Determining the best candidates for Natural Area protection is a complex process. Natural area conservation planning focuses on areas of high biodiversity. We use the following tools, concepts and resources to evaluate and manage sites.
The value of biodiversity (the variety of life and its processes)
Minnesota's biodiversity has evolved over millennia into complex ecosystems. A myriad of species interact with each other and environmental factors such as soils, topography, hydrology and climate within these ecosystems.
Preserving biodiversity has benefits (ecosystem services) such as:
- Maintaining healthy, stable plant and animal populations
- Protecting genetic diversity
- Protecting water and soil resources
- Filtering pollution and nutrient recycling
- Contributing to climate stability and carbon storage
- Recovering from catastrophic events
- Providing sources for food, medicine and other products
- Research, education and monitoring
- Recreation, tourism and inspiration
In areas where biodiversity is threatened, losing species can affect the ecosystem's ability to function properly and provide these services. Maintaining biodiversity reduces voids and the entire ecosystem maintains a higher degree of resilience.
Conservation planning for natural areas focuses on areas of high biodiversity as well as habitats for rare species.
Resilience as a strategy
Resilience is the capacity of an ecosystem to cope with disturbance. Resilience is critical to reducing climate change and fragmentation from land development. As climate change affects ecosystems they will face increasing vulnerability. An effective strategy at easing these negative impacts is to build resilience into native communities by:
- Creating large protected areas and corridors to provide pathways for species to migrate to more suitable habitats
- Preserving a greater variety of habitats for desirable species
The SNA program is using both strategies for resilience to maintain Minnesota's biodiversity.
Biodiversity significance rankings
Biodiversity significance is a ranking based on the size and condition of native plant communities and how they fit in an ecological landscape. It also includes the presence or absence of rare species populations. The rankings are 'outstanding', 'high', 'moderate' and 'below'. Ecologists with the Minnesota Biological Survey determine this status. This ranking is used to help prioritize Natural Area protection efforts.
Minnesota's Ecological Classification System (ECS)
Ecological landscape classifications are used to identify, describe, and map progressively smaller areas of land with increasingly uniform ecological features. Minnesota's Ecological Classification System (ECS) uses biotic and environmental factors, including climate, geology, topography, soils, hydrology and vegetation.
The largest units of the ECS are provinces and are defined primarily by climate. Minnesota has four provinces. Provinces are divided into 10 sections based on glacial deposits, topography and plant distributions. The 26 subsections of the ECS are further refined by local vegetation, especially trees, among other factors. Individual Scientific and Natural Areas note the subsection in which they are located. Native plant communities are a finer grading of the classification system.
Minnesota's Native Plant Communities
Local groupings of trees, shrubs, grasses and forbs that interact with each other and their environment are called native plant communities and are characterized by the kinds and quantities of species they contain. They form recognizable units, such as oak savannas, pine forests, cattail marshes and other communities that tend to repeat over space and time.
Plant communities are subject to change. They form in response to climate and nutrients, as well as catastrophic flooding and fires. In the absence of change, they can be fairly stable over time. However they can also develop into something complete new. For example, a beaver dam can cause significant flooding and as a result, over a period of time, a new community will form in the flooded area. Places where native species have been largely replaced are no longer considered native plant communities.
Native plant communities serve as the basis for evaluating Scientific and Natural Area priorities. The Minnesota Biological Survey has identified, surveyed, and prioritized communities and rare species for research and conservation. Minnesota's Native Plant Community Classification serves as a standard for ecologists to identify and assess communities. Some individual Scientific and Natural Areas have detail maps showing their native plant communities
Minnesota's Rare Species
Rare species, are defined under Minnesota law as endangered, threatened, or of special concern. The DNR identifies which species are at greatest risk of disappearance. The law restricts harming those species that are designated as endangered or threatened. Natural Areas protect critical habitat for these rare species.
You can learn more about the tools, concepts and resources the program uses for protection in the Strategic Land Protection Plan.