This dataset was last updated 02/2017. This version includes a new tidal restrictions metric that assesses the effect of undersized culverts and bridges on tidal regime.The previous version (3.1) was updated on 05/2016 by incorporating a revised version of the land cover classification, DSLland Version 3.1, developed by UMass, which included the addition of The Nature Conservancy’s Northeast lakes and ponds classification.
This dataset depicts the ecological integrity of locations (represented by 30 m grid cells) throughout the northeastern United States based on environmental conditions existing in approximately 2010. Ecological integrity is defined as the ability of an area (e.g., local site or landscape) to sustain important ecological functions over the long term. In particular, the functions include the long-term ability to support biodiversity and the ecosystem processes necessary to sustain biodiversity. The Index of Ecological Integrity (IEI) is expressed on a relative scale (0 to 1)* for ecosystems mapped on a modified version of the Northeast Terrestrial Habitat Map developed by the Nature Conservancy and the northeastern states. Ecosystems are the finest scale level of the ecological classification hierarchy. Classes include “Northeastern Interior Pine Barrens” and “Acidic Cliff and Talus”. *NOTE - Data displayed in web mapper are values 0 - 100.
This version of ecological integrity includes two categories of landscape metrics:
• Intactness – the freedom from human impairment (anthropogenic stressors), measured as a combination of a number of stressor metrics.
• Resiliency – the capacity to recover from disturbance and stress, measured as a combination of the connectedness and similarity to neighboring natural areas.
This ecological integrity dataset is one of a larger set of results developed by the Designing Sustainable Landscapes project led by Professor Kevin McGarigal of UMass Amherst. Projected future ecological integrity for 2030 and 2080 are also being developed based on models of development (urban growth), climate change, and forest change. More information and detailed documentation for the Designing Sustainable Landscapes project, which includes many additional datasets, is available at: http://www.umass.edu/landeco/research/dsl/dsl.html.
More details about the calculation of the Index of Ecological Integrity are as follows. The basic building blocks of the index are a series of Ecological Settings, each of which is a spatial dataset encompassing the Northeastern U.S. The ecological settings represent a broad but carefully selected suite of biophysical variables representing the natural and anthropogenic environment at each location for each time step used in the Designing Sustainable Landscapes project. Each ecological setting is available as a separate spatial dataset. One of the key components is the DSLland dataset, which is a modified version of the Northeast Terrestrial Wildlife Habitat Map developed by The Nature Conservancy and the northeastern states. Other settings include variables such as temperature, soil depth, above-ground live biomass, extent of development, and traffic rate. A series of metrics, such as the intensity of urban development and the degree to which ecosystems are connected, are calculated from these ecological settings.The metrics are integrated in weighted linear combinations to calculate IEI based on the opinions of expert teams as to the importance of each metric in determining the ecological integrity of the different ecosystem types.
In the final IEI, results are re-scaled by ecosystem type to make comparisons more meaningful. For example, marshes are ranked relative to other marshes rather than in comparison to forests or other ecosystem types. Hence, IEI represents a cell’s percentile within its group, e.g., a cell of Laurentian-Acadian freshwater marsh with an IEI of 80 is in the top 20% of Laurentian-Acadian freshwater marshes.The specific metrics for IEI, each of which is available as a separate dataset, are the following:
Intactness Metrics: 1) Habitat loss – the intensity of habitat loss due to development in the neighborhood of each cell 2) Watershed habitat loss (aquatic metric) – the intensity of habitat loss due to development upstream of the cell 3) Road traffic – the intensity of traffic in the neighborhood of the cell 4) Mowing and plowing – the intensity of agriculture in the vicinity of the cell, reflecting mortality to organisms from mowing and plowing 5) Edge effects – the effects of human-induced edges on ecosystems 6) Watershed road salt (aquatic metric) – the density of upstream roads, a surrogate for road salt application rates 7) Watershed road sediment (aquatic metric) – the density of upstream roads, a surrogate for road sediment production rates 8) Nutrient enrichment (aquatic metric) – the intensity of residential and agricultural land uses upstream of each cell a surrogate for fertilizer application rates 9) Watershed imperviousness (aquatic metric) – the intensity of impervious surface (such as roads and buildings) upstream of the cell 10) Dams (aquatic metric) – the number and proximity of dams upstream of the cell 11) Biotic alterations – the intensity of development in the neighborhood of the cell, calculated separately as a surrogate for four effects: a) edge predators (such as raccoons and skunks), b) domestic predators (such as cats), c) invasive earthworms, and d) invasive plants
Resiliency Metrics: 1) Connectedness – the degree to which development and ecologically dissimilar sites interfere with connections between the cell and ecologically similar neighbors 2) Aquatic connectedness – the degree to which connections along streams and rivers are diminished by barriers such as dams and culverts 3) Similarity – the similarity (lack of contrast) between the environment of a cell and its surroundings (with higher similarity implying greater resilience)