An ecology of suboptimals? Lessons learned from balancing green and gray in cities

Urban Farm DB summary

A perspective article discusses biodiversity conservation in cities as often afflicted by "suboptimal" situations where human needs and nature's needs are imbalanced or in conflict. In human-dominated landscapes, land use intensification often replaces large habitat patches critical for metapopulation stability with smaller, isolated patches, a pattern Island Biogeography Theory predicts will reduce biodiversity; this may be most extreme in cities experiencing rapid population growth and infrastructure densification, where small urban green spaces, balconies, home and allotment gardens, small forest patches and green walls, become the primary compensatory interventions for retaining habitat. However, under certain conservation frameworks (land-sparing vs. land-sharing, the SLOSS debate), such small, scattered urban green spaces may be predicted to produce suboptimal or even detrimental biodiversity outcomes if their size and isolation prevent them from sustaining viable population sizes. The article notes this "ecology of suboptimals" framing risks a futile perspective on nature conservation in densifying cities, while also considering how rethinking urban environments in light of this situation might be approached.