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BOARD02067
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Last modified
8/16/2009 3:10:40 PM
Creation date
10/4/2006 7:08:49 AM
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Board Meetings
Board Meeting Date
3/29/1999
Description
South Platte Director's Report - Preble's Meadow Jumping Mouse Status Report
Board Meetings - Doc Type
Memo
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<br />. <br /> <br />common feature along streams and ditches. PMJM is found to sleep, forage, travel, and <br />reproduce in the shrublands. However, many mice spend a significant amount of time (as <br />much as 5 hours during the night, Tanya Shenk, 1998, unpublished data) in adjacent <br />grasslands presumably feeding. Therefore, we need to consider what would be the <br />potential impact of habitat loss within the entire area occupied by the mice, independent <br />of shrublands or in combination with shrublands. <br /> <br />Diagnosis <br /> <br />Theory: We believe that the maximum allowable disturbance area for riparian <br />shrubs should continue to be based on the home range as stated in issues 1 and 2 <br />above. This is based on the current knowledge that the home range is centered on <br />shrublands (based on the essential functions performed by that vegetation type). <br />However, a home range may include other elements of the species' habitat. It is <br />. likely that feeding habitat is often more variable and extensive than shrub habitat. <br /> <br />. <br /> <br />Data: The minimum size of a home range is defined in issues 1 and 2 above. In <br />contrast we do not have a good description of the feeding habitat. The locations <br />and dimensions of the feeding areas are known to be within 328ft (100 m) from <br />riparian shrublands (R. Schorr, 1995, unpublished data; T. Shenk, 1999, <br />unpublished data). This area includes both sides of the stream. We also know <br />that observed densities of PMJM along a stream reach is lower than 100% <br />occupation at the rate of minimum home range size. The maximum allowable <br />area of disturbance of foraging habitat should be based on the average area of <br />occupation by a mouse, which tells us the area in which a home range is likely to <br />occur. This is derived from assumption number 4 (below) where an individual <br />mouse's home range occupies, on average, an area approximately 109 ft (33 m) <br />parallel to the stream and 300 ft perpendicular to each side of the stream. This is <br />an area of 65,400 ft2. 5% of that area is 3,270 ft2 (-304 m2) and is believed to <br />represent an insignificant area of impact if it is non-shrub land. This is based oa <br />the ideas of probability and significance presented above. Since we have already <br />stated that 530 ft2 (50 sq meters) of riparian shrublands is a maximum habitat that <br />should disturbed, we believe that of the whole 3,270 sq ft (304 sq m), not more <br />than 530 ft2 (50 sq m) can consist of riparian shrublands. This leaves a balance <br />of 2,740 fe or an approximate area of 52ft x 52ft of non-riparian shrub1ands that <br />can be altered in each 65,400 sq ft and is predicted to have a non-significant <br />impact on Preble's meadow jumping mouse or its habitat. <br /> <br />. <br /> <br />Assumptions include: <br />1. Minimum home range size is -.25 acres (0.1 ha)(Rob Schorr, 1998, <br />unpublished data). <br />2. Shrubs are of disproportionate importance to the mouse relative to non- <br />shrubland. <br />3. Rough forbs are also important for PMJM (as cover), but relatively rare in <br />the areas considered. <br /> <br />7 <br />
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