Unexpected phenological responses of butterflies to the interaction of urbanization and geographic temperature

Abstract

Urbanization and global climate change can profoundly alter biological systems, yet scientists often analyze their effects separately. We test how the timing of life cycle events (phenology) is jointly influenced by these two components of global change. To do so, we use a long‐term phenological data set of 20 common butterfly species from 83 sites across the state of Ohio, USA, with sites that range from rural undeveloped areas to moderately sized cities. These sites span a latitudinal gradient in mean temperature of several °C, mimicking the range of projected global climate warming effects through the end of the century. Although shifts toward earlier phenology are typical of species' responses to either global climate change or urbanization, we found that their interaction delayed several Ohio butterfly species' first appearance and peak abundance phenology. Exploitative species exhibited smaller delays in first appearance and peak abundance phenology in areas that were urbanized and geographically warm. Our results show that phenological responses to urbanization are contingent upon geographic variation in temperature, and that the impacts of urbanization and global climate change should be considered simultaneously when developing forecasts of biological responses to environmental change.

The influence of life history traits on the phenological response of British butterflies to climate variability since the late‐19th century

“…However, contrary to these results, an analysis of central European Lepidoptera by Altermatt () suggests that there has been a delay in phenology of late‐flying lepidopteran species since 1980. Diamond et al () found that several butterfly species occupying urban environments in Ohio, USA, also exhibited delayed phenology in response to rising temperatures.…”

Impact of urbanization on abundance and phenology of caterpillars and consequences for breeding in an insectivorous bird

“…In contrast, the appearance of 28 European butterfly species in human settlements is 9–10 d later than in forests and agricultural areas (Altermatt ), and urbanization is associated with phenological delays in first and peak appearance dates of several North American butterfly species (Diamond et al. ). The dates of arboreal caterpillar biomass peaks, however, did not differ consistently between an urban parkland area and a woodland habitat in central Poland (Wawrzyniak et al.…”

Dynamic Models for Longitudinal Butterfly Data

“…Phenological studies have typically involved measures such as mean first encounter, mean peak encounter and mean length of the flight period (Roy and Sparks 2000;Diamond et al 2014;Karlsson 2014), which may be driven by observer behaviour. The improved estimates of phenology from dynamic models provide the opportunity to study linkages between changes in phenology and changes in abundance and productivity, for example phenological mismatch (Hindle et al 2015).…”