|
Functions
& Conditions -
Evaluating the Physical Features
Amount,
location, and causes of bare ground
| Bare
ground--soil that is not covered by vegetation, litter or duff,
downed woody material, or rocks--is highly susceptible to erosion
(Figure 2-13). It may contribute both to overland sediment flow
and to the erosion of streambanks. In both cases, it can affect
water quality as well as the loss of valuable soil and acreage.
Soil not covered by desirable vegetation is a prime area for
invasion of noxious weeds or other undesirable plant species.
Bare ground increases the possibility of compaction or bank
shearing by hoofed animals, vehicles, or people. This reduces
the water-holding capacity of the soil. |
|
Figure
2-13
This bare ground is the result of a blown-out
beaver dam. Obviously, the streambanks are now
susceptible to compaction, erosion, and weed infestation.
|
|
|
|
Figure
2-14
The evident healing of this streambank is the
result of a management change which reduced the
length of time cattle graze this pasture in any
one period. |
|
|
One
of the difficulties in assessing this aspect of riparian health
is that many riparian areas will naturally have bare soil.
After high flow events, bare soil in the form of trapped sediment
could indicate riparian vegetation on the site is performing
its sediment-trapping function. On the other hand, such a
situation could also reflect an unstable situation further
upstream.
The presence
of perennial riparian vegetation on formerly raw streambanks,
as illustrated in Figure 2-14, is often an indication of an
improving situation.
|
It is
important to try to determine what caused the bare ground.
If it is related to or caused by human activities or has been
increased by management practices, it is more likely to indicate
a deteriorating situation somewhere along the stream. Some
human activities which can lead to increased bare ground are
livestock mismanagement, poor road construction, excessive
ATV use, poorly located timber harvest skid trails, and improper
mining activities. |
|