GrassSHC Woody Transitions [U.S. Fish and Wildlife Service] Full Details
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Full Details
- Title:
- GrassSHC Woody Transitions [U.S. Fish and Wildlife Service]
- Description:
- File-based data for download: http://rangeland.ntsg.umt.edu/data/rap/rap-derivatives/great-plains/woody-transitions/transitions-30m/great-plains-transitions-30-2019.tif This product provides a rapid screening tool for identifying the leading edge of vegetation transitions in Great Plains rangelands and serves as an early warning for the loss of intact rangelands to woody expansion. Alternative ecological states are incapable of coexisting in the same space at a given point in time (Uden et al. 2019). For example, a savanna represents co-dominance of grasses and trees, meaning that grass-tree functional groups relatively coexist in the same space over time. In contrast, grass-tree functional groups fail to coexist in many regions of the world and represent fundamental alternative states in those instances. Transitions from one state to another are known to exhibit strong spatial order (Roberts et al. 2019; Allen et al. 2016); therefore, functional groups that do not coexist should covary negatively in space. This data product maps the geographic boundaries between grassy and woody states at two scales. When the geographic location of these boundaries change over time, rangeland resilience is being eroded (Uden et al. 2019) and the system is increasingly vulnerable to being lost to woody expansion. This is represented in the data product when a signal is present in a given year, persistent over multiple years, and non-stationarity in its geographic location over time.For planning purposes, two scales were pulled from a multitude of scales in a multi-scale analysis (following Uden et al. 2019) and provided as woody transitions layers. The broad-scale layer is computed and visualized to represent the boundary of the Great Plains grasslands biome, with scale being a product of both moving window (i.e., kernel) dimension and pixel resolution (i.e., grain). The broad-scale layer was computed with a 139 x 139-pixel moving window algorithm at 240-meter resolution. A second, moderate-scale was computed and visualized for regional-scale planning and represents the general spatial boundaries between alternative grassy and woody ecological states at a more detailed resolution. The moderate-scale layer was computed with an 81 x 81-pixel moving window algorithm at 30-meter resolution. Increasingly negative spatial covariance values between grass and tree functional groups represent increasingly severe segregation of grass/tree functional groups in space. Fill value = NA/NoData; corresponds to developed areas, croplands, or water, as classified in the 2011 National Land Cover Database (Homer et al. 2015), or wetlands and their 60-m buffers, as delineated in the National Wetlands Inventory (U.S. Fish and Wildlife Service 2019).Data use and interpretation must follow guidelines set forth athttp://rangelands.app, Uden et al. (2019), and Allred et al. (2020).Reminders and limitations: Transition data are meant to be combined with RAP cover data and local expert knowledge to understand vegetation change and is not meant to replace those products.When mapping spatial covariance data, upper and lower values over which the color ramp is stretched influence the sensitivity of the early warning signal of vegetation change and the display of transition severity. Such optimization of images may be useful for mapping variability over different ranges of transition severity in different locations; however, users should be advised that these adjustments also affect the potential for false positives/negatives in spatial transition detection. Transition signals were computed for conservation planning at two scales and represent a subset of a more robust multi-scale analysis. Cross-scale considerations of transitions will elucidate patches of intact rangeland vegetation nested within broader regional patterns shown here. Product testing is underway on cross-scale products and outputs.Only one functional group combination from RAP data is present in this data. Alternative functional group combinations may provide additional insights into vegetation transitions at various scales.
- Creator:
- Department of the Interior
- Provider:
- U.S. Fish and Wildlife Service Open Data
- Resource Class:
- Datasets and Web services
- Resource Type:
- Vector data
- Temporal Coverage:
- Last modified 2022-03-10
- Date Issued:
- 2021-04-09
- Place:
- Rights:
- Transition data are meant to be combined with RAP cover data and local expert knowledge to understand vegetation change and is not meant to replace those products.When mapping spatial covariance data, upper and lower values over which the color ramp is stretched influence the sensitivity of the early warning signal of vegetation change and the display of transition severity. Such optimization of images may be useful for mapping variability over different ranges of transition severity in different locations; however, users should be advised that these adjustments also affect the potential for false positives/negatives in spatial transition detection.Transition signals were computed for conservation planning at two scales and represent a subset of a more robust multi-scale analysis. Cross-scale considerations of transitions will elucidate patches of intact rangeland vegetation nested within broader regional patterns shown here. Product testing is underway on cross-scale products and outputs.Only one functional group combination from RAP data is present in this data. Alternative functional group combinations may provide additional insights into vegetation transitions at various scales.
- Access Rights:
- Public
- Format:
- Shapefile
- Language:
- English
- Date Added:
- 2023-08-11