One of the premises behind the development of Michigan's Wildlife Action Plan is the need to preserve the full breadth of Michigan's wildlife diversity. One of the initial steps taken to address this need was to identify species of greatest conservation need (SCGN), which are those species of aquatic and terrestrial wildlife with small or declining populations or other characteristics that make them vulnerable. These species were identified based on available data, scientific literature reviews and the informed opinions of species experts (see Identification of SGCN for a more detailed description).

The SGCN represent the fine-filter in this planning process, their needs not addressed through conservation at the coarse-filter, landscape feature level, must be identified to ensure the conservation of Michigan's wildlife diversity. This is one of the primary purposes of the SGCN summaries. Additionally, SGCN will be a key component in monitoring the effectiveness of conservation actions and the success of this action plan. Therefore, the summaries have been developed to provide baseline information on SGCN.

The information provided in the summaries represents the current state of knowledge of the full set of 404 SGCN. The summaries describe general abundance, distribution, landscape feature associations, and known threats, as well as issues of importance to the individual species (see descriptions below).

This information is expected to be valuable to conservation partners, including local and regional land managers, conservation organizations, private landowners and other individuals interested in conservation of a particular species or taxonomic group. It can also help these partners identify SGCN that may occur in their areas of responsibility.

Priority Conservation Needs
The most frequently identified need in the following SGCN summaries is filling knowledge gaps about species' distribution and population status. The need for better understanding of habitat usage, threats and general life history is also commonly mentioned. Priority needs for fish include those previously mentioned, as well as, identification of spawning habitat and movement information. Additional priority needs for mussels and snails include identification of host species. Priority threats and conservation actions at the statewide level are identified in the Statewide Assessments.

Data Descriptions

Distribution Maps
A population distribution map is provided for each species for which data are available. Distribution of terrestrial species is presented by county, whereas distribution of aquatic species is presented with point data. Distribution maps for crossover species (those that use both aquatic and terrestrial landscape features during their life cycles) were created in the manner that best represents the available data. Available data were of a variety of types and from a variety of sources. Aquatic distribution maps were based completely on documented locations of species, whereas the terrestrial maps were based on a mixture of documented locations and current range, with the data type reflected in the map legend. These maps reflect the current state of knowledge and species may occur outside of areas indicated.

Spatially explicit data were not available for all species known to use resources within Michigan's landscapes nor for all known locations of SGCN. Maps with a 'No Data' label indicate thatspatially explicit data are lacking or that current data do not indicate the existence of a population in Michigan. Some known locations may not be included on distribution maps, even when mentioned in the accompanying text due to a lack of spatially explicit data. When location data for a species were limited, historical and recent locations were combined to more accurately represent the potential distribution of the species. When the distribution represented on the map differs significantly from the known current locations, this difference is recognized in the accompanying text.

Distribution & Abundance
Each SGCN summary includes a description of the distribution and abundance of the species in Michigan, if known. Each summary also notes whether the species is currently federally or State listed as endangered or threatened, or whether the species has been recognized as a Special Concern species by MNFI. Species considered extirpated in the State may still be protected under the State endangered species legislation, and are therefore included in the set of SGCN.

Associated Landscape Features
The associations with landscape features identified within the SGCN summaries include all landscape features used by the species, regardless of frequency of use or preferences, based on review of scientific literature and comments from species experts.

Associated Threats
Each SGCN summary lists all identified threats to the species, not just those to which the species is most susceptible; threats to which species are believed to be less susceptible should also be monitored to ensure they do not become more significant problems in the future.