The aquatic core networks is one of a suite of products from the Nature’s Network project (naturesnetwork.org).
These datasets represent the aquatic core networks, which include lotic and lentic core areas and aquatic buffers. NOTE - The aquatic buffers dataset has been converted to integers and only contain values of 90 -100 (0.9 - 1) for online purposes, the original dataset is included in the download and contains all values. All datasets in this map are included in the download.
The aquatic core networks represents intact, well-connected stream reaches, lakes, and ponds in the Northeast and Mid-Atlantic region that, if protected as part of stream networks and watersheds, will continue to support a broad diversity of aquatic species and the ecosystems on which they depend. The cores include especially intact, resilient examples of each major aquatic ecological system across the region along with habitat for priority aquatic species. The core network offers 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 aquatic core networks are comprised of three datasets: lotic (river and stream) cores, lentic (lake and pond) cores, and the aquatic buffers. The lotic cores and lentic cores represent the most intact examples of each aquatic habitat class based on UMass’ Index of Ecological Integrity (IEI). IEI assesses 21 stream classes based on gradient, temperature, and size (lotic) and 12 lake/pond classes based on temperature, depth, and trophic class (lentic). The cores also represent habitat for representative priority aquatic species using a range of these habitat types across the region. These include headwater streams with the highest probability of occurrence for Eastern brook trout, and known rivers and streams supporting Atlantic and shortnose sturgeon, salter brook trout, the highest priority watersheds for alewife, American shad, and blueback herring, and priority rearing habitat for Atlantic salmon in the Gulf of Maine watershed. Lentic cores also include lakes and ponds with the highest habitat suitability for common loon. Aquatic buffers surround the aquatic (both lotic and lentic) cores. Buffers represent the areas estimated to have a strong influence on the integrity of the aquatic cores based on watershed processes. They include the areas that are hydrologically connected to the cores, based on the idea that human actions (such as development or pollution) within the buffer area may impact the integrity of the aquatic cores. As a result, the land underlying the buffers is not necessarily of high ecological integrity.
The aquatic core and buffer network can serve as a starting point for a regional conservation network that can be used in combination with other sources of information to direct action. Suggestions include:
Lotic and lentic cores can serve as a starting point for a regional conservation network that can be used in combination with other sources of information to direct action. Suggestions include:
Description and Derivation
The aquatic core network is based on a set of regional analyses that assess the physical and biological value of aquatic systems and species across the Northeast region. The core area network integrate five components
This version of aquatic core areas is based on stratifying the ecosystem input, the Aquatic Index of Ecological Integrity, by large watershed (HUC 6 level). This ensures that core areas are well-distributed across the landscape. However, in this stratified version, the core areas do not comprise 30% of each watershed. Once the core "seeds" were determined, the entire corresponding lake or pond was deemed a lentic core, and the lotic cores were grown out giving priority to long continuous high-quality areas, rather than alligning with watershed boundaries. This stratification also means that some of the highest quality examples of ecosystems and habitats from a regional perspective are not included in core areas, where their inclusion would otherwise result in more than 30% of the aquascape in the region. A complementary version of aquatic core areas that is not stratified by watershed is also available as part of the Nature’s Network package.
These core areas and buffers are intended to be overlain with additional analyses including Freshwater Resilience Highest and High watersheds developed by The Nature Conservancy and the version of regionally scaled, unstratified aquatic core areas.
Attribute Information and Field Definitions
Known Issues and Uncertainties
As with any project carried out across such a large area, aquatic core networks are subject to limitations. The results by themselves are not a prescription for on-the-ground action; users are encouraged to verify, with field visits and site-specific knowledge, the value of any areas identified in the project. Known issues and uncertainties include the following:
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Potential Metadata Source