In the next fifty years, it is projected that two-thirds of humanity will live in cities which will lead to a vast increase of urbanization and sprawl. Yet despite the pervasiveness of urban land cover, few studies have assessed the suitability of habitat in private home gardens along an urban to rural gradient. We aim to characterize the land surrounding households who have enrolled in the Bring Conservation Home (BCH) certification program through St. Louis Audubon Society to determine if intra-residential biodiversity contributes to habitat viability for urban species. Individual residences were ranked silver, gold, or platinum based on native plant prevalence and diversity, canopy stratification and water conservation; control residences were those enrolled in the program but who have not met the requirements for certification. Utilizing land cover data, census block demographics and remote sensing we quantified the habitat connectivity between enrolled houses, how information about the BCH program spreads and how the distance from the urban core effects social and spatial connectivity. Utilizing this information will be influential in assessing the effectiveness of this residential program once combined with community structure data from sampling three prevalent urban taxa––bees, birds and mosquitos.
Results/Conclusions
There are 962 houses enrolled in the BCH Program. Of those, 100 are in the city of St. Louis (urban), 639 in the surrounding suburbs and 223 in the outer exurbs. 764 houses are enrolled but have not met the requirements to be certified. 131 are certified the lowest level of silver, 44 are gold and 23 homes have the highest platinum certification level. The distribution of certification levels are slightly dependent on geographic area (p=0.049). All urban houses have notably higher levels of urban land cover within 50 and 250 m-radius buffers while having lower amounts of grass and deciduous tree cover compared to suburban and exurban houses. Gold and platinum houses often enrolled in the program earlier (pre 2015), while houses enrolled but not certified joined more recently (2016-18). Preliminary analysis indicates that there is spatial clustering of enrolled houses, most likely due to social forces between neighbors. This clustering increases the continuity of habitat which could influence the response of the three taxa due to the scale at which they each operate. Future analysis will incorporate Google Street View to characterize both canopy stratification and plant diversity of the front yards surrounding enrolled houses.