They’re against science and free speech » « To boldly go where everyone has gone before

The nefarious prickly pear

I’ve always taken cactuses for granted — I’ve lived in deserts before, and they’re just there, growing all over the place, and familiar part of the landscape. I didn’t think about the fact that they’re an entirely American clade, or that they could be a destructive invasive species elsewhere. I didn’t know that they were a major pest in Australia, along with rabbits and cane toads (Australians keep bringing in alien species that devastate their ecologies, in desperate attempts to counter the previous wave of invaders). So this was an informative video for me.

It’s also an example of where bringing in yet-another-foreign species, in this case moths and scale insects, defeated the problematic invasive species. For now.

They’re against science and free speech » « To boldly go where everyone has gone before

Comments

  1. francesconic says

    We export alien species that devastate ecologies too. How are those fire prone Eucalypts doing in California ?

  2. raven says

    Prickly pears in South Africa
    From Wikipedia, the free encyclopedia

    In South Africa, many species of Opuntia are considered highly invasive including O. aurantiaca, O. elata, O. engelmannii, O. ficus-indica, O. humifusa, O. leucotricha, O. microdasys, O. monacantha, O. pubescens, O. robusta, O. salmiana, O. spinulifera, O. stricta and O. tomentosa. These species are classified as Category 1 invaders, and targeted for national eradication; most activities with regards to the species are prohibited (such as importing, propagating, introducing, translocating or trading).[1]

    Opuntia ficus-indica (known as the prickly pear) is a plant that has been part of the landscape of South Africa for over 250 years.[2][3]

    Arrival and spread
    The prickly pear was brought to South Africa, from the Americas, in the mid-18th century.[2] When it established itself in the Eastern Cape and Karoo, it took control of the environment around it because of being drought resistant, able to reproduce without seeds as well as its “extensive seed dispersal”.[5] It thrived in these regions, where the original vegetation had already been disturbed by settlers.[5]

    Uses
    Part of what facilitated the spread of the prickly pear was its utility. The plant was used by a variety of people: It has “been, at some time, of importance to white commercial farmers, farmworkers, African landholders and urban communities”.[6] The fruit can be eaten or turned into jams, preserves, beers, wines and soaps and the leaves can be used as medication.[7] In addition, prickly pear can be useful fodder, particularly during drought, when few other plants survive.
    and
    In 1932 biological control in the form of, particularly, the cochineal and phycitid moth, was introduced and was highly effective.[3] It is largely due to this that, in 2002, there was a tenth of the number of prickly pear left when compared with the 1930s.[16]

    They did the same thing in South Africa before they did it in Australia.

    Prickly Pear cactus was introduced into South Africa in the 1700s. It became an invasive species and took over many areas. They ended that problem in 1932 by introducing insect predators.

    I’ve eaten the fruits of Prickly Pears before, harvested from wild plants.
    They are very good.

  3. birgerjohansson says

    Hmm…the biggest invasive species from 1492 onwards has been Europeans. People descended from my country seem especially prone to become bigoted christians or far-right conservatives with destructive consequences for the land.
    (With exception for the guy who built the Monitor, he was great)

  4. says

    Whenever humans upset the balance in an ecosystem, it is always a disaster. The human mind is not capable of taking all the myriad of factors into account when they insert a new factor into an ecosystem. I’m sure that, a.i. modeled on the human mind, will also be incapable of meddling successfully with the incredible complexity of an ecosystem. Prime example of human hubris and folly: the deadly biosphere experiment in arizona.

  5. lasius says

    There may be one species that managed to get to the old world without human help. A species that conveniently spreads via birds.

    This is also something I always notice in movies and games that are set in the ancient Mediterranean world. They often show Opuntia cacti long before they would be introduced from America.

  6. robro says

    francesconic — Those Eucs are doing fine but they do like to fall down.

    It’s the Acacias that are the real bother when they flower in the Spring. I’ve never suffered from allergies, but when the little stand of Acacia next door to us bloomed this Spring, it hit me hard.

    Here’s one from the Marin County naturalist…yeah liberal bastions have those: She says that the Summer time browning of the hills in California is not natural. It’s the result of the native grasses being supplanted by invasive grasses from Europe to feed livestock. The native grasses were long rooted and would stay green all summer. We passed a little plot of native grasses the other day and they were as green as could be.

    Anyway, I think it’s all a product of colonialism.

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