Recovery Plan for the Northern Spotted Owl - DRAFT
Recovery Plan for the Northern Spotted Owl - DRAFT Recovery Plan for the Northern Spotted Owl - DRAFT
Table B.8. Tree density (number of trees per acre) by dbh class in Oregon andWashington provinces.dbh Nest Nest Roost/ Old-Province (inches) site stand Forage Forage GrowthOregon 3-9 54aCoast 10-19 25Range 20-39 17240 12Western 3-9 6 2aOregon 10-19 33Cascades 20-39 21Ž40 12Western 4-12 58b 94c 115dWashington 12-20 31 52 60Cascades 20-35 23 41 42>35 10 23 143-9 64a10-19 3420-39 27>39 10Olympic 4-12 89ePeninsula 12-20 3320-35 36>35 33Eastern 4-13 129f 117fWashington 13-23 35 29Cascades 23-33 16 10>33 2 36- 9 5999-21 5921-32 13>32 3a Spies (1991)b Hamer (1988) (dbh class definitions differed slightly those given; second size class was 11.20")c Allen et al. (1989) (Mt. Baker-Snoqualmie National Forest)d Allen et al. (1989) (Gifford-Pinchot National Forest)e Allen et al (1989) (Olympic National Forest)Buchanan (1991) and (pers comm.)9 Benson (1991b)I300
ITable B.9. Snag density (number of snags per acre) by dbh class in Oregon andWashington provinces.dbh Nest Nest Roost/ Old-Province (inches) Site Stand Forage GrowthOregon >0 1 6 aCoastRange >20 7Western >0 25aOregonCascades >20 11Western >0 30aWashington >4 42b 33C 41 dCascades >20 18 7 7 15Olympic >4 25 ePeninsula >20 10Eastern 4-13 1 f 13fWashington 14-23 4 6Cascades >23 2 2>10 59>20 1a Spies et al. (1988)b Hamer (1988)C Allen et al. (1988) (Mt Baker-Snoqualmie National Forest)d Allen et al. (1989) (Gifford-Pinchot National Forest)e Allen et al (1989) (Olympic National Forest)f Buchanan (1991)9 Benson (1991b).~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~........../This type of information is particularly useful in defining habitat categories.These efforts, however, must proceed with caution. For example, the resultssuggest that utilized sites studied to date tend to have trees of several differentdiameters (including some large trees), high canopy cover, and dominance byconifers, and that a hardwood understory is usually present in California butis not present in Washington and most of Oregon. As we have stressed, however,these generalizations describe average values in the study; they do notnecessarily describe the features present at each site. Thus, birds might usesome sites with a few large trees and few other trees but use other sites with nolarge trees but many smaller trees. This differential use might occur within orbetween home ranges. In either cases, the study-wide averages would be asreported earlier. Bingham (pers. comm.) has suggested that the values inTable B. 10 may characterize utilized sites in mature stands but may notcharacterize utilized sites in old-growth stands very well. This suggestioncould be investigated by comparing results for home ranges dominated by oldgrowthstands with home ranges dominated by mature stands.Improved descriptions of utilized sites might be obtained by defining a habitatcategory using several habitat variables. For example, we might examine thestudy-wide averages reported in Tables B.2 through B.9 and then define ahabitat category as including stands with canopy cover exceeding 80 percent301
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- Page 276 and 277: Obviously, these statements hold on
- Page 278 and 279: Table A.6. Reliability of trend est
- Page 280 and 281: Demographic AnalysisAs noted earlie
- Page 282 and 283: the estimate (using the simple equa
- Page 284 and 285: however, we know little about the b
- Page 286 and 287: Table A.8. Summary of information n
- Page 288 and 289: predict the power achieved by diffe
- Page 290 and 291: Other studiestached. If dispersing
- Page 292 and 293: impractical at present. We describe
- Page 294 and 295: Conclusionsthe year effect can be i
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- Page 302 and 303: owls. Consequently, the issue of wh
- Page 304 and 305: Use of the informationAssessments a
- Page 306 and 307: Recent LiteratureWe might begin by
- Page 308 and 309: Kerms (1989) measured habitat struc
- Page 310 and 311: Hamer (pers. comm.) described 11 ne
- Page 312 and 313: Table B.3. Percent hardwoods in the
- Page 314 and 315: Table B.5. Comparison of habitats u
- Page 318 and 319: and numbers of trees, and percent o
- Page 320 and 321: Under this hypothesis, owl fitness
- Page 322 and 323: suitable habitat for that region (m
- Page 324 and 325: ResultsDiscussionspotted owl habita
- Page 326 and 327: __Discussiondata from 41 sites in t
- Page 328 and 329: Recommendations for Future Research
- Page 330 and 331: 314
- Page 332 and 333: Hamer, T. 1988. Home range size of
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- Page 338 and 339: Parameter Estimatesfor Individual S
- Page 340 and 341: provided in Table C. 5. Study of th
- Page 342 and 343: Table C.6. Summary of statistics re
- Page 344 and 345: 3. ConclusionsThis source of bias i
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- Page 348 and 349: Gray Wolf .........................
- Page 350 and 351: formed during the initial meeting t
- Page 352 and 353: provide habitat for the numerous sp
- Page 354 and 355: The ApproachA committee of the Reco
- Page 356 and 357: The List of Threatened and Endanger
- Page 358 and 359: Mammalsoldest trees in a stand. Eig
- Page 360 and 361: ABBFigure D. 1. Distribution of: a)
- Page 362 and 363: KTable D.3. A list of threatened an
- Page 364 and 365: Fishestheir dispersal capabilities
Table B.8. Tree density (number of trees per acre) by dbh class in Oregon andWashington provinces.dbh Nest Nest Roost/ Old-Province (inches) site stand Forage Forage GrowthOregon 3-9 54aCoast 10-19 25Range 20-39 17240 12Western 3-9 6 2aOregon 10-19 33Cascades 20-39 21Ž40 12Western 4-12 58b 94c 115dWashington 12-20 31 52 60Cascades 20-35 23 41 42>35 10 23 143-9 64a10-19 3420-39 27>39 10Olympic 4-12 89ePeninsula 12-20 3320-35 36>35 33Eastern 4-13 129f 117fWashington 13-23 35 29Cascades 23-33 16 10>33 2 36- 9 5999-21 5921-32 13>32 3a Spies (1991)b Hamer (1988) (dbh class definitions differed slightly those given; second size class was 11.20")c Allen et al. (1989) (Mt. Baker-Snoqualmie National Forest)d Allen et al. (1989) (Gif<strong>for</strong>d-Pinchot National Forest)e Allen et al (1989) (Olympic National Forest)Buchanan (1991) and (pers comm.)9 Benson (1991b)I300
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