The most significant predictors of insect biodiversity in Los Angeles are proximity to the mountains and temperature stability throughout the year, according to a study us co-authored with Brian V. Brown from the Los Angeles Museum of Natural History and colleagues at the University of Southern California and California State University.
The project used museum data BioSCAN Projectwhere volunteers in Los Angeles allowed insect traps to be installed on their properties between 2014 and 2018.
The analysis showed some surprising results. For example, land value has had little impact on the overall diversity of arthropods, specifically spiders and insects. This discovery challenges the “luxury hypothesis”, the notion that wealthier neighborhoods, which tend to have more treeswe always have greater biodiversity – an assumption that is generally true for birds It is mammalsIncluding bats.
The BioSCAN study identified more than 400 different species of insects in Greater Los Angeles, many surviving despite the loss of pavement and habitat.
In fact, urban environments may be attractive to some invasive arthropod species. Often called urban opportunists, such species often emerge in waves that replace or restrict current species. For example, about 20 years ago, black widow spiders native to Los Angeles (Latrodectus hesperus) began to be replaced by brown widow spiders (geometric Latrodectus). Recent evidence shows that these intruders are now being replaced by noble false widow spiders (Steatoda nobilis).
Why does this matter
Insect populations are essential for people, which depend on them to provide pollination, decompose plant and animal material, and control insect pests. These services are so important in cities as in rural environments – and are provided free of charge by insects.
Imagine a city where organic waste, such as dead animals or plants, does not decompose. A city without insects would also mean an environment without birds and most other types of wildlife, many of which depend on insects for food. Such a place would also have no flowers, fruits or vegetables growing. In fact, a world without insects would be a world without humans.
Low arthropod diversity can lead to ecosystem imbalance. A 2022 study found that pests such as sap-feeding aphids can spread out of control in highly urban areas because there aren’t enough predators, like beetles and spiders, to keep them in check.
Most biodiversity studies are carried out in natural or even protected areasBut increasingly scientists are recognizing that urban areas can harbor many species. Understanding biodiversity in urban areas is important because cities are expected to continue to spread – with the forecast of the United Nations Urban populations will grow by 2.5 billion by 2050.
What is not yet known
Although we now know which factors most strongly influence arthropod diversity in Los Angeles, we do not fully understand how this diversity translates into healthy urban ecosystems.
Scientists know More species lead to healthier urban ecosystems, but not all species contribute equally. For example, planting pollinator-friendly plants They are a relatively easy intervention in urban environments, but will not benefit all insect species.
What is the next
As part of the BioSCAN project, volunteers also allowed the installation of bioacoustic monitors on their properties, so that future studies can include bats, which are also crucial for pollination and pest control in cities.
Additionally, researchers at the University of Southern California continue to study the same dataset to understand seasonality in urban arthropod communities. In a warmer climate, this knowledge could help predict future changes in insect populations.
Overall, insights from these studies can help inform urban planning and development to support insect biodiversity, especially as cities expand through urban sprawl.
This article was republished from The conversation, an independent, nonprofit news organization that brings you trusted facts and analysis to help you understand our complex world. It was written by: Laura Melissa Guzman, USC Dornsife College of Letters, Arts and Sciences; Charles Lehnen, USC Dornsife College of Letters, Arts and SciencesIt is Teagan Baiotto, University of Southern California
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Laura Melissa Guzman receives funding from the Conservation, Food and Health Foundation.
Charles Lehnen is receiving funding from external sources Iguanas on Balance Grant and Gold Family Fellowship, as well as internal funding sources from USC USC Provost Fellowship, USC Graduate School Travel/Research Award, PhD Academy Scholarship & Research Fund, and USC Graduate Student Government GSG Professional Development Fund.
Teagan Baiotto does not work for, consult with, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond her academic appointment.
