Spatio-temporal access to protected areas from Australian significant urban areas

Abstract

There are many positive effects of the natural environment on human health and wellbeing. These benefits are closely linked to people's accessibility to protected areas like National Parks. In this study, we quantified spatial and temporal relationships between the extent of protected areas in, and adjacent to, significant urban areas (SUAs) in Australia, the populations of SUAs, and the network service area of connecting SUAs with protected areas between 2001 and 2024. To evaluate the accessibility of SUAs to protected areas, we developed a gravitybased accessibility index using a network analysis approach. The Gravity Index is a relative measure of attractiveness of a protected area in terms of the distance that needs to be travelled to access it, and the level of possible "congestion" placed on it from the population of the surrounding network service area. SUAs with a high value for the Gravity Index reflect shorter distances to travel to protected areas, along with fewer people per unit of area visiting protected areas (low congestion). Our results reveal marked differences in the Gravity Index for SUAs across Australia. Some SUAs, such as Hobart and Canberra, were characterized by a comparatively high Gravity Index, indicating extensive protected areas within a short distance of those population centres. Others, such as Melbourne (Australia's fastest growing SUA), had a very low and declining Gravity Index, associated with high population growth (1.8 million in 24 years), small fragmented existing protected areas surrounding the city, and limited additional land added to the protected area network over the period of population growth. Our results identify priority SUAs (such as Melbourne) where there is a need to expand the protected area network through, for example, changing land tenures to National Parks.