Urban growth and pedestrian thermal comfort

Melbourne is the second largest city in Australia, and its population is anticipated to reach 6.5 million by 2050. In October 2013, Plan Melbourne was released by Victorian government, aiming to intensify several districts to protect the suburbs from urban sprawl. The City of Melbourne’s draft municipal strategic statement identified City North as a great urban renewal area which can accommodate a significant part of the growth. Given the previous heat-related incidence in Melbourne in 2009, the potential threat to human health and pedestrian comfort will be exacerbated, if planning professionals exclude climatic conscious urban design in their practices. Therefore, this study aims to investigate the effect of the future structural plans on the microclimate and pedestrian thermal comfort in City North through numerical simulations. A three dimensional numerical modelling system, ENVI-met was used for the simulation. Field measurements were conducted across the study area to validate the simulated outputs. A clear reduction was reported in the average daytime mean radiant temperature, surface temperature and PMV values after implementing “Plan Melbourne” strategies. The outcomes of this study will assist urban planners in developing the policies which can effectively decrease the vulnerability to the heat stress at pedestrian level.

Unhealthy landscapes: policy recommendations on land use change and infectious disease emergence

Anthropogenic land use changes drive a range of infectious disease outbreaks and emergence events and modify the transmission of endemic infections. These drivers include agricultural encroachment, deforestation, road construction, dam building, irrigation, wetland modification, mining, the concentration or expansion of urban environments, coastal zone degradation, and other activities. These changes in turn cause a cascade of factors that exacerbate infectious disease emergence, such as forest fragmentation, disease introduction, pollution, poverty, and human migration. The Working Group on Land Use Change and Disease Emergence grew out of a special colloquium that convened international experts in infectious diseases, ecology, and environmental health to assess the current state of knowledge and to develop recommendations for addressing these environmental health challenges. The group established a systems model approach and priority lists of infectious diseases affected by ecologic degradation. Policy-relevant levels of the model include specific health risk factors, landscape or habitat change, and institutional (economic and behavioral) levels. The group recommended creating Centers of Excellence in Ecology and Health Research and Training, based at regional universities and/or research institutes with close links to the surrounding communities. The centers' objectives would be 3-fold: a) to provide information to local communities about the links between environmental change and public health ; b) to facilitate fully interdisciplinary research from a variety of natural, social, and health sciences and train professionals who can conduct interdisciplinary research ; and c) to engage in science-based communication and assessment for policy making toward sustainable health and ecosystems.

Compact development minimizes the impacts of urban growth on native mammals

Unprecedented global human population growth and rapid urbanization of rural and natural lands highlight the urgent need to integrate biodiversity conservation into planning for urban growth. A challenging question for applied ecologists to answer is: What pattern of urban growth meets future housing demand whilst minimizing impacts on biodiversity? We quantified the consequences for mammals of meeting future housing demand under different patterns of compact and dispersed urban growth in an urbanizing forested landscape in south-eastern Australia. Using empirical data, we predicted impacts on mammals of urban growth scenarios that varied in housing density (compact versus dispersed) and location of development for four target numbers of new dwellings. We predicted that compact developments (i.e. high-density housing) reduced up to 6% of the area of occupancy or abundance of five of the six mammal species examined. In contrast, dispersed developments (i.e. low-density housing) led to increased mammal abundance overall, although results varied between species: as dwellings increased, the abundance or occurrence of two species increased (up to ∼100%), one species showed no change, and three species declined (up to ∼39%). Two ground-dwelling mammal species (Antechinus stuartii and Rattus fuscipes) and a tree-dwelling species (Petaurus australis) were predicted to decline considerably under dispersed rather than compact development. The strongest negative effect of dispersed development was for Petaurus australis (a species more abundant in forested interiors) which exhibited up to a 39% reduction in abundance due to forest loss and an extended negative edge effect from urban settlements into adjacent forests. Synthesis and applications. Our findings demonstrate that, when aiming to meet demand for housing, any form of compact development (i.e. high-density housing) has fewer detrimental impacts on forest-dwelling mammals than dispersed development (i.e. low-density housing). This is because compact development concentrates the negative effects of housing into a small area whilst at the same time preserving large expanses of forests and the fauna they sustain. Landscape planning and urban growth policies must consider the trade-off between the intensity of the threat and area of sprawl when aiming to reduce urbanization impacts.