This has been a fascinating thread in its own odd way. The query seems
absurd at first blush, but worms do pull decaying leafmatter partway down
their tunnel in order to avoid being out where salamanders might get them
at night or birds get them during the day if they were eating above
ground, or where sun or drying winds might dessicate them. Small
earthworms wouldn't pull anything into their tunnel large enough for us to
notice, but a big nightcrawler do, & periodically a set of leaves will
be spotted standing straight up on the surface of the ground, with just
the stem in the ground. In some locations the worms do such a good job of
pulling small leaves underground that all the fallen leaves vanish after
one night of rain; it's part of how worms churn the soil & keep organic
matter well-stirred into the topsoil.
We tend to think of the doings of worms as 100% good. But the worm's
leaf-snatching activity is not invariably a good thing. Most of the worms
in our landscapes are invasive species that did not exist in North America
before the arrival of Europeans, & native plants don't always cohabit with
these worms successfully. In many forested areas none of these worms are
found, if fishermen never introduced them, & in such truly "natural" North
American wildernesses the undergrowth can be very different than what is
found growing where European worms have gotten established.
THere are a large number of native plants that evolved to thrive in
decaying leafmatter as it accumulates on the surface of the ground, such
as trilliums. Some of the worms burrow very deeply, & pull leaves &
beneficial fungus lower than small plants' roots will ever reach;
furthermore, by eating up all the beneficial fungus in a given area, even
shrubs & trees can begin to languish, because trees & shrubs cannot
process their nutrients without beneficial fungus in the soil to assist in
sugar conversion, plus the beneficial fungus that worms turn to
worm-castings or pull too deep into the soil are pathogen-retardants &
when the healthy fungus is all eaten up or dragged too deep, the entire
ecosystem of that area becomes more susceptible to disease. Furthermore, a
layer of leaflitter in a forest serves as the forest's "skin," & without
it invasive plant species that did not evolve for leaflittered forest
floors get established & crowd out native plants. For all these reasons
which begin with the introduction of alien worms, the most sensitive
native plant species are dying out of some regions because of the rising
population of invasive worms.
Here's a fine introductory article on the bad worms can do as they remove
decaying leaves & funguses from the ecosystem:
http://www.wvnps.org/earthworms.html
In the garden this does not necessarily apply as many of our plants come
from the same regions where the worms originate & are adapted to them, &
we tend to ammend soils in our gardens with manure topcoatings or other
organic methods that keep the microorgism population, including beneficial
fungus, very high. Even our habit of watering regularly keeps
micropopulations at maximum. And folks such as myself who grow dogtooth
lilies & trilliums & native ferns which evolved in heavy leaflitter
uneaten by worms, we can make the extra effort to insure that autumn
leaves are moved to places around these plants.
But in the nearby woods the worms can be harmful. Forest ecology tends to
be stable, or changes from type of forest to another over a period of
centuries, unlike a dynamic garden that changes rapidly. The doings of
worms in the garden fascilitates rapid growth & rapid changes, but in the
wilderness the same worms hamper stability & slow change.
-paghat the ratgirl
--
Get your Paghat the Ratgirl T-Shirt he
http://www.paghat.com/giftshop.html
"History, I believe, furnishes no example of a priest-ridden
people maintaining a free civil government." -Thomas Jefferson