August 2, 2016
Los Angeles is a stunningly metamorphic place. A vast, industry- and people-dense metropolis, L.A. lives in the global psyche as the frontier of opportunity and personal transformation. Everything about L.A.—its geographic boundaries, the contours of its built environment, the languages and culture and impulses of its residents—is in a permanent state of flux. The city becomes nearly unrecognizable from one generation to the next. Our planet is in a state of equally dramatic transformation. The Earth is rapidly being reconfigured into sprawling urban centers, like L.A. According to the World Health Organization (WHO), “The urban population in 2014 accounted for 54% of the total global population, up from 34% in 1960, and continues to grow.” Interestingly, WHO notes that the growth is concentrated in less developed regions of the world. For that reason, the May 20, 2016 edition of the journal Science was dedicated to our “Urban Planet.” The introduction to the special issue, titled “Cities are the Future,” describes the impact of global urbanization. “The implications are sobering. The land area needed to provide city residents with food, energy, and materials is expanding; this ecological footprint is often 200 times greater than the area of a city itself. The resulting carbon emissions, added to those from cities themselves, mean that urbanization is now the main driver of climate change.” A “perspective” in Science’s blowout issue, written by Terry Hartig and Peter H. Kahn, Jr., and titled “Living in Cities, Naturally,” addresses some of the physical and psychological malaise that urban residents can experience when they are disconnected from the natural world. They also discuss an impact of urbanization that may be more subtle but far-reaching. When city dwellers are divorced from nature and a sense of the richness of the natural world, they start to normalize environmental degradation in what Hartig and Kahn call “environmental generational amnesia.” “[P]eople do not feel the urgency or magnitude of problems because the experiential baseline has shifted.” In other words, to paraphrase Donald Rumsfeld, urban dwellers don’t know what they don’t know about environmental change. They have no real reference point. They can only measure changes to their natural environment based on vague memories of childhood experiences. “Providing opportunities for people to experience more robust, healthy, and even wilder forms of nature in cities offers an important solution to this collective loss of memory and can counter the shifting baseline,” Hartig and Kahn write. L.A. Can Lead the Way Greg Pauly, curator of herpetology and co-director of NHMLA’s Urban Nature Research Center (UNRC), grew up in a suburban neighborhood near San Jose, California. He spent his afternoons wandering the nearby hills searching for lizards. He also rescued and rehabilitated a menagerie of three-legged, no-tailed lizards that had been maimed by neighborhood cats. His early relationship with these lizards, and the acute awareness of the natural and unnatural environments which they navigated, spurred his desire to study and protect them. “When my father was growing up in Pasadena, horned lizards were a common part of the landscape. That species is now entirely gone from the L.A. basin. At the UNRC, we’re trying to understand how species have responded to urbanization and how their distributions are changing.”
Once common, the majestic horned lizard is no longer found in the L.A. Basin. Argentine ants have displaced native ant species on which the horned lizard feeds. The well-camouflaged lizard above was recently photographed in Kern County. Photo by: Martin Schlageter “Los Angeles is a biodiversity hotspot,” says UNRC co-director Brian Brown. “It’s an area of great diversity, but it is also under great threat. Through collaborations and access to scientific resources, UNRC is creating the world’s largest urban biodiversity survey. Our research can help inform urban planning policies to minimize impacts on native species.” We are well past the era of boosters selling the young L.A. as a utopia of unbridled innovation, opportunity and wellness. And we are also beyond the bleak, Blade Runner-esque dystopian vision of L.A. that dominated in the latter half of the past century. Like all cities, Los Angeles, even at its urban core, remains a dynamic, living ecosystem. Understanding, protecting and promoting the region’s biodiversity is our next frontier. If you’d like to be involved in efforts to document and protect L.A.’s biodiversity, check out our Citizen Science program. Or you can donate to the UNRC.
August 11, 2012
Lots of people in the L.A. area have been complaining about the heat. Over the last week, cities in our region have been experiencing temperatures well into the 90s. On Monday, Woodland Hills reached 108 degrees!Whenever the temperature rises like this, I start to notice ants indoors. Only this morning during our Nature Lab meeting, I found a trail of ants leading to the sink, and another leading to the snack shelf.The ants I found are Argentine Ants, Linepithema humile. They are an introduced species from South America (Argentina and Brazil) and are now considered the most common ant in our area. According to the Insects of the Los Angeles Basin book, these ants were "introduced to New Orleans before 1891 in coffee shipments from Brazil, and it has since spread rapidly over much of the United States."This is what the same book has to say about their pest status:"The species is one of the most persistent and troublesome of all our house-infesting ants. Argentine Ant workers seek out and feed on almost every type of food, although they are especially fond of sweets. Making themselves most objectionable, the ants invade the house through minute crevices and cracks—filing along baseboards, across sinks, and over walls and tables in endless trails."How do you feel about ants in your home? While writing this blog, I've found it interesting to ponder this question. As you may have noticed I am a nature lover, however I am definitely not a fan of ants in my house and will go to great lengths to remove them. Many times this feels like a losing battle, especially because I'm not one for spraying pesticides all over the place I live.
Argentine Ant about to take drink of water in our Nature Lab trailer(It is one eighth of an inch long)The Argies, as we "fondly" refer to them, have also been found throughout the North Campus. This isn't surprising as it is well documented that this ant species has displaced many of our native ants. According to Alex Wild, author of the Myrmecos ant blog, Argentine Ants, "can drive native arthropods to extinction, instigating changes that ripple through ecosystems. In California, horned lizard populations plummet. In South Africa, plant reproduction is disrupted. Worldwide, the Argentine Ant is a persistent house and crop pest. This is not a good ant." Here are some pictures of their activities on the North Campus:
Argentine Ants killed all the paper wasps in this nest
Argentine Ants tending citrus scales in our orange treesWhen I found the ants had killed all the paper wasps in the nest pictured above, I have to admit I was disappointed. I know many would be cheering for the ants, as paper wasps are viewed as a pest themselves. However, I had already become invested in the livelihood of that particular wasp nest and would check up on it every time I was out in the gardens. I find it infinitely interesting to ponder our notion of pest. What is acceptable in some circumstances is unacceptable in others. However, I still haven't come across anyone who is a fan of Argentine Ants!Need tips of managing ants in your home? Check out the UC Davis Integrated Pest Management website.