Impact of Urbanization on Macro-Moth Species Composition in Central Illinois

Abstract

In recent years, there has been a concerning decline in invertebrate populations worldwide. Coined an “Ecological Armageddon”, studies suggest an alarming 82% decrease in populations. Insects, as crucial components of many ecosystems, play vital roles in nutrient cycling, pollination, and food web support. Various arthropod populations, including that of moths and butterflies, have shown significant declines, impacting ecosystems globally. Central Illinois, once dominated by tallgrass prairies and deciduous forests, has experienced extensive agricultural and urban expansion, leading to habitat loss and degradation and, ultimately, a reduced invertebrate population.

This study aimed to assess the impact of urbanization on macro-moth diversity using urban vs. natural landscape categories determined by data from the National Land Cover Database (NLCD). Universal blacklight traps were placed in selected sites throughout Peoria and Tazewell counties, with each macro-moth being identified to species level. To quantify species composition, richness, and diversity, comparing urban and natural categories, calculating alpha (⍺) diversity, beta (β) diversity, creating species rarefaction curves, running principal component analysis (PCA), generating linear regression models and comparing moth communities composition by regionally common, uncommon, rare, or exotic species. This analysis encompasses data from 32 trap locations over two years, collected in the summer months of 2023 and 2024. Over 15,680 individual macro moths and 453 different species were recorded across all sites. The data supports that urbanization does not impact macro moth diversity metrics between sites and individual traps but does impact macro-moth species composition and species richness when looked at on an urbanization gradient with more uncommon and exotic species in natural trap locations. This study also states the potential for five new moth species in Peoria Illinois, showing range expansion.