Urban Butterfly Pollinator Biodiversity in Zoological Gardens of the Southwest USA

Urbanization and climate change are exerting increasing pressure on biodiversity, particularly in rapidly growing cities of the southwestern United States. While urban development is generally associated with reduced species richness, responses among insect pollinators, including butterflies, are highly variable and shaped by habitat availability, resource distribution, and landscape structure. Concurrently, increasing aridity and extreme heat events linked to climate change pose additional risks to ectothermic organisms such as butterflies. Urban green spaces can function as hotspots, yet the role of zoological gardens in supporting local pollinator biodiversity remains poorly understood. Here, we use community science data from eButterfly and iNaturalist to compare butterfly species richness and diversity within zoos to those of their surrounding urban landscapes across five southwestern USA cities. Contrary to previous work comparing botanical gardens, we found that zoos consistently exhibited low to moderate species richness and diversity relative to comparable areas within their respective cities, falling well below our predetermined hotspot thresholds. We conclude that while zoological gardens, unlike botanical gardens, may not currently function as localized biodiversity hotspots within their urban matrix in these arid environments, they support functional urban pollinator communities. Thus, the current and future local conservation value of zoos could be substantially enhanced through targeted pollinator habitat management and expanded community science monitoring.