Lentic Cores, Unstratified include especially intact, resilient examples of each lake and pond class across the region, along with habitat for common loon, a species that represents the needs of other fish and wildlife that depend upon healthy northern lakes. The cores offer guidance for conserving aquatic biodiversity and ecological function into the future by providing tools to help identify, prioritize, protect, and effectively manage the full range of aquatic systems in the region along with representative and priority fish and wildlife species.

The major differences between this unstratified version and Lentic Core Areas, Stratified by Watershed are: 1) this version comprises ~13% (by area) of all lakes and ponds in the Northeast (~19% excluding lakes > 8,094 ha/20,000 acres) rather than ~20% (~30% excluding large lakes); 2) areas of highest integrity and resilience for the generation of core areas were identified on the scale of the entire Northeast, without first stratifying ecosystem components by HUC6 watershed.; 3) this version is not associated with aquatic buffers.

Intended Uses

• Determine where to start protection and management for a range of intact aquatic systems
  
• Identify areas and networks of high ecological value
  
• Restore connectivity to otherwise intact areas

Core areas can be viewed as among the best places to start for protection of lands and waters in their natural state. It is recommended that this set of core areas be used in conjunction with the Aquatic Core Networks. Areas of overlap between core areas in this dataset and the cores that are stratified by watershed are of high priority from both the perspective of the full Northeast region and within the corresponding watershed. They may be especially promising locales to investigate for potential conservation action. See the Lotic Core Areas (Stratified by Watershed) for additional descriptions of potential uses.

Description and Derivation

Aquatic core areas are based on a set of regional GIS analyses designed to assess the physical and biological value of  aquatic systems and species across the Northeast and Mid-Atlantic, and to identify the most important places for them. This version of lentic core areas integrates two components:

1. The most intact, resilient locations of each of 12 lake/pond habitat classes across the Northeast and Mid-Atlantic. These classes were mapped by The Nature Conservancy working with the Northeast state fish and wildlife agencies and the North Atlantic LCC (Olivero and Anderson 2008). The integrity of these systems was assessed using the Index of Ecological Integrity developed by the University of Massachusetts Amherst.
   
2. Lentic (lake and pond) cores representing the highest landscape capability for breeding common loon (representative species for intact northern lakes) that were not already captured on the basis of ecological integrity. Common loon habitat capability for the region has been mapped by UMass Amherst and is available as a separate product (Landscape Capability for Common Loon).
   

Lentic core areas were initiated from focal areas (“seeds”) with ecological integrity higher than a certain threshold. Seeds reaching a minimum size were expanded to encompass the entire water body (i.e, pond or lake), providing additional ecological value and resilience to both short- and long-term change, as well as logical units for lentic cores. Large lakes (exceeding 8,094 ha/20,000 acres) were excluded. These initial ecosystem-based cores were supplemented with areas important for the Common Loon.

This version of aquatic core areas does not include stratification of ecosystem components. This ensures that the highest quality examples of ecosystems are represented in the core areas. However, this also results in a less well-distributed and well-connected set of core areas compared to the watershed-stratified version.