Burger 



Chapter 16 



Inland Habitat Associations in British Columbia 



A: Fixed station intensive surveys 

 Percentage of old-growth in Watershed 



40 T 



0-25 M 25-50 D 50-75 D 75-100 



31 



34 



June 



July 



CO 



Tn 



S.2 

 <n 



o 



'is 



3 

 1 



4- 



B: Road surveys 



No surveys 



May 



June 



July 



Figure 3 Mean numbers of Marbled Murrelet detections in intensive fixed station (A) 

 and general road surveys (B), in relation to the percentage cover of remaining old- 

 growth forest in the sampled watersheds on Vancouver Island (from Savard and 

 Lemon, in press). Sample sizes (n) shown above columns are numbers of surveys. 



close to old-growth (within 200 m in fixed stations and 

 within 500 m in road transects) had higher detection rates 

 than those further away. 



These studies confirm that murrelets avoid second-growth 

 forests, even those 60-120 years old. Furthermore, the 

 Vancouver Island results tentatively suggest that murrelets 

 do not pack into the remaining old-growth with increased 

 density; reduced habitat leads to reduced populations. 



Relationship Between Landscape 

 and Stand 



Distance to Salt Water and Location Within the Watershed 



Savard and Lemon (in press) found no significant 

 correlation between detection frequency and distance from 

 salt water (using intervals of 0-5, 5-15, and >15 km) at 151 



stations on Vancouver Island in May and July, but found a 

 negative correlation in June. They found no effects of distance 

 to open ocean (beyond the inlets) in any month. The location 

 of fixed stations within each watershed did not affect detection 

 rates (each watershed was divided into four zones, from 

 mouth to headwaters), although road surveys showed 

 significantly higher detections in the centers of the watersheds. 

 These data indicate that Marbled Murrelets are able to access 

 all of Vancouver Island, although only a small portion might 

 be suitable nesting habitat. 



The effect of distance from the ocean was tested in the 

 Carmanah and Walbran watersheds in which unbroken old- 

 growth forest extends from the ocean almost to the headwaters 

 for 21 and 18 km, respectively. Manley and others (1992) 

 reported a significant negative correlation between detection 

 rates and distance from the ocean at six stations in Carmanah- 



154 



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



