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My
study focused on determining home ranges, movements, activities,
habitat use, and habitat linkages of black bears during the pre-construction
phase of the research. Field personnel collected information on
bear locations and movements from June 2000-June 2001 on the 12,240-ha
treatment area (the area of highway construction), and a 12,266-ha
control area (no highway construction). These data will serve as
the baseline for comparisons with data collected after the anticipated
completion of the new highway in 2005.
Project
personnel collected 1,909 daily telemetry locations and 2,569 hourly
telemetry locations on 35 radiocollared bears (9 M: 26 F). Based
on the 95% fixed-kernel home range method, home ranges on the treatment
area averaged 5.3 km2 for females (n = 9) and 70.7 km2 (n = 4) for
males. The average annual home range for females on the control
area was 3.1 km2 (n = 14), and 14.2 km2 for males (n = 3). Female
home ranges on the treatment area were larger than on the control
area (Z = 2.87, P = 0.003), with extensive home-range overlap on
both areas.
Although
daily activity patterns did not differ for spring or summer, I observed
a disproportionate number of active observations during fall (X2
= 17.4, df = 3, P < 0.001), particularly in the evening. Land
cover was not associated with daily activity patterns. Hourly movement
rates differed between the study areas, with greatest rates on the
control area. Furthermore, hourly movements of females on the control
area were greater than those of males.
I
used the weights-of-evidence technique for analysis of habitat selection;
this technique is a discrete, multivariate method for combining
spatial data to predict habitat use. The final model was based on
1,811 daily telemetry locations and included the variables forest
cohesion, forest diversity, and forest-agriculture edge density
(all measured at a 0.20-sq km scale). The overall conditional independence
ratio of the model was 0.97, indicating that one of the primary
model assumptions was met. The model performed well; the highest
predicted probability category included only 23.8% of the study
area but contained 56% of the bear locations reserved for model
testing. Contrast values indicated that forest cohesion and forest-agriculture
edge density were the most influential variables to predict black
bear habitat use.
I
used predicted probabilities of bear occurrence from the weights-of-evidence
model in a least-cost-path analysis to delineate habitat linkages
for the 2 study areas and for the Albemarle-Pamlico Peninsula region.
Habitat linkages on the treatment area and between the 2 study areas
coincided with the underpass locations of the new highway. Regionally,
habitat linkages often converged near underpass sites as well, suggesting
that these underpasses may have both regional and local importance.
Results
of my study provide baseline data on the spatial ecology of black
bears prior to construction of the new highway. Changes in home
ranges, movements, and habitat use based on comparisons with post-construction
data will be useful to assess whether the new section of highway
affects the ecology of the resident black bear population.
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