Government views Monarch Butterfly Releases as a threat to Western Milkweeds

[Patrick Foley]

Mark,

The best source I know is the edited volume Extinction Rates, Lawton, J. H.
and R. M May 1995, Oxford University Press.

Extinction rates vary taxonomically and regionally. Moreover estimates can
be made in several very different ways. To get an overview, see Table 1.2
in May, Lawton and Stork from this volume. Since 1600, based on "certified"
extinctions and IUCN listings of threatened, vulnerable and endangered,
they estimate (sorry about the formatting):

                                % extinct        % IUCN threatened
Molluscs                        0.2                    0.4
Crustaceans                    0.01                0.3
Insects                            0.006            0.09
Fishes                            0.1                2
Amphibians                    0.1                2
Reptiles                            0.4               3
Birds                                1                   11
Mammals                        1                     11

Total animals                0.04                0.3

Total Plants                0.2                    9

To translate these per 400 year rates a into annual rates b set

    1 - a = exp(-400 b) and solve for b

To get rates for 1000 years c set

    1 - c = exp(-1000 b) and solve for c

A short table (note a, b and c are fractions not per cents; you must add 2
zeros to the numbers above to get a rates)
a                b                c
0.0001    0.000000025    0.000025
0.0001    0.00000025      0.00025
0.001     0.0000025        0.0025
0.01       0.000025          0.025
0.1        0.00026            0.23

In other words, if a taxon loses 0.01 (that is 1%) of its species in 400
years, it can expect to lose 0.000025 (0.0025 %) per year and 0.025 (2.5%)
per one thousand years.

The actual extinctions and IUCN threatened numbers are appalling, but they
probably represent the vulnerable tip of the iceberg. The most vulnerable
large bird and mammal species have already gone extinct or are likely to do
so soon. The vast iceberg of extinctions to emerge are the "walking dead",
the species doomed to extinction by the anthropogenic deterioration of
their habitat. Given species area curves that are rather consistent, we can
predict the number but not the identity of species that will go exinct when
local extinction vs speciation and colonization dynamics have settled down
to new, less generous equilibria. This will take thousands of years, but it
will involve hundreds of thousands of species.

Patrick Foley
patfoley at csus.edu



Mark Walker wrote:

> What has the (estimated) extinction rate been over the past 1000 years?
>
> > -----Original Message-----
> > From: Patrick Foley [mailto:patfoley at csus.edu]
> > Sent: Saturday, December 08, 2001 7:00 PM
> > To: monarch at saber.net
> > Cc: LEPS-L at lists.yale.edu
> > Subject: Re: Government views Monarch Butterfly Releases as a
> > threat to
> > Western Milkweeds
>
> <snip>
> > As often happens in environmentalist-development debates, one
> > side is not worried
> > about cumulative impacts, because the immediate effects seem
> > so small. Lomborg, in
> > his recent book the Skeptical Environmentalist, argues that
> > an extinction rate of
> > 0.7% per 50 years is manageable and hardly worthy of
> > hysteria. To me, this
> > extinction rate will lead to 13% of the species on earth
> > going extinct over the
> > next 1000 years. (exp(-0.007*20 half-centuries)= 0.87). If
> > this doesn't trouble
> > you, consider the results of another 6000 years of human
> > history. You should only
> > worry about the environment if you are rooting, as I am, for
> > human civilization to
> > last ... or at least start.
> >
> >
> > Patrick Foley
> > patfoley at csus.edu
> >
> >


 
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