Author Identifiers

Danica-Lea Larcombe

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


School of Science

First Advisor

Pierre Horwitz

Second Advisor

Eddie Van Etten

Third Advisor

Susan Prescott


Disconnection from nature puts high-rise dwellers at risk of chronic disease and poor mental health, two major healthcare budget items. Many reports in the literature state compromised mental health, partly due to the ‘grey’ landscape of many apartment buildings, particularly in low socioeconomic areas. Lifestyle is also affected by influences of floor level and sociodemographic status. In high-density cities around the world, high-rise developments (solving urban sprawl) are increasingly being built without consideration for incorporating greenspace. The sheer height of these buildings means that dwellers are physically separated from earth and potentially beneficial soil and plant microbes. Environmental biodiversity is important to human health influencing biophilic mental relationships and physical, social and microbial characteristics. Evidence indicates soil (comprising rich diversity of microbes) is an important component in maintaining immunological health. Human skin is continually exposed both to the environment and to cleaning and hygiene tasks that contribute to skin microbial composition. The study sought to answer a vital question: How do floor level and the lack of plants and soil in high rise apartments affect the health of humans living in those environments?

The longitudinal intervention study (over a 12-month period), had a ‘before’ and ‘after’ component using an independent variable (real and fake indoor plants), and dependent measurable variables (the skin microbiota and lifestyle factors). The latter were derived from self-assessed questionnaires and developed to source lifestyle and health information from fifty-nine eligible respondents from Perth, Western Australia. Relationships between sociodemographic data, floor level, health and lifestyle were analysed using Principal Component Analyses. Pilot skin microbiota (16S DNA) results were analysed for ten respondents before and after the study. My comprehensive literature review revealed that existing theories have neglected to account for relationships between high-rise apartment dwellers, lifestyle, environmental and human microbial biodiversity. Survey findings dispute historical literature on high-rises, finding that floor level does not affect mental health. Analysis of a survey on nature relatedness (21-scale NRS)showed respondents’ living on lower floors were progressively more connected to nature than those on higher floor levels (particularly when compared to employed residents on upper floors). Collectively, the NRS did not predict naturistic lifestyle behaviour, which contrasted with previous studies. After the intervention, real plant recipients demonstrated a significantly higher frequency of visiting parks and consuming fruit and vegetables compared to those with fake plants. Pilot skin microbiome respondents that received real plants showed: a) greater increase in OTU richness than those receiving fake plants, significant at the p

A high-rise conceptual model is presented due to overall social justice findings. Landscape architecture in conjunction with government development policies is paramount to enabling ecological justice and accessibility to nature, as well as providing the right microbial balance for high-rise apartment buildings. Encouragement of naturistic behaviour would be beneficial for residents on higher floor levels. Growing indoor plants increases naturistic behaviour and microbial species richness over time, a novel discovery that is promising for human health.

Available for download on Wednesday, May 10, 2023


Paper Location