The southern water snake

California will gain a new invasive species every 60 days. According to the Center for Invasive Species Research at UC Riverside, some of these could lead to economic losses to the state of about $3 billion each year. We’ll discuss the issues surrounding invasive species from Scotch broom to Asian carp and beyond.

Bryan Walsh, senior writer for TIME Magazine and author of TIME's recent invasive species cover story
Mark Hoddle, director for the Center for Invasive Species and researcher, Department of Entomology at UC Riverside
David Lodge, director of the Environmental Change Initiative at the University of Notre Dame

  • Livegreen

    This is yet another example of why the environment MUST be factored into our international trade agreements.

    What are some of the key steps that can help reduce the spread of invasive species? With such an enormous problem it is important to do something and start somewhere…

  • Sanhita Datta

    I am surprised to have the issue of xenophobia brought into the discussion of invasive species. Xenophobia (as it pertains to social sciences) is hatred directed by one group of humans to another. The key point here is that all humans belong to the same species, Homo sapiens. Ecologists are talking about DIFFERENT species. Perhaps people need to better educated about what the term “species” mean.

    • jurgispilis

      I always thought xenophobia is fear of the warrior princess.

  • Ben Rawner

    Why is it that when its a plant we want its transplanted, while if its something we dont want, it’s invasive. Isn’t the earth ever-evolving?

    • Sanhita Datta

      You need to take an Ecology class to really understand this. They can devastate an ecosystem at a rate way faster than any natural evolution and local populations cannot adapt at that rate.

  • Sam Badger

    Not all invasive species are similarly bad, and some amount of species “invasion” is inevitable even without humanity. Is there an attempt to triage the response to invasive species? Should we allow some to thrive unmolested? After all the Monterrey Cypress is “invasive” in San Francisco as it is native to the coast a hundred miles or so south, yet the tree beautifies the city and doesn’t seem to cause too much harm.

  • Anne Schulte

    I’m pretty sure my mom died fighting an invasive species. I remember her spending hot summer days out in our 9 acre yard in Colorado spraying thistles with poison to prevent them from taking over the meadow. She would wear a mask – {not a respirator but a particulate mask) — and therefore, probably, inhaled a concentration of this poison as it absorbed onto her mask. She died of an undetermined neurological disease (which was diagnosed as MS but her autopsy results showed that it was not MS). I blame the thistles and her determination/dedication/decision to fight them.

  • Sam Badger

    Are we going to remove the eucalyptus trees? Or perhaps introduce Koalas to keep their numbers in check …

  • Tom

    The northern pike in Lake Davis in 1997 was a huge headache. The state spent millions to eradicate it – to prevent destruction of salmon and trout populations.
    Other invasive species in California;
    Red eared slider turtle (released pets) – endangering the western pond turtle.
    Wild boars
    European carp – purposely introduced even though anglers didn’t want it.
    Ice plant – creating havoc along the coast.
    Eucalyptus tree – highly flammable and increased damage in the Oakland fire of 1991.

    • L A

      Eucalyptus trees are not invasive. They rarely reseed. That they were widely planted and that they are highly flammable does not make them an invasive species.

      • Tom

        Incorrect. Eucalyptus trees were introduced from Australia. They are not native to California. They may not seed but they can spread quickly through suckers from the roots – cutting down a eucalyptus tree does no good because the suckers will sprout up and take the old tree’s place. In places where eucalyptus trees take over, native trees like oaks don’t grow. That means less food for wildlife that depend on acorns and native berries.

        • L A

          I know eucalyptus are native to Australia. I didn’t say they are native to California. Some eucalyptus do resprout–the blue gum (Eucalyptus globulus) is the one that resprouted after the cold winter and then burned the following year in the Oakland hills.

          Here is a link to Cal-IPC and a list of invasive plants in California. The only eucalyptus listed is E. camaldulensis and its rating is “limited”. Not high, not moderate but limited. So I question the implication that eucs are taking over. As I said, the blue gum will resprout. If you really want to get rid of a euc, keep cutting the regrowth and it will die of starvation.

          Yes oaks won’t grow where eucalyptus are growing. Not much else does. But the widespread planting of eucalyptus happened a long time ago, didn’t it? I don’t think people are planting eucs on their large properties. I do see a lot of olive trees being planted. Another non-native.
          I think there are many other plants that actually are invasive that we should be concerned about and I am tired of eucalyptus bashing using incorrect information and misusing the term invasive. Yes I like eucalyptus and they have become part of the look of California. I was born in 1948 so I saw lots of eucalyptus in Sonoma county as a child as well as native oaks, madrone, manzanita and pepperwood.
          Thanks for engaging in this conversation.

  • Tom

    Sam – it’s very dangerous to introduce a new species to control another invasive species. Somebody got the bright idea of introducing the mongoose to Hawaii to control rats. The mongoose is diurnal and the rat is nocturnal so that failed but the mongoose wiped out multiple bird populations.
    Another example was the gypsy moth – somebody introduced the tachnid fly, a caterpillar parasite. Turned out that the tachnid fly isn’t a specialist and it spread across the country preying on numerous caterpillars and reducing other butterfly and moth populations without having any effect on gypsy moths.

    • Sanhita Datta

      Thank you. Actually that is a great example to answer Ben Rawner’s question. The Hawaiian birds were evolved to hide from predators up in the air. So, their predator avoidance response was often freezing in one spot. This made them very easy prey for all the introduced mammals. The birds could not possibly “evolve” that quickly and literally became sitting ducks.

      • Tom

        The pet trade has produced some pretty horrific invasive species. As mentioned, the Burmese python in Florida. The snakehead fish in Maryland is another. Some people think the goldfish is benign but it’s just a carp and if you throw a goldfish into the nearest pond, you’re establishing a new carp population.

  • Guest

    Here in California, there is an organization called PlantRight which is a cooperative effort between environmental groups, academics, and horticultural industry representatives. Their goal is to reduce the introduction of invasive plants via the nursery trade. They conduct nursery surveys statewide each spring to understand which species are being sold in order to better understand which plants are a problem. They provide suggested alternatives to commonly propagated invasives and are piloting a pre-introduction plant evaluation tool to help the horticulture industry save money by not developing invasive varieties for sale. I am not a PlantRight representative, but I think it is a step in the right direction and a good approach since it draws in groups from a variety of backgrounds.

  • Brett Cox

    To an extraterrestrial observer, it would be painfully obvious that one particular invasive species is ravaging the earth. That species is not the Burmese python, nor the zebra mussel, nor the yellow star thistle.

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