Research Studies

Earthworm Studies

The following research studies have been undertaken as part of the partnership between the Land Restoration Department and Philadelphia University’s Environmental and Conservation Biology program.
Invasive Earthworm Management Trials 
The Problem:       
Invasive earthworms (Amynthas spp.) disrupt nutrient cycles, increase soil erosion, remove leaf litter, support the growth of invasive plant species and destroy the forest floor habitat in urban temperate deciduous forests of the Northeastern United States.  Studies along the eastern seaboard indicate that worm density increases with urban development and disturbance. Effective earthworm management treatments are needed for successful forest regeneration and biodiversity enhancement on urban restoration sites.

Our Pilot Study:
From 2002-2003, a pilot study measured Asian earthworm (Amythas hilgendorfi and agrestis) responses to 26 treatments (control, black walnuts (Juglans nigra), white pine needles (Pinus alba), tobacco (Nicotiana spp.), wasabi, sulfur, Aluminum sulphate, sand, and diatomaceous earth).  Soil chemical and physical properties were also assessed.

Our Research Trial:
The best six treatments were selected from the pilot study and a two year trial with five replications was initiated in 2003 and completed in summer 2005.  Both soil fungal to bacterial levels as well as Red-backed salamander populations were measured in the trial because they are indicators of forest health.  Soil chemical and physical properties were also assessed. Click here for the complete report on Microbial assessment of effective earthworm management trials for restoration of an urban temperate forest site.


Deer Management

Since the 1970s development has been putting a great deal of pressure on local deer populations. With the loss of habitat and forest fragmentation, and natural predators, deer populations have grown exponentially.

Typically the holding capacity for deer in one square mile – or about 500 acres – is 8 to 10 deer. Of course this may vary depending on the health of the land. In 1999 The Schuylkill Center was carrying approximately 200+ deer on 340 acres.

The high number of deer has a direct impact on the health of our ecosystem. The forest is comprised of four distinct layers: canopy, understory, shrub, and herbaceous. These are extremely important components of a healthy system. Removing any of these layers can have an adverse affect on the function of our forest, such as increased erosion, habitat loss, and the inability to regulate temperature. This altered forest structure can become increasingly fragile and unstable. In areas where deer populations are high, the shrub and herbaceous layers tend to be nonexistent. High populations of deer can also have and adverse affect on the herd itself. When there are too many deer, disease can become more prevalent, along with the increase of ticks and Lyme. Unfortunately, as the populations grow so does the need to manage the size of the herd.

It is important to know that managing deer populations is not just about eliminating deer. It is about studying the entire system and making informed decisions about the health and function of the entire forest system. It means monitoring the deer herd for optimal health and survivability. It means protecting restored ecosystems to ensure stability through diversity – plant and animal.

Deer management by hunting alone is a one pronged approach and does not take into account other aspects of the forest system. The management approach that we have adopted at The Schuylkill Center is a multi-system approach that includes hunting along with fencing, strategic planting, and natural barriers. We are striving to return The Schuylkill Center's grounds to a condition in which deer are a part of an intact, fully functioning forest ecosystem, one that has a balance among all its parts and can sustain maximum biological diversity.

Fortunately, since the beginning of our deer management program in 2000, we are noticing significant changes in our forest, due to the presence of a diverse community of plants and animals. The shrub and herbaceous layers are regenerating after twenty or more years, we are gaining significant habitat for threatened animal species and, most importantly, our deer population is.


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