• Home
  • About
  • Data & Tools
  • Learning
  • In Action
  • Resources
  • Contact

Aquatic Core Networks

Aquatic Core Networks

Connected network of intact and diverse aquatic systems that provide habitat for resident and anadromous fish, as well as other organisms, and benefits for people such as recreation and clean water.

 

  • Access Datasets

    View or download the Aquatic Core Networks dataset

  • Watch webinar

    View a previously recorded webinar that walks through basic information about the Aquatic Core Networks

  • Quick start guide

    A downloadable PDF that provides an overview of the Aquatic Core Networks product

Quick start guide

Description
Intended uses
Get started
Background
Known issues and uncertainties
Links for technical information
Description
Aquatic core networks are 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 support a broad diversity of aquatic species and the ecosystems on which they depend.

 

The aquatic core areas include especially intact, resilient examples of each stream class and type of lake and pond across the region, along with habitat for priority aquatic species. The core network information 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 areas are bordered by aquatic buffers. Aquatic buffers represent the areas estimated to have a strong influence on the integrity of the aquatic cores. Controlling pollution, erosion, and other human influences within the aquatic buffers can help prevent adverse impacts to the aquatic core areas.
Together with the terrestrial core areas and connectors, aquatic core areas and buffers provide the primary network of resilient and ecologically intact habitats that will support biodiversity under changing conditions in the Northeast and Mid-Atlantic region. These areas represent a “coarse-filter” approach to biodiversity conservation and provide strategic guidance for conserving natural areas and the fish and wildlife that they support. They are complemented by the “fine-filter” approach of the Habitat Importance and Condition for Imperiled Species

Intended uses
  • Determine where to start protection and management for a range of intact aquatic systems
  • Identify areas and networks of high ecological value
  • Pinpoint important terrestrial areas (aquatic buffers) where protection and restoration actions can benefit the integrity of aquatic core areas
  • Restore connectivity to otherwise intact areas
Get started
You can explore the Aquatic Core Networks map on the North Atlantic LCC Conservation Planning Atlas. Notice that there are two types of aquatic core areas: one for rivers and streams (“lotic core areas”) and one for lakes and ponds (“lentic core areas”). For either type, you can zoom into areas of interest using the Zoom Tool, and you can find information about why a core area is important using the Identify Tool.

 

The aquatic core 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.  You might explore it in combination with:

  • Other data layers to identify additional areas of high ecological value. Layers to consider include: 1) the terrestrial core-connector network, 2) The Nature Conservancy’s (TNC) Freshwater Resilience Networks, 3) the aquatic Index of Ecological Integrity, 4) habitat maps for Common Loon and important fish species (brook trout, Atlantic salmon, and other anadromous species), and 5) habitat condition for imperiled species.
  • Aquatic connectivity restoration priorities to identify areas where restoring connectivity will add value to areas that are already intact.
  • The secured lands layer to identify aquatic core areas and buffers that remain unsecured from development, and thus could represent priorities for protection.
  • The probability of development layer and regional vulnerability layers to identify places in the aquatic core area network that are relatively vulnerable to future development, and thus could represent priorities for protection.
  • Resource priorities identified at the state or local level, but that are not available across the entire region (e.g., from State Wildlife Action Plans, towns, and land trusts), to further rank areas for land protection.

With a free DataBasin account, you can upload your organization’s priorities into a private map for comparison with the terrestrial core-connector network, or you can download the network for analysis in your own GIS.

Background
Aquatic core networks are based on a set of regional analyses that assess the physical and biological value of aquatic systems and species across the Northeast and Mid-Atlantic region. The aquatic cores integrate five components:

  1. The most intact, resilient locations of each of 21 stream habitat classes and 12 lake/pond habitat classes in large watersheds (HUC6 level) 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 (McGarigal et al. 2016).
  2. Lotic (river and stream) core areas representing the highest probability of occurrence for Eastern brook trout (representative species for cold headwater streams) not captured by lotic ecosystem cores. Brook trout current probability of occurrence is based on a model developed by Ben Letcher and colleagues at the USGS Conte Anadromous Fish Lab.
  3. Known stream reaches with existing occurrences for Atlantic and shortnose sturgeon and sea-run (salter) brook trout, along with top 5% of watersheds for alewife, American shad, and blueback herring, based on analyses by Trout Unlimited and The Nature Conservancy.
  4. Priority rearing habitat for Atlantic salmon in the Gulf of Maine watershed, as mapped by the U.S. Fish and Wildlife Service and NOAA, where not otherwise already captured.
  5. Lentic (lake and pond) cores representing the highest landscape capability for breeding common loon (representative species for intact northern lakes) not captured by lentic ecosystem cores. Common loon habitat capability for the region has been mapped by UMass Amherst (McGarigal et al. 2016).

Collectively, the river and stream cores encompass about 30% of the stream miles of the Northeast and Mid-Atlantic region. The lake and pond cores encompass about 30% of the lake and pond area of the region, not including the 14 lakes larger than 20,000 acres in the region.
Once the aquatic core areas were identified, aquatic buffers were defined to depict upslope and upstream areas most likely to have a strong influence on the integrity of the aquatic core areas through processes such as runoff.

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:

 

  • The results do not incorporate important social, economic, or feasibility factors.
  • Users are cautioned against using the data on too small an area (for example, a small parcel of land), as the data may not be sufficiently accurate at that level of resolution.
  • The classification and mapping of aquatic ecological systems is known to be imperfect, which consequently affects the mapped values for ecosystem integrity and species habitat. While the ecosystem mapping is anticipated to correctly reflect broad patterns of ecosystem occurrence, errors in classification and placement do occur, as with any regional GIS data. In addition, errors in mapping and alignment of hydrography, development, roads, traffic rates, and a number of other data layers can affect the model results.
  • It is not possible to map all factors affecting ecological integrity and species habitat across the Northeast, and the omission of such factors can be anticipated to create some limitations in the results. Examples are listed below.
    • The aquatic core networks do not currently account for flow impairment as this information is only available at the medium resolution (1:100k) hydrography.
    • The aquatic core networks do not include information on non-indigenous aquatic species, or instream habitat quality because the available data are too coarse (HUC 8 watersheds) for the region.
    • Core areas do not account for instream habitat quality because there are no consistent data across region; partners can incorporate local or state data if available.
  • The core area network approach by design does not explicitly identify the most important areas for rare aquatic species; however some additional areas are covered with the Habitat Condition for Imperiled Species dataset component and should be used as a complement to the aquatic cores networks.
  • No one segment of a stream or river, such as depicted by a lotic core, can be conceived of as independent of the larger, continuous stream network of which it is a part. Core areas define particular areas of high integrity and importance to aquatic species, but ultimately conservation of the full network is critically important as well.
Links for technical information
Aquatic core networks

 

Inputs to aquatic core networks

 

   Northeast aquatic classifications for rivers and streams and lakes and ponds

   Index of Ecological Integrity

Additional documentation from UMass Designing Sustainable Landscapes project

Data downloads

Aquatic
Aquatic Core Networks
  • Lotic Core Areas, Stratified by Watershed, Northeast U.S.
  • Lentic Core Areas, Stratified by Watershed, Northeast U.S.
  • Aquatic Buffers, Northeast U.S.
OpenDownload
Supporting data
Aquatic Core Networks, Regional Unstratified
  • Lotic Core Areas, Unstratified, Northeast U.S.
  • Lentic Core Areas, Unstratified, Northeast U.S.
OpenDownload
Aquatic Index of Ecological Integrity, Northeast U.S.OpenDownload
Freshwater Resilience by Watershed, Northeast U.S.OpenDownload
Important Anadromous Fish Habitat, including Salmon, Northeast U.S.
  • Important Anadromous Fish Habitat, Northeast U.S.
  • Atlantic Salmon Rearing Areas, Maine
OpenDownload
Brook Trout Probability of Occurrence, Northeast U.S.OpenDownload
Landscape Capability for Common Loon, Version 3.0, Northeast U.S.OpenDownload
Nature's Network Conservation Design
Imperiled Species
Terrestrial and Wetland Core-Connector Network
Aquatic Core Networks
Regional Connectivity and Marsh Migration
Prioritization Tool

Photos courtesy: USFWS, Nicholas A. Tonelli

  • Home
  • About
  • Data & Tools
  • Learning
  • In Action
  • Resources
  • Contact

Welcome to the Nature's Network Prioritization Tool

Using this tool, you can create custom models based on a catalog of over 400 metrics that will help address particular conservation and restoration questions. Some key features:

  • Quickly create custom prioritization maps
  • PDF and CSV outputs
  • Over 400 metrics

Metric description

Name:

Description:

Unit:

Full documentation link:

How does this work?

Load a model

What do these weights mean?

Each weight is a multiplier

When deciding how to assign weights, it is important to understand that each weight is a multiplier for its coresponding metric. After the tool standardizes the raw units of a metric to a quantile scale (0-1), it then multiplies that new value by the given weight. Any negative weight is flipped to a positive number and multiplied by the inverse of the metric's quantile score (this is to ensure a positive weighted score that is more intuitive for comparison). For more information, click "How does this work?" in the first panel above.

Caution

Use this control with a single map

This control limits the display of both the left and right maps. However, because the maps share the same legend, it can be difficult to distinguish them when parts of each are transparent. To avoid confusion, we recommend that this subset control be used when displaying a single map.

May not be useful for datasets with a small range or limited sample size

Each rank represents the percent of planning units less than or equal to this rank. As a result, for datasets with very small range (e.g. count of restoration practices in a single year) or limited sample size, there may be many planning units that share the same value (e.g., 0). In some of those cases, the minimum percentile rank could be relatively high and the subset controls may not seem to have an effect. If this appears to be happening, try clicking on a planning unit with a low score color to see what its percentile rank is.

Metric list