EFFECTS OF TIMBER HARVESTING NEAR NEST SITES ON THEREPRODUCTIVE SUCCESS OF NORTHERN GOSHAWKS(ACCIPITER GENTILIS)

摘要

We assessed the effects of timber harvesting near nest sites on the reproductive success of the Northern Goshawk Actipiter gentilis Harvest trials were implemented at 27 of 79 known nest areas, and the median post-treatment monitoring period was 3 yr range = 1-7 We used a mean nest area size of 24 ha, based on the average number and spacing of nests within nest areas, to assess the impact of harvesting Harvesting trials consisted of clear cutting, with the amount of nest area harvested ranging from 5.5% From 1996 2002, we found no significant difference in nest area reoccupation frequencies or fledging rates of goshawks between treatment areas and control areas P > 0.10. Even treatment areas with >50% of the nest-area stand removed N = 7 did not exhibit reduced reoccupation or fledging rates These results are preliminary, pending longer post-treatment monitoring to address high annual variation and a potential lag effect that may be exhibited by the goshawks If these results are consistentover a longer period, they may support de-emphasis of management and research effort at the nest-area scale and greater emphasis at the territory and landscape scales to examine correlations between timber harvesting and territory abandonment and population declines reported in other studies.