The scaling down of landscape maintenance during the Circuit Breaker helped create an outburst of urban biodiversity - an important indicator of a city’s ecological health and resilience. However, should this state of unmanaged Nature – seen by some as messy & posing safety risk – be the objective? With her research, Yun Hye Hwang, an Associate Professor in National University of Singapore’s Master of Landscape Architecture programme, advocates a middle way: applying landscape design principles & long-term maintenance practice that encourage spontaneous flora diversity, yet experiment to find a degree of naturalness accepted by the public. This article explores how Singapore’s landscape architecture practice may adopt these principles to create ecologically robust, managerially sustainable urban greenery.
Along with the spotlight casted on the climate & biodiversity emergency, the byword “City in Nature” becomes increasingly familiar. Part of the Singapore Green Plan 2030, restoring Nature into the urban fabric is supposed to create a liveable, ecologically sustainable & resilient city to mitigate the impacts of climate change. Beyond Singapore’s designated nature reserves, landscapes such urban parks & Park Connector Network, skyrise greenery, streetscape, and green verges make up a large network of greenery with immense capacity to increase ecological connectivity & health, create diverse habitats, and perform ecosystem services.
One way to utilize this capacity is to incorporate spontaneous vegetation into urban greenery. The Circuit Breaker and its accompanying absence of landscape management provided an island-wide experiment of letting natural growth proliferate. The result? Increased wildflowers population was swiftly followed by increased fauna diversity – bees, butterflies, dragonflies, birds etc. However, despite nature enthusiasts voicing their approval and petitioning for a scaled-back maintenance, the ‘messy’ lawns were eventually back to their usual neatness. Potential issues such as dengue control operations and fire hazard during dry weather were cited as reasons. Can a city exist ‘in Nature’ without adopting Nature’s inherent properties - messy, unpredictable, teeming with redundant members?
Perhaps, the best approach to harness the ecological potential of spontaneous flora diversity in urban greenery is neither a lack of consideration for it in design & management, nor a fully hands-off, ‘leave Nature untouched’ mindset. Recent research by Assoc Prof Hwang Yun Hye takes a closer look at short-term vegetation changes in three of Singapore’s urban parks, and her findings may help landscape architects better understand the opportunities & challenges in incorporating natural growth to design more sustainable landscapes.
Her research, titled ‘Short-term vegetation changes in tropical urban parks: Patterns and design-management implications’, compared three urban parks to study how their initial design, followed by management activities, influence subsequent flora & fauna biodiversity. The sites of Bishan- Ang Mo Kio (AMK) park, Enabling Village and Esplanade Forecourts were selected as they are urban parks with comparatively naturalistic & diverse planting schemes, conventional maintenance activities and available records of planting upon completion of construction.
Observations and vegetation biodiversity surveys were conducted in 2018 at four selected areas – two from Bishan park and one each from Enabling Village and Esplanade Forecourts. The team also studied ‘Before’ and ‘Current’ (as of 2018) photographs (Fig. 3 – Fig. 6), did field investigations, and conducted interviews with the parks’ landscape managers on the maintenance regime (Fig. 7).
The vegetation survey findings were documented in a series of maps & graphs (Fig. 8 and Fig. 9) and analysed. In all the sites, vegetated areas & species richness increased over time despite regular maintenance regime, with both native & non-native species taken into consideration. Several key findings:
- Plots along the water edge at sites Bishan-AMK park and Enabling Village showed the most diversity increase, which could be due to plant dispersal by fluctuating water flows & aquatic ecosystems encouraging floral diversity.
- Areas under planted trees are generally well-established. This microhabitat is conducive to higher plant diversity, probably because in tropical climate there are naturally growing shade-loving plants.
- Open lawns in Bishan -AMK park and vegetated areas in Esplanade Forecourts heavily managed for aesthetic & safety reasons showed least increase in biodiversity.
- The vegetation changes above are also influenced by different maintenance methods & frequencies applied at different areas
From the findings, several principles can be derived to guide landscape architecture practice in accommodating dynamic vegetation changes, while managing public perception. A combination of the research team’s recommendations and this article author’s suggestions are laid out below:
a) Design urban green spaces with the potential to accommodate heterogeneous habitats
All urban landscapes can inherently contribute to the city’s biodiversity. As such, green & blue elements can be allocated to create various microclimates within the site, to attract/ accommodate particular flora & fauna - considerations include landforms, soil types, shade/ light conditions, open/ enclosed surroundings, configuration & ecological function of planting. For example, creating shaded microhabitats under trees or next to buildings using plant as food sources, or allocating diverse, naturalistic planting along water edge to attract fauna such as dragonflies & certain birds, etc. The combination of such semi-natural urban green spaces can work synergistically with existing natural areas to have a positive impact on the city’s ecological systems as an organic whole.
b) Strategic placement of ‘light touch’/ less intensively maintained areas
To encourage natural growth and further increase types of microhabitats on site, maintenance frequency can be reasonably reduced to let plants overgrow. While this is easier to apply in parks setting, designers may also consider allocating non-accessible, less visible green spaces for such ‘light touch’ maintenance, for example extensive roof gardens. As long as such areas look reasonably neat from a distance, the public may accept a degree of “messiness”. Designing a neater landscape around more naturalistic planting areas can also communicate ‘cue of care’ that the area is well kept, with more frequent maintenance of the perimeter plants but leaving the spontaneous growth within undisturbed.
c) Consider and visualize growth of vegetation over time in planting design
A key point of the research is for designers to consider how vegetation changes over time will shape landscapes – thinking beyond the post-construction period to consider a time frame of 30, 50, even 100 years. To illustrate, Fig. 10 shows the vegetation changes in Bishan -AMK park in a decade. Note the areas of spontaneous vegetation along the plains & water edge.
One way to accommodate plant growth over time is to design the planting structure as multi-layered vegetation to mimic natural succession process of our native tropical forest, with a mix of fast-growing pioneer trees, slower-growing canopy species, shrubs, grasses & sedges, creepers and groundcovers. Other possible ways include designing surrounding shrubs in relation of maturing canopy tree sizes and spacing the plants according to growth speed & form. Unfortunately, often clients/ owners request for “instant effect”. The solution could be to specify different planting size & spacing – compact/ closer planting at highlight areas but further apart at less prominent/ low-traffic areas.
d) Integrate sustainable, long-term maintenance practice in shaping the landscape
The research documented vegetation changes occurring post-construction, and showed maintenance regimes as the main factor influencing vegetation growth with time, for example by varying the frequency of trimming vegetation, progressive removal & addition of species, or less intense regime at some areas. To this end, landscape practitioners would first need to have the vision/ intent of how their landscape design will evolve over time as mentioned above, and then specify more detailed maintenance requirements / having different maintenance zones as guidelines for owners/ clients. Critical to achieving this would be to discuss with client’s operations team and softscape contractors as early as possible to understand any concerns & limitations, e.g., whether a more complex/ differentiated maintenance regime would be acceptable in view of reduced maintenance frequency & ecological benefits. More detail/ precise maintenance standard would also hopefully pave the way for more sophisticated landscape care in future. For example, selective weeding of invasive species compared to current practice of weeding/ mowing indiscriminately.
e) Transdisciplinary approach
Landscapes with spontaneous vegetation can be an opportunity to educate people on ecological health & biodiversity, and what it means to live in a City in Nature. To build up knowledge and expertise on ecological knowledge there could be collaborations with ecologists/ nature groups to review design options and to monitor biodiversity changes at a project’s naturalistic planting plots over time.
Government initiatives such as the Rewilding Plan, implementation of Nature Ways and creation of several Nature Parks coupled with projects such as Enabling Village or Esplanade Forecourts have helped provide visual reference and raise awareness of a more heterogeneous, naturalistic landscape typology. Yet, doubts remain when it comes to advocating for the ‘wild & messy’ aesthetics of an ecologically focused & sustainable landscape. Landscape architect, considerate of architectural, social & cultural context, yet rooted in environmental principles, plays an irreplaceable role to truly incorporate Nature into the urban setting. We have our work cut out in introducing the ecological perspective early, highlighting its importance to clients, contractors, landscape managers and users, and thinking long term in designing Singapore’s urban landscapes.
Authors:
Shiela Carelnina is an accredited landscape architect in Singapore with nine years’ experience on projects ranging from parks, mixed-use, residential & healthcare. She is very nervous about Earth’s future, yet hopeful that through landscape architecture she can play a part in shaping it. She advocates not eating, or at least reducing eating meat, for a healthier self & planet.
References:
- Hwang, Y. H., See, S. C., & Patil, M. A. (2021). Short-term vegetation changes in tropical urban parks: Patterns and design-management implications. Urban Forestry & Urban Greening, 127240.
- Hwang, Y. H., et al. (2019). Vegetation changes in Bishan- Ang Mo Kio Park and Esplanade Forecourts.
- Morrison, Simon. (2021) City in Nature? Can nature and people be good neighbours?