Artificial Light at Night Creates a Network of Habitat Patches for an Urban Arthropod Community
Research or Creativity Area
Natural Sciences
Abstract
Artificial light at night (ALAN) is increasing, and it is linked to global biodiversity losses caused by alterations in animals’ circadian rhythms, activity patterns, and phenology. To examine ALAN’s effects on community dynamics, previous work has typically introduced ALAN into ALAN-naïve communities and/or focused on large-scale spatial effects by comparing sites separated by >1 km. However, ALAN sources (e.g., street lamps) often create patches of light across a landscape, and animal assemblages can vary on a fine spatial scale. Therefore, we used pitfall trapping in the urban setting of the University of the Pacific in Stockton, CA, to track the diurnal and nocturnal community composition of terrestrial invertebrates on a fine spatial scale (2-6 m) across which illuminance (lux) varied 10-fold to determine: (1) the effects of ALAN on a nocturnal animal community, and (2) whether the effects carryover into diurnal communities. Across 38 transects, we collected over 30,000 individuals from 43 families. We found that overall richness, diversity, and abundance in nocturnal communities was highest near ALAN sources. However, there were no carryover effects of ALAN on diurnal communities. Thus, for animals in areas subjected to longstanding ALAN (our study system is ~100 years old), the mosaic of nighttime lighting in urban ecosystems may serve as a network of habitat patches, rather an array of ecological traps.
Location
Don and Karen DeRosa University Center (DUC) Room 214
Start Date
27-4-2024 11:15 AM
End Date
27-4-2024 11:30 AM
Artificial Light at Night Creates a Network of Habitat Patches for an Urban Arthropod Community
Don and Karen DeRosa University Center (DUC) Room 214
Artificial light at night (ALAN) is increasing, and it is linked to global biodiversity losses caused by alterations in animals’ circadian rhythms, activity patterns, and phenology. To examine ALAN’s effects on community dynamics, previous work has typically introduced ALAN into ALAN-naïve communities and/or focused on large-scale spatial effects by comparing sites separated by >1 km. However, ALAN sources (e.g., street lamps) often create patches of light across a landscape, and animal assemblages can vary on a fine spatial scale. Therefore, we used pitfall trapping in the urban setting of the University of the Pacific in Stockton, CA, to track the diurnal and nocturnal community composition of terrestrial invertebrates on a fine spatial scale (2-6 m) across which illuminance (lux) varied 10-fold to determine: (1) the effects of ALAN on a nocturnal animal community, and (2) whether the effects carryover into diurnal communities. Across 38 transects, we collected over 30,000 individuals from 43 families. We found that overall richness, diversity, and abundance in nocturnal communities was highest near ALAN sources. However, there were no carryover effects of ALAN on diurnal communities. Thus, for animals in areas subjected to longstanding ALAN (our study system is ~100 years old), the mosaic of nighttime lighting in urban ecosystems may serve as a network of habitat patches, rather an array of ecological traps.
