Effects of Deer Browsing on Bird Habitat Following Forest Management Practices
Patrick J. Rusz, Ph.D., Director of Wildlife Programs, Michigan Wildlife Conservancy
Nora Howlett, Research Assistant, MWC
Anna Wright, Research Assistant, MWC
Nora Howlett, Research Assistant, MWC
Anna Wright, Research Assistant, MWC
In the 1970s, ecologists and land managers began to rethink forest management strategies. More emphasis was subsequently placed on ensuring regeneration of multiple tree species and reducing potential impacts of fragmentation on forest interior birds and other wildlife species. However, in the nearly 50 years since, potential benefits of carefully-planned forest management have continued to be reduced by deer browsing.
Many studies, including some long-term efforts, have shown that deer browsing reduces or eliminates regeneration of palatable plant species, increases invasion or regeneration of less palatable species, may reduce overall stem density in the understory and groundcover, and often quickly results in dense growth of ferns, woodland sedge, and other herbaceous plants that halt growth of woody plants. Among the "losers" in such scenarios are some of the "area sensitive" birds, such as the ovenbird, wood thrush, veery, and hermit thrush. Nesting success for these low or ground-nesting species seems to depend on dense regrowth of certain woody plants, and related structural diversity that makes it harder for predators to find nests.
Retention of logging debris, especially tree tops, is a cost-effective method of reducing deer browsing impacts on regeneration and habitat for certain birds following forest management practices. However, some selective cuttings may not result in enough over-lapping material to prevent significant browsing, especially when and where deer are highly-motivated. Supplemental hinge-cutting of trees and/or herbicide treatments of ferns may be necessary to meet management objectives. Long-term research/demonstration projects are needed to better assess costs and determine which plant and bird species are most likely to benefit. Ignoring the impacts of deer on regeneration following cuttings will likely continue to negate some of the opportunities and benefits of forest management strategies.
For the complete presentation in powerpoint format, click here.
Many studies, including some long-term efforts, have shown that deer browsing reduces or eliminates regeneration of palatable plant species, increases invasion or regeneration of less palatable species, may reduce overall stem density in the understory and groundcover, and often quickly results in dense growth of ferns, woodland sedge, and other herbaceous plants that halt growth of woody plants. Among the "losers" in such scenarios are some of the "area sensitive" birds, such as the ovenbird, wood thrush, veery, and hermit thrush. Nesting success for these low or ground-nesting species seems to depend on dense regrowth of certain woody plants, and related structural diversity that makes it harder for predators to find nests.
Retention of logging debris, especially tree tops, is a cost-effective method of reducing deer browsing impacts on regeneration and habitat for certain birds following forest management practices. However, some selective cuttings may not result in enough over-lapping material to prevent significant browsing, especially when and where deer are highly-motivated. Supplemental hinge-cutting of trees and/or herbicide treatments of ferns may be necessary to meet management objectives. Long-term research/demonstration projects are needed to better assess costs and determine which plant and bird species are most likely to benefit. Ignoring the impacts of deer on regeneration following cuttings will likely continue to negate some of the opportunities and benefits of forest management strategies.
For the complete presentation in powerpoint format, click here.