WSP00036

• File Number: 8200.750
• Description: San Juan River General
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 3/1/1975
• Author: BOR
• Title: San Juan Ecology Project - Interim Progress Report - March 1975
• Water Supply Pro - Doc Type: Report/Study

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/ '1971-72
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1972-73

SEPT

Figure 2. Elevation of wintering elk on Missionary Ridge.

elk had proceeded to a lower elevation (2300 meters)
than either of the previous two winters. This
reflects the severity of the 1972-73 winter. As in
previous winters, elk again moved up and utilized
the open, south facing, oak brush slopes (approxi-
mately 2615 meters elevation) during February and
March. Thi's past winter, however, in contrast to the
earlier two winters, heavy storms continued through
Apr!l. As a result, rather than continuing a slow
up-slope migration as seen in 1970-71 and 1971-72
elk migrated down to the valley floor.

Habitat and Aspect -

Tables 1 and 2 show that habitats and aspects occupied
1n 1972-73 were very similar to those reported for
previous years.

Table 1. Percentage of elk sighted in each habitat
type on Missionary Ridge, winter 1972-73.
Total Mean E1ev. Habitat
~ ~ (meters) ~ Oak Aspen Conifer
9-10-72 63 3125 54 27 3 16
10-10-72 112 3100 65 8 7 20
11-10-72 43 2900 12 67 21
12-10-72 35 2950 43 51 6
1- 5-73 74 2300 51 4 45
2- 2-73 28 2475 4 39 7 50
3- 2-73 19 2675 84 16
3-30-73 35 2400 80 20
4-27-73 56 2100 54 21 25
Total % 31 38 9 22

Table 2. Percentage of e1
Missionary Ridge
Total Mean E1ev
Date ~ meters
9-10-72 63 3125
10-10-72 112 3100
11-10-72 43 2900
12-10-72 35 2950
1- 5-73 74 2300
2- 2-73 28 2475
3- 2-73 19 2675
3-30-73 35 2400
4-27-73 ~j 56 2100
Total %

PR MAY
sighted on each-aspect of
winter 1972-73.
Aspect 1/
!!!! ~ West
75 25
21 30 49
77 23
86 14
27 27 58
39 61
42 58
54 46
46
5 42 43

11 None were seen on north spects.
I/ Readings for this date d not include elk sighted
(54%) in the valley, and therefore not considered
on any given aspect.

In all, there seems to be indication that fescue
and/or oak habitats on sou h aspects are used to a
~igher degree than other h bitat types or aspects
during the winter period. Snow on south aspects
quite often melts off betw en storms, except in years
pf heavy accumulation. As a result, they provide,s
more favorable winter habi st with the decreased snow
~over, increased food avai ability, and increased
temperatures.

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