A recent decline in ovenbirds (Seiurus aurocapilla), a ground-nesting migratory songbird, in forests in the northern Midwest United States is being linked by scientists to a seemingly unlikely culprit: earthworms.
A new survey conducted in Minnesota's Chippewa National Forest and Wisconsin's Chequamegon-Nicolet National Forest by a research team led by Scott Loss of the University of Minnesota and the Smithsonian Migratory Bird Center has revealed a direct link between the presence of invasive European earthworms (Lumbricus spp.) and reduced numbers of ovenbirds in mixed sugar maple and basswood forests.
The results are detailed in a paper published online in the scientific journal, Landscape Ecology.
European earthworms are invading previously earthworm-free hardwood forests in North America the scientists say, and consuming the rich layer of leaf litter on the forest floor. In turn, herbaceous plants that thrive in thick leaf litter and provide cover for ground-nesting birds are thinning out, replaced by grasses and sedges.
As a result, ovenbird nests are more visible and vulnerable to predators and ovenbirds searching for nesting sites reject these low-cover areas outright. Areas of reduced leaf litter also contain fewer bugs for the ovenbirds to eat, requiring them to establish larger territories, resulting in fewer birds over a given area.
The worms invading northern Midwestern forests (and forests in the northeastern U.S. and Canada) have been in the U.S. since soon after the first European settlers arrived. Loss explains the worms were brought over inadvertently in the ballast of ships, in the root balls of agricultural plants or on purpose for use in gardening. Only now is the leading edge of their continued invasion, caused mainly by logging activities and fishermen dumping their bait, reaching interior wilderness areas such as parts of the study site in the remote forests of Wisconsin and M
'/>"/>
| Contact: Lindsay Renick Mayer 202-633-3081 Smithsonian Source:Eurekalert |
Related biology news :
1. MU scientists study how to improve pesticide efficiency
2. Studying the importance of biological rhythms for the ecological performance of plants
3. Nowhere to hide: Study finds future of Sumatran tigers threatened by human disturbances
4. Cleveland Clinic Childrens Hospital launches study to genetically test for autism
5. Iowa State, Ames Lab chemists aid study of mutated plants that may be better for biofuels
6. UBC researcher invents lab on a chip device to study malaria
7. Ice Age coyotes were supersized compared to coyotes today, fossil study reveals
8. Coral reef study traces indirect effects of overfishing
9. Traces of listeria found in Vancouver ready-to-eat fish products: UBC study
10. Study IDs new marine protected areas in Madagascar
11. Invasive plant protects Australian lizards from invasive toad: Study
 |
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |