Making Invasive Species Useful at the Zoo


The bad news: Exotic acacia trees pose a pesky problem for native coastal dunes at Los Angeles International Airport. The good news: Giraffes like them—a lot. (Los Angeles Times)

Use our resources to better understand invasive species and how to control them.

No, this isn't the L.A. Zoo and that tree isn't invasive. This gorgeous giraffe is assessing the all-natural acacia buffet in Serengeti National Park, Tanzania. Photograph by George F. Mobley, National Geographic
No, this isn’t the L.A. Zoo and that tree isn’t invasive. This gorgeous giraffe is assessing the all-natural acacia buffet in Serengeti National Park, Tanzania.
Photograph by George F. Mobley, National Geographic

Discussion Ideas

  • The LA Times article says acacia trees pose a “pesky problem” for coastal dunes near Los Angeles International Airport (LAX). Why are the acacia trees “bad news” in LA? Read the short introduction to our encyclopedic entry on invasive species for some help.
    • Acacia trees are an invasive species in Los Angeles’ coastal dunes. This means two things.
      • First, the trees are a non-native species (sometimes called an exotic species). They do not naturally grow in the dunes. According to LAX, acacia trees were imported from Australia in the early 20th century when the region was being developed for residential and business purposes.
      • Second, the trees harm the natural environment. Not facing the natural climate hazards they do in their native Australian habitat, the acacias have choked out the dunes’ native plants and the food webs. In particular, acacias have threatened the coast buckwheat, a plant necessary for the survival of the El Segundo blue butterfly, an endangered species.
  • The partnership between LAX and the LA Zoo has benefits for both organizations, as well as residents of Los Angeles. How does the partnership benefit LAX? the zoo? Angelenos? the environment? Take a look at this press release from the airport for some help.
    • LAX: The partnership reduces costs to maintain the LAX Coastal Dunes Improvement Project. Airport workers no longer need to clear dunes of acacias and transport them to the city’s recycling site.
    • LA Zoo: The partnership provides several benefits for the zoo. The airport provides the acacia for free, so the zoo no longer has to spend as much money on food for exotic animals such as giraffes, elephants, and rhinos. The animals love the plant, which is related to the African acacia they would eat in the wild. According to the press release, “almost every part of the acacia tree is edible to one kind of animal or another,” so very little goes to waste.
    • Angelenos: LA taxpayers are saving some money, preserving the little undeveloped land that remains of the dunes, and patting themselves on the back for being sustainable. The zoo and airport are at least partly public departments, and the cooperation saves money on food for the animals, transportation, and plant-removal labor. The city’s landfills are also spared “green waste” (material that could otherwise be recycled), which ultimately saves money, the environment, and valuable real estate.
    • Environment. The most direct benefit of the partnership for the environment is the re-introduction of native plants and animals to the coastal dunes. Coast buckwheat and El Segundo blue butterflies have a greater chance for survival with the removal of the invasive acacia.
  • The innovative program described in the LA Times article is one way a community is dealing with an invasive species—feed it to other (non-invasive) species! What other ways can individuals, communities, and countries work to eradicate or at least reduce the impact of invasive species? These ideas might get you started.
    • Individual: Eat an alien invader! Help conquer ocean invaders by including them in your meals. Here are a couple recipes from Nat Geo explorers.
    • Communities: Community groups can work to reduce invasive species through eradication or mitigation programs. Read about how one group in the San Francisco Bay Area used a “low-toxic” pesticide to reduce the impact of the invasive Spartina plant in the estuary.
    • Government: Local, regional, and national governments can work to reduce invasive species through strict laws. Read the short section “Eradicating Invasive Species” in our encyclopedic entry for some examples of aggressive (violent!) government action to combat invasive species. Sometimes, however, the invasive species are just too resilient and cannot be eradicated. Watch our video on cane toads, an invasive species in Australia, for an example of just such a species. All Australia can do is deal with the “invasion” and stop it from getting worse. According to the Australian government, “[r]ecent research documented the ability of some native species to adjust their behavior and avoid interactions with cane toads if they can survive their initial exposure to toad toxins . . . Preventing cane toads from arriving on toad-free islands will be an important part of future cane toad management. Additionally, protecting discrete areas of high biodiversity value, using the best available trapping and exclusion techniques, is important.”

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