The ecohydrological cost of lawns

Lawns are a more than $40 billion industry in the US, where they cover almost 2% of the land area, more than the largest irrigated crop (corn). While they provide benefits such as acting as a carbon sink, reducing runoff and the heat island effect, and aesthetic value, lawns also have environmental costs, such as the wasteful consumption of water, pollution to local water bodies from fertilizers and pesticides, and the effect on pollinators of both pesticides and the reduced biodiversity of monoculture lawns. Despite their high costs and ambiguous utility, society continues to place a high value on traditional green lawns, even when the local climate is unsuitable, often resulting in an unproductive use of resources. Here, we provide a comprehensive synthesis of previous studies which examine the costs and benefits (i.e., ecosystem services) of lawns. We then develop coupled models for water and biogeochemical cycling, which capture the essential environmental variables, to explore the relationship of costs and benefits to management strategies and other factors. A clear assessment of the costs associated with lawns and the benefits and tradeoffs of optimal use of limited space and resources is critical in the current period of climate change, population growth, and urbanization.