Hongkongers’ Perceptions of Urban Green Space Plants and Biodiversity

As the world talks about biodiversity, the conservation of native species has become a major issue. Native plants provide food and ideal habitats for various animals and microorganisms; animals in turn disperse the seeds, creating a mutually beneficial environment for future generations to flourish. Such habitats support a wide variety of animal and plant species, provide a more stable ecological environment, and avoid the problem of species homogenisation, thus enhancing fauna and flora diversity in the vicinity. Native plants, also known as indigenous plants, are resistant to local diseases and pests, and require less watering, fertilising and pest control. If used for urban greening, they would produce lower urban carbon footprint than exotic species. A recent study published in the journal Nature suggests that a diverse forest can raise the soil carbon storage and nitrogen storage for over a decade.

Earlier, I assessed plant species diversity in Hong Kong's urban green space (UGS), and found that more than 70% of the plants are exotic species, and only about 20% are native species.

Understanding how the public evaluates UGS attributes and plant species characteristics can provide reference for green space designs that meet public expectation. In another study, I surveyed 827 adult Hong Kong residents to assess their perception of UGS attributes and plant species.

The results revealed that most people have different levels of misconceptions about native and exotic plants. Most people thought "exotic plants can provide corresponding food source for native wildlife", but the fact is, exotic plants cannot provide food source that fully meets the needs of native wildlife. Some rare animals depend on certain native plants for their survival, such as the red lacewing butterfly and its host plant king snake creeper; the white dragontail and Illigera celebica; the golden birdwing and India birthwort. If the host plants which the animals feed on disappear, the survival of the animals will also be threatened.

The public's intention is vital to the concept design of public green space. Therefore, this study was conducted using Principal component analysis (PCA) and Cluster analysis (CA) to allow for better generalisation.

Evaluation of UGS attributes

Based on the evaluation of UGS attributes, respondents are categorised into three groups: Ecological group (31%), Eclectic group (33%) and Pragmatic group (36%). The study shows that among the many design considerations, safety, naturalness and environmental friendliness of UGS are more important to the public, while the nurturing of wildlife is less important.

Three variables (plant species knowledge, gender, and education level) are statistically correlated with respondents' ratings of UGS attributes. There were fewer women than men in the ecological group, and women rated the pragmatic attributes (safety, space design, and adequacy of facilities) higher. One possibility is that women are more likely to take their children to parks and are therefore more concerned about safety and facilities. It proves that people’s motivation for UGS use affects their attitude towards its design. The ecological group has a better plant species knowledge, whereas the pragmatic group is less knowledgeable in this field. Plant species knowledge is positively correlated with the assessment of green attributes (environmental conservation, natural scenery, plant species diversity, nurturing of wildlife) and negatively correlated with the assessment of pragmatic attributes. Meanwhile, respondents belonging to the eclectic group (give high ratings on all attributes) are generally less educated, but there is no significant difference in the ratings of green and pragmatic attributes by education level.

Ecological group emphasised natural scenery rather than artificial elements, and regards UGS as a place to experience nature and nurture urban ecology. Ecological group expects plant species in UGS to be of high conservation value, while pragmatic group expects plant species to be "harmless”— safe (non-toxic/thornless), attracting no pests and dangerous insects, and producing no nuisance. The results can be used as a reference for UGS's plant selection strategy to fulfill different functions and cater for target users.

Hongkongers’ Evaluation of Plant Species Characteristics in UGS

Based on the evaluation of plant species characteristics, respondents can be categorised into three groups: Conservation supporters (23%), All-round perfectionists (43%) and Safety defenders (34%). In terms of plant species characteristics, all-round perfectionists account for over 40% of the respondents, and most of the respondents considers all positive plant characteristics to be important. However, it has been found that while the public hopes green plants could provide food source for urban wildlife, plant characteristics of native plants are also the least important consideration. Such contradiction reflects the public's misperception, which ignores the importance of native plants in greening. Therefore, we should actively promote the benefits of native plants and inculcate proper knowledge of greening to the public, so as to achieve ecological harmony in the city.

All three categories of respondents agree that "the selection of plant species for public green space in Hong Kong lacks variety ". Respondents who emphasise the conservation value of plant species (i.e. conservation supporters) are particularly concerned about the selection of plant species, expressing dissatisfaction with the current selection strategy.

For dense cities like Hong Kong, landscape architects and greening managers may consider adopting dualistic zonation with different attributes in large urban parks:

·Natural Ecology Zone: A naturalistic or ecologically designed core area, where suitable native plants or plants with high ecological and conservation values (such as fleshy-fruited, thorny plant species) are planted with minimal horticultural input.

·Recreational Facilities Zone: Adopt a general horticultural design and intensive horticultural management in areas with high density of recreational and fitness facilities, catering for the fitness and socialising needs of people of different ages, as well as the physical and psychological security towards plant choices for people using the area.

The findings here can help improve the design and plant selection of UGS. Equipping one park with diversified design features can meet different expectations and needs of the residents, so that the general public can enjoy the wildlife even without having to go to country parks.