Documentation
regarding the development of the swan breeding habitat knowledge base.
11 April
1999
Richard S. Sojda
This documentation describes the underlying ecological logic behind
the development of the swan breeding habitat knowledge base. The
knowledge, itself, resulted from knowledge engineering sessions held with
Mr. Todd Grant and Dr. Leigh Fredrickson.
Depth
and Size Tree
The following table shows
the criteria used to determine the "confidence" values that are assigned
in the depth and size tree. E.g., row one of the table means:
if
((>= 30% has a depth between 6" - 40" and >= 5 acres
(or
> few hundred acres and >= 10 contiguous acres are 6" - 40"))
then
we are
100 percent confident that the wetland is the correct depth
and
we are 95 percent confident that the wetland is large enough
else
wetland
is neither the correct depth nor large enough
|
Confidence
for Depth
|
6"-40"
|
Confidence
for Size
|
>5 Acres
|
|
100
|
X
|
95
|
X
|
|
0
|
|
0
|
|
Prelaying
Food Tree
The following table shows
the criteria used to determine the "confidence" values that are assigned
in the prelaying food tree. E.g., row one of the table means:
if
unfrozen
three weeks preceding laying
and
>= 30% has vegetation with large, below-ground resources
then
we are
100 percent confident that prelaying food resources are sufficient
|
Confidence
|
Ice Free
|
30% Sago
|
50% Leafy
|
Nearby Wetland
Ice Free
|
Nearby Wetland
30% Sago
|
Nearby Wetland
50% Leafy
|
Arrive Fat
|
|
100
|
X
|
X
|
|
|
|
|
|
|
100
|
X
|
|
X
|
|
|
|
|
|
100
|
|
|
|
X
|
X
|
|
|
|
100
|
|
|
|
X
|
|
X
|
|
|
80
|
|
|
|
|
|
|
X
|
|
0
|
X
|
|
|
|
|
|
|
|
0
|
|
|
|
X
|
|
|
|
Such a table can appear deceptively
simple. It required a tree with 64 rules/end-nodes to implement.
Nest
Sites Tree
The following table shows
the criteria used to determine the "confidence" values that are assigned
in the nest sites tree. E.g., row one of the table means:
if
robust
emergents are present
and
interspersion can be classified as near the hemi-marsh stage
then
we are
95 percent confident that potential nest sites exist
|
Confidence
|
Emergents
|
Hemi-marsh
|
Muskrats or
Beaver
|
Floating Vegetation
|
40 Meter Vegetation
Band
|
|
95
|
X
|
X
|
|
|
|
|
95
|
X
|
|
X
|
|
|
|
90
|
X
|
|
|
X
|
|
|
90
|
|
|
|
|
X
|
|
0
|
X
|
|
|
|
|
|
0
|
|
|
|
|
|
Brood
Habitat Tree
The following table shows
the criteria used to determine the "confidence" values set in the brood
habitat tree. E.g., row one of the table means:
if
some water
remains available until typical fledging time
and
dry sites for brooding exist the first few weeks after hatch
and
emergents are growing at or just above the water's surface during brood
rearing
then
we are
100 percent confident that brood habitat is sufficient
|
Confidence
|
Brood Water
|
Dry Sites -
Brooding
|
Food: Emergents
|
Food: Submer-gents
|
Food: Treadling
|
|
100
|
X
|
X
|
X
|
|
|
|
100
|
X
|
X
|
|
X
|
|
|
90
|
X
|
X
|
|
|
X
|
|
85
|
X
|
|
X
|
|
|
|
85
|
X
|
|
|
X
|
|
|
75
|
X
|
|
|
|
X
|
|
0
|
X
|
X
|
|
|
|
Ice Free
Period and Nest Flooding Trees
These two parameters go through
some representational gymnastics to stay consistent, but eventually are
interpreted as relatively straightforward probabilities as depicted in
the "Final Assessment" table, below.
Calculating
the Final Assessment of Breeding Habitat
Variables, created for each
critical ecological parameter, are given values during a consultation.
Then, the variables are combined with the following algorithm:
if
>= one
parameter fails
then
final
assessment = 0
else
final
assessment = (Depth + Size + PreLay + Nest + Brood) * Ice * Flood
Internally, each ecological
parameter is actually associated with two variables, one for the number
of "points" to add to the total and one for the number to be used as a
multiplier to the total number of points. Eighteen rules are actually needed
to calculate the value for "Final Assessment", which is described to the
user as :
This is a somewhat arbitrary
assessment of the degree to which this wetland represents ideal habitat
for breeding trumpeter swans, based on a synthesis of all information.
On a scale of 0-100, the higher the number, the more confident one can
be that satisfactory habitat exists. A zero indicates that at least one
habitat component is severely compromised.
The value of each additive and
multiplier variable assigned for each value of an ecological parameter
are provided in the following table.
|
Ecological
Parameter
|
Parameter?s
Value
|
"Points" to
Be Added
|
Value of Multiplier
|
|
Depth
|
Fails
|
0
|
0
|
| |
Passes*
|
25
|
1
|
|
Size
|
Fails
|
0
|
0
|
| |
Passes*
|
25
|
1
|
|
Ice Free
|
10-6*
|
0
|
1
|
|
[no.
years out of 10]
|
5-3
|
0
|
0.4
|
| |
0-2
|
0
|
0
|
|
Prelaying
|
100*
|
15
|
1
|
|
[confidence
value
|
80
|
10
|
1
|
|
From
tree]
|
Fails
|
0
|
0
|
|
Nest Sites
|
95*
|
20
|
1
|
|
[confidence
value
|
90
|
15
|
1
|
|
From
tree]
|
Fails
|
0
|
0
|
|
Brood Habitat
|
90/100*
|
15
|
1
|
|
[confidence
value
|
75/85
|
10
|
1
|
|
From
tree]
|
Fails
|
0
|
0
|
|
Nest Flooding
|
10-6*
|
0
|
0
|
|
[no.
years out of 10]
|
5-3
|
0
|
0.6
|
| |
0-2
|
0
|
1
|
* For the values of the ecological
parameters marked with an asterisk, the system would calculate the value
for "final assessment" to be 100, i.e., we are 100 percent confident that
such a wetland represents satisfactory breeding habitat.
Return to the Swan Management Decision Support
System homepage.
USDI
- Geological Survey
Biological
Resources Division
Northern
Rocky Mountain Science Center
Maintainer: Rick Sojda
(sojda@swan.msu.montana.edu)