Small Bug, Big Impact

This past month, I visited Delaware Water Gap National Recreation Area for a conference. You might think this NPS unit would be located in Delaware, but it's actually where the Delaware River borders the states of New Jersey and Pennsylvania along the Kittatinny Ridge. It has a rich history of different people groups settling in the area because of the abundant natural resources.

The sights and sounds just 5 hours south of NH were welcomed to this Southern Appalachian Mountain lover. I saw species of butterflies and wildflowers I had missed these past 3 years like the red-spotted purple butterfly and the deep purple flowers of NY ironweed.

But I also encountered something that I did not miss - the hemlock wooly adelgid, an invasive insect from Asia, most likely introduced through trade living on wooden crates. The trail to Dingman's Falls was once a cool, dark hemlock forest, but today after decades of wooly adelgid infestation, the hemlocks have died and many have fallen down, opening up the canopy above.

More sunlight might not seem so bad at first, but biologists become concerned when they consider what the hemlock trees were shading for so long. Cool mountain creeks and streams where salamanders and insects abide. Many of these critters cannot tolerate temperatures above a specific threshold. The extra sunlight could potentially raise the average water temperature above this threshold and cause a die off or at the very least cause stress that can make them more susceptible to diseases.

These small creatures are the basis of the food chain and make up a high percentage of biomass (because there are so many of them) in the hemlock forests. This has effects on the organisms that are higher in the food chain too and disrupts the whole ecosystem. Biologists are wondering if another tree or shrub will take the place of the hemlocks in these forests and shade the streams.