An Assessment of the Knowledge and Demand of Young Residents regarding the Ecological Services of Urban Green Spaces in Phnom Penh, Cambodia

The fast and steady economic growth and social changes in recent years in Cambodia have brought rapid expansion and restructuring to its cities. These phenomena have brought numerous challenges including threats to urban green spaces (UGS's). This study addresses problems of UGS's by investigating the knowledge and perceptions of young residents of Phnom Penh (YRPPs) toward UGS's in relation to the following: (1) basic knowledge of YRPPs on ecological services (KES) of UGS's; (2) perceptions of YRPPs on the current state of UGS's (PUGS's) in Phnom Penh; (3) demand of YRPPs for UGS's in the city (DUGS); and (4) associations between KES, PUGS's, social profiles (SoPs), and DUGS. A questionnaire was designed to solicit knowledge from 554 respondents randomly selected from the study area. The findings revealed that 83.1% of total respondents strongly recognized ecological services of UGS's. Four subgroups of ecological services, namely microclimate (89.7%), environmental quality and functions (83.8%), recreational and public health services (88.5%), and economic benefits (70.4%) were all rated highly. Because the current state of UGS's was very poor (68.4%), demand for UGS's was high (94.43%). Public toilets (84.7%) and rubbish bins (75.6%) were both rated the poorest. The PUGS's were significantly associated with KES (r = 0.307, F (3, 543) = 18.83, p < 0.001). This study offers a deep understanding about knowledge and demand of YRPPs for UGS's.


Introduction
The fast and steady economic growth and social changes in recent years in Cambodia have brought rapid expansion and restructuring of its cities.The phenomena have raised numerous challenges including the loss of urban green spaces (UGS's).Urban green spaces (UGS's) are key components of the ecosystem services that clearly contribute to the improvement of quality of life, public health, landscape design, and environmental quality [1][2][3][4][5].There are many studies that affirm the benefits of ecological services of UGS's to residents [6][7][8][9][10][11].Some important ecological services of UGS's are the promotion of the well-being of people [12][13][14][15][16][17][18][19], recreational activities [20,21], the mitigation of high temperatures [6,[22][23][24], the abatement of air pollution [25], the sequestration of CO 2 and release of more O 2 [5,26], noise reduction [22], the provision of wildlife habitats [27][28][29][30], the prevention of flood and soil erosion [31], the improvement of city amenities [32,33], and an increase in property (land and house) values [34][35][36][37].However, many of these benefits are determined by the different levels of species group, canopy cover, size, and shape of UGS's [38].Notably, the above studies only focused on roles and benefits of UGS's to people, and there is scant research regarding perceptions and knowledge of people toward UGS's, particularly from a perspective of people living in developing countries [7,[39][40][41].A study of perceptions and attitudes of residents toward UGS's in Guangzhou by A.Y.H. Lo and C.Y. Jim suggested that research to deepen the understanding of public perceptions toward UGS's is needed in order to design and plan suitable and amenable urban areas for people to live in [42].Additionally, understanding people's needs and expectations of UGS's have important policy and cost-effectiveness implications.Assessing user feedback, attitudes and behavior could help in designing UGS's that are socially relevant and inclusive [42,43].Furthermore, many of the above studies mainly investigate perceptions and attitudes of people in general and do not reflect a specific group of the population.The lack of relevant knowledge and different social and cultural context of users could affect their attitudes and behavior toward UGS's.The level of people's knowledge and perceptions of the use of UGS's may also influence demand and decision-making behavior.It is of great interest in Cambodia due to scarce information about this issue.Therefore, this study aimed to contribute more insight into basic knowledge and the use of UGS's in a fast growing city in Cambodia.The study sought to fill in this gap from perspectives of young residents of Phnom Penh (YRPPs) by addressing the following research purposes: (1) to examine the knowledge of YRPPs toward ecological services of UGS's (KES); (2) to investigate perceptions of YRPPs toward the state of current green spaces (PUGS's) in Phnom Penh; (3) to identify the demands of YRPPs for the design of UGS's (DUGS) in the city; and (4) to find the associations between KES, PUGS's, social profiles (SoPs), and demand for green space (DUGS).

Study Area
Phnom Penh is the capital city of Cambodia with an area of 678.47 km 2 , equal to 0.37% of the country's total landmass of 181,035 km 2 .It sits on a flat alluvial flood plain on the western bank of the great Mekong River, where it is easily flooded during the rainy season.To the north, west, and south of the city are ring roads that are built as dikes that protect the city from seasonal floods [44].The average temperature is 29 ˝C with precipitation of 1493.70 mm/year (2011).Phnom Penh is the fastest growing urban area in East Asia and has been growing at a rate of 4.4% per year from 920,000 to more than 1.4 million people between 2000 and 2010, reaching more than 1.8 million in 2012.The population aged 15 to 35 represents 46.41% of the urban population [45].Due to the rapid pace of development and the number of people flocking to the city for work, study, and living in recent years, Phnom Penh has expanded its administrative areas from 7 districts (Khans) and 66 communes (Sangkat) in 2008 to 12 districts, 96 communes, and 909 villages in 2013 (See Figure 1) [46].
In Cambodia, self-employment in small business and agriculture is common, and it is hard to gather accurate income data for these types of employment.About 45.3% of Cambodian people, of whom people whose ages are 15-64 years were mainly employed in the agricultural sector as skilled agricultural, forestry, and fishery workers, represented the largest percentage of the total employed population in 2014.The average wages and salaries per month varied considerably between the different geographical domains in Cambodia.Specifically, the average wages and salaries of Phnom Penh residents per month was 1,385,000 riels in 2014 (about US$ 340; US$ 1 = 4065.04riels) [47].

Questionnaire Design and Measurement
This was a questionnaire-based, quantitative study.It employed a self-selected sample, which is a non-probability sampling technique.A web-based questionnaire, a new kind of research method via the Internet [48], was designed.Additionally, the questionnaire consisted of four parts: Social profiles (SoPs) of YRPPs including information such as gender, age, level of education, employment, and income (in USD) were addressed in Part 1.The basic knowledge of YRPPs toward ecological services (KES) of UGS's was elicited in Part 2. In this part,19 items of ecological services were adopted from the studies by Miller [49] and C.Y. Jim and Wendy Y. Chen [1].The degree of KES was measured by using ordinal numerical 4-Likert scales ranging from "not important (1)" to "very important (4)", whereas Part 3 sought the perceptions of YRPPs on the current state of UGS's (PUGS's) in Phnom Penh by allowing 5 options on the Likert scale, ranging from "strongly disagree (1)" to "strongly agree (5)".The last part of the questionnaire was to identify YRPPs' demand for UGS's (DUGS) in the capital.Respondents were given 5-Likert scales, ranging from "no need at all (1)" to "strongly needed (5)" for this part.

Samples and Procedures
The questionnaires were first sent via Facebook, Wechat, and e-mail to 150 randomly selected respondents.These first respondents were requested to re-share the questionnaire to at least two of their friends to fill in the questionnaire.At the same time, three undergraduate students were clearly instructed by a researcher about the study purpose and questionnaire.They carried out face-to-face interviews with about 350 respondents.All respondents who live in Phnom Penh were eligible to participate in this study.The questionnaire was designed in both English and Khmer (Cambodian language) languages, with clear guidelines and easy-to-understand statements from which respondents could choose to express their perceptions and attitudes toward UGS's.

Data Analysis
The data collected was analyzed using IBM SPSS v.20 (IBM, Armonk, NY, USA).Descriptive statistics were used to examine the respondents' characteristics, perceptions, and attitudes.

Questionnaire Design and Measurement
This was a questionnaire-based, quantitative study.It employed a self-selected sample, which is a non-probability sampling technique.A web-based questionnaire, a new kind of research method via the Internet [48], was designed.Additionally, the questionnaire consisted of four parts: Social profiles (SoPs) of YRPPs including information such as gender, age, level of education, employment, and income (in USD) were addressed in Part 1.The basic knowledge of YRPPs toward ecological services (KES) of UGS's was elicited in Part 2. In this part, 19 items of ecological services were adopted from the studies by Miller [49] and C.Y. Jim and Wendy Y. Chen [1].The degree of KES was measured by using ordinal numerical 4-Likert scales ranging from "not important (1)" to "very important (4)", whereas Part 3 sought the perceptions of YRPPs on the current state of UGS's (PUGS's) in Phnom Penh by allowing 5 options on the Likert scale, ranging from "strongly disagree (1)" to "strongly agree ( 5)".The last part of the questionnaire was to identify YRPPs' demand for UGS's (DUGS) in the capital.Respondents were given 5-Likert scales, ranging from "no need at all (1)" to "strongly needed (5)" for this part.

Samples and Procedures
The questionnaires were first sent via Facebook, Wechat, and e-mail to 150 randomly selected respondents.These first respondents were requested to re-share the questionnaire to at least two of their friends to fill in the questionnaire.At the same time, three undergraduate students were clearly instructed by a researcher about the study purpose and questionnaire.They carried out face-to-face interviews with about 350 respondents.All respondents who live in Phnom Penh were eligible to participate in this study.The questionnaire was designed in both English and Khmer (Cambodian language) languages, with clear guidelines and easy-to-understand statements from which respondents could choose to express their perceptions and attitudes toward UGS's.

Data Analysis
The data collected was analyzed using IBM SPSS v.20 (IBM, Armonk, NY, USA).Descriptive statistics were used to examine the respondents' characteristics, perceptions, and attitudes.Relationships among constructs were analyzed by using one-way analysis of variance (ANOVA), bivariate correlation, and multiple regression models.

Social Profiles of YRPPs
A total of 321 online samples were received from respondents among which 229 were fully completed with a response rate of 71.33%, whereas 343 face-to-face interviews were carried out, of which 325 were fully completed with a response rate of 94.75%.The online response rate was lower than face-to-face interviews due to Internet accessibility problems.Completed samples totaled 554 (female = 54.2% vs. 45.8%,Median = 2, SD = 0.499) with a response rate of 83.04%, and the reliability of Cronbach's alpha was 0.749.

Knowledge Base of YRPPs on Ecological Services Generated by UGS's
The division of 19 ecological services into four groups and the calculation of each group average score revealed the relative importance attached to different attributes and groups.Most of the respondents rated ecological services "very important", of which some services were rated remarkably high.The rates of "very important" and "important" to every individual service varied from 56.2% (noise abatement) to 94.2% (lower temperature and aesthetic enhancement).The highest average group score was 53.3% for recreation and public health and 45.4% for the microclimate that respondents rated "important" and "very important", respectively (Table 2).The less tangible and indirect services, namely, O 2 release (60.5%,Mean = 4.52, Median = 5.0, SD = 0.673) and CO 2 sequestration (57.2%, Mean = 4.49, Median = 5.0, SD = 0.665) were rated highest as "very important" services.Gathering and networking services (59.0%,Mean = 3.89, Median = 4.0, SD = 0.801) received high scores followed by increased humidity and opportunities to contact with nature (57.8%,Mean = 4.17, Median = 4.0, SD = 0.765).Species conservation was also scored very high (55.6%,Mean = 4.41, Median = 4.0, SD = 0.768), which was similar to the air pollution absorption (52.3%, Mean = 3.78, Median = 4.0, SD = 0.844).a Rank of each service was basically on the percentage of each service in the column of "very important".
Notably, respondents strongly recognized the recreation and public health services provided by UGS's.They rated recreational places (54.7%, Mean = 4.22, Median = 4.0, SD = 0.686) and public health improvement (49.6%, Mean = 4.38, Median = 4.0, SD = 0.640) very high.However, it was noticed that respondents seemed not to recognize the economic benefits such as an increase in asset value (15.9%,Mean = 3.76, Median = 4.0, SD = 0.811) and boosting small establishments (21.7%, Mean = 3.90, Median = 4.0, SD = 0.788), which were not rated as highly.Noise abatement received a lower score, rated by respondents after economic benefits of UGS's.
Overall, on average, only 3.7% of respondents chose "not important", ranging from 0.9% for air pollution absorption to 8.1% for gathering and networking.Meanwhile, on average, 13.3% of respondents chose "not sure" with the highest proportion on noise abatement (26.0%).Controversially, the majority of the respondents chose "important" (47.9%) and "very important" (35.2%), showing that 83.1% of respondents strongly recognized the important roles of UGS's in generating ecological services.

Associations between KES, PUGS's, SoPs, and DUGS
The relationships between KES, PUGS's, SoPs, and DUGS are shown in Table 5.The bivariate correlation analysis showed that DUGS was positively correlated with KES (r = 0.295, p < 0.001), and SoPs were also significantly positively correlated with KES (r = 0.130, p < 0.001), but DUGS was not significantly correlated with PUGS's (r = ´0.087,p < 0.05).Furthermore, the multiple regression analysis showed that only KES was positively correlated with DUGS (r = 0.307, F (3, 543) = 18.83, p < 0.001), while other PUGS's and SoPs were not (p > 0.05).Therefore, the strongest predictor for DUGS is KES (b = 0.301, p < 0.001), but only a 9.4% variance of DUGS (r 2 = 0.094) can be explained by KES; therefore, DUGS can be explained by other variables.The DUGS would increase 0.301 (b = 0.301) if there were an increase in KES.The PUGS's and SoPs were not good predictors of DUGS, so they could be deleted.

Discussion
The results revealed that 83.1% of respondents (YRPPs) strongly recognized the important roles UGS's play in generating ecological services for environmental, social, and economic benefits.The ratings were different from one service to another (the highest was 60.5% on O 2 release, while the lowest was 15.9% on increasing property value).Although the population of this study consisted only of young residents, which thus does not represent the points of view of the entire population of the city, this result is consistent with many other studies on the perceptions and attitudes toward UGS's indicating that perceptions and attitudes toward UGS's are complex and have different psychological points of view related to age, race, religion, gender, education, income, and experience [5,[39][40][41]50].Realistically, the different social contexts and backgrounds of respondents would also influence the perceptions and attitudes toward UGS's.For example, a study by C.Y. Chen and W. Y. Chen in Guangzhou, China, indicated that, although the importance of ecosystem services to wildlife habitat and species conservation were rated very low, and the use of green spaces to demarcate the different types of landscape and land use was hardly noticed or appreciated by the residents, UGS's were strongly recognized by Guangzhou residents [1].Another study of urban park use in England and Wales pointed out that the overwhelming popularity of natural features were reminiscent of an ideal rural arcadia [5,51].A study of the urban forest in Finland revealed that the benefits related to nature were valued most, outdoor activities were rated important, and climate and environmental quality such as pollution mitigation and noise abatement were the least important [52].Consistently, a study in Mandeville city in New Orleans, USA, about residents' attitudes toward urban forestry showed that aesthetic value and shading were rated the most important, whereas wildlife habitat, the amelioration of urban climate, and the increase in property values were rated important.The benefits related to environmental quality, such as the control of dust, wind, and storm water, were ranked low, while economic values of UGS's were rated the least important in both Finland and Mandeville [5,52,53].
If basic knowledge about UGS's increase, the demand for UGS's may also increase.The results of this study revealed that 94.43% of YRPPs demanded in the city (34.9% rated them as "needed", and 59.51% rated them as "strongly needed").It was statistically consistent with the result that 83.1% of YRPPs recognized the importance of the ecological services of UGS's.By contrast, the current state of UGS's in Phnom Penh was not satisfactory for residents of this city.For instance, 58.7% of YRPPs rated them as "poor", and 9.7% rated them as "very poor", due to the basic characteristics and services of UGS's.The highest percentage of poor quality ratings of the components of UGS's were given to public toilets (75.3%) and rubbish bins (70.4%).This suggests that the government should offer sufficient public toilets and care more about waste management in UGS's of the city so that its residents can access comfortable recreational places freely.A percentage of 61.1% of respondents felt strongly that the government must not only guarantee the quality but also the safety of UGS's for visitors.
Differences in perceptions of the current state of UGS's and social profiles of respondents such as gender, income, education, and age were not statistically significant with the demand for urban green spaces; however, demand will likely increase when YRPPs increasingly recognize (KES) the important roles of UGS's (r = 0.307, F (3, 543) = 18.83, p < 0.001).In addition, this demand would also increase if the perception of YRPPs toward the current state of UGS's were to positively increase.

Conclusions and Implications
The findings of this study revealed that the majority of YRPPs strongly recognized the ecological services of urban green spaces (UGS's).The study also pointed out the perceptions of YRPPs toward the current state of UGS's in Phnom Penh, where YRPPs rated its quality as "very poor".Relationships between social profiles, the basic knowledge of respondents of ecological services, perceptions toward UGS's, and the demand for UGS's were examined.Statistically, respondents' social profile factor was significantly associated with the basic knowledge of ecological services such that the stronger the knowledge the respondents had on ecological services, the higher the demand for urban green spaces they had.These findings are consistent with similar studies conducted elsewhere, where UGS's were usually perceived to bring multiple benefits other than negative impacts [1,19].
Ecosystem services of UGS's in Phnom Penh are not equally appreciated by the people and government.Inevitably, accessibility to the current UGS's for recreational activities in Phnom Penh still lags behind.Thus, the findings suggest that public preference and attitude concerning UGS's are circumscribed by two factors.First, there is a universal human desire to redesign the tenuous link between humans and nature; second, there is acquired cultural influence on the functions of UGS's in cities.The amount of information, knowledge, and experience that residents have affects responses and behaviors [1].Therefore, this study suggests government and policy makers in Cambodia, and real estate developers, should pay more attention to the attachment of more green spaces to their projects in the city.Not only do more UGS's improve city amenities, environmental friendliness, and the public health of residents, but they also attract users and investors and improve property values [53].

Table 1 .
Social profile of respondents of Phnom Penh.

Table 2 .
Basic knowledge of residents of Phnom Penh toward ecological services of urban green spaces (UGS's).

Table 3 .
Perception of young residents of Phnom Penh (YRPPs) toward current state of UGS's. PUGS'

Table 4 .
The demands of YRPPs for UGS's.

Table 5 .
Correlation between KES, PUGS's, SoPs, and DUGS.KES = Basic knowledge of YRPPs on ecological service, PUGS's = perception of YRPPs on the current state of urban green spaces, SoPs = social profile of respondents, DUGS = demand of YRPPs for urban green spaces.b * p-value < 0.05 was significant, ** p < 0.001 was significant. a