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* Metric Name: Present Day Connectivity in California (Omniscape)  

* Tier: 1  

* Data Vintage: last updated 01/2023  

* Unit Of Measure: Categorical; 11 (listed above)  

* Metric Definition and Relevance: This data represents a wall-to-wall characterization of regional habitat connectivity potential in California for plant and animal species whose movement is inhibited by developed or agricultural land uses. 

This model of present-day connectivity assumes there will be more ‘current
flow’, representing wildlife movement, coming from and going to areas that are
less modified. Wildlife may encounter barriers and land uses that are not
conducive to movement en route. They may avoid moving through these areas
entirely or these areas will increase their risk of harm. Land use, energy
infrastructure, roads, and night lights are some of the factors that affect
the ‘resistance’ to movement in this analysis.

Present Day Connectivity is partitioned into 11 classes (and the code used in
the data):

  1. 3 - Land use may restrict movement:
  2. 4 - Permeable lands that contribute little to regional connectivity
  3. 19 - Impeded
  4. 25 - Diffuse - Med
  5. 29 - Diffuse - High
  6. 31 - Intensified - Low
  7. 35 - Intensified - Med
  8. 39 - Intensified - High
  9. 41 - Channelized - Low
  10. 45 - Channelized - Med
  11. 49 - Channelized - High

Connectivity classes are assembled into categories based on whether an area
had more or less flow than would be expected in the absence of barriers. For
example, when animal movement is restricted by surrounding land uses, it
channelizes into a single movement pathway, or a linkage. These
**Intensified** and **Channelized** linkages are areas with more flow and far
more flow, respectively, than would be expected in the absence of nearby
barriers to movement. **Diffuse** connectivity areas are broadly, permeable
areas with as much flow as is expected. Roads and intensive development can
cause complete or partial barriers to animal movement, impeding their ability
to traverse the landscape. **Impeded** areas are areas where there is less
flow than is expected.

The Omniscape output ‘current flow’ was classified into high, medium and low
classes and further categorized by the amount of flow compared to what would
be expected in the absence of barriers. The ‘Channelized’ class has 1.7 times
more flow than expected in the absence of barriers and represents the last
remaining natural pathway through a modified landscape. The ‘Intensified’
class has 1.3-1.7 times more flow than expected and represents areas where
there are a few remaining natural pathways. The ‘Diffuse’ class has as much
flow as expected and represents lands that have many or unlimited movement
options.

  

* Creation Method: The approach uses Omniscape, a modified version of Circuitscape (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.  

* Credits: The Nature Conservancy (TNC) Omniscape [c.k.stanley@tnc.org](mailto:c.k.stanley@tnc.org) [The Nature Conservancy: A World Where People & Nature Thrive](https://www.nature.org/en-us/)