|
Newsletter
June
2001
Keeping
Invasive Plants Out of Forest Fragments
MILBROOK, New York, January 29, 2001 (ENS) - Fragmented
forest habitats are vulnerable in part because they have
more edges, which are susceptible to invasion by non-native
species. While the obvious solution of minimizing the amount
of edge is not always feasible, there may be another effective
approach: intact edges can help keep seeds out of the forest
interior, according to new research in the February issue
of "Conservation Biology."
"Our work addresses the impact of forest fragmentation
at the 'neighborhood' scale - what happens when developers
put up a new strip mall or housing complex. The development
of our landscapes continually fragments forests and [that]
should be considered when thinking about the distribution
and degree of aggregation of homes," said Mary Cadenasso
of the Institute for Ecosystem Studies in Milbrook, New
York, who did this work with Steward Pickett of the same
institution.
Cadenasso and Pickett measured how many seeds blew from
an old field into an adjacent deciduous forest patch, a
common type of edge in New England. The researchers studied
seeds that are dispersed by the wind because many invasive
plants have wind borne seeds.
To
see how the forest edge's structure affected seed invasion,
the researchers compared two types of edges: intact and
thinned.
They
created 130 feet of thinned edge by removing all trees,
shrubs and branches that were less than half the height
of the forest canopy. This thinning extended 65 feet into
the forest patch. The resulting thinned edge resembled that
created by logging or a large blowdown.
The researchers found that four times as many wind borne
seeds crossed the thinned edge than the intact edge. They
also found that seeds crossing the thinned edge penetrated
2.5 times deeper into the forest - 145 feet into the "thinned
edge" forest versus 55 feet across the "intact
edge" forest.
To help protect forest fragments from invasive weeds, Cadenasso
and Pickett recommend "sealing" the edge by planting
it with dense native shrubs, vines and understory trees,
as well as removing non-native plants from the edge.
How
to keep invasive plants out of forest fragments
Fragmented
habitat is vulnerable partly because it has more edges,
which are susceptible to invasion by non-native species.
While the obvious solution of minimizing the amount of edge
is not always feasible, there may be another effective approach:
intact edges can help keep seeds out of the forest interior,
according to new research in the February issue of Conservation
Biology.
"Our work addresses the impact of forest fragmentation
at the 'neighborhood' scale -- what happens when developers
put up a new strip mall or housing complex. The development
of our landscapes continually fragments forests and [that]
should be considered when thinking about the distribution
and degree of aggregation of homes," says Mary Cadenasso
of the Institute for Ecosystem Studies in Milbrook, New
York, who did this work with Steward Pickett of the same
institution.
Cadenasso and Pickett measured how many seeds blew from
an old field into an adjacent deciduous forest patch, a
common type of edge in New England. The researchers studied
seeds that are dispersed by the wind because many invasive
plants have wind-borne seeds. To see how the forest edge's
structure affected seed invasion, the researchers compared
two types of edges: intact and thinned. They created 130
feet of thinned edge by removing all trees, shrubs and branches
that were less than half the height of the forest canopy;
this thinning extended 65 feet into the forest patch. The
resulting thinned edge resembled that created by logging
or a large blowdown.
The researchers found that four times as many wind-borne
seeds crossed the thinned edge than the intact edge. They
also found that seeds crossing the thinned edge penetrated
2.5 times deeper into the forest (145 feet into the "thinned
edge" forest vs. 55 feet across the "intact edge"
forest).
To help protect forest fragments from invasive weeds, Cadenasso
and Pickett recommend "sealing" the edge by planting
it densely with native shrubs, vines and understory trees,
as well as removing non-native plants from the edge.
Comment
on this Article
>>
Go to Top
<< Back to Newsletter
|
