You are here: Home / Research Topics / Research Highlights / Individual Highlight

Research Highlights

Individual Highlight

Invasive Plant Erodes Bird Song Diversity via Food Chain Effects

Photo of Adult chipping sparrow banded to allow individual identification (photo by A. Benson) Aubree Benson, University of MontanaAdult chipping sparrow banded to allow individual identification (photo by A. Benson) Aubree Benson, University of MontanaSnapshot : Although plant invaders are known for their negative effects on natural systems, the extent of these impacts is often unknown. Forest Service scientists studied how invasion of spotted knapweed (Centaurea stoebe) into grasslands of western Montana impacted native species from plants to insects to birds.

Principal Investigators(s) :
Ortega, Yvette K. Pearson, Dean E.
Research Location : Montana
Research Station : Rocky Mountain Research Station (RMRS)
Year : 2015
Highlight ID : 835

Summary

Although plant invaders are known for their negative effects on natural systems, the extent of these impacts is often unknown. Forest Service scientists studied how invasion of spotted knapweed (Centaurea stoebe) into grasslands of western Montana impacted native species from plants to insects to birds. Native plants declined with increasing levels of invasion, as did important insect groups that provide food for ground foraging songbirds such as chipping sparrows. Chipping sparrows breeding in knapweed-invaded habitat produced fewer young and had lower site faithfulness compared to birds in habitat dominated by native vegetation. As a result, the prevalence of yearling versus older adults was twice as high in invaded compared to native habitat, a shift that affected the way song was passed between generations.

Before they breed for the first time, chipping sparrows adopt a signature song kept for life. Yearlings in our study did so primarily by matching the songs of older birds rather than introducing new ones. Therefore, in invaded habitat where there were relatively few older birds to serve as teachers, the number of song types was reduced by nearly 20 percent, mirroring the loss of native plant and insect resources. Song diversity may provide a novel way to assess the sensitivity of birds to habitat change.

Forest Service Partners

External Partners

  • Northern Region / Lolo National Forest
  • Aubree Benson, University of Montana
  • Erick Greene, University of Montana

Strategic
Program Areas

Priority
Areas