Habitats
in the nearshore zone
|
Coarse woody debris (CWD)
Original land survey
records show that "Big Woods" originally covered this part of
the state. Hardwoods, mainly red oak, sugar maple, basswood, and
American elm dominated these forests.The land around your lake,
the riparian zone, also consisted of these large trees which shaded
the shoreline and provided a steady supply of organic matter in
the form of leaves,branches and logs to the near shore area.Aquatic
organisms in the lakes and streams of this area evolved during a
time when large trees must have often fallen into the water.
|
|
|
|
|
When human development came to the shoreline, trees were removed,
and logs were often pulled out of the lake. It was once common practice
to remove logs from trout streams too. Now scientists and resource
managers have come to realize the importance of coarse woody debris
in aquatic ecosystems (and forested ecosystems as well). |
|
Lakeshore development
may affect woody debris abundance in the littoral zone and adversely
effect lake ecosystems because coarse woody debris does the following
for your lake:
- provides
physical structure for aquatic organisms
- alters water
movements and other hydrologic processes
- affects
the flow of organic matter from the terrestrial ecosystem into
surface waters and affects the transport of organic material within
the aquatic environment
|
| Trees
that fall into the water create important fish habitat. Small fish
feed on the invertebrates (insects and zooplankton) in the wood and
use the cover to hide from predators. Musky, and other large predatory
fish, often stalk these logs looking for prey. |
 |
A study by the University of Wisconsin Center for Limnology studied
fish habitat in 16 northern Wisconsin lakes. Their study showed that
as homes become denser the number of fallen trees decreases. Research
on the importance of CWD has really just begun. We'll most likely
be hearing more in the near future. This trend cannot be totally reversed
but shoreland property owners can help. Fisheries management often
involves the addition of "structure", cribs etc. You could accomplish
similar goals by not removing that branch or log that falls into the
lake.
|
Aquatic
macrophyte beds - see Aquatic Plants
|
Habitats in the off shore zone |
|
| Out
in the deeper, or limnetic part of the lake the plankton take over.
Plankton is a term used to describe those organisms that float freely
in the open waters of the lake. Included in this group are the zooplankton
(animals) and phytoplankton (algae). Fish, of course, also roam around
out here. In a more productive lake the area fish have to roam around
gets smaller and smaller as summer progresses. Oxygen in the deeper
waters becomes scarcer as dead algae and other detritus rains down
into the hypolimnion. Most fish won't be able to survive in dissolved
oxygen concentrations less than 5 mg/L. Here's where the RUSS
data can help you determine where the fish may or may not be.
|
 |
| |
|
|
