ABSTRACT
Urban ecosystems may have unique costs or disservices that are not present or are negligible in natural ecosystems. In designed and human-dominated ecosystems, failing to account for the resource and maintenance requirements of landscape designs can lead to errors in estimating the magnitude or value of ecosystem services. While natural ecosystems are comprised of organisms, populations, and species that have adapted to local environmental constraints, constructed ecosystems such as cultivated urban gardens and greenspace almost invariably require initial or ongoing resources inputs. Landscape cultivation often involves externalities that have remote or indirect environmental consequences. Urban flora and fauna have measurable impacts on human health, and these are not always positive. Land use and management decisions about urban greenspace have detectable effects on urban wildlife populations, which often differ physiologically and ecologically from rural populations. Plant, algal, lichen, and fungal components of urban ecosystems may have direct impacts on human health including toxicity when ingested or released into water bodies.
