Doug Tallamy

From Observatory

Author Photo Doug Tallamy by Rob Cardillo.jpg
Author Photo Doug Tallamy by Rob Cardillo.jpg
Doug Tallamy
Scientist. Writer

Doug Tallamy is the T. A. Baker Professor of Agriculture in the Department of Entomology and Wildlife Ecology at the University of Delaware and co-founder of Homegrown National Park.

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Doug Tallamy is the T. A. Baker Professor of Agriculture in the Department of Entomology and Wildlife Ecology at the University of Delaware and co-founder of Homegrown National Park. He is the author of The Nature of Oaks, Nature's Best Hope, The Living Landscape, and Bringing Nature Home.

New York Times | 2021

In this piece by Margaret Roach, Doug Tallamy explains why oak trees are so critical to ecosystems.

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Co-authors: Desiree L. Narango and Garrison Piel | BioOne | November 2021

The richness, abundance, and biomass of phytophagous arthropods like lepidopteran larvae is highly uneven among sympatric tree taxa. Optimal foraging theory predicts that predation pressure will be greatest on foraging substrates that support the highest abundance and/or diversity of prey, thus offering the greatest reward and maximizing fitness. Predation pressure can also vary with the nutritional or energetic needs of predators across the annual cycle. For insectivorous birds, prioritizing foraging effort in trees that support the most insect prey can benefit individuals by improving their foraging efficiency, condition, and ultimately fitness.

However, we lack an understanding of how trees vary in their support of bird foraging activity across seasons and among plant taxa. We used plasticine caterpillar models to measure avian predation rates on 9 native North American tree species that vary in caterpillar-hosting potential. We measured avian predation rates during May, June, and October to compare caterpillar mortality in seasons that vary in life-history needs, abundance, and diversity of avian predators. We modeled daily survivorship and total mortality using Cox-proportional hazard models and logistic regression.

We found that, across seasons, caterpillars had significantly higher predation rates on trees that are predicted by literature host records to support the most species of caterpillars (β = 0.22 ± 0.05, 95% CI = [0.13,0.32], z = 4.73, P < 0.0001). Caterpillars had the highest mortality in June, coinciding with avian breeding seasons, and the lowest rates in October, coinciding with fall migration and dispersal. Our study suggests that birds disproportionately forage on trees that have the highest potential to support caterpillar richness and presumably prey biomass.

The observed pattern of non-random foraging has many implications; for example, the utility of using informed tree selection to improve bird foraging in managed ecosystems or potential negative implications to bird populations of forest-composition shifts due to climate change. Applying this information to habitat restoration will enable land managers to better support avian populations by planting trees that best support foraging substrates for insectivorous birds in managed ecosystems.

February 2020

“Tallamy lays out all you need to know to participate in one of the great conservation projects of our time. Read it and get started!” —Elizabeth Kolbert, Pulitzer Prize-winning author of The Sixth Extinction

Douglas W. Tallamy’s first book, Bringing Nature Home, awakened thousands of readers to an urgent situation: wildlife populations are in decline because the native plants they depend on are fast disappearing. His solution? Plant more natives. In this new book, Tallamy takes the next step and outlines his vision for a grassroots approach to conservation. Nature’s Best Hope shows how homeowners everywhere can turn their yards into conservation corridors that provide wildlife habitats. Because this approach relies on the initiatives of private individuals, it is immune from the whims of government policy. Even more important, it’s practical, effective, and easy—you will walk away with specific suggestions you can incorporate into your own yard.

If you’re concerned about doing something good for the environment, Nature’s Best Hope is the blueprint you need. By acting now, you can help preserve our precious wildlife—and the planet—for future generations.

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