Includes five landscape change scenarios: 1) baseline 70-year (2010-2080) climate change and urban growth scenario without additional land protection; 2) same as #1 but with 25% more demand for new development; 3) same as #1 but with increased sprawl to the pattern of development; 4) same as #1 but with both 25% more demand for new development and increased sprawl; and 5) same as #1 but with additional terrestrial reserve areas (core areas) protected from development as established for Nature\u27s Network landscape design (www.naturesnetwork.org).https://scholarworks.umass.edu/data/1034/thumbnail.jp

Compton, Brad

DeLuca, Bill

Grand, Joanna

McGarigal, Kevin

Plunkett, Ethan

English

ScholarWorks@UMass Amherst

University of Massachusetts AmherstScholarWorks@UMass AmherstData and Datasets2017Designing Sustainable Landscapes: The index ofecological impactKevin McGarigalUniversity of Massachusetts AmherstBrad ComptonUniversity of Massachusetts AmherstEthan PlunkettUniversity of Massachusetts AmherstBill DeLucaUniversity of Massachusetts AmherstJoanna GrandUniversity of Massachusetts AmherstFollow this and additional works at: https://scholarworks.umass.edu/dataPart of the Sustainability CommonsThis Data is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Data and Datasets by anauthorized administrator of ScholarWorks@UMass Amherst. For more information, please contact scholarworks@library.umass.edu.Recommended CitationMcGarigal, Kevin; Compton, Brad; Plunkett, Ethan; DeLuca, Bill; and Grand, Joanna, "Designing Sustainable Landscapes: The indexof ecological impact" (2017). Data and Datasets. 34.https://scholarworks.umass.edu/data/34 Designing Sustainable Landscapes:   Index of Ecological Impact  A project of the University of Massachusetts Landscape Ecology Lab  Principals: • Kevin McGarigal, Professor • Brad Compton, Research Associate • Ethan Plunkett, Research Associate • Bill DeLuca, Research Associate • Joanna Grand, Research Associate  With support from: • North Atlantic Landscape Conservation Cooperative (US Fish and Wildlife Service, Northeast Region) • Northeast Climate Science Center (USGS) • University of Massachusetts, Amherst      Reference: McGarigal K, Compton BW, Plunkett EB, DeLuca WV, and Grand J. 2017. Designing sustainable landscapes: index of ecological impact. Report to the North Atlantic Conservation Cooperative, US Fish and Wildlife Service, Northeast Region.  DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 2 of 7  Updated on 30 April 2018  General description The index of ecological impact (ecoImpact) is a measure of the relative change in ecological integrity over time under a specific landscape change scenario. This document provides a description of ecoImpact as computed and used to compare different landscape change scenarios associated with various applications. See McGarigal et al (2018a,b) for details on two of the completed applications to date. For a detailed description of ecoImpact and the associated index of ecological integrity (IEI) in the context of the broader ecological integrity assessment of the Designing Sustainable Landscapes (DSL) project, see the technical document on integrity (McGarigal et al 2017).  Briefly, ecoImpact is derived from IEI, which is a composite index derived from several individual metrics measuring the intactness (i.e., freedom from anthropogenic disturbance or stress) and/or resiliency (i.e., ability to recover from anthropogenic disturbance or stress) of a site as applied to each unique ecosystem. IEI characterizes the integrity of sites relative to other sites in a similar ecological setting or ecosystem. Thus, it is a static measure of ecological integrity based on a snapshot of the landscape. IEI can be equally useful to assess the change in ecological integrity over time under a specific landscape change scenario. For this purpose, we developed ecoImpact to measure the change in IEI between the current and future time steps relative to the current IEI; i.e., effectively delta IEI times current IEI. A site that experiences a major loss of IEI has a high predicted ecological impact; for example, a loss of 0.5 IEI units reflects a greater relative impact than a loss of  Figure 1. ecoImpact metric under a baseline 70-year urban growth scenario for a single stochastic simulation, shown here for an area east of Nashua, New Hampshire. Large negative values indicate areas of high predicted ecological impact of the forecasted landscape changes and represent places with high current ecological integrity (i.e., high IEI in 2010) and relatively large predicted loss of ecological integrity over time. Development, roads, and other non-forested areas are shown in gray. DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 3 of 7  Updated on 30 April 2018  0.2 units. Moreover, the loss of 0.2 units from a site that has a current IEI of 0.9 is more consequential than the same absolute loss from a site that has a current IEI of 0.5. Thus, ecoImpact reflects not only the magnitude of IEI loss, but also where it matters most—sites with high initial ecological integrity. ecoImpact has a theoretical range of -1 (when a cell with initial IEI =1 gets developed) to +0.25 (when a cell with initial IEI =0.5 gets restored to the maximum IEI), but in practice it will rarely approach the upper limit and only infrequently will it even be > 0 (denoting an improvement in IEI). In addition, because IEI is scaled by ecological setting or ecosystem and geographic extent, as described below, ecoImpact also varies depending on the geographic extent used to scale IEI for the baseline condition. Use and interpretation of this layer As described above, ecoImpact is a composite index that measures the change in IEI over time where it matters most (i.e., sites with high initial IEI) under a specific landscape change scenario; thus, it is a synoptic measure of impacts to local ecological integrity that combines many different elements of integrity into a single index. The use of ecoImpact should be guided by the following considerations: • As described above, ecoImpact is a composite index derived from the individual intactness and resiliency metrics; it is a synoptic measure of the predicted local ecological impact of landscape change and represents the principal result of our coarse-filter assessment of the ecological impact of the forecasted landscape changes. In contrast to IEI, ecoImpact is delta-scaled (see below) to reflect the percentage loss of IEI from cells of high baseline IEI largely independent of their ecological setting or ecosystem, and is only modestly affect by the geographic extent of the analysis. Briefly, as described in the following section, the individual raw metrics are first delta-rescaled, then combined in a weighted linear function specific to each ecological setting or ecosystem, and then multiplied by the baseline IEI to produce the final ecoImpact index for each landscape comparison. The end result is that a cell with maximum baseline IEI (1) that loses all of its IEI (1→0) in the alternative landscape (e.g., projected future landscape) gets a value of -1, indicating the maximum possible ecological impact. Conversely, a cell that experienced no change in IEI would get would get a value of 0, indicating no ecological impact. Lastly, a cell that experienced a gain in IEI would get a positive value that has an upper limit of 0.25, although in practice positive values are rare and typically very small. • It is important to recognize the relative nature of ecoImpact and how it differs from IEI. Whereas IEI is always relative to the ecological system of a cell and the geographic extent of the scaling, the ecoImpact of a cell is always relative to itself (regardless of ecosystem or landscape extent) under the baseline condition. The ecoImpact of a cell reflects how much the integrity of the cell (as measured by IEI) decreases as a result of the forecasted landscape changes relative to the initial or baseline IEI of the cell. Thus, ecoImpact compares a cell to itself — e.g., the change in integrity over time — whereas IEI compares a cell to other cells of the same ecological setting or ecosystem within the specified geographic extent. While this interpretation is roughly correct, it is not DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 4 of 7  Updated on 30 April 2018  entirely so. ecoImpact involves multiplying the weighted linear combination of delta-rescaled metrics by the baseline IEI. Therefore, technically speaking the ecological setting or ecosystem of the cell and the geographic extent of the analysis have an effect on the final computed value, but the role of ecosystem membership and geographic extent is relatively minor compared to IEI. Because of the relative nature of ecoImpact, it can be used as a comparative index to compare one site to another or to compare the same site to itself under different landscape change scenarios. • While ecoImpact has a wide variety of potential uses, perhaps its most significant application is to  facilitate efforts of organizations seeking to conserve biodiversity to identify and prioritize places of high ecological value for conservation action (e.g., land protection) that are highly vulnerable to predicted landscape changes (e.g., urban growth). Other uses include, but are not limited to, monitoring changes over time in the ecological condition of the landscape and evaluating the potential impacts of land use/land cover change scenarios on the ecological integrity of the landscape, as in the SPRAWL and INTEGRITY papers referenced below.  Derivation of this layer The derivation of ecoImpact consists of rescaling the individual raw ecological integrity metrics, but using a different rescaling procedure than used with IEI, then combining the metrics into the composite index, and then computing the final index. Each of these steps are described in the following sections. Delta-rescaling.—The embedded use of quantile-rescaling in IEI suffers from what we refer to as the "Bill Gates" effect when used for scenario comparison. Note, quantile rescaling involves transforming the raw IEI values into their corresponding quantiles by ecosystem, so that the xth quantile represents the top x% of the cells in each ecosystem. The "Bill Gates" effect occurs when the value of the raw metric is decreased in a cell but it remains the highest valued cell -- the quantile is unchanged. This is analogous to taking millions of dollars away from Bill Gates and yet he remains one of the richest persons around. Likewise, a small absolute change in a raw metric can under certain circumstances result in a large change in its quantile, even though the ecological difference is trivial. Therefore, the use of quantile-rescaling is not appropriate if we want to be sensitive to any absolute change in the integrity metrics. To address these issues, we developed delta-rescaling as an alternative to quantile-rescaling that is more meaningful when comparing among scenarios (or timesteps of a single scenario).  Delta-rescaling is rather complicated in detail. Briefly, delta-rescaling involves computing the difference in the metric from its baseline value at timestep 0. Thus, delta-rescaling does not involve comparing the condition of a cell to ecologically similar cells of the same ecological system, but rather comparing the condition of a cell to itself under the baseline (e.g., timestep 0) condition. These delta-rescaled metrics can then be combined in a weighted linear combination to form a composite delta ecological integrity index, and this composite index can be multiplied by the ecological integrity index (IEI) of the cell under the baseline scenario to derive an "impact" index (ecoImpact), as described below.  DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 5 of 7  Updated on 30 April 2018  Unfortunately, since the raw metrics are on different scales, we can't simply compute the delta between the current and future timesteps, as the raw deltas would also be on different scales. But in order to combine the metrics into a composite index they must be placed on the same or similar scale. A simple solution would be to range rescale each raw metric so that it ranges 0-1. However, range rescaling is very sensitive to extreme values and most of the raw metrics have positively or right-skewed distributions containing relatively few very large values. To address this issue we instead use a rather complicated rescaling procedure, as follows:  1) For each raw stressor metric at the fullest geographic extent, we find its 90th quantile benchmark and apply a logistic transformation such that this benchmark ends up with a score of 0.95, as follows:  𝑟𝑒𝑠𝑐𝑎𝑙𝑒𝑑.𝑚𝑒𝑡𝑟𝑖𝑐 = � 1𝑒�−𝑟𝑎𝑤.𝑚𝑒𝑡𝑟𝑖𝑐𝑠� � + 1� ∗ 2 − 1 𝑠 = −𝑏𝑒𝑛𝑐ℎ𝑚𝑎𝑟𝑘𝑙𝑛�2 1.95� − 1� The end result is that each rescaled stressor metric ranges from 0~1. 2) For the aquatic connectedness (aqconnect) metric, we compute the maximum value of aqconnect (aqcmax) for each cell by running it without the anthropogenic settings variables (i.e., as if there were no road-stream crossings and dams), find the 95th quantile of aqcmax, and rescale the metric as follows:  𝑟𝑒𝑠𝑐𝑎𝑙𝑒𝑑.𝑎𝑞𝑐𝑜𝑛𝑛𝑒𝑐𝑡 = 0.95𝑞𝑢𝑎𝑛𝑡𝑖𝑙𝑒(𝑎𝑞𝑐𝑚𝑎𝑥, 0.95) The end result is that rescaled aqconnect ranges from 0 ~ 1.  3) For the connectedness and similarity metrics, which scale naturally from 0~1 (for a highly similar and connected neighborhood), we keep them in their raw scale form.   Figure G1. Logistic transformation of a raw metric scaled 0-135 with a 90th quantile of 120 as used in delta-rescaling. The rescaled metric ranges from 0~1 with a value of 0.95 (red line) for the 90th quantile. DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 6 of 7  Updated on 30 April 2018  After rescaling each of the integrity metrics, we compute the difference (or delta) between the baseline (e.g., timestep 0) value and the alternative (e.g., future landscape) value. These delta-rescaled metrics have a theoretical range of -1 to 1. A value of -1 indicates the maximum potential loss of IEI (e.g., a cell with the maximum IEI gets developed), whereas a value of 1 indicates the maximum potential increase in IEI (e.g., a developed cell is restored to the maximum IEI). These delta-rescaled metrics are combined into a composite index as described next.  Ecological integrity models.—After delta-rescaling, the metrics are all on approximately the same scale. The next step is to combine the delta-rescaled metrics into a composite index. To do this we apply the ecological integrity models described in the text for IEI.  Computing the final index.—After combining the delta-rescaled metrics in a weighted linear combination, we multiply the value by the baseline value of IEI (e.g., the value in timestep 0). In this manner, roughly speaking the index is designed to reflect the percentage change in IEI (as estimated via delta-rescaling) where it matters most — areas with high initial IEI. For example, the ecological impact is relatively greater (and thus more important) for a cell with a delta score of -0.4 and an initial IEI of 1 compared to a cell with the same delta score but an initial IEI of 0.5. The final index has a theoretical range of -1 (when a cell with initial IEI=1 gets developed) to +0.25 (when a cell with initial IEI=0.5 gets restored to the maximum IEI), but in practice it will rarely approach the upper limit and only infrequently will it even be > 0 (denoting an improvement in IEI). In addition, because IEI is scaled by ecological setting or ecosystem and geographic extent, as described in the text for IEI, ecoImpact also varies depending on the geographic extent used to scale IEI for the baseline condition. GIS metadata This data product is distributed as a geotiff raster (30 m cells). The cell value = ecoImpact and ranges from -1 (maximum impact) to +0.25 (maximum improvement in ecological value). As described above, this data product can be scaled by any geographic extent and for any landscape change scenario, but the products distributed here are scaled by the Northeast region and for the landscape change scenarios reported in the SPRAWL and INTEGRITY papers (McGarigal et al 2018a,b), as follows:  • DSL_ecoImpact_baseline_v3.0.tif = ecoImpact under the baseline urban growth scenario  • DSL_ecoImpact_plusDemand_v3.0.tif = ecoImpact under the 25% increased demand scenario • DSL_ecoImpact_plusSprawl_v3.0.tif =- ecoImpact under the increased sprawl scenario • DSL_ecoImpact_plusBoth_v3.0.tif = ecoImpact under the 25% increased demand plus increased sprawl scenario DSL Data Product:  Index of Ecological Impact (SPRAWL paper)  Author: K. McGarigal Page 7 of 7  Updated on 30 April 2018  • DSL_ecoImpact_NaturesNetwork_v3.0.tif  = ecoImpact under the Nature's Network landscape conservation design scenario (www.naturesnetwork.org) in which 25% of the landscape was protected from future development in reserve area Literature Cited McGarigal K, Compton BW, Plunkett EB, DeLuca WV, and Grand J. 2017. Designing sustainable landscapes products, including technical documentation and data products. https://scholarworks.umass.edu/designing_sustainable_landscapes/ McGarigal K; Plunkett EB; Willey LL; Compton BW; DeLuca WV; Grand J. 2018a. Modeling non-stationary urban growth: the SPRAWL model and the ecological impacts of development. Landscape and Urban Planning [in press]. McGarigal K; Compton BW; Plunkett EB; DeLuca WV; Grand J; Ene Eduard; Jackson S. In review. A landscape index of ecological integrity to inform landscape conservation. Landscape Ecology.  

Designing Sustainable Landscapes: The index of ecological impact

The primary file is a PDF document that provides a description of the ecological impact metric that is suitable for both applications found in the associated datasets (described in greater detail below).
Dataset 1: The ecological impact associated with the SPRAWL paper [updated 3/17/2017] — includes two landscape change scenarios: 1) baseline 70-year (2010-2080) climate change and urban growth scenario without additional land protection, and 2) same 70-year landscape change scenario but with additional terrestrial reserve areas (core areas) protected from development as established for Nature's Network landscape design (www.naturesnetwork.org).
Dataset 2: The ecological impact associated with the INTEGRITY paper [updated 3/17/2017] — includes five landscape change scenarios: 1) baseline 70-year (2010-2080) climate change and urban growth scenario without additional land protection; 2) same as #1 but with 25% more demand for new development; 3) same as #1 but with increased sprawl to the pattern of development; 4) same as #1 but with both 25% more demand for new development and increased sprawl; and 5) same as #1 but with additional terrestrial reserve areas (core areas) protected from development as established for Nature's Network landscape design (www.naturesnetwork.org).Includes five landscape change scenarios: 1) baseline 70-year (2010-2080) climate change and urban growth scenario without additional land protection; 2) same as #1 but with 25% more demand for new development; 3) same as #1 but with increased sprawl to the pattern of development; 4) same as #1 but with both 25% more demand for new development and increased sprawl; and 5) same as #1 but with additional terrestrial reserve areas (core areas) protected from development as established for Nature's Network landscape design (www.naturesnetwork.org)

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Designing Sustainable Landscapes: The index of ecological impact

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