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Final Walden Biodiversity Report

My final summary report on the groupings of organisms and the people who found them during Walden Biodiversity Days in 2009 and 1998 is finished and can be downloaded here (5.7 MB). These events wouldn’t have been possible without hundreds of experts and helpers...

Berry Bad Guests: Invasive Aliens at the Dinner Table

In the run-up to Thanksgiving this week Shannon Mullen of National Public Radio interviewed me and Martha Stewart about Oriental Bittersweet, one of the most aggressively destructive invasive plants in the North East US and a staple of holiday decorations. Not...

The Results are In

My thanks go out to many people for helping make Walden Biodiversity Day II in July a success. Our report and checklists are complete and now combine data from the historic 1998 Biodiversity Day with this summer’s event. The total number of species seen in 1998 and...

Biodiversity Day Photo Gallery

Since Biodiversity Day in July I’ve been working on a combined species list for the 1998 and 2009 events, and beginning to assemble an online gallery of all the photos we’ve received. Here’s a...

Trolling for Leeches

Sometimes you’ve got to roll up your sleeves – or pants leg – to get the job done, as I was doing to identify leeches in the Concord woods during Walden Biodiversity Day, a 24-hour bio-blitz to inventory all species that can be seen with the naked...

Spreading the Word

Here’s a clip of my recent appearance on WCVB-TV’s Chronicle, once again trying to spread the word about the problem of invasive alien species. When I say that, I know most people think of UFOs and little green men. Producer Ernie Sarro even leavened this...

Walden Biodiversity Day

On July 3rd and 4th I’ll be leading the second Walden Biodiversity Day, a gathering of top naturalists and field biologists — many of whom participated in the first Biodiversity Day in 1998 — who will fan out to find, identify and photograph over a thousand...

When Birds Go Bad

As reported by the Wall Street Journal: a tiny blackbird has been tormenting pedestrians in the heart of San Francisco’s financial district, guarding his nest in a behavior called “mobbing.” But has this bird gone bad or is he just getting back at...

Nature Sense

Here are some excerpts from “Nature Sense with Peter Alden” produced by Ernie Sarro. Invasive alien plants are a major threat to America’s native plants and trees. Look for my regular segment on The Expert Series which airs on many community access...