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The power of community science to quantify ecological interactions in cities
February 10, 2021

Southern Alligator Lizard during an attack by a cat; iNaturalist 1733118 by Kristin Papoi and Violet Gibbs


Article Details:


Putman, B. J., R. Williams, E. Li, and G. B. Pauly. 2021. The power of community science to quantify ecological interactions in cities. Nature Scientific Reports 11:3069.

Organisms and their natural history—learning what they do out there, imagining what it’s like to be them—often are at the core of why a scientific paper is interesting. As a teenager marooned in Missouri, I was introduced to Texas Alligator Lizards by reading a book about amphibians and reptiles. It was love at first sight, and later field encounters with that and several related species confirmed the attraction. These are slow-moving animals, prone to folding their smallish legs and slithering like snakes. Alligator lizards often flick their slightly forked tongues, evidently more dependent on chemical senses than many other lizards; as other naturalists also have remarked, they seem unusually intelligent as reptiles go, especially deliberate and aware. They also are shy and secretive, so we know little about most species—no published studies, for example, address the natural diet of Madrean Alligator Lizards, despite their widespread occurrence in Arizona. Until the report featured here, a claim that someone accumulated 6,700 observations of Southern Alligator Lizards, of which 1,688 would qualify as “research grade,” would have struck me, a life-long alligator lizard aficionado, as preposterous.

Fig. 1. iNaturalist observations of lizards during or after interacting with cats in the Southern California study area. (A) Cat attacking a Southern Alligator Lizard (Elgaria multicarinata) that has autotomized [broken off] its formerly complete, original tail; iNaturalist 2734344 by Annie Stevens. (B) Cat (note head and ears in lower left of photo) attacking a Southern Alligator Lizard that has autotomized its tail; iNaturalist 6012370 by Dawn S. Chianese. (C, D) Southern Alligator Lizard during and after an attack by a cat; iNaturalist 1733118 by Kristin Papoi and Violet Gibbs. (E) Southern Alligator Lizard with a tail injury after being caught by a cat; the fresh tissue at the tail tip is a re-growing tail following an autotomy event several weeks prior to this observation; iNaturalist 1447779 by iNaturalist user biesman. (F) Autotomized tail from a Southern Alligator Lizard on a neighborhood sidewalk following an attack by a cat; iNaturalist 2766323 by Patricia Simpson. (G) Western Fence Lizard (Sceloporus occidentalis) caught by a cat; iNaturalist 23869292 by Sharon Nakata. (H) Side-blotched Lizard (Uta stansburiana) caught by a cat; iNaturalist 8274946 by Maiz Connolly, who noted that “as soon as the cat dropped the lizard, the lizard dropped its tail, which wriggled enough to keep the cat’s attention while it made its escape.” (From Putman et al. 2021).

Enter Greg Pauly, curator of herpetology at the Natural History Museum of Los Angeles County (NHMLAC), who for the last decade has pioneered using community science to gather credible data on western North American amphibians and reptiles. Greg is insatiably curious, gregarious, and committed to both science and education—so perhaps it’s not surprising he jumped at the chance to engage fellow Californians in learning more about their biological surroundings, by taking advantage of the iNaturalist platform. A resulting paper, led by former NHMLAC postdoctoral fellow Breanna Putman and featured here, beautifully illustrates the potential of this approach for studying a poorly known species and its responses to urbanization.

The problems addressed by Putman, Pauly, and coauthors are of a sort about which it’s easy to speculate, but for which it is much harder to gain definitive data. They also entail a topic on which conservationists and animal lovers (many of us are both) argue among themselves, sometimes bitterly—the effects of domestic cats on native species in human-dominated landscapes. That potential for controversy makes it all the more crucial that the authors of this study have detailed a clever methodology and stringent criteria for using geo-referenced photographs to assess predation and parasitism. With a resulting 723 and 157 cases for analysis, respectively, they show that Southern Alligator Lizards in urban areas incur increases in the former and decreases in the latter. These results, in some ways unexpected, will inspire those of us concerned with how urbanization threatens biodiversity to think harder about solutions. We can do that better now, armed with the new evidence from this paper.

Meet Harry Greene

Harry W. Greene is emeritus professor of ecology and evolutionary biology at Cornell University, author of Snakes: The Evolution of Mystery in Nature and Tracks and Shadows: Field Biology as Art, and a member of the NHI’s science advisory council.
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