J. Bourque et Ma. Villard, Effects of selection cutting and landscape-scale harvesting on the reproductive success of two neotropical migrant bird species, CONSER BIOL, 15(1), 2001, pp. 184-195
We measured the effects of forest harvesting at two spatial scales on the p
roductivity of two Neotropical migrant bird species, the Black-throated Blu
e Warbler (Dendroica caerulescens) and the Ovenbird (Seiurus aurocapillus).
We selected two forest landscapes representing extremes in harvesting inte
nsity for northwestern New Brunswick, Canada. Within each landscape, we sel
ected study plots located either in recent (<5 years) selection-cut stands
(30% removal every 20 years) or in stands that were lightly harvested at le
ast 30 year ago. Black-throated Blue Warblers reached higher densities in s
election cuts, but their reproductive performance (pairing and fledging suc
cess) did not suffer significantly between stand types (uncut vs. selection
cut) or between landscape types (intensity vs. moderately harvested). In 1
998, nonetheless, 61% of the estimated number of fledglings produced in our
plots were born in selection cuts. In contrast, this proportion was only 2
3% for Ovenbirds in 1998 and 1999 combined. Ovenbirds had lower densities,
and their reproductive performance was significantly lower in selection cut
s than in uncut plots. These results indicate that the effects of selection
cutting on demography are species-specific and that Ovenbird persistence i
n selection cuts may be compromised unless the intensity or frequency of cu
tting is decreased.