Quality Of Urban Green Space Research Articles

The perception of urban green space during the COVID-19 pandemic: The case of Wrocław

Green spaces are integral to urban landscape, serving ecological, health, and recreational functions. During the pandemic, urban green spaces were crucial for enabling safe social distancing and enhancing well-being. This study delves into the perception, accessibilities, and qualities of urban green spaces in Wrocław during and after the pandemic. A survey was conducted to understand causes and effects of diverse usage of the urban green space, assessing changes in usage frequency before, during, and after lockdown, as well as public awareness of benefits associated with green spaces. Proximity to green spaces emerges as a key factor as people prefer easily and quick access to these areas. The study also noted a partial modification of social behaviour and increased social and ecological awareness. The results reveal evident development of new daily habits. Although the beginning of the pandemic led to discomfort, adaptive behaviours soon followed, changing daily routines and previous leisure activities. Given the findings on availability and adequacy of green spaces, it is advisable to rearrange these areas to meet the diverse needs of inhabitants.

More green but less just? Analyzing urban green spaces, participation, and environmental justice in Amsterdam

Cities worldwide are taking action to increase the amount and quality of urban green spaces. However, not all efforts for the greening of cities produce just and inclusive outcomes. For more inclusive urban greening processes, scholars have proposed incentivizing residents’ participation in planning and implementing green initiatives that promote creating and maintaining green spaces. However, further in-depth analysis of the connection between implementing new urban green spaces and environmental (in)justice is needed to understand how unjust outcomes might emerge due to policies aiming to promote the uptake of urban green through citizen engagement. To investigate the justice implications of policies that aim to create new urban green spaces through citizen participation, this article combines GIS analysis and qualitative analysis of 26 semi-structured interviews to evaluate the process and outcomes of the Green Agenda policy in Amsterdam. The Green Agenda (Agenda Groen) is a municipal policy supporting citizens’ initiatives to uptake urban green. Through the analysis of this case study, the article aims to identify factors that create barriers to achieving just outcomes during the implementation of policies for urban greening. Results indicate that although the approach has successfully increased the amount of urban green in Amsterdam, the presence of barriers that impede procedural justice and lack of recognition made the urban greening process less just. The three underlying factors that create barriers in Amsterdam are the centralization of the government, the lack of support for local organizations, and the effect of socioeconomic characteristics on inclusion and participation. The article concludes by discussing the synergies and tradeoffs between identified barriers and suggesting solutions to be integrated into future policies for more successful and just greening processes.

Impact of maintenance regimes on species richness in newly established perennial wildflower meadows

Perennial wildflower meadows contribute to the enhancement of the quality of urban green spaces, of-fering benefits for both people and wildlife. Significant impact is attributed to management in fostering species-diverse plant communities. However, there are not enough studies exploring the influence of early maintenance regimes on plant diversity. A three-year experiment was conducted to investigate the impact of maintenance regimes on newly established perennial wildflower meadows and the influence of sowing mix on species richness. Three types of perennial wildflower seed mixes were sown on arable land and managed differently during the initial year. Results indicate statistical significance for each main effect, including maintenance type and sowing mix, with no significant interaction between these factors. Mowing during the early growth stage is shown to increase species richness, while no significant difference is observed between weeded and unmanaged plots. The dry meadow sowing mix demonstrates the highest diversity index (Shannon-Weaver, 1963). Maintenance regimes exhibit a significant influence on species richness independently of the sowing mix used. Furthermore, mowing during the early growth stage is found to enhance species diversity in the long term. These findings provide beneficial insights for the more efficient management and establishment of species-rich wildflower perennial meadows in both urban and suburban environments, particularly in areas with a significant soil weed seed bank.

Technological features of cultural ecosystem services assessment

The benefits that city residents receive from green spaces related to maintaining their health are a group of cultural ecosystem services (CES). To avoid subjectivity in the assessment of CES, there is a methodology based on determining the effectiveness of green spaces in providing them. Currently, there is no technological scheme for assessing the CES available to urban planners. Accordingly, the purpose of the paper is to highlight the technological features of the CES assessment. Methodologically, the work consists in creating a geodatabase (DB) on the state of green spaces and anthropogenic pressure on them. All the calculation indicators proposed in the methodology should be included in the database as attributes, and their calculation should be performed as working scenarios documented in the form of automated calculation models, etc. The technology is based on QGIS/SAGA spatial analysis tools (QGIS version 3.32.1-Lima), which contains the necessary basic geoprocessing algorithms and modules for calculating the CES. The technology for estimating CES is presented in the Model_CES. The functioning of the Model_CES depends on the amount and quality of input data. As input data, the database includes information on: urban green spaces; vegetation; landscapes; areas with multi-age urban development; local areas of urban population concentration; survey statistics, etc. Attribute information is the basis for the correct operation of the Model_CES algorithms, in particular, the calculation of parameters by which it is proposed to assess the volume of CES. Adequate to the parameters, a file database in the GeoPackage format was formed in accordance with the standards of the Open Geospatial Consortium - Model_CES, which contains the input data sets: tabular: "survey_all"; vector: "Vegetation", "BGI", "local_district", "hollow", "age_consruct". Technological procedures and algorithm for calculating CES volumes and risks of their loss in Model_CES form calculation blocks: 1. a block for determining the potential of green spaces in providing CES; 2. a block for determining the effectiveness of the green space in providing CES - the real supply of CES; 3. a block for calculating the volume of ecosystem services and the risks of their loss; 4. a block for calculating the score of alternative availability of the green space. As a result, the proposed algorithm produces the output geodataset "BGI_CES". After the implementation of the technology, this dataset contains attribute information about each green space, in particular, their ability to provide cultural ecosystem services, efficiency in providing CES, the volume of CES and the risks of their loss. Thus, the paper solves the scientific task of creating an assessment technology that meets the following requirements: it is suitable for processing information that is spatially distributed; it is focused on the availability of uncertain and often limited data; it is available for use by specialists of design and other institutions that may be limited in data. The presented technology can be used in urban planning practice as a tool for improving the quality of urban green spaces, their sustainable development and providing citizens with the maximum amount of CES.

Travel preference: an indicator of the benefits of urban green space

ABSTRACT Urban Green Space (UGS) plays a crucial socio-cultural role in improving the quality of life. Assessment of quantity, quality, and accessibility determines whether the UGS are important social benefits. The travel preference of urban residents is a good indicator for the social relevance of UGS. This study integrates remote sensing and geographic big data to quantitatively analyze and evaluate the social benefits of urban green space. We propose a Green Social Benefit Index (GSBI) based on remote sensing retrieval and classification of urban green space. The GSBI is combined with the data on population mobility to investigate the influence of urban green space on residents’ behavior. The results show that urban residents prefer to move around in places with a higher quantity and quality of urban green space. The magnitude of the influence of urban green spatial features on population heat difference shows that accessibility > quantity > quality. The social benefits of urban green space are higher in middle centers compared to urban centers and city borders. The relationship between urban mobility and urban green space may suggest how to improve the distribution of green space in urban areas. This study could be a reference for the government planning department.

AN EXPLORATORY STUDY OF THE EVOLUTION OF URBAN GREEN SPACES IN LISBON USING DIACHRONIC ANALYSIS OF ORTHOPHOTO MAPS

Green urbanism, namely in the form of consolidated urban green spaces (UGSs), has gained traction along with the reformist impetus of urban design, based on the ideal of efficient, functional, sustainable cities that promote a better quality of life for their citizens and on the notion of making urban expansion compatible with natural resources. Using a diachronic analysis (1995–2020) of the orthophoto maps of 38 UGSs included in the last version of the main municipality’s legislation, framed within the Plano Director Municipal (PDM), whose first version was approved in 1994, we assessed the situation and evolution of the UGSs in the centre of Lisbon, Portugal. We conclude that with fewer or more incidences, depending on the periods analysed, the structure of UGSs in the centre of Lisbon has undergone significant changes, whether in terms of the implementation and requalification of existing UGSs or in terms of the increment and quality of UGSs (space created), thus respecting to a lesser or greater degree the strategic lines defined in various plans, as is the case of the PDM itself, but also of other important documents, such as the Carta Estratégica 2010–2024, Estratégia de Reabilitação Urbana 2011–2024 and Estratégia Regional de Lisboa 2030.

Spatio-Temporal Pattern of Urban Green Space in Chengdu Urban Center under Rapid Urbanization: From the Policy-Oriented Perspective

Urban green space (UGS) is increasingly recognized as a nature-based solution to achieving urban sustainable development. Under rapid urbanization, greening policies are often the main driving factor behind the restoration or even growth of UGS. In this study, Chengdu, the pioneering “park city” in China, is chosen as a representative region. Based on land use/land cover (LULC) and normalized difference vegetation index (NDVI) data, indicators that can reflect both UGS quantity and quality are constructed and the spatio-temporal characteristics of UGS in original and expanding urban areas are also explored at different greening policy stages. The findings show that, from 2000 to 2022, the basic trend of UGS reduction during urbanization remained unchanged, despite the greening policies implemented in Chengdu. However, the original urban area has evolved into a new urban area. This has been achieved by integrating the expanded urban area with higher greening rates, resulting in the greening rate in 2022 (44.61%) being restored to the 2000 level (44.21%). The implementation of green policies in Chengdu is primarily reflected in improved UGS quality, especially in the stage of the ecological garden city construction (2008–2018). Specifically, the UGS quality in the original urban area has been improved by 25.25%. Overall, the UGS quality in Chengdu Urban Center has improved, changing from a medium level in 2000 to a medium-high level in 2022. The construction of a national demonstration zone of the park city provides an opportunity for the UGS quantity to increase and quality to improve in Chengdu in the future. However, effectively considering the development positioning of the Tianfu Granary to coordinate the relationship between UGS and high-quality farmland is a huge challenge for urban sustainable development in Chengdu.

Urban Green Spaces in Bamako and Sikasso, Mali: Land Use Changes and Perceptions

Increasing land use and land cover change and climate change have considerable impacts on urban green spaces and their ecosystem services. These impacts result in a loss of urban green space and particularly weaken the climate resilience of urban populations. Landsat imagery data from 1990 to 2020 were used to track the spatio-temporal dynamics of urban sprawl and its influence on the loss of urban green space in Bamako and Sikasso in Mali. Furthermore, a survey of local stakeholders was conducted to capture the perceptions of the status of urban green space. The results of the land use/land cover analysis of the cities between 1990 and 2020 showed that most of the vegetation classes, mainly urban green spaces, have been converted into built-up and bare land in both cities during the last 30 years. In Bamako, built-up land has risen from 5421 hectares in 1990 to 13,350 hectares in 2020, and in Sikasso, from 929 hectares in 1990 to 2213 hectares in 2020. Respondents mentioned street trees as the prevalent type of urban green spaces in both cities (20% of the respondents in Bamako and 24% in Sikasso). In addition, the majority of respondents perceived urban green spaces in Sikasso as having a good status and in Bamako as having a good or moderate status. This study recommends improving the number and quality of urban green spaces, which are crucial for the provision of ecosystem services and for the resilience of cities against climate change.

A systematic review of resprouting in woody plants and potential implications for the management of urban plantings.

Naturalistic plantings, such as meadow-style plantings, can improve the quality of urban green spaces through aesthetic, biodiversity and low maintenance features. Species selection for, and maintenance of naturalistic plantings are key to their success. While herbaceous and grassy meadows can be mowed, naturalistic plantings with woody plants require more intense maintenance to remove biomass and promote resprouting. We aim to understand woody plant responses to diverse disturbance regimes to potentially inform the selection and management of woody species in urban plantings. We conducted a quantitative systematic literature review of 72 papers and investigated what main external (climate, disturbance regime) and internal (buds, life stage, storage reserves) factors influence the resprouting response of woody plants. We found resprouting literature is geographically widespread for woody plants, but studies are skewed towards Temperate climates in USA and Australia, with a focus on high severity and high frequency fire disturbance. Resprouting response was mostly defined as a continuous response to disturbance dependent on disturbance regime, climate and plant traits. Maintenance and management of naturalistic woody plantings, through hard pruning techniques such as coppicing, may be informed by analogous high severity and high frequency disturbance studies. However, the literature on woody plant resprouting has several knowledge gaps for lower severity and lower frequency disturbance regimes and in more arid climates. Future research should evaluate the response of naturalistic woody plantings to disturbance in specific urban contexts.

Stopover habitat quality of urban green space for migratory landbirds and the impact of urban wilding measures

Stopover habitat quality of urban green space for migratory landbirds and the impact of urban wilding measures

A silk-floss tree (Ceiba speciosa) provides an oasis for floral visitors in an otherwise hostile suburban-farmland environment

ABSTRACT Keystone components in green urban spaces can make a big difference in supporting either impoverished or rich animal communities. Trees that produce thousands of flowers at densities higher than that of herbs and produce much more nectar than the latter can be such keystone structures. However, there is a lack of specific information on trees, both native and alien, and their flower visitors in urban/suburban contexts, which blurs the conservation role that such species can perform. In 2019 and 2020, we thoroughly recorded the flower visitors to a silk-floss tree in suburban Guadalajara, Mexico. To our knowledge, this is the first comprehensive inventory of silk-floss tree flower visitors. We documented 79 species/morphospecies of insects; eight of birds, and one of mammals visiting the flowers. All, except two, are native to the region; three are endemic/quasi-endemic to Mexico. Besides direct and indirect floral resources, the silk-floss tree offered perches, resting/hiding cover, nesting substrate, and seed fibres used by several birds, and feeding substrate for gleaning insectivorous birds. Four species are on one or more conservation listings: monarch butterfly (endangered), pink-spotted swallowtail (vulnerable), sparkling-tailed hummingbird (threatened), and lesser long-nosed bat (near-threatened). Our data supports that small patches can enhance the quality of urban green spaces, and that rather than geographic origin, flower output drives visitation. Alien trees can be pollination enhancement ‘devices’ for imperilled pollination networks. Silk-floss trees are a potential option for conservation-oriented urban greening, as well as to contribute to enhancing human enjoyment of nature, and provide opportunities for public outreach.

Predicting context-sensitive urban green space quality to support urban green infrastructure planning

Urban green spaces (UGSs) support human health and well-being in diverse ways. In addition to their availability and accessibility, also the quality of UGSs is relevant for understanding human-environment interactions between urban populations and their local UGS. However, data on UGS quality are rarely available with the geographic coverage required for spatial decision making and urban green infrastructure (UGI) planning and management.This study uses data from a large-scale public participation GIS (PPGIS) survey to predict perceived UGS quality across the city of Espoo, Finland. The respondents (n 3,132) mapped over 8,500 frequently visited sites situated in UGSs. Generalized linear mixed models were used to study associations between the perceived place quality of the respondent-mapped sites and diverse objectively measured UGS characteristics. The presence of blue elements, high forest biodiversity, level of UGS maintenance, and low daytime noise exposure contributed to positive perceptions of UGS quality, while daytime noise exposure and decreasing UGS size were associated with negative perceptions.The model was extrapolated spatially to predict perceived UGS quality across the entire city, revealing local differences in the accessibility of high-quality UGS. The results exemplify how both UGS quantity and quality are relevant for understanding the mechanisms leading to UGS visitation and the health and well-being benefits gained from UGS use and exposure. Moreover, the study demonstrates how UGS characteristics valued by the local population may be identified to support local UGI planning and management.

The natural focus: Combining deep learning and eye-tracking to understand public perceptions of urban ecosystem aesthetics

Public perceptions of ecological aesthetics are a crucial component in evaluations of the quality of urban green spaces (UGSs) and in guiding urban planning, design and renewal practices. In this paper, we propose a novel methodological framework that combines deep learning and eye-tracking to investigate the relationships between landscape elements, features, visual focus and public ecosystem aesthetic perceptions of UGSs. Our Public Ecosystem Aesthetic Perceptions (PEAP) model emphasises interactions between ecosystem quality and landscape aesthetic quality. To validate the model, we conducted a study in Shanghai, China, where we selected 54 representative UGSs for photography, perception surveys, and image processing. The results demonstrated that visual focus acts as a mediator between landscape stimuli (landscape elements and features) and perceptions of ecosystem aesthetics. Notably, we found that natural elements elicited significantly stronger visual focus than artificial elements. Thus, our PEAP approach can enhance understanding of aesthetic qualities of landscapes and ecological qualities of urban ecosystems, enabling creation of more aesthetically pleasing and ecologically sustainable UGSs.

Developing a Qualitative Urban Green Spaces Index Applied to a Mediterranean City

As a primary goal, urban green spaces (UGSs) have been linked to several aspects of inhabitants’ wellbeing. Quality could be a way to intervene in the UGS–human health interaction. For that purpose, we developed an urban green space quality index (UGS QIndex) applied to a Mediterranean region, Sousse City. This index was based on a set of criteria, indicators, and elements chosen after bibliographical research related to UGS quality assessment tools and their contribution to the Sustainable Development Goals. Then, we evaluated the quality of the Sousse Ramparts Gardens using the UGS QIndex. In fact, this index includes 41 elements grouped into 23 indicators covering seven thematic criteria: environmental regulating capacity, functional amenities, aesthetic amenities, landscape features, integration in its surroundings, development policy objectives, and space issues. According to the UGS QIndex, Bab El Gharbi garden exceeds Bab El Finga garden in terms of its scenery, aesthetics, and functionality. This index could be used by city planners to improve their UGS’s capacity to satisfy the inhabitants’ requirements. Otherwise, it needs to be enhanced and tailored to various types of UGSs and then applied to other Mediterranean cities, as well as cities suffering from UGS degradation.

Association between UGS patterns and residents' health status: A report on residents' health in China's old industrial areas

BackgroundOld industrial areas have low quality and spatial differentiation of urban green space (UGS), which makes it difficult to meet the public's physical activity needs and leads to increased health risks. The purpose of this study is to explore the equity of UGS patterns in old industrial areas and its internal relationship with residents' health status. MethodsThis study selecteds relevant indicators to evaluate the equity of UGS patterns in the Harbin area and used linear regression analysis to explore the correlation between attributes of old industrial areas and UGS patterns. Additionally, this study explored the spatial correlation of UGSs using Moran's index and hotspot analysis. Finally, a report on residents' health was generated through a questionnaire survey, using linear regression analysis to explore the factors affecting residents' self-rated health and the significance of their correlation. ResultsThe results showed that there is an excess supply around the core industrial zone in the west, while the rural areas in the south face a serious shortage of supply. The significance between the factors representing age and income in industrial attributes and UGS pattern was less than 0.05. We observed that residents' self-rated health was positively affected by the intensity of physical activity (low intensity B = 2.073, medium intensity B = 2.359, high intensity B = 2.512) and the frequency of physical activity (B = 1.174). Ages (B = −0.597) and three generations living together (B = −3.191), which represent the industrial attributes, had a negative impact on residents' self-rated health. ConclusionTo a certain extent, industrial attributes aggravate the mismatch of UGS patterns, leading to abnormal areas in spatial clustering. The quality of UGS in the old industrial zone is low and the movement is not strong; thus, the population characteristics and income have become the important factors affecting the health of residents.

The influence path of community green exposure index on activity behavior under multi-dimensional spatial perception.

The purpose of this research is to reveal the internal relationship among community green space, space perception, and activity behavior response to supplement the lack of research results on the binary relationship between green space and behavior. Nine residential community green spaces and 398 residents were selected as the research objects. Thematic clustering and factor identification were used to determine the spatial dimensions of community green space that residents were concerned about. The analysis of the green exposure index, spatial perception evaluation, and activity behavior survey were combined to determine the influence of the green exposure index on spatial perception and activity behavior and its internal correlation path. According to research data, the community green view index (GVI) and normalized difference vegetation index (NDVI) negatively affected the perception factor, while the perception factor positively affected the activity frequency. The SEM model shows that the green exposure index stimulated activity behavior through the intermediate effect of the internal perception path of perceived landscape quality, perceived workability, and perceived accessibility. Spatial perception as the basis of the instantaneous emotional reaction process may affect people's choices for activities but be unable to extend the duration of the activities. The internal association among community green space, spatial perception, and physical activity behavior develops on the basis of spatial patterns at certain scales. This study provides a theoretical basis for understanding the spatial experience and residents' behavioral needs, evaluating the quality of urban green space scientifically, and promoting the optimization of community green space structure.

Reinventing the Urban Neighborhood Green Index in the Context of Urban Ecology as a Conceptual Framework in Northern Nicosia, Cyprus

Today, one in two people live in urban environments, and this number is expected to rise. Urban ecology is among the main concepts of the ecological urban planning agenda for cities where the consequences of global warming and climate change are increasing day by day. Urban open green spaces provide a variety of ecosystem services for city dwellers. It is important that green spaces are accessible, efficient, walkable and properly planned in the city. Within this framework, via the relevant theoretical evaluation, a conceptual framework was constructed to redefine the urban neighborhood green index. Regarding the existing definitions within the related literature, this developed index includes quantitative, qualitative and perceptual parameters and has been newly introduced to measure and analyze green spaces in a more comprehensive layout. There is also a need to establish an ecological approach to urban planning to increase the quantity and quality of urban green spaces in Cyprus, including in Northern Nicosia. Therefore, Northern Nicosia, with its three selected neighborhoods, was chosen as the study area. As the main methodology of the study, a thorough assessment of the quantitative component of the developed index with its four parameters of per-capita green space, proximity to green space, area percentages and type of green spaces is made. Maps from the Town Planning Department and satellite images from the Nicosia Turkish Municipality and GIS were used for this quantitative measurement. Based on the findings, it can be argued that the urban green spaces are not sufficient when assessed based on most of the parameters evaluated within the study to construct a comprehensive green space index. It was found that the green spaces in the city are accessible, being within 337 m, which is reasonable. However, there are very few active and accessible open green areas in these neighborhoods within the 300 and 500 m buffers, as a remarkable number of the green spaces, which are shown on the map, are in an abandoned condition. In addition, the amount of active green space per capita is 3.35 m2, which is well below the 9 m2 predicted by WHO. The area percentages of the neighborhoods are also below the required standards. Therefore, the findings show that Northern Nicosia can benefit by addressing these deficiencies to achieve a higher urban neighborhood green index. Furthermore, the theoretical model is efficient for the assessment of urban spaces at the neighborhood scale and can be used in other cities worldwide, especially in cities with a relatively low density. In sum, this study, which considered not only the quantitative parameters but also the qualitative and perceptual features, has the potential to expand scientific knowledge on measuring and analyzing urban neighborhood green spaces.

Quality of urban green spaces and nutritional status: an epidemiological study in an urban context using Street View technology

Quality of urban green spaces and nutritional status: an epidemiological study in an urban context using Street View technology

Integrating public perceptions of proximity and quality in the modelling of urban green space access

Access to urban green space (UGS) is associated with a number of physical and social benefits. Recognizing the importance of UGS access for people’s wellbeing, several methods have been proposed to model UGS accessibility and highlight areas underserviced by UGS. However, existing methodologies have several limitations. Models often make use of universal, normative maximum travel distances, which may not reflect the distances people actually travel to reach UGS they regularly visit. Additionally, many of these analyses do not consider UGS quality, which will largely influence use and experience of these spaces and may act as a pull factor affecting the distance people are willing to travel to visit a UGS. Those methods that do integrate quality often rely on proxies, such as size or number of amenities, and fail to consider perceived quality. To address these limitations, we propose a methodology that integrates user perception and the actual distance people are prepared to travel into a quality-accessibility (QA) analysis applied at the building block scale. Information on travel distance and quality are gathered from a public participation GIS survey conducted in the Brussels Capital Region. The results of the analysis highlight inequalities in access to specific, essential UGS experiences throughout the region. Insights provided by this analysis can help planners prioritize interventions to improve access to experiences provided by UGS in parts of the city where interventions are most needed.

Urban Renewal Path, Streetscape Enhancement, take green as a Strategy: a case study in Mong Kok

Rapid urbanization and high-density development will continue to reduce people's access to nature, which has aroused people's concern about the quality of urban green spaces. Urban green spaces have been recognized as a vital element in enhancing the overall livability and aesthetics of cities. As an integral component of urban green space, street greening is a commonly employed strategy within streetscape enhancement, with the aim of enhancing the overall appearance and functionality of urban streets. However, strategies for green spaces as a common enhancement method along street environments should be reevaluated. This paper aims to investigate how open spaces can play a crucial role in enhancing street environments and address the challenges of limited public space in high-density cities like Hong Kong. The study is conducted in Mong Kok, in Hong Kong which serves as a unique example of high-density urban streets. In the context of the urban framework from 1950s, Mong Kok's spatial constraints coexists with its continuous and vibrant street facades, giving rise to its unique Mong Kok culture and becoming a distinctive emblem of Hong Kong’s street character. Based on the present situation and challenges of public open space in Hong Kong and the review of international cases, theories and policies, this paper discusses the methods to strategize the shortage of urban public space while improving its quality. As a result, more opportunities will be provided for leisure and social interaction and ultimately enriching the quality and sustainability of public realm as a whole.