For the fourth week of Huntingdon Landmarks Inc.’s summer walking tour series Thursday, Huntingdon County Conservation District’s watershed specialist Logan Stenger gave a presentation on the ecology of the Juniata River.
He shared the way the state’s plant life and waterways have evolved since Pennsylvania was first settled as a vast forest.
When Europeans settled Pennsylvania they not only deforested the area to build homes and plant crops, but they brought with them various diseases which took a toll on the area’s tree population.
American chestnut trees were the most prevalent and made up about one out of four trees.
The Europeans brought with them the Chinese chestnut blight, which the American trees could not keep up with, and it, “totally changed the ecology of Pennsylvania,” said Stenger.
Specifically, the waterways were lined with American and slippery elm trees, which again were no match for the Dutch elm disease.
People began clearing paths through the woods to the river so that they would have access to the water on their new property. This is still seen today, as people, “like to have clear, open sight-lines to the river.”
However, the practice of removing streamside trees and vegetation is the cause of the number one pollutant to Pennsylvania waterways—sediment.
Sediment is the amount of dirt in the water and is one of the factors that determines water quality, as well as pH, dissolved oxygen, temperature and hardness of the water.
Everything that enters the waterway affects the water downstream of it.
Huntingdon County is within the Chesapeake Bay Watershed, meaning that all the rain that falls here will eventually end up there.
The Juniata River is the largest tributary to the Susquehanna River, which flows directly into the Chesapeake Bay.
At 104 miles long, the Juniata River begins in Alexandria, where the Frankstown and Little Juniata branches come together, and eventually flows into the Susquehanna at Duncannon.
Western Pennsylvania is in the Ohio River watershed, and Eastern Pennsylvania water flows into the Delaware River.
These watersheds have different features which determine the life they can support.
As the native trees near the rivers have changed since Pennsylvania was settled, so have the fish species.
For example, migratory fish in the Susquehanna River watershed cannot move from saltwater to freshwater to spawn, because many do not make it back upstream over the fish ladders at all the dams that have been built.
The Delaware River does not have any dams, meaning that migratory fish in that watershed still have the luxury to swim freely.
Migratory fish, such as shad, striped bass, sturgeon and freshwater eels used to dominate the local waterways.
The freshwater eels have recently been reintroduced to help sustain the freshwater mussel population, though the eels themselves would have to travel to saltwater to spawn.
Aside from dam construction, overfishing also had an impact on the populations of shad and also eels, which were often sold to New York City restaurants as a delicacy.
Though such reintroduction efforts would create a river more similar to how it once was, some things will never be as they were.
For example, even smallmouth bass, which attract people specifically to this area for fishing, were brought here from the Ohio River Watershed, meaning that they are not native to the watershed.
The temperature of the water also plays a large role on the life it can sustain.
Small streams that begin in the mountains are colder than the wide rivers which open up and are warmed by the air.
Even in these larger rivers there are deep pockets of colder water, and different species of fish prefer to live in different temperatures of water.
Brook and lake trout, the only two trout species native to this area, are among those which prefer cold water.
Overall water quality has a large impact on the species that live there, and this can be easily studied by observing the macro-invertebrates, such as insects, crustaceans and mollusks.
Fish are able to leave water that is not suitable to their needs, but these creatures cannot as easily move. Many of them live at the bottom of the river, and, “may stay within one square meter for months at a time,” said Stenger.
He explained that a strong indicator of stream health is an abundant and diverse population of macro-invertebrates.
Certain species are more tolerant of pollutants than others, and a scarcity of those that are more sensitive can show that there might be something off-balance about the water’s quality.
Stenger shared that he believes the most effective way to ensure stream health is through education.
Substances such as salt, herbicides and medicines can negatively impact the waterways, and installation of rain gardens and rain barrels can help reduce the amount of sediment in the water.
Olivia can be reached at firstname.lastname@example.org.