A grayscale map of the Apostle Islands
and the adjacent mainland of Bayfield
and Ashland counties is shown on the
blue background of Lake Superior.
The Apostle Islands National Lakeshore
boundary is indicated in red and
the adjacent study area boundary on
the mainland is indicated in black.
A list of disturbance agents in the
lower right corner shows a different
color indicator for each agent.
Beaver blowdown development fire
forest harvest and forest pathogen.
The following series of maps will
show the location and extent of the
disturbance agents within the Apostle
Island study area from 1990 through 2018.
This map shows 1990.
1991
1992
1993 throughout the 1990s,
Forest harvest is the most obvious
disturbance in the study area,
all of it occurring on the mainland.
Other disturbances are small enough
to be nearly unnoticeable until 1993,
when small areas of development
indicated by black polygons appear
in parts of the mainland study area.
1994 some Beaver activity
appears, indicated in pink.
1995
1996
1997
1998
1999 the outbreak of a forest
pathogen is indicated in blue in
a localized area on the southwest
border of the mainland study area.
2000
2001 a significant outbreak of
forest pathogen occurs in 2001,
turning much of the mainland study area,
Blue. This is a defoliation event
caused by forest tent caterpillars.
It is important to note that
this is not a permanent change.
The leaves grow back the following year.
2002 there is very little
disturbance of any kind anywhere
on the mainland or in the islands.
2003 two noticeable areas of
development indicated in black
appear in the central and northern
portions of the mainland study area.
2004 widely distributed development
appears on the mainland.
Similar patches of development will
be seen over the next three years.
2005
2006
2007 a moderately large area of
development is concentrated in the
central part of the mainland study area.
2008
2009
2010
2011 A small amount of blowdown indicated
in orange occurs near the southern
boundary of the mainland study area.
2012
2013
2014
2015
2016 There is a significant blowdown
event in 2016 occurring in a
northwest to southeast direction in
two locations on the mainland and
on three of the Apostle Islands,
Michigan, Stockton, and Oak.
2017
2018 Forest Harvest was the most
common disturbance on the mainland
portion of the study area, occurring
in each year from 1990 through 2018.
It is important to remember that many
of these disturbances are temporary
changes and the affected areas continue
to function as natural habitats,
but at a different stage of maturation.
Forest harvests change forests to open areas,
but these areas eventually return to forest.
Tent caterpillars stripped the
leaves from trees in one year,
but they grow back the next.
It is only the development of land
that creates permanent change.
This map combines all the disturbances that
occurred over the entire 28 year period.
Green and Blue Forest harvest and
forest pathogen are the most prominent
colors throughout the mainland.
Part of the study area.
As we've seen disturbance on the
islands from one year to the next
does not show up well on these maps.
But in this cumulative view,
we see the small spots of disturbance
within the national lakeshore boundary.
Zooming into the national lakeshore boundary,
we can see small pockets of disturbance
on less than half the islands. Blow
down in orange is the most common
followed by forest pathogen in
blue and beaver activity in pink.
But if we take away the
short term disturbances,
the ones that do not change a
long term natural state of the
habitat and show only development
disturbances for the entire
period of 1990 through 2018,
we see no such permanent disturbance
on any of the islands in the
national lakeshore boundary.
We will now show each of the maps from 1990
through 2018 at one second intervals.
To illustrate how changes
shift across the landscape.
National Park Service.
Arrowhead and the logo of the
Great Lakes Inventory and
Monitoring Network appear on a
background of green, Gray water.
The title says to see the full
report from this project.
Visit our website.
Www.nps.gov/M slash GLKN slash
landscape hyphen dynamics dot HTM.