SDE Raster Dataset
Tags
connectivity, habitat, barriers
This analysis represents a wall-to-wall picture of regional habitat connectivity for plant and animal species whose movement is limited by developed and agricultural land uses. The approach uses a modified version of Circuitscape ( http://www.circuitscape.org/) with a moving-window algorithm to quantify ecological flow (potential connectivity) among all pixels within a 50km radius. Circuitscape treats landscapes as resistive surfaces, where high-quality movement habitat has low resistance and barriers have high resistance. The algorithm incorporates all possible pathways between movement sources and destinations and identifies areas of high flow via low-resistance routes, i.e., routes presenting relatively low movement difficulty because of lower human modification, and thus mortality risk.
The final classified dataset, intermediate products, and input data layers can be explored in this web application www.tinyurl.com/ca-connectivity .
Classified connectivity categories :
Channelized an area where connectivity options are constrained; often the last remaining option for connectivity between natural areas through a modified environment.
Intensified land use, infrastructure and water bodies reduce the options for potential plant and animal movement between natural areas through a modified environment.
Diffuse current flow, or potential connectivity, is diffuse because there are many options for movement through mostly natural lands with fewer fragmentation barriers.
Impeded Human land uses inhibit movement.
Land use may restrict movement : Primarily agricultural land uses.
Locally permeable lands that contribute little to regional connectivity : Primarily areas along the coast.
Other Terms :
Flow potential expected current flow based on the naturalneses of potential connections (sources) in the absence of barriers to movement (i.e. no resistance), a null model.
Current Flow a metric of potential connectivity resulting from the naturalneses of potential connections (sources) and anthropogenic barriers to movement (resistance).
Punch-throughs areas with high current flow despite anthropogenic land uses. These areas may only contribute to regional connectivity following barrier removal or habitat enhancement.
Current flow through and along a highway areas where highways are most likely to influence regional habitat connectivity.
Resistance a measure of the degree of human modification of lands assumed to restrict movement to varying degrees. Based off of the Human Modification layer.
Source naturalness of lands can inform connectivity need by indicating areas where species are more likely to be moving from and to. Based off of the Human Modification layer.
Raster data from TNC representing the categories described above broken into high, medium, and low flow and a layer file to symbolize and provide names to those categories.
The Nature Conservancy, California Chapter. 2018. Landscape Connectivity using Omniscape.
Disclaimer : The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Extent
| West | -125.127131 | East | -112.871325 |
| North | 43.499608 | South | 31.268813 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
Disclaimer : The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.