CHAPTER 1 Introduction Why it is Important to Preserve Open Space Safeguarding the natural resources and processes that provide benefits for all of us (such as clean air, clean water, waste decomposition, and nutrient recycling) ranks among the greatest contem- porary environmental challenges. In 1968 Garrett Hardin published a landmark paper entitled “The Tragedy of the Commons” in which he described the consequences of our failure to take individual or collective ownership of vital ecosystem components. The subsequent passage by the federal government of the Clean Air Act, the Clean Water Act, the Endangered Species Act, and the Environmental Quality Act in the late 1960s and early 1970s was an important regulatory step taken to protect these vital functions of the environment. However, the continuing reality of global warming, species extinctions, dwindling water supplies, depletion of fisheries, and col- lapse of ecosystems is compelling proof that stronger action is needed. The intention in this update of the Montgomery County Natural Areas Inventory is to identify landscapes of several thousand acres each in which important ecological functions can be pre- served and or restored, and to outline management strategies needed to promote the continuation of those essential ecological functions. Ecosystem Services Open space protects the life support system for humans as well as wildlife. While we humans may not live directly in the fields, forests or streams, we depend on those natural systems to carry out essential ecosystem services such as water purification, oxygen production, and waste de- composition. Other services provided by natural systems include ground water recharge, flood control, soil building, climate moderation, pollination, and mineral recycling. Natural systems also contain a reservoir of biological diversity in the myriad organisms large and small that are part of functioning ecosystems. Stream Health – We withdraw water from aquifers, streams and reservoirs, use it, treat it, and return it to the natural system for further purification. Even after household wastewater has passed through a sewage treatment facility and been discharged into a stream, more cleansing takes place as the flowing water is exposed to sun and oxygen from the atmosphere and the ac- tion of microorganisms. If a stream receives too much waste, its ability to restore water quality may be exceeded, leading to algae blooms and fish kills. Flow in theWissahickon Creek, for example, can be as much as 90 percent sewage treatment plant effluent during periods of drought when many of the stream’s smaller tributaries dry up. The health of our streams is also dependent on sufficient ground water to maintain stable mini- mum flow year round. Protecting open space insures that there are forested areas where rain and melting snow can soak into the ground, thus maintaining the underground aquifer that feeds the streams. Soil permeability is greatest in forested land; however, with the loss of natural vegeta- Natural Areas Inventory Update 2007 tion, runoff increases and ground water recharge is reduced. When too much of the land surface is covered with impermeable or less permeable surfaces such as roofs, paving, and even lawns, water cannot penetrate as well. Water Supply – A lowered water table can have a negative impact on water supply, aquatic habitats, and soil erosion. Ten percent of Montgomery County residents and approximately 30 percent of the public water systems in the county depend on wells. Reductions in the water table may mean that wells go dry, which could leave these residents and purveyors without a reliable water supply. In addition, streams may have drastically reduced flow between storms, especially in the summer, which results in the loss of aquatic habitat. Furthermore, when rainstorms occur, the rapid runoff from impervious surfaces results in frequent flooding, accompanied by scouring. These conditions leave little life in the streams. Bank erosion is accelerated and suspended silt further degrades water quality. Because the water cycle’s proper functioning is closely related to the existence of open space we must carefully manage the impact development is having on our streams, to insure that water supplies remain reliable into the future. Floodplains – Floodplains are an important part of the hydrological system. Formed by the ac- tion of streams over time, floodplains are the waterway’s safety valve. They provide a place for water to spread out during periods of high flow. The speed of water movement is slowed and silt is deposited, building up alluvial floodplain terraces. Floodplains have their own community of plants and animals that are adapted to occasional inundation. Carbon Sequestration – Forests and other natural vegetation remove carbon dioxide from the atmosphere through the process of photosynthesis, and incorporate it into carbon-containing compounds in plant tissue and organic resides such as leaf litter. Carbon sequestration is an important process for slowing the increase of CO2 in the atmosphere that has been linked to climate change. Quality of Life A network of open space makes Mont- gomery County a more desirable place to live, visit, and work through protection of its distinctive resources. Studies have shown that open space and associated amenities such as trails are often consid- ered by businesses looking to relocate. For residents, quality of life benefits include the following areas: Spring-beauty is a common early spring wildflower in moist woods Recreation – The popularity of the throughout the county Schuylkill and Perkiomen Trails is evi- dence of the demand for outdoor recreation opportunities such as bicycling and hiking. Natural areas foster peace of mind, enjoyment, and recreation through such activities as bird watching, 10 Natural Areas Inventory Update 2007 wild flower observation, nature photography, hunting, and fishing. Bird watching, in particular, is a rapidly growing outdoor activity with many local adherents. Pennsylvania Audubon’s desig- nation of three Important Bird Areas (IBAs) in the county has further stimulated this interest. In addition, wildflower diversity, which is especially high in the areas of diabase geology in the western part of the county (see section of geology and physiography below), has long stimulated the interest of local amateur botanists. Health – A quiet walk in the woods can provide a respite from the human-dominated landscape and restore one’s mental and spiritual health. Merely driving a scenic country road can provide relaxation and pleasure. In addition, outdoor active recreation provides health benefits by pro- moting physical activity such as walking, bicycling, and jogging. Economic – Open space can benefit communities through the positive economic impact that they can generate. New businesses may choose to locate in the area due to open space amenities that enhance community attractiveness and redevelopment initiatives. In addition, preserved open space often increases surrounding property values. Social/Cultural – Montgomery County’s network of open space contributes to community building by linking communities along trails and greenways. It offers places where people can interact with other members of the community. People may also build pride in their community assets such as heritage areas, farms, and rural areas. Residents and visitors can also choose to take advantage of educational opportunities that the out-of-doors provides. Study Methods Designation of Landscapes In commissioning a re-examination of natural areas in Montgomery County, the planning com- mission specified a “systems” approach focused on “sustainable landscapes.” Our first step was to examine aerial photography of the county looking for areas that retained a high percentage of forest cover. Using ArcGIS version 9 and spatial data sets obtained from the planning commis- sion and Pennsylvania Spatial Data Access (PASDA) website we created overlays of the highest priority sites from the 1995 Natural Areas Inventory, publicly owned land, floodplains, and wet- lands. We also took into consideration planned and existing trail corridors and areas designated as Important Bird Areas (IBAs). By drawing polygons that included areas of continuous, or nearly continuous, forest cover we identified 13 conservation landscapes, each with a core area of protected land (Figure 1.1). Not surprisingly, the landscapes were either rocky areas of diabase geology or riparian corridors. All but one of the 18 highest priority sites from the previous Natural Areas Inventory were included in our landscapes. Norritonville Woods was excluded because it did not meet the criteria for connectivity or presence of a core area of protected land. The intent of taking a landscape approach to open space preservation is to maximize the po- tential for long-term sustainability of individual sites by protecting the landscape context and enhancing connectivity. The landscapes, at several thousand acres each, are intended to be Natural Areas Inventory Update 2007 11 big enough to preserve important ecological functions critical to maintaining the life support system for the county as a whole. This approach will be implemented through a combination of public and private ownership, easements, and voluntary implementation of appropriate man- agement strategies and techniques. Survey Methods Surveys were conducted of selected tracts within each landscape to document elements of bio- logical diversity including