Planet of the Arthropods

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comparative diversity of animal groupsI’m on the radio! Skeptically Speaking asked me to talk a little bit about insect conservation, in order to round out an interview with the author of Rat Island. (I haven’t read the book yet, but it looks pretty fascinating.)

I mostly discussed the 2012 report “Spineless”, published by IUCN (The International Union for Conservation of Nature).  You might recognize IUCN as author of the Red List, the definitive international list of species that are at risk of extinction.

Why should we care about a bunch of squishy boneless animals?
Because invertebrates make up EIGHTY PERCENT OF ALL MULTICELLULAR SPECIES ON EARTH.  They truly are the “little things that run the world.”  The IUCN report suggests that 20% of those species are at risk. That is a big deal.

The report itself is fairly accessible to the lay reader, and includes lots of data, citations, and lovely photos of what we will be missing if we don’t start paying attention.

Download and read the report here.

The topic I discussed was ecosystem services–the stuff we get for free simply by living on earth:

“The Millennium Ecosystem Assessment – a four-year United Nations assessment of the condition and trends of the world’s ecosystems – categorizes ecosystem services as:

  • Provisioning Services or the provision of food, fresh water, fuel, fiber, and other goods;
  • Regulating Services such as climate, water, and disease regulation as well as pollination;
  • Supporting Services such as soil formation and nutrient cycling; and
  • Cultural Services such as educational, aesthetic, and cultural heritage values as well as recreation and tourism.”

For some reason, I ended up talking about poop and waste removal more than other ecosystem services, but insects also make up a major part of food chains all over the world. Birds and fish eat them. People eat them. They pollinate our crops and feed the world.  Bugs are damn important.

We also talked a little bit about pest control services that intact ecosystems provide.  For example, a 2009 study found that low-diversity cropping systems–think thousands of acres of corn and soybeans and nothing else–had 24% fewer predators.

We lose ecosystem services when we lose biodiversity.

To give you a sense of just how big the problem of species loss is, check out this diagram about terrestrial invertebrates from the IUCN report. This includes insects,  spiders, and all the other spineless things that live on land.

holy crap

You can see from this that 38% of the species in the IUCN database are already extinct or endangered. Thirty. Eight. Percent.

An additional 20% of species are listed as vulnerable to extinction.
OVER HALF of the species that are in the terrestrial invertebrate IUCN database are at risk of extinction or already gone!

What’s that grey category labeled “DD”? “Data Deficient.” Species are classified as Data Deficient on the IUCN Red List if there is inadequate information to evaluate their extinction risk.  Of the species with a listing for IUCN, we don’t know enough about 17% of them to assign a conservation status.

Here’s another way of looking at that.  This is how IUCN organizes their categories of extinction risk, from high to low:

IUCN categories

How many species is the IUCN diagram of terrestrial invertebrate conservation statuses based on? 3,623 species.

How many species of insects and spiders are there, that we know about? Over a million.
How many species of insects and spiders do we estimate actually exist, that are not included in this diagram? Over 5 million.
They don’t show up; we don’t even know enough to include them as “Not Evaluated.”

Chapter One of the IUCN report has the title “The Unraveling Underworld.” Yes. It is unraveling.
I can’t tell you what the consequences of species loss will be, but I can tell you I am sure it won’t be a good thing.

In the interview I mostly focused on how these changes will affect humans economically. We live in a time when utilitarian value is king; and when people are out of work and having trouble making ends meet, it’s really hard to argue that we should save a bug because it’s pretty.

But the truth is we just don’t know.
We don’t know which insects are the important ones. We don’t know which species is the one that when we lose it, things fall apart.

I think Aldo Leopold said it best:

“The last word in ignorance is the man who says of an animal or plant: “What good is it?”  If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.”

6 thoughts on “Planet of the Arthropods

  1. I sometimes think that’s the most valuable part of scientific training (especially any kind of training in ecology)–being taught to recognize how very much we don’t know about how the world works and why it does, and how inextricably interwoven all of its species are. If only that knowledge could eat away at our ignorance and hubris before it’s too late…

  2. Many people might consider this study and ask, “If we drive a significant number of invertebrate species to extinction, would it endanger the survival of the human species”” I’d ask, “I we drive the human species to extinction, wouldn’t the great majority of the millions of other species be better off?” I believe the answer to the second question is obvious, but many (most?) people seem to think that the only important entities on this planet are them. It saddens me to think that we’ve already aided the extinction of 7% of known species.

  3. Oroboros

    I don’t know if you’re familiar with the poet W.S. Merwin. He accepted the US Poet Laureate award a couple years ago so that he could have a chance to tell Obama what we’re losing. He’s also got a foundation in Hawaii that is devoted to restoring native biodiversity.

    I mention him because poetry performs a valuable service of eulogy to what we’ve lost. I think that grieving is important and can lead us to double our efforts to save what remains.

    After The Alphabets
    by W. S. Merwin

    I am trying to decipher the language of insects
    they are the tongues of the future
    their vocabularies describe buildings as food
    they can instruct of dark water and the veins of trees
    they can convey what they do not know
    and what is known at a distance
    and what nobody knows
    they have terms for making music with the legs
    they can recount changing in a sleep like death
    they can sing with wings
    the speakers are their own meaning in a grammar without horizons
    they are wholly articulate
    they are never important they are everything

    To the Insects
    by W. S. Merwin

    Elders

    we have been here so short a time
    and we pretend that we have invented memory

    we have forgotten what it is like to be you
    who do not remember us

    we remember imagining that what survived us
    would be like us

    and would remember the world as it appears to us
    but it will be your eyes that will fill with light

    we kill you again and again
    and we turn into you

    eating the forests
    eating the earth and the water

    and dying of them
    departing from ourselves

    leaving you the morning
    in its antiquity

  4. In case anyone wants to know more about where all my (and IUCN’s) numbers came from for species diversity, they are mostly from this review paper:
    http://www.sciencedirect.com/science/article/pii/S0169534712001231

    Which is fairly readable–especially for a peer reviewed journal :)

    What we know and don’t know about Earth’s missing biodiversity
    Scheffers, et al Trends in Ecology & Evolution 27, 2012.
    Estimates of non-microbial diversity on Earth range from 2 million to over 50 million species,
    with great uncertainties in numbers of insects, fungi, nematodes, and deep-sea organisms.
    We summarize estimates for major taxa, the methods used to obtain them.

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