Rockville Hills Regional Park is home to a variety of plant and animal species each thriving in their own special niches. These special niches are the building blocks that comprise the Park’s various plant communities and habitats, which form the Park’s ecosystem. The Park is comprised of multiple plant communities, which include oak woodlands, grassland savannas, chaparral and various aquatic habitats. The Park’s Management Plan focuses on preserving and restoring these precious natural resources.
A particularly unique habitat is the Park’s chaparral community, which is approximately 80 acres (Figure 11 Rockville Hills Regional Park Management Plan). While some may think chaparral plant communities are comprised of only a few uninteresting “shrubs” this community hides a host of amazing, exotic looking wildflowers, endless reptiles, large and small mammals and interesting spiders. Wildlife thrives in this area of the Park because of the dense and almost impenetrable short, fierce shrubs and rocky dry soil. The plant community provides valuable habitat and camouflage for mammals, many snakes, lizards, birds and reptiles. This chaparral is extremely fire prone and if left unchecked burns about every 10 years! The “rebirth” from a fire is necessary for the community’s health and sustainability. The Park’s chaparral had become a serious fire hazard. Modern theories suggest that fire suppression, preventing fires was better than allowing wildfires to burn, which consume and reduce fuels. This process keeps the habitat healthy and balanced.
Another way to reduce the risk of fire is through grazing. In June of 2004, the City partnered with Citation Northern for a very successful project. The project goal was to reduce the fuel load within the chaparral community while maintaining the ecological value for wildlife. The project encompassed approximately 25 acres and was accomplished by using 800 goats over a 6-week period. Fencing was moved as necessary to allow the goats to feed on new vegetation and to prevent overgrazing of sensitive chaparral plants.
In July of 2006 the City undertook the process again using sheep, which were managed with a full time on-site Sheppard.
This is the most prominent habitat within the Park. It is important because it provides nursery habitat for the Acorn Woodpecker as well as a valuable food source for native mammals such as Black Tail Deer and the Beechi Ground Squirrel. The Oak Woodlands are a majestic treasure to be enjoyed for generations of visitors to come. Unfortunately, this valuable resource is threatened by Sudden Oak Death Disease (SOD). SOD is an infection that damages the valuable cambium layer causing the tree to be unable to move food from the roots to the leaves. SOD effectively closes off the millions of small veins that form the trees vascular system. Trees within the Park have been fortunate and have not caught the disease. The City plans to implement a SOD monitoring program in the future.
The Parks unique ecosystem is threatened by a variety of forces, some caused by wayward visitors but others much more subtle. Invasive weeds, which were introduced when settlers came to these areas, have left their lasting unalterable effect on the landscape. A goal of the Management Plan is to reduce and where possible, eradicate non-native invasive weeds. Phase one and two of the invasive weed projects were completed in July 2004 and July 2005 by the Sacramento Conservation Corp. As a result of the severe winter storms in 2005/2006 the City was unable to contract with the Sacramento Conservation Corp to perform an additional annual invasive weed abatement project in 2006. Instead, a small amount of abatement was accomplished using local volunteers.
Two enhancement projects that was undertaken to the protect and enhance the Park's various streams and lakes. The City of Fairfield agreed to let Citation Northern Restoration restore the lower lake and ephemeral stream in August 2003 and to restore the Upper Lake and ephemeral stream in October 2005. Part of the restoration was to install fencing to keep cattle from accessing the lakes as well as to protect the new restoration plantings. An integral part of being able to undertake these projects was the City’s ability to successfully install cattle water troughs. This allowed cattle to continue to graze within the Park while restricting them from trampling the sensitive stream and lake edges.
The wetland and riparian restoration project areas were shaped, planted and enclosed with cattle fencing. Fencing was installed to keep cattle out of these areas per the Management Plan and to allow the restoration plantings to establish themselves. Hiker walkthrough gates were installed at appropriate locations, allowing visitors to continue to access the area while limiting bikers from using unauthorized trails in the restoration area. Much of this fencing will be removed once the restoration plantings have established themselves. Establishment is expected to take 5 years.
These projects provide additional habitat for aquatic and invertebrate species. The lower pond restoration has already been extremely successful as nursery habitat for several types of waterfowl including wood ducks and American Kestrels, the smallest North American Raptor.
Citation Northern funded these enhancement projects and they donated to have a vault toilet installed.