Life-history traits modulate the influence of environmental stressors on biodiversity: the case of fireflies, climate, and artificial light at night
Khattar, Gabriel et al. (2022), Life-history traits modulate the influence of environmental stressors on biodiversity: the case of fireflies, climate, and artificial light at night, Dryad, Dataset, https://doi.org/10.5061/dryad.ghx3ffbrq
Sampling was carried out in the Serra dos Órgãos National Park (22°28ʹ S, 43°02ʹ W WGS 84), one of the oldest conservation units in Brazil that spans 20,024 ha. with elevations ranging from 80 to 2263 meters above sea level. Along an elevational transect that ranges from 100 to 2100 meters above sea level, two flight-interception Malaise traps were placed at elevational intervals of approximately 150 meters, summing up to 15 sampled elevations (see Supp. Material Fig. I). The collecting bottle of each trap was replaced in monthly intervals (30 days) from December 2014 to November 2015, summing up to approximately 360 samples in total (2 traps × 15 elevations × 12 months). To control for potential false absences associated with intra-annual dynamics in population demographics, we considered all species sampled in a given elevation over the year as the operational definition of community used in further analyses. This allowed for more accurate characterization of the spatial structure of firefly communities because it maximized the detection of: (i) species that coexist as juveniles in a focal site, but that emerge as (detectable) flying adults in different moments of the year, and; (ii) species that emerge as flying adults in different locations and during previous moments in time but that immigrate to the focal location and become part of the existing community.
A data logger was placed close to each pair of traps to record hourly variation in temperature and air relative humidity over the entire sampling period. We then calculated mean daily temperature, mean daily thermal amplitude, and mean air relative humidity in each site over the whole sampling period.
To obtain data on ALAN, we used our samples' geographic coordinates to extract radiance values (i.e., amount of light emitted or reflected by a surface that is detected by an optical system, units in nW/cm2×sr) estimated from the satellite imagery fostered by the United States National Oceanic and Atmospheric Administration Earth Observation Group (https://ngdc.noaa.gov/eog/download.html) and processed by the Radiance Light Trends web application (Stare & Kyba, 2019). This web application uses data from visible infrared imaging radiometer day-night-band (VIIRS DNB) satellite system to display information about radiance at the resolution of 0.5 square km. The VIIRS DNB satellite system measures ALAN in the broad spectral range of 500 to 900 nm. This spectral range overlaps with the spectral sensitivity of photoreceptors in firefly species, being an appropriate measure of the large-scale effects of ALAN on the sensory environment of fireflies.
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Award: 400261/2014-6
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Award: 465562/2014-0