Two light pollution research updates

I’m usually one to announce research results and not grant funding, but the funders put out a release and Tweet, so it is officially news that we are starting a new 2-year project: Coast Light: Actionable Science to Manage Coastal Nightscapes. The funding is from USC Sea Grant and includes in-kind contributions from many partners that will make the project possible — including data, labor, and/or time from Los Angeles County Museum of Natural History (collaborating on measuring influence of light on settlement rates of marine invertebrates), The Aerospace Corporation (providing coastal night light measurements by cubesat!), Los Angeles Audubon Society and the many volunteer snowy plover monitors, and Professor Karen Martin at Pepperdine (grunion data).  More about the project as it develops — I’ll be co-advising a Ph.D. student from Biological Sciences who will be the official Sea Grant Trainee on the project.


Preliminary results from analysis of radiance-weighted nighttime boat detections by month off the coast of southern California (Gutierrez-Dewar, Elvidge, and Longcore, unpublished data).

Our Park Light research efforts are coming to an interim head, as at least three lab members will present at the Los Angeles Geospatial Summit on February 23.  Harrison Knapp and Ben Banet will present a classification of National Park Service units based on the lighting conditions inside the parks and in buffers surrounding them, so that parks can know what other parks face similar issues for light pollution management.  Eliza Gutierrez-Dewar has some very interesting results looking at the spatial and temporal distribution of squid boats off the Pacific Coast, which can be identified using night lights because of the bright lights used by squid fishers to attract the squid up near the surface where they can be caught.  This project builds on data produced by an automated boat detection algorithm developed by Chris Elvidge’s group at NOAA and is of significant interest to land managers looking to protect sensitive seabird nesting sites from excessive light (and associated predation risk) during nesting season. We may have another poster, but I have not reviewed the final program yet.

Cryptic Biodiversity Abounds in Los Angeles

Cryptic Biodiversity Abounds in Los Angeles

Cities are often perceived as biodiversity wastelands. Adding to that perception is the common result of research surveys of urban biodiversity, which often report limited and declining numbers of species (1). Concealed by that preconception, however, is the extraordinary undiscovered biodiversity that still exists, even in the most urban of environments. Much of this biodiversity is cryptic, defined as “invisible to the naked eye, dormant species, and other species present in such low numbers that they go undetected” (2). Urban biodiversity goes under-recognized both in these small, rare, or morphologically confusing groups and because the assumption is often that nothing is to be found.

Contradicting this perspective are new results from a unique urban biodiversity study that has yielded dozens of new species of flies in the family Phoridae from a mere three months of sampling in backyards in Los Angeles, California (3). The findings come from a project called “BioSCAN” (Biodiversity Science, City and Nature), conducted by the Natural History Museum of Los Angeles County (4). The intent of the project is to inventory the insect biodiversity of Los Angeles. The study focuses on insects because their small size, relatively sedentary habits, and life history diversity could reasonably be expected to make them sensitive responders to varying urban conditions (5, 6).

BioSCAN is based on thirty sampling sites, each with a tent-like Malaise trap and a microclimate weather station, arrayed from the urban core of Los Angeles out to the nearby less-urbanized foothills. Each trap’s sampling bottle is changed weekly, and the study will sample for three years. The diversity data, in conjunction with physical measurements from the microclimate stations and landscape parameters (e.g. local percentage of hardscape, plant species adjacent to the trap, population density, proximity to roads and highways) will be used to develop mechanistic hypotheses about the causes of differences in biodiversity across these conditions.

Access for sampling is a major challenge in urban areas. It is logistically and bureaucratically impractical to deploy thirty sampling stations for three years in urban public or agency land with reasonable security. The solution was to situate most of BioSCAN’s thirty sampling sites in the backyards of volunteers, taking advantage of personal commitments of private property. Involving fewer than thirty families, this is not a typical crowd-sourced “citizen science” program. The intimate involvement between site hosts and researchers, however, has injected science and biodiversity appreciation into the daily life of the site hosts and grounded the researchers in the public life of their city.

Where is previously unknown diversity showing up in the urban environment? Unsurprisingly, it is in the world of small insects — what Piotr Nasrecki has termed “the smaller majority” (7). Like other current research exploring the biodiversity of human-dominated spaces, such as assessments of urban ants through the School of Ants project (8) and bees and butterflies of the Bronx and East Harlem (9), cryptic biodiversity abounds. So far, the BioSCAN survey has yielded at least eighty species in the single phorid fly genus Megaselia, of which thirty are new to science (3). Phoridae is the first taxon that the researchers have examined in depth. Even in one of the most heavily studied insect groups in the world, the drosophilid fruit flies, the survey has yielded unsuspected new finds (10). Finding such undescribed diversity strongly suggests that further exploration will yield dozens of new species across the insect taxa.

Although it would be efficient and ultimately necessary to discern the full range of insect biodiversity through genetic techniques (11), the early results rely on traditional taxonomy, with Hartop and colleagues illustrating the diagnostic differences in genitalia of the thirty new species in careful hand-drawn figures (3). The illustrations highlight the craftsman-like dedication required of traditional insect taxonomy and will be an irreplaceable educational tool in educating Los Angeles schoolchildren how 30 different kinds of flies could be so similar and yet different.

The results from Los Angeles are establishing baselines of species distribution. Not enough is known about these groups to even predict whether the species are native and continue to thrive in the urban forest of Los Angeles neighborhoods or whether they represent cosmopolitan species that might be found in other cities. Documenting and understanding patterns of seemingly inconsequential species groups is important, as shown by the utter lack of knowledge about the prior distributions of emerging pathogens such as the fungi Batrachochytrium dendrobatidis, which was cryptic biodiversity until it was identified as a pathogen responsible for decline and extinction of amphibians (12, 13) and Geomyces destructans, responsible for white nose syndrome and resulting collapse of bat populations in North America (14). If we know more about the nature of the surface of the moon than we do of the microbes and microscopic insects of our cities — and we do — society will remain vulnerable to the unintended consequences of global homogenization and transportation of that biota. And urban planning cannot fully incorporate biodiversity unless we actually how the full range of biodiversity is affected by urbanization.

The study of urban ecology also inevitably involves working with the people living in the research area. Rather than being seen as a challenge, that is a strongly positive benefit of urban work. People who experience nature care more about conserving it (15). Conservation of worldwide biodiversity, even outside of urban areas, depends on large numbers of people caring about it. Paradoxically, therefore, the fate of global biodiversity conservation rests on how city dwellers — now a majority group — experience urban nature (16, 17).

Literature Cited

  1. M. L. McKinney, Effects of urbanization on species richness: A review of plants and animals. Urban Ecosystems 11, 161-176 (2008).
  2. G. F. Esteban, B. J. Finlay, Conservation work is incomplete without cryptic biodiversity. Nature 463, 293 (2010).
  3. E. A. Hartop, B. V. Brown, R. H. L. Disney, Opportunity in our ignorance: urban biodiversity study reveals 30 new species and one new Nearctic record for Megaselia (Diptera: Phoridae) in Los Angeles (California, USA). Zootaxa 3941, 451–484 (2015).
  4. B. V. Brown, A. Borkent, R. Wetzer, D. Pentcheff, New types of Inventories at the Natural History Museum of Los Angeles County. Am. Entomol. 60, 231–234 (2014).
  5. C. Kremen et al., Terrestrial arthropod assemblages: their use in conservation planning. Conserv. Biol. 7, 796–808 (1993).
  6. T. Longcore, Terrestrial arthropods as indicators of ecological restoration success in coastal sage scrub (California, USA). Restor. Ecol. 11, 397–409 (2003).
  7. P. Naskrecki, The smaller majority: the hidden world of the animals that dominate the tropics. (Harvard University Press, 2005).
  8. A. Lucky et al., Ecologists, educators, and writers collaborate with the public to assess backyard diversity in The School of Ants Project. Ecosphere 5, 78 (2014).
  9. K. C. Matteson, G. A. Langellotto, Determinates of inner city butterfly and bee species richness. Urban Ecosystems 13, 333–347 (2010).
  10. D. Grimaldi et al., Strange little flies in the big city: exotic flower-breeding Drosophilidae (Diptera) in urban Los Angeles. PLoS ONE, (in press).
  11. R. Meier, W. Wong, A. Srivathsan, M. Foo, $1 DNA barcodes for reconstructing complex phenomes and finding rare species in specimen‐rich samples. Cladistics in press, (2015).
  12. J. E. Longcore, A. P. Pessier, D. K. Nichols, Batrachochytrium dendrobatidis gen. et sp. nov., a chytrid pathogenic to amphibians. Mycologia 91, 219–227 (1999).
  13. M. C. Fisher, T. W. Garner, S. F. Walker, Global emergence of Batrachochytrium dendrobatidis and amphibian chytridiomycosis in space, time, and host. Annu. Rev. Microbiol. 63, 291–310 (2009).
  14. A. Gargas, M. Trest, M. Christensen, T. J. Volk, D. Blehert, Geomyces destructans sp. nov. associated with bat white-nose syndrome. Mycotaxon 108, 147–154 (2009).
  15. J. R. Miller, Biodiversity conservation and the extinction of experience. Trends Ecol. Evol. 20, 430–434 (2005).
  16. R. Dunn, M. Gavin, M. Sanchez, J. Solomon, The pigeon paradox: dependence of global conservation on urban nature. Conserv. Biol. 20, 1814–1816 (2006).
  17. E. W. Sanderson, A. Huron, Conservation in the city. Conserv. Biol. 25, 421-423 (2011).