Ecological Resilience of Small Urban Parks: System Functionality and Adaptation to Disturbances

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandling

  • Zanariah Binti JasmaniI
Rapid urbanisation has led to urban densification and urban green spaces becoming smaller and more fragmented. However, the capability of small urban green spaces (e.g. parks) to support ecological functioning and as habitats for urban species remains largely unexplored, particularly in tropical regions. This PhD thesis is based on research conducted in Malaysia between 2013 and 2016. The research is at the interface of urban ecology, landscape architecture and the management of urban green space. The overall aim of the PhD study is to gain deeper knowledge about the characteristics of small urban parks in Malaysia (using the case study of Petaling Jaya) through investigation of their social and ecological qualities for enhancing ecological resilience. The central hypothesis of the study is that small urban parks’ physical characteristics, vegetation diversity and structure and human factors all influence their ecological quality, functioning and biodiversity. The key research question of this PhD study is: ‘how are human and ecological components interrelated in small urban parks?’ This PhD study comprises three main parts: a method developed for assessing the social-ecological characteristics of small urban parks (study I), the use of small urban parks by bird and butterfly species as ecological indicators (studies II and III) and recommendations for planning, design and management of small urban parks (study IV). Nine small urban parks in Petaling Jaya, Malaysia were investigated using the combined field survey method of structured observation and field measurements. Inspired by the literature and previous works, this study developed a framework to assess the important features of small urban parks according to three categories of explanatory variables: physical characteristics, vegetation diversity and human factors. Birds and butterflies (response variables) were used as indicators for assessing ecological functions and biodiversity because they show clear responses to environmental change and both taxa are relatively easy to identify. Each category of explanatory variable consists of several sub-variables or attributes. The attributes of physical characteristics include park size, land use, park shape, proximity to a road and the presence of a water element. Elements relating to vegetation diversity, such as the presence and share of native and exotic species, presence of flowering plants and the percentage of canopy cover, are also examined. Human factors include activities, visitor density, noise levels and smells. This study’s analysis uses mixed methods to explain and compare quantitative results with qualitative findings. Pearson correlations were first performed to examine the relationships between the response and explanatory variables. Then, multiple regressions, followed by analysis of Akaike’s Information 4 Criterion (AIC), were conducted to identify which of the explanatory variables have a significant effect on and are the best predictors of the richness and abundance of bird and butterfly species in small urban parks. The results of the analysis and subsequent discussion on birds and butterflies are explained separately in detail in studies II and III. Throughout the field survey, a total of 22 bird and 23 butterfly species were recorded. Most of the birds and butterflies observed are common species in urban parks in Malaysia, and may be regarded as generalist species and urban adapters. However, a few passage migrant birds also had a presence in small urban parks. A total of 89 different plant species, comprising trees, palms and shrubs, were recorded. There are similarities in plant species across all the small parks studied, which may be due to the landscaping guidelines provided by the municipality. Overall, exotic vegetation was planted more than native vegetation. Small urban parks were used mainly for utilitarian purposes (42%, e.g. for walking or motorcyclist access), recreation (32%, e.g. for relaxing or family outings) and sports, play and special occasions (26%). The statistical results demonstrate that the percentage of canopy cover (negative relation) and park size (positive relation) are the best predictors of the richness of bird species in small urban parks. For bird abundance in small parks, the percentage of canopy cover (negative relation) and native vegetation species (positive relation) are the best predictors. Meanwhile, the richness of butterfly species can be best predicted by the percentage of canopy cover (positive relation) and shrub species (positive relation). For butterfly abundance, the percentage of canopy cover (positive relation) and number of native vegetation (positive relation) are the best predictors. Observations revealed that activities in the surrounding areas influence the presence of birds in the small urban park. Birds and butterflies react differently to various park maintenance practices (e.g. mowing). Based on the overall results, findings and discussion of the key features for bird and butterfly richness and abundance, study IV proposes nine recommendations for small urban parks to improve their ecological functions and enhance biodiversity. These recommendations aim to provide landscape architects, urban planners, park managers and municipalities with several strategies to enhance the biodiversity and ecological qualities of small urban parks which can directly promote ecological resilience. Although this study was conducted in the tropical country of Malaysia, the overall findings and considerations are also applicable to many cities in the Western world. The present study does not conclude that small urban parks are better than large parks, but rather aims to provide solutions for small green spaces to support ecological functions and serve as refuges for urban wildlife as cities become more densified.
OriginalsprogEngelsk
ForlagDepartment of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen
StatusUdgivet - 2016

ID: 167475105