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Prince William Conservation Alliance
Explore, Enjoy & Protect Local Natural Areas

Community Report
November 5, 2009
Newsletter Archive
When preserving land to protect ecological systems, there are two principles that are critical: preserve the biggest, widest pieces possible, and preserve the biggest buffers possible.
By preserving the biggest, widest chunk possible, you preserve the maximum amount of functionality within forest systems.
Upland Depression Swamps occur in a highly restricted range almost entirely within the metropolitan Washington, DC portion of the Culpeper Basin.

This unique resource, due to the presence of wetland hydrology in an upland setting, is classified as an isolated wetland.
The highly limited range of Upland Depression Swamps coincides with large-scale suburban development, placing this plant community at high risk for disappearance.

NatureServe, an international network of natural heritage programs, rates Upland Depression Swamps as G2, meaning they are globally imperiled.

The other threatened plant community at Silver Lake is a Basic Oak-Hickory Forest , rated G3, meaning this community type is vulnerable to extirpation.

The term “basic” refers to this community’s occurrence on basic, as opposed to acidic soil.
These basic soils derive from the underlying diabase (a.k.a. bluestone) and metabasalt rocks common in the Culpeper Basin. Basic soil is more fertile than acidic soil, so this community supports a high level of plant diversity.

   Globally Rare Natural Areas at Silver Lake   

1Parkland for Plants, People and Wildlife
1st Thursday Speaker Series

When: Thursday, Nov. 5 at 7:30 pm

Speaker: Charles Smith, Fairfax County Park Authority Natural Resource Specialist and Prince William Wildflower Society

Where: Bull Run Unitarian Church, Bull Run Unitarian Universalist Church, 9350 Main Street, Manassas 

The Virginia Dept. of Conservation and Recreation has recognized the significance of the globally rare Upland Depression Swamp and Basic Oak-Hickory Forest at Silver Lake.

Given that the Silver Lake property is public land, protecting these resources would seem to be an easy task. But that's not the case here because the globally rare natural areas were identified only after the fact - after the County accepted the property and, more importantly, after the County drew the borders of the middle school site in an area that includes both resources.

If the globally rare plant communities had been identified in a timely manner, it would have been easy to locate the school site in an area that left these resources on the parkland portion of Silver Lake, where they could have been protected.

The good news is that School Board members, working with the Park Authority, are making their best effort to protect these important natural areas. Although the outcome is still not certain, there are opportunities for success.   

At the same time, government is in process of updating the County's environmental policies. The current draft, which is receiving significant opposition from developers, calls for expanded environmental information early in the development process as well as County efforts aimed as establishing baseline data for natural resources.

Knowing what natural resources a community possesses is a critical step towards protecting them. Silver Lake is a case in point.

The 230-acre Silver Lake Park opened October 1 for hiking, biking, horseback riding and fishing. This new park includes an approximate 25-acre lake, 7-acre abandoned quarry, fields and forests. 

The Upland Depression Swamp and Basic Oak-Hickory Forests were originally discovered by Charles Smith when he visited the site in early September to assess habitat areas at the request of the Park Authority. Since then, the VA Dept. of Conservation and Recreation Natural Heritage Division has visited Silver Lake and verified Charles' findings. 

 Please join us this evening, 7:30 p.m., when speaker Charles Smith will share information on the natural assets found at Silver Lake, land management options that enhance parkland for the benefit of people, plants and wildlife.