Category Archives: Articles

Native Pollinators

Matthew Shepherd & Mace Vaughan, The Xerces Society

“The conservation biology issues are not simply esoteric concerns relevant only to middle-class bird-watchers and bug-netters. These issues should strike a chord in every person who cares about where our food comes from and whether it is wholesome to eat.” — Stephen L. Buchmann and Gary Nabhan, The Forgotten Pollinators

Pollinators are among the hardest working creatures of the natural world. Pollination, the transfer of pollen grains from the anther to the stigma of the same or another flower, is necessary for plants to produce seeds and fruit. Up to 80 percent of the world’s flowering plants rely on animals – pollinators – for this transfer. Insects pollinate two thirds of the world’s crop species, whose fruits and seeds together provide 15 to 30 percent of the foods and beverages that we consume-approximately one out of every four mouthfuls. Continue reading

Enhancing Nest Sites for Native Bee Crop Pollinators

by Mace Vaughan & Scott Hoffman Black

The European honey bee receives most of the credit for crop pollination, but the number of managed honey bee hives is half of what it was in the 1950s; and this number continues to decline. Native bees, however, also contribute significantly to crop pollination and, on farms with significant natural habitat located nearby, may even provide all of the required pollination for some crops.

To support the native bee community, it is essential to provide nesting sites, in addition to floral resources. Unfortunately, heavily managed farm landscapes often lack the untilled ground, tree snags, plants, and small cavities that native bees require for nest construction. Improving the nesting opportunities for these important pollinators will increase their populations which can lead to higher crop yields, reduced dependence on imported European honey bees, and improved on-farm biodiversity. Continue reading

Site Evaluation for Habitat Restoration Plant Selection

by Julie Whitacre, Fourth Corner Nurseries

While making decisions about which plant species are appropriate for restoration projects, several physical characteristics of the project site should be considered. Each plant species has preferences for physical conditions; some plants are very widely adaptable to moisture regimes, soil conditions, and light levels, and others are fairly demanding in their habitat requirements. Charts detailing the habitat preferences of northwest native plants are available in the “Resources” section of our website. This article will focus on riparian projects, with examples of species common in western Washington, Oregon and British Columbia; similar steps, however, can be adapted to other habitat types. Continue reading

Selecting Native Plants for Wetland, Riparian, and Wildlife Buffer Plantings

by Richard T. Haard, Ph.D., Propagation Manager, Fourth Corner Nurseries

For the past 15 years the protection and enhancement of wetlands has become a major mission for state and federal governments. With the passage of the Clean Water Act, the new regulations have affected how we practice agriculture and conduct commercial and residential developments. In addition, riparian habitats have been enhanced or given protection, in part because of the listing of some fish species under the Endangered Species Act. Continue reading

Investigating Green Roof Performance

in the Puget Sound, Georgia Basin:  Stormwater, Plant Communities, and Beyond

by Danielle L. Pierce and Ken Yocom

What is a green roof?

Green roof systems are described as an extension of the existing roof which involves a high quality water proofing and root repellant system, a drainage system, filter cloth, a lightweight growing medium and plants.1While there is some debate as to the effectiveness of green roof structures at addressing some of the larger issues associated with urban environmental degradations and climate change, green roofs have been found be beneficial. For example, these systems have been found to lower rooftop and building temperatures, thereby reducing the urban heat island effect found in so many of today’s cities, as well as improving the quality of stormwater runoff while decreasing the amount of runoff during storm events. Green roofs also slow precipitation that rooftops capture so that when it drains to the public sewer system, or some other receiving body, it happens over a period of hours and sometimes days rather than minutes or seconds.  This reduction in rainwater release dampens the pulse, or volume of water, that must be transported off-site and treated in wastewater plants. In cities or areas with combined rainwater and sewer systems, such as Seattle and Portland, this pulse sometimes overwhelms the wastewater treatment plant, resulting in released sewage and rainwater. In our region, preventing combined sewer overflows is an important action for improving the ecological health of Puget Sound and other large bodies of water. Continue reading