Developed as an extension of cityLAB's Backyard Homes study, the Backyard BI(h)OME is an ultra-modern, lightweight accessory dwelling unit that has the potential to meet the current demand for 100,000 additional housing units in Los Angeles while also serving as a biome by providing habitats for other species, too. The BI(h)OME is flexibly designed to meet the needs of almost any household (housing for an elderly parent, a returning college graduate, a rental unit, etc.) while maintaining the benefits of of easy maintenance and affordability. The environmental impact of the structure over its entire life cycle is between ten and a hundred times less than a conventional auxiliary dwelling. In addition to this, the BI(h)OME is designed to accommodate multiple species in several ways: at the base of the BI(h)OME, the rocks in a gabion wall provide habitat; one wall of the BI(h)OME can be configured as an edible garden; while modular units can be added to provide homes for animals.