The effects of urban habitats on herbivore life history and street tree ecosystem services

Trees are essential to urban habitats because they provide services that benefit the environment and improve human health. Unfortunately, urban trees often have more herbivorous insect pests than rural trees but the mechanisms that drive these infestations and consequences of them are not well documented. Here, we examine how temperature and drought stress affect the life history of a scale insect, Melanaspis tenebricosa (Comstock) (Hemiptera: Diaspididae), on one of the most commonly planted street trees in the eastern U.S. Next, we determine how pest abundance, temperature, and drought stress affect ecosystem services provided by street trees. Our analyses indicate that both temperature and drought stress contribute to scale insect abundance, while the combination of these factors affect tree ecosystem services. Our results suggest that pest abundance may increase and street tree ecosystem services may decline as urban expansion and global warming exacerbate the urban heat island effect. This presents a gloomy outlook for urban forests and emphasizes the need for novel management practices.