Ecosystem properties in urban areas vary with habitat type and settlement age

Abstract

Urban ecosystems comprise a range of habitats that support key ecosystem processes that are fundamental for the functioning of their soils. Relatively little is known about how different types of urban greenspaces and settlement ages influence the functioning of these important environments. We evaluated how four types of urban greenspaces (habitat types: natural areas, parks, gardens, roadside verges) and three settlement ages (5 to 150 years) influence multiple plant and soil ecosystem properties at 60 sites in two seasons in urban areas in eastern Australia. The type of urban greenspace and the age of the settlement influenced their ecosystem properties. In particular, habitat type had a greater effect on nutrient pools and plant biomass than settlement age, with greater nutrient pools in household gardens, but lower plant cover and plant height on roadside verges. Natural areas supported richer plant communities. We found that soil pH and soil moisture (particularly in summer) explained the contrasting effects of urban environments and settlement age on fundamental ecosystem properties. Older settlements tended to have lower soil pH, which was generally associated with greater enzyme concentrations. Soil pH effects varied depending on functions and season. Our work highlights the importance of considering settlement age and urban greenspace type for understanding the complexity of urban ecosystems, and the functions that they provide to humanity. Understanding the links between urban habitats, settlement age and ecological functions is a first step to promoting practices that sustain healthy and productive urban environments.