气候变化领域集成服务门户(CCPortal): Hardwood-softwood composition influences early-instar larval dispersal mortality during a spruce budworm outbreak

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DOI	10.1016/j.foreco.2020.118035
	Hardwood-softwood composition influences early-instar larval dispersal mortality during a spruce budworm outbreak
	Zhang B.; MacLean D.A.; Johns R.C.; Eveleigh E.S.; Edwards S.
发表日期	2020
ISSN	0378-1127
卷号	463
英文摘要	Spruce budworm (Choristoneura fumiferana Clem.) defoliation of balsam fir (Abies balsamea (L.) Mill.) has been shown to be less severe in stands with higher hardwood (broadleaved trees) content during both building and declining phases of budworm outbreaks. Reduced defoliation associated with forest composition could be explained by habitat fragmentation and/or natural enemy hypotheses, which posit higher early-instar larval dispersal loss or more intense parasitism in hardwood-softwood mixed stands than in pure balsam fir stands, respectively. We carried out field studies in 27 hardwood, mixedwood, and softwood plots with varied balsam fir-hardwood composition to assess effects of forest composition on: 1) first- and second-instar larval dispersal loss, and 2) stage-specific spruce budworm density and parasitism rates. Results indicated that increasing hardwood content increased second-instar (L2) dispersal losses. Stand type significantly affected dispersal loss of L2 larvae, both measured directly for three years and sampled on balsam fir seedlings. Post-hoc pair-wise comparisons indicated that L2 dispersal loss was less in softwood than in mixedwood or hardwood stand types based on measurements on ground traps and less in softwood and mixedwood than in hardwood stands based on sampling budworm larvae on regeneration. This suggested that high early-instar larval dispersal loss is a plausible explanation for the decreased spruce budworm density and balsam fir defoliation associated with increasing hardwood content. Stand type did not significantly affect parasitism rates. © 2020 Elsevier B.V.
关键词	Ecosystems Reforestation Softwoods Abies balsamea Choristoneura fumiferana Defoliation Habitat fragmentation Parasitoids Hardwoods defoliation dispersal forest ecosystem habitat fragmentation hypothesis testing mortality natural enemy parasitism pest outbreak wood quality Abies Balsamea Defoliation Ecosystems Hardwoods Reforestation Softwoods Abies balsamea Choristoneura fumiferana
语种	英语
来源机构	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132891
推荐引用方式 GB/T 7714	Zhang B.,MacLean D.A.,Johns R.C.,et al. Hardwood-softwood composition influences early-instar larval dispersal mortality during a spruce budworm outbreak[J]. Forest Ecology and Management,2020,463.
APA	Zhang B.,MacLean D.A.,Johns R.C.,Eveleigh E.S.,&Edwards S..(2020).Hardwood-softwood composition influences early-instar larval dispersal mortality during a spruce budworm outbreak.,463.
MLA	Zhang B.,et al."Hardwood-softwood composition influences early-instar larval dispersal mortality during a spruce budworm outbreak".463(2020).