (Va). Residents in Xi'an and Hami preferred a higher relative humidity (RH). Residents in Beijing and Hami preferred a lower Va to improve OTC related to local climatic characteristics. 2) Xi'an residents had the highest neutral UTCI (NUTCI) (17.3 °C), followed by Beijing (17.0 °C) and Hami (6.4 °C). Xi'an residents had slightly wider neutral UTCI range (NUTCIR) (7.9–26.7 °C) compared to Beijing (8.7–25.4 °C), while Hami residents had the narrowest NUTCIR (1.5–11.3 °C). The “no thermal stress” range in the three cities was 6.1–26.0 °C in Beijing, 6.7–25.5 °C in Xi'an, and −2.2–12.2 °C in Hami. 3) Calibrated thermal indices, based on the ASHRAE 7–point scale, were gained to judge the thermal qualities of an environment for all three cities.

北京城市蝴蝶蜜源植物网络特征及重要蜜源植物识别

物种间相互作用网络研究能为物种多样性的保护、城市生态系统稳定性的维持提供指导。基于群落水平的城市蝴蝶蜜源植物互作网络的研究较少，对城市蝴蝶蜜源网络结构缺乏深入认识。研究在国内城市生态系统中构建蝴蝶蜜源网络，并探讨不同类型植物对网络特征的影响。2020年6-9月，在北京26个城市公园中记录访花蝴蝶和蜜源植物物种及互作频次，采用交互多样性（ID）、交互均匀性（IE）、专业化程度（H2'）定量化生态网络结构特征，采用Kruskal-Wallis秩和检验和变差分解分析不同生长型、起源、栽培方式的植物类型对网络结构的影响差异。采用物种的伙伴多样性（PD）和专业化程度（d'）识别重要蜜源植物。研究结果表明：（1）北京城市公园中22种蝴蝶与81种开花植物的交互作用，形成趋于泛化的生态网络结构；（2）不同生长型及不同起源的植物-蝴蝶网络的交互多样性及专业化程度有显著差异，草本及乡土植物对丰富网络中交互多样性和支持专业性更高的蝴蝶物种具重要作用，而植物的栽培方式对蜜源网络结构影响较小；（3）伙伴多样性高且专业化程度高的植物可被视为重要蜜源植物。基于蝴蝶多样性保护的目标，在城市生态系统中，绿色空间应注重构建乡土草本植物群落，优先选择重要蜜源植物。我们的发现印证了蝴蝶-蜜源植物生态网络方法作为联结生态研究和城市绿地实践管理的有效工具，能为城市生态系统中生物多样性保护提供科学策略，具有重要意义。;Study on ecological networks about species interactions provides a basis for species diversity protection, and it is beneficial for the maintenance of urban ecosystem stability. However, urban ecological network study between butterfly and plant based on community level still leaves a huge blank, therefore, the knowledge of butterfly-nectar plant network structure needs an in-depth understanding. To our knowledge, ours is the first study focusing on butterfly-nectar plant network in urban ecosystems in China and evaluating the effects of different type of plants on butterfly-nectar plant network. In this study, we surveyed flower visiting butterfly species and nectariferous plant species and the interaction frequency in 26 urban parks in Beijing, China from June to September in 2020. The butterfly-nectar plant bipartite network was built. We identified five quantitative metrics on two hierarchical levels (network and species) to describe network patterns and species' interaction. Metrics on network level were interaction diversity (ID), interaction evenness (IE) and network specialization (H2'). Moreover, we analyzed the effect of different vegetation types on the network structure differences, including different type of growth form, origin, and cultivation plant, using Kruskal-Wallis test and variance partitioning analysis. Metrics on species level were partner diversity (PD) and species specialization (d') for identifying important nectariferous plant species that provide a key and central role to the stability of the structure of network. The results are as follows: (1) 22 species of butterfly and 81 species of flowering plants of interaction were observed and the butterfly-nectar plant network tended to be generalized. (2) The interaction diversity and specialization of two growth form plant-butterfly network were significantly different (P<0.01), and same to of two origin plant. Furthermore, herbs and native plants played an important role in maintaining the interaction diversity and specialized butterfly species in the network. Interestingly, cultivation type of plants had little effect on nectar network structure. (3) Plants with high partner diversity and high degree of specialization could be regarded as important nectariferous plant species. Consequently, in order to protect butterfly diversity, native herbaceous plant community should be constructed in green space of urban ecosystem, and important nectariferous plant species should be given top priority to grow. Our findings confirm that the butterfly-nectar plant ecological network can provide a scientific strategy for biodiversity conservation in urban ecosystems. It could be an effective tool to link ecology research with urban green space practice management.

城市公园春季声景观与植被结构的关系

城市公园是城市生态系统的重要组成部分和城市生物多样性热点地区，具有丰富的声景观资源。由于声景观及声学方法具有信息量大，成本低，低侵入的特点，因此其研究和应用对生态系统健康及监测具有较高价值。声景观研究通过总结生物声的活动或多样性来衡量生物多样性。记录了北京20个城市公园的春季声景观，使用定量方法描述了声景观特征与变化；测试三种了已被证明与生物多样性相关并被广泛使用的声学指数（BIO、ADI、NDSI）与植被群落关系，完成了城市环境中声景观与环境关系的初步探究。研究结果表明：（1）声学指数能够有效表征城市公园声景观信息，具有显著的时间动态特性，能准确反映鸟类黎明合唱等重要生物生态活动；（2）声学强度指数也具有显著的时间动态变化和沿频率梯度的变化，不同的频率区间反映了不同声学群落的活动信息；（3）植被结构尤其是垂直结构对声景观起着重要作用，垂直异质性越大，声学多样性越高。发现支持声景观作为公园植被状况的度量，强调了其作为生物多样性和生态系统健康状况监测方法，用于城市管理和可持续发展的巨大潜力。;Urban foresters are addressing the challenges of urban biodiversity loss through management plans to adapt to urbanization. Protecting the integrity of the urban ecosystem requires long-term monitoring and planning for resilience as well as effective management. Urban parks are important parts of the urban ecosystem and hot spots of urban biodiversity, with rich soundscape resources. Due to the informative, low-cost, and low-impact features, soundscape-related researches and applications have a great potential of monitoring ecosystem health. Acoustic indices have been commonly used in soundscape ecology researches to measure biodiversity conditions by summarizing the activity or diversity of biological sounds. In this study, we recorded the soundscapes of 20 city parks within Beijing urban area in spring, trying to describe the characteristics and changes of soundscape quantificationally. A total of 23,040 minutes of sound materials were automatically sampled from raw data using Python. Then we calculated three widely used acoustic indices (BIO, ADI, NDSI) that have been proven to be related to biodiversity. The soundscape intensity index, power spectral density (PSD), was calculated to measure acoustic features along every frequency interval. All the indices' calculation is based on R studio. Spearman rho correlation analysis and principal component analysis were carried out to explore how environmental vegetation structures affecting soundscape in park habitats. The results show that (1) acoustic indices can not only effectively characterize the soundscape information of urban parks, but also have significantly time-dynamic characteristics, which can accurately reflect important biological activities and ecological processes such as bird dawn chorus. (2) The acoustic intensity index also reflects significantly temporal variations and changes along the frequency intervals. Different frequency interval groups reflect the corresponding activity information of acoustic communities. These results also provide more supports to the acoustic niche hypothesis (ANH) theory. (3) Our PCA modelling results show that the vegetation structure, especially the vertical structure, plays an important role in urban soundscapes. More vertical heterogeneity or multilayered vegetation, is associated with more acoustic diversity in urban parks. In the absence of historical soundscape data, we systematically collected and analyzed the soundscape of urban parks in Beijing. This is a pilot study for soundscape in Beijing urban parks. Our findings support soundscape as a measurement of habitat vegetation status and emphasize its great potential for urban management and sustainable development in biodiversity and ecosystem monitoring, which will enable regular assessment of urban parks and forests to inform adaptive planning and management strategies.

The effects of residential greenspace on avian Biodiversity in Beijing

Residential communities are the primary living spaces for people in China. Their associated greenspaces are important elements of the urban ecosystem, providing neighborhood ecosystem services and hosting bird populations of differing community structures compared with other urban green areas. This study analyzes avian community characteristics within residential communities and their differences compared with urban parks in Beijing. Furthermore, we assess the key environmental factors determining species composition and population sizes and the spatial scales at which these factors are most significant. We randomly selected 27 residential communities to assess the habitat structure and landscape characteristics that underpin residential avian assemblages across multiple spatial scales. Independent sample t-test and model selection methods based on AICc were used for data analysis. Eurasian Tree Sparrow (Passer montanus) (hereafter ETS) alone accounted for 91.0% of total individuals. Compared with urban parks, more migrants and omnivores were found in residential communities. Within-site forest patch connectivity simultaneously decided resident species diversity and individual abundance, with the exception of ETS. Tree species richness and coverage are key predictors for resident species richness and ETS numbers, respectively. Even in the most urbanized species, ETS retained ecological attributes found in “wilder” settings. Residential communities skewed toward avian communities with dominant numbers of ETS. In these low-quality habitats, our results suggest that landscape configuration is more important than local habitat structure. Within-site habitat connectivity and the number of surrounding forest patches with shorter between-patch distances deserve more attention in future landscape design for residential communities.

Heavy metal(loid)s in the topsoil of urban parks in Beijing, China: Concentrations, potential sources, and risk assessment

Urban parks play an important role in the urban ecosystem and are also used by residents for recreation. The environmental quality of urban park soils might influence human health following long-term exposure. To assess potential sources and pollution risks of heavy metal(loid)s in the topsoil of urban parks, we subjected metal concentrations in soil samples from 121 parks in the Beijing urban area to geostatistical analyses, conditional inference tree (CIT) analyses, ecological risk and human health risk assessment. CIT effectively explained the influence of human activity on the spatial variation and accumulation of soil metal(loid)s and identified the contributions of natural and anthropogenic inputs. The main factors influencing the accumulation of heavy metal(loid)s, including urbanization duration, park age, per capita GDP, industrial output, and coal consumption, were evaluated by CIT. Except for Cr and Ni, the average concentrations of the metal(loid)s tested (Cu, Pb, Zn, Hg, As, and Cd) were higher than the background values. In the urban parks, Ni and Cr derived mostly from soil parent materials. Concentrations of Cu, Zn, Pb, Cd, As, and Hg were strongly associated with human influences, including industrial, agricultural, and traffic activity. After assessing health and ecological risks, we conclude that heavy metal(loid)s in the soil of Beijing urban parks pose no obvious health risk to humans, and the ecological risk is also low.

Potential sources, influencing factors, and health risks of polycyclic aromatic hydrocarbons (PAHs) in the surface soil of urban parks in Beijing, China

Urban parks are an important part of the urban ecological environment. The environmental quality of parks is related to human health. To evaluate sources of polycyclic aromatic hydrocarbons (PAHs) in soils of urban parks and their possible health risks, soil samples from 122 parks in Beijing, China, were collected and analyzed. The total content of 16 PAHs between 0.066 and 6.867 mg/kg. Four-ring PAHs were predominant, followed by 5-ring PAHs, while the fraction of 2-ring PAHs was the lowest. The dominant PAHs sources were found to be coal combustion and oil fuels such as gasoline and diesel. A conditional inference tree (CIT) was used to identify the key influencing factors for PAHs. Traffic emissions was the most important factor, followed by coal consumption, as well as the history and location of the park. Incremental lifetime cancer risk (ILCR) for urban park soil in Beijing were low under normal conditions. The soil PAHs exposure pathway risk for both children and adults decreased in the following order: ingestion > dermal contact > inhalation. The risk from soil in parks to children’s health is slightly higher than that of adults, although the health risk due to exposure to PAHs was not extraordinary. Ecosystem risk was negligible.

The Distribution and Accessibility of Urban Parks in Beijing, China: Implications of Social Equity.

As public service facilities, urban parks offer many benefits for daily life and social activities for residents. However, the accessibility of public parks to urban residents is often unevenly distributed in spaces that cannot be utilized fully. Here, we used the urban parks in Beijing, China as a case study and examined the relationship between urban park accessibility and population distribution at different administrative levels. Gini coefficient and Lorenz curve were used to evaluate the social equity of urban park accessibility, and the location quotient was used to identify the spatial difference between urban parks and resident population. The results of our study show that the urban park accessibility varies at district and subdistrict levels and that places with more urban parks usually have higher accessibility. Very importantly, the spatial equity is different from the social equity, a mismatch exists between the spatial distribution of urban parks and population, particularly for the elderly residents. These results generate valuable insights, as, in China and many developing countries, current urban public green space planning only uses the ratio of public green space to urban construction land and the per capita public green area.

A demand index for recreational ecosystem services associated with urban parks in Beijing, China

Good planning for urban parks requires an analysis of the quantitative relationship between the distribution of an urban population and the demand for recreational ecosystem services (RES). A barrier to RES quantification is the lack of connections between survey materials and spatial data. This study developed a logistic regression model for the demand for RES associated with urban parks based on the characteristics of individual visitor and their willingness to visit parks. The model was fitted by a questionnaire survey completed by 4096 park visitors and was used to predict the RES demand in 317 sub-districts of Beijing. Results showed that: (1) park visitors rated sightseeing as the most important, followed by jogging, boating, partying, cycling, and fishing in Beijing's parks; (2) high-income and older residents had higher willingness to visit the parks than did low-income and younger park visitors; (3) the fringe areas between the urban and rural regions showed a relatively low demand index for RES. This study exhibits a feasible method to predict RES demand based on surveys and statistical data. Our research suggests that improving park planning necessitates developing a diverse recreational infrastructure, a tradeoff among different stakeholders, and spatial optimization for sustainable urban development. The results provide a potential tool that can be used to assess the balance of RES in a scenario of urbanization and population growth.

Status of an alien turtle in city park waters and its potential threats to local biodiversity: the red-eared slider in Beijing

Invasive alien species pose a serious threat to native biodiversity and the ecosystem structure through predation or competition, and this threat is especially severe in China. Red-eared sliders (Trachemys scripta elegans) were introduced to mainland China to meet demands for food, traditional Chinese medicine, and the pet trade. However, there has been a lack of field surveys to assess the population, behavior and ecological impacts of introduced red-eared sliders in urban aquatic ecosystems in northern China. We conducted such research in 33 urban parks in Beijing from April to November 2016. The alien sliders were recorded on 514 occasions at 19 parks, and 45 individuals were captured from 4 parks to evaluate their diet composition and reproductive status. The observations showed that red-eared sliders accounted for 95% of the recorded turtles in the parks. The male to female ratio was 1.0:3.5, and the ratio of adults to juveniles was 1.0:3.1. According to stomach content analysis, the sliders fed mainly on animals: the dominant prey were Gastropoda, Osteichthyes, Crustacea, Hexapoda, Bivalvia, Reptilia and Aves in descending order. The high frequency (83%) of follicles and oviduct development in adult females suggested a strong reproductive capacity, which was further supported by one case of early female maturity. Bacteriological examinations demonstrated that the carrying rate of Salmonella bacteria was up to 17.6%. This study demonstrated that red-eared sliders have successfully colonized the waters of urban parks in Beijing and potentially threaten native aquatic biodiversity.

Ring roads and urban biodiversity: distribution of butterflies in urban parks in Beijing city and correlations with other indicator species

The capital of China, Beijing, has a history of more than 800 years of urbanization, representing a unique site for studies of urban ecology. Urbanization can severely impact butterfly communities, yet there have been no reports of the species richness and distribution of butterflies in urban parks in Beijing. Here, we conducted the first butterfly survey in ten urban parks in Beijing and estimated butterfly species richness. Subsequently, we examined the distribution pattern of butterfly species and analyzed correlations between butterfly species richness with park variables (age, area and distance to city center), and richness of other bioindicator groups (birds and plants). We collected 587 individual butterflies belonging to 31 species from five families; 74% of the species were considered cosmopolitan. The highest butterfly species richness and abundance was recorded at parks located at the edge of city and species richness was significantly positively correlated with distance from city center (p < 0.05). No significant correlations were detected between the species richness and park age, park area and other bioindicator groups (p > 0.05). Our study provides the first data of butterfly species in urban Beijing, and serves as a baseline for further surveys and conservation efforts.

Multi-scale factors influencing the characteristics of avian communities in urban parks across Beijing during the breeding season.

Understanding the factors that influence the characteristics of avian communities using urban parks at both the patch and landscape level is important to focus management effort towards enhancing bird diversity. Here, we investigated this issue during the breeding season across urban parks in Beijing, China, using high-resolution satellite imagery. Fifty-two bird species were recorded across 29 parks. Analysis of residence type of birds showed that passengers were the most prevalent (37%), indicating that Beijing is a major node in the East Asian–Australasian Flyway. Park size was crucial for total species abundance, but foliage height diversity was the most important factor influencing avian species diversity. Thus, optimizing the configuration of vertical vegetation structure in certain park areas is critical for supporting avian communities in urban parks. Human visitation also showed negative impact on species diversity. At the landscape level, the percentage of artificial surface and largest patch index of woodland in the buffer region significantly affected total species richness, with insectivores and granivores being more sensitive to the landscape pattern of the buffer region. In conclusion, urban birds in Beijing are influenced by various multi-scale factors; however, these effects vary with different feeding types.