Author: Suranga Wadduwage
Wadduwage, Suranga, 2019 Evaluation of Agricultural Land Transitions on Urban Fringes, Flinders University, College of Science and Engineering
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In a human-dominant land system, the investigation of peri-urban agricultural land transition phenomena is challenging as they occur under the effects of urban sprawl, in which complex land change drives insights into the transitional processes of land use. Considering urban-to-rural (U–R) landscapes as a single land system that consists of socio-economic, environmental and institutional land-governing influences, this study focuses on the complexities associated with agricultural land transition processes: the spatial, behavioural and temporal dynamics. The study explores the agricultural land-use presence and its vulnerability to urban sprawl while using peri-urban farmers’ land-use decision behaviours to develop an agent-centric model to understand the complex land transitions on the fringes of the city of Adelaide in South Australia.
The first part of this research investigates the peri-urban land parcel spatial structure and land-use compositional arrangement focusing on agricultural land fragmentation. For this purpose, the author developed urban-to-rural land-use gradients, in parallel with landscape metrics, to analyse the landscape’s spatio-structural changes and their effects on agricultural land parcel arrangements. The author shows the prospects of using a relationship between two landscape metrics—mean parcel size (MPS) and parcel density (PD)—to identify land fragmented areas along the gradients while quantifying the agricultural land presence in the fragmented zones for informed planning decisions.
The second part of this study analyses the vulnerability of peri-urban agricultural land to urban sprawl at a local level under opposing policy directions—economic development and environmental protection. For this purpose, land administrative scenarios were developed using spatially-explicit, multi-criteria models that considered the geographic and socio-economic aspects and the land-use plans of the study area. In this analysis, the author used grid-based spatial overlay techniques to develop the Landscape Vulnerability Index to spatially visualize and quantify the effects of sprawl, with respect to geographic locations. The results show that agricultural land vulnerability is inevitable in both scenarios, and that the spatial quantifications of agricultural land in a local government area are useful as they assist in transferring scientific knowledge into practice in local land-use planning.
The third part of this research explores the characteristics of peri-urban farmers—their demography, production and farming motivations—while exploring the drivers behind their land-use decisions, decision-making profiles and their land-use decision behaviours. For this purpose, the author used a questionnaire survey to collect information from a sample of 168 farmers to represent a population of over 5,000 peri-urban farmers on the Adelaide city fringes. The study then developed descriptive statistics that were used to identify farming characteristics while using factor dimension reduction techniques to identify the key drivers behind decisions. Cluster analysis was used to identify decision-making profiles and their decision rules were employed to make assumptions for the development of the agent-centric model. The results show the advantage of using the motivations of farmers towards land management to identify decision-making profiles and decision behaviours and when making assumptions for agent-centric modelling.
The final part of this research explores the characteristics of the agricultural land transition process (land-change patterns and system feedback) and their responses under varying model environments. Spatially-explicit agent-based model simulations (using NetLogo) were used to analyse the agricultural land transitional processes while creating hypothetical parameter set-ups for the opposing policy directions (economic development and environmental protection). The results demonstrate that agricultural land transitional processes on the Adelaide city fringes are highly path-dependent, but less self-organized, and are largely dependent on land administration and economic effects.
Keywords: Land systems, Land-use change, urban-to-rural gradients, urban fringe, Peri-urban development, land fragmentation, agricultural land-use, agricultural land vulnerability, Land-use policy, Land-use planning, Land transition; complexity, Scenario analysis, farmers land-use decisions, factor analysis, cluster analysis, GIS; spatial, land-use modelling, agent-based modelling
Subject: Environmental Science thesis
Thesis type: Doctor of Philosophy
Completed: 2019
School: College of Science and Engineering
Supervisor: Professor Andrew Millington