Summary:

Mosquito populations are expanding globally, often in response to human-driven environmental change, with implications for both ecological and public health. However, the specific drivers of mosquito abundance, particularly at the ends of their temporal ranges, such as high-elevation landscapes, remains poorly understood. 

In this study, we investigated how the introduction of non-native species, host community composition, and seasonal climate variation influence adult mosquito populations across a network of alpine lakes within the Inyo National Forest in California’s Eastern Sierra Nevada. We conducted field surveys during the summers of 2023 and 2024, collecting over 21,000 mosquitoes and analyzing their blood meals, as well as landscape and environmental covariates.

 Our results indicate that human activity was the strongest predictor of relative mosquito abundance, with models suggesting up to a two-fold increase in mosquito density at more heavily visited sites. A significant interaction between human activity and seasonal timing was revealed, with the effect being strongest early in the season. A lag effect from prior-year visitation also further influenced current-year mosquito emergence. In contrast, we found no significant association between mosquito density and the presence of introduced nonnative trout, despite their known ecological impacts. Blood meal analysis confirmed that humans and their domestic animals were the predominant hosts across all sites. 

These findings highlight how recreation-driven human presence can shape mosquito dynamics in protected areas and suggest that high-elevation landscapes may face increasing mosquito nuisance and potential disease risk as climate change and visitation continue to rise.

Some AMAZING pictures taken during the 2024 field season by research assistant Kate Joos!