Miller and Ralph 



Chapter 20 



Inland Habitat Relationships in California 



Table 5 For central California: Summary of detections 1 and status for Marbled Murrelet stations surveyed in old-growth forests within state and national 

 parks during the summer, 1993 



'Includes only detections within 100 meters of observer 

 Standardized detections 



Table 6 For northern California: Summary of detections 1 and status of Marbled Murrelet stations surveyed in old-growth forests within the state and national 

 parks during the summer, 1993 



'Includes only detections within 100 meters of observer 

 Standardized detections 



The proportion of Occupied stations was significantly 

 higher at stations of less than 100-m elevation than at stations 

 >200 m (P < 0.0001) (table 6). The proportion of stations 

 with no detections was significantly higher in the >300 m 

 category and significantly lower in the <100 m category. 



Inland Range 



We found highest frequencies of presence (89.05 percent) 

 and occupancy (21.91 percent) at stands and stations within 

 10 km of the coast (table 7). The proportion of Occupied 

 sites decreased in the 10- to 20-km band. The number of 

 stations with detections declined by more than 99 percent 

 from the 30- to 40-km to the 40- to 50-km band, although 



four times the number of stations were surveyed in the 40- to 

 50-km band. The proportion of Occupied stations declined 

 rapidly beyond 30 km from the coast. 



Discussion 



Stand Study 



The most important factor in indicating Occupied stands 

 was density of the old-growth cover, that is, the percent of 

 the area covered by the crowns of old-growth trees. Occupied 

 stands had a higher percentage of old-growth cover than 

 stands with murrelets only present, or in stands with no 

 detections. These relationships are consistent with those 



212 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



