Viable Ecosystems 

Primary Objective: Conserve, protect, and restore aquatic and terrestrial ecosystems

Our ecosystems will be more viable when we recogonize the environmental services they provide and treat our lands and waters as assets to be managed and protected.

Viable Ecosystem Indicators

State of Our Environment 2007

The City of Ann Arbor protects about 1,200 acres of natural areas, including Bird Hills, Black Pond Woods, Sugarbush, Barton and 70 other sites scattered throughout the City . Approximately 15 acres of natural area have been purchased and another 49 acres preserved, over the past two years.

Surveys of Ann Arbor 's public natural areas have revealed a surprising abundance of biological diversity both in plant populations and wildlife. Most southeastern Michigan ecosystem types are represented in the parks, from wetlands such as marshes and fens, to upland prairies, savannas and forests. While trends throughout the region are downwards, the City natural area ecosystem types are stable. 

Getting people involved helps maintain the health of the local ecosystems, and also helps secure a trend towards preservation. Each year Natural Area Preservation works to expand its volunteer base, and employs an active crew of people to manage its natural areas.

Background  

As development in the Ann Arbor area replaces open fields and woodlands with buildings, lawns, and parking areas, habitat for plants and animals is diminished. Environmental effects result not only from the direct habitat loss, but also because of fragmentation of the remaining habitat with roads and utilities, and degradation of nearby natural features via stormwater run-off.  The natural areas protected within Ann Arbor City parks contain a variety of ecosystem types, and contribute to the survival of plants and animals native to Michigan.  

The vegetation we see growing around the city is very different today than what existed prior to European settlement. Many of our native woodlands, savannas, prairies, and wetlands were replaced by farmland, and then by the urbanized environment. Many non-native trees, shrubs, and other types of vegetation have been planted over the last 150 years for wind protection, landscaping, erosion control, and other human needs. Some of these plants have now naturalized and compete with what little native vegetation remains. The most aggressive of these plants are considered invasive species because they can choke out any other plants, turning an area into an inhospitable thicket.

In addition, the genetic diversity of our landscape has been reduced over time. While over 150 species and varieties are represented in the Ann Arbor street tree population, fully 34% of the trees are maples.  In fact, the top ten species comprise 72% of the street tree population. Thus plant populations are more susceptible to major losses due to pests or environmental stresses.  The Emerald ash borer infestation is a dramatic example of the vulnerability of our street tree population.The City of Ann Arbor is committed to diversifying the urban forest. Our goal is to establish a street tree population with no more than 5% of any one species and no more than 15% of any one genus. The recommended list of trees now includes more than sixty species and varieties.  In 2005-2007, over thirty different tree species and varieties were planted. 

The natural areas protected within Ann Arbor City parks contribute to the survival of wildlife native to Michigan. Wildlife of interest in our parks includes mammals, birds, butterflies, amphibians, and reptiles, some of which are protected as threatened or endangered species. Within Ann Arbor, the areas most likely to contain threatened or endangered animals are sandy, wet bottomlands and wetlands along the Huron River, along its tributaries, and in the many small pocket wetlands in native forest fragments. Many of these areas can be quite small in size. The protection of threatened and endangered species and their habitats is regulated by the State of Michigan , Department of Natural Resources (MDNR), in cooperation with the US Fish and Wildlife Service.

What the City of Ann Arbor is Doing

• Annually, 500+ volunteers contribute 5000+ hours of effort to natural area preservation
• Prescribed ecological burns are conducted on an average of 100 acres of fire-dependent landscape
• Approximately 154 acres of the City's highest quality natural areas are managed in an almost weed-free condition
• Biological surveys and photo-monitoring get the public involved and help in monitoring the long-term sustainability of natural areas.
• Natural Area Preservation in the City of Ann Arbor government monitors new invasive species occurrences and maintains up-to-date invasive species list.
• Natural Area Preservation is managing the habitat of our resident animal species to foster their survival. Volunteer surveys of animal populations provide data that helps the City to assess their status on an annual basis.
• Urban forest canopy assessment
• Long-term planning to diversify street tree and park tree populations
• Replanting street and park trees lost to Emerald Ash Borer

More information on these activities: Natural Area Preservation and Forestry and Parks Operations

You Can Help

• Volunteer with Natural Area Preservation or with the Adopt-A-Park program.
• Use native plants in landscaping projects.
• Pass on what you know to others by volunteering to speak at seminars/workshops, or just chatting with your neighbor.