(Award-winning) Light Pollution Research at USC Undergraduate Symposium

(Award-winning) Light Pollution Research at USC Undergraduate Symposium

We participated in force in the 20th University of Southern California Undergraduate Symposium for Scholarly and Creative Work. Our contributions included:

  1. Classification System for National Park Sites Based on Nightscape Lighting Profiles (Harrison Knapp and Benjamin Banet)
  2. Spatiotemporal Analysis of Lighted Boats at Night (Eliza Gutierrez-Dewar)
  3. A Photographic Light Pollution Assessment Across Western Public Lands (Benjamin Banet)
  4. Characterization of Spatial and Spectral Distribution of Outdoor Lighting at Wrigley Marine Science Center (Camille Verendia, Lisa Cortright, and Jasper McEvoy)

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    Amanda Gilmore, who worked this semester on habitat modeling for invasive lionfish, presented her ongoing work with our colleague Dr. An-Min Wu.

    Awards were won. Eliza took the 2nd Place award in physical sciences for her work analyzing squid boat lights off the coast of California, while Ben won Honorable Mention for his field work documenting light pollution on public lands across much of the American West with hemispherical photography.


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    Acknowledgments are in order. Funding from the Undergraduate Research Associates Program, Summer Undergraduate Research Fellowship, and Student Opportunities for Undergraduate Research (all at USC) made this work possible.  We also had funding from the National Park Service via the Southern California Research Learning Center for part of Ben’s work (the part in the Santa Monica Mountains National Recreation Area and Channel Islands National Park).  Eliza’s work was made possible by collaboration with Chris Elvidge at NOAA, who provided the outputs of their boat detection algorithm. The Wrigley Institute and Wrigley Marine Science Center supported the lighting assessment there with travel, room, and board. Photos from the symposium and awards dinner are by Susan Kamei; I was at the AAG annual meeting.

Lab Work in Knowable Magazine Profile

Screen Shot 2018-03-26 at 9.38.02 PM.pngReporter Stephanie Pain contributed an excellent summary of recent research on light pollution, “There Goes the Night,” with interviews and summaries of research from around the world.  Knowable Magazine is the partner publication to the Annual Reviews series, which recently published a review from the Gaston lab, Impacts of Artificial Light at Night on Biological Timings.  Our favorite part, however, is that the article included an image from Ben Banet, who graduates this spring with an interdisciplinary B.S. in conservation and GIS that focused on light pollution.  His image of the Smithsonian research hut on Mt. Whitney with the glow of Los Angeles on the horizon 285 km in the distance provided a striking illustration for the article.

Spatial and Temporal Analysis of Nighttime Lighting In and Around National Parks


Yu Chuan Shan, Ben Banet, and I have been working the past couple of years on developing a monthly database of upward radiance from within and buffers around all of the National Park units in the United States.  They are presenting the research today at the USC undergraduate research symposium.  The results presented only scratch the surface of what we can do to analyze this high-resolution database over space and time.

Shan also put together a website to walk through the project.

The poster can be downloaded here. Please cite as:

Shan, Yu Chuan, Ben Banet, and Travis Longcore. 2017. Spatial and Temporal Analysis of Nighttime Lighting In and Around National Parks. USC Undergraduate Symposium for Scholarly and Creative Work (Los Angeles, April 12, 2017).

Predicting Continental-Scale Bird Migration Routes from Landscape Parameters

William Winters, one of my GIST students, successfully filed his MS thesis last fall, in which he created proof-of-concept models for bird migration routes at the continental scale.  We developed the topic as a way to fill in a missing scale in the efforts to reduce mortality of birds at towers and buildings.  At the scale of the building and tower, mitigations are now available, including lights-out during migration, and changing the lighting scheme on towers.  But what locations are most likely to have high levels of birds during migration, outside those already known as migratory hotspots (e.g., Cape May)?

Put another way, what places on the landscape are especially bad for tall towers and buildings because they are likely to kill more birds?  Are there really fewer birds killed at obstructions in the western part of the Great Plains as the records in our 2012 PLoS ONE paper might suggest?

Residuals in tower height-mortality regression at communication towers (Longcore et al. 2012).

Residuals in tower height-mortality regression at communication towers (Longcore et al. 2012). Note that the towers along the Front Range of the Rockies killed fewer birds than expected.

I posed the question of whether one could model probable migratory routes using least-cost path analysis and a simple set of physical parameters for sets of known wintering and breeding grounds for Neotropical migrant birds.  William ran with it.

A least-cost corridor raster for Red-eyed Vireos migrating from the Northern Atlantic forest to South America.

A least-cost corridor raster for Red-eyed Vireos migrating from the Northern Atlantic forest to South America (Winters 2015).

After some careful thinking about resolution and projection, William settled upon topography (slope) as a metric of landscape resistance, along with wind and an additional resistance value for crossing the Gulf of Mexico. Then, using pairs of wintering and breeding grounds for Red-eyed Vireo, Kirtland’s Warbler, and Golden-cheeked Warbler, he developed models to predict northbound and southbound migration routes.

The resulting maps, which were the result of some experimentation and comparison with existing observations compiled for the species in the literature and on eBird provide proof-of-concept that one could develop maps for whole species by linking together known wintering and breeding grounds.

Fall and Spring migration routes predicted for Kirtland's Warbler from Michigan only.

Fall migration route predicted for Kirtland’s Warbler from Michigan only (Winters 2015).

The maps show that the least-cost paths for the spring and fall migrations might be different.  For example, the models for Red-eyed Vireos southbound from New England funnel through the Florida Peninsula in the Fall, and return via the Gulf Coast of Florida in the Spring.

To see the full thesis, including many more maps, visit the USC Library website at this link: Identifying areas of high risk for avian mortality by performing a least accumulated-cost analysis.

MS Thesis: Habitat Use by Rare Sonoran Pronghorn on Military Training Range

MS Thesis: Habitat Use by Rare Sonoran Pronghorn on Military Training Range

Distribution of Sonoran pronghorn (Antilocapra americana sonoriensis) on an active Air Force tactical range
Samuel Price

Thesis Chair: Travis Longcore | Thesis Committee: Darren Ruddell, Su Jin Lee

The population of Sonoran pronghorn (SPH; Antilocapra americana sonoriensis), an endangered subspecies within the United States (US), has fluctuated from an estimated 282 individuals in 1994 to 21 in 2002 and back up to over 150 as of August 2014. As the population continues to recover from drought-associated stressors, more SPH frequent the Barry M. Goldwater military tactical range and the United States Air Force (USAF) closes more targets from training for longer periods of time. In this thesis, hotspot analyses are combined with maximum entropy distribution modeling to understand the geographic and seasonal variation in SPH distribution at North and South Tactical Ranges (NTAC, STAC) in the Barry M. Goldwater Range East, Arizona using data from a monitoring effort begun in 1997. Results show hotspots of high densities of SPH near strafing and bombing targets, supporting previous studies using fewer data. In Maxent-derived habitat models, distance from targets had the strongest effect on model performance, followed by slope of the ground. According to the models, distance from roads had no effect on the SPH locations, nor did distance from observer. Prior studies attribute SPH preference for areas near targets to attractiveness of forb growth following disturbance as forage, and high visibility resulting from few tall shrubs or bushes. Output from the distribution model provides a predictive map of habitat use that can be used to evaluate effects of range use on SPH in the future.

MS Thesis Recreates Historical Topography of Lower Ballona Watershed

MS Thesis Recreates Historical Topography of Lower Ballona Watershed

3D Visualization Models as a Tool for Reconstructing the Historical Landscape of the Ballona Watershed

Committee Chair: Travis Longcore | Committee Members: Yao-Yi Chiang, John Wilson

Ever-increasing demand on Earth’s finite natural resources and land requires environmental planners to employ informed and successful management of environments. Historical resources enhance environmental management by providing information to compare past landscapes to contemporary, urbanized states. In this study, heterogeneous historical resources were converted into GIS datasets to reconstruct the Ballona Creek watershed in Los Angeles, California as a three-dimensional (3D) model. To develop the 3D terrain, contour lines were extracted from early 20th century United States Geological Survey (USGS) topographic maps. Transforming contour lines into a Digital Elevation Models (DEM) enabled creation of 3D models to visualize the terrain of the Ballona Creek watershed before the region was heavily urbanized. To increase the effectiveness and functionality of these models, 3D vegetation and hydrography features were also added to the terrain to “paint a picture” of the historic extent of the Ballona Creek watershed. The historic 3D topography allowed calculation of elevation changes occurring over the last century to the Ballona Creek watershed and provided visualizations of previously reconstructed historical habitats. These visualizations and associated analyses comparing historic and current conditions provide a historical perspective for environmental planners to identify landscape changes and current trajectories of urbanized landscapes. These results suggest that 3D visualizations models, synthesized from an array of historical resources, can effectively deliver information about past landscapes to environmental planners, decision makers, and the public.

Tuning LEDs to Minimize Insect Attraction

Tuning LEDs to Minimize Insect Attraction

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Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.