Temperature accounts for the biodiversity of a hyperdiverse group of insects in urban Los Angeles

Abstract

The urban heat island effect is a worldwide phenomenon that has been linked to species distributions and abundances in cities. However, effects of urban heat on biotic communities are nearly impossible to disentangle from effects of land cover in most cases because hotter urban sites also have less vegetation and more impervious surfaces than cooler sites within cities. We sampled phorid flies, one of the largest, most biologically diverse families of true flies (Insecta: Diptera: Phoridae), at 30 sites distributed within the central Los Angeles Basin, where we found that temperature and the density of urban land cover are decoupled. Abundance, richness, and community composition of phorids inside urban Los Angeles were most parsimoniously accounted for by mean air temperature in the week preceding sampling. Sites with intermediate mean temperatures had more phorid fly individuals and higher richness. Communities were more even at urban sites with lower minimum temperatures and sites located further away from natural areas, suggesting that communities separated from natural source populations may be more homogenized. Species composition was best explained by minimum temperature. Inasmuch as warmer areas within cities can predict future effects of climate change, phorid fly communities are likely to shift nonlinearly under future climates in more natural areas. Exhaustive surveys of biotic communities within cities, such as the one we describe here, can provide baselines for determining the effects of urban and global climate warming as they intensify.

Local‐ and landscape‐scale variables shape insect diversity in an urban biodiversity hot spot

“…This corroborates previous findings of limited spatial patterns in insect diversity in the urban center of Los Angeles (McGlynn et al. ).…”

“…Due to intermittent temporary mechanical failures of the weather stations, local environmental data was occasionally interpolated from within a collection period by estimating the value of a missing parameter using its relationship to the same parameter at a site with similar microclimate (McGlynn et al. ). We down‐sampled high‐resolution weather station data to a weekly temporal resolution appropriate to our insect sampling regime.…”

“…, McGlynn et al. ). How local communities of organisms are affected by fine‐scale site characteristics across the broad‐scale urban gradient is often unaddressed because it requires replication of habitat types across the urban gradient (Goddard et al.…”

Home range expansion in response to temperature by evening bats (Nycticeius humeralis) in an urban environment

“…We observed a positive correlation between size and the proportion of home range that fell within the surrounding neighborhood and the number of swimming pools We acknowledged that the increase in range size with swimming pools was likely a result of autocorrelation; however, we might not have observed such as strong positive correlation if bats were equally utilizing areas with and without swimming pools. We also acknowledge that bats could have been expanding their ranges to increase foraging opportunities [22,23]. As water sources become limited, there may be a similar trend in prey distribution and abundance.…”

Spatial Configuration and Extent Explains the Urban Heat Mitigation Potential due to Green Spaces: Analysis over Addis Ababa, Ethiopia

“…Relative to the rural regions, urban areas have distinct morphology, geometry, and infrastructure that contributes to the UHI. Changes in land use and land cover result in an abundance of built impervious surfaces and depletion of green vegetation covers, causing alterations in the surface energy fluxes [6][7][8][9], distribution and composition of biodiversity [10,11], increasing anthropogenic heat releases [12], and human health [13,14]. As a result, how to understand and mitigate these adverse impacts has become a key study topic in urban ecology, geography, and climatology [15][16][17][18].…”