Beaver dams are important factors in bolstering the diversity of migratory songbirds in the semi-arid regions of western North America. A study conducted by scientists with the Wildlife Conservation Society have discovered that the dams beavers build create ponds. Those ponds, in turn, support an abundance of wetland vegetation—habitat that is critical for birds. The study revealed that the more beaver dams there were, the more diverse and abundant the local songbird populations became.

Hilary Cooke is the lead author of the study, and states "[The habitat created by beaver ponds] is critical to birds in semi-arid regions yet has been severely degraded or lost through much of the West. Our results suggest that management of beavers may be an important tool for restoring habitat and reversing bird declines."

Beavers suffered significant declines in the 1800s when they were targeted for their fur. Additionally, beavers are viewed as pest species since they fell trees and flood property. But beavers play an important role in they ecosystems they belong to. They help to repair degraded riparian habitats and the dams they build can replenish local water tables and create much needed wetlands.

This study is not the first to suggest that beaver dams contribute to species diversity. In 2007, I blogged about research published by scientists at the University of Alberta, Canaday, which revealed that beavers help to protect amphibians as well.

Find out more:

• Beavers: Dam good for songbirds (Eurekalert)
• Riparian Restoration and Songbirds (Wildlife Conservation Society)

Vegetation on mountains varies with altitude in response to changes in local environmental conditions. As you move up a mountain, you travel along a mosaic of gradients (climate, soil conditions, moisture, species composition). For example, the higher you venture, the lower the temperature falls. Wind speeds strengthen and precipitation is more abundant as you approach the summit. Where temperatures drop below freezing, rainfall turns to snowfall.

Linda Rayor, a senior research associate of arthropod behavior at Cornell University, has an infectious passion for arachnids. She teaches a much-loved course in spider biology at Cornell, in which her engaging teaching style seldom fails to turn spider-fearing arachnophobes into inquisitive and enthusiastic arachnophiles.

Rayor's teachings are not restricted to the university lecture hall. For more than a decade, Rayor has led a highly successful outreach program that empowers students to talk about biology and entomology in classrooms, clubs, and community groups. Her teachings also extend to the web, where Cornell University has also posted a series of videos on spider biology in which Linda Rayor shares her spider biology knowledge and unique teaching style with the online community.