Mountain Lion Connectivity – ArcGIS Pro Corridor Model

Main Connectivity Map

This map shows a composite cost surface symbolized from green to red, where green areas represent low movement cost (landscapes that are relatively permeable and suitable for mountain lions) and red areas represent high movement cost (barriers such as dense development, busy roads, or exposed terrain). A least-cost wildlife corridor is extracted across this surface to connect core mountain lion habitats in the mountains northwest of Los Angeles.

Corridors matter because they restore functional connectivity between isolated habitat patches, reduce road-kill risk at major highways, and maintain gene flow so small, fragmented populations don’t collapse through inbreeding. The underlying cost surface weights four criteria derived in ArcGIS Pro: distance from roads, legal protection status, rugged terrain, and dense land cover. Least-cost paths are then traced across this cost surface to identify candidate overpass locations and priority parcels for protection.

Main layers Cost raster Corridor Core habitats Habitat labels

Map legend

Cost surface (green = low movement cost, red = high movement cost)

Least-cost corridor

Core mountain lion habitats

Input Layers

These are the main inputs that feed into the ArcGIS Pro cost-surface and corridor model: distance to roads, ruggedness, land cover classes, and protected areas.

1. Distance to roads (Mapbox tiles, derived from ArcGIS Pro)

This map shows a distance-to-roads raster surface with a simplified roads network overlaid. In the ArcGIS Pro model, raw roads features are rasterized and converted to a continuous Euclidean distance or distance-accumulation surface. That distance is then rescaled so areas very close to roads receive high cost and more remote terrain receives lower cost. Here the raster is used as a continuous background, with the vector roads overlay highlighting the infrastructure that fragments habitat.

Distance map layers Roads overlay

2. Terrain ruggedness

Rugged terrain is a crucial part of the corridor model. It gives mountain lions places to hide, stalk prey, and avoid human disturbance, while also making development less likely. In this workflow, ruggedness is defined as the local range in elevation: for each cell in the elevation raster, a neighborhood is examined and the difference between the minimum and maximum elevation is computed. Large ranges correspond to steep, broken terrain.

In ArcGIS Pro, this is implemented with the Focal Statistics tool, using the RANGE statistic over a moving window. The resulting ruggedness raster is later rescaled so that higher ruggedness (larger elevation range) is assigned lower cost, prioritizing complex terrain as safer movement habitat for mountain lions.

Ruggedness (local elevation range)

Low ruggedness (flat / gentle)

Moderate ruggedness

High ruggedness (steep / complex)

3. Land cover and protected areas (static inputs)

These PNGs are exported directly from the ArcGIS Pro project. They represent the categorical inputs that were reclassified and weighted in the cost surface: land cover (NLCD-like classes) and legal protection status of land parcels.

Land cover classes used as one of the primary cost criteria. In the cost-surface model, **dense vegetation cover types such as evergreen forest, mixed forest, and shrub/scrub are assigned the lowest cost**, reflecting their importance as secure movement habitat. More open or intensively modified cover types—cultivated crops, barren land, and highly developed areas—are assigned progressively higher costs because they expose lions to human activity and increase mortality risk.

Protected areas (PAD-US) — This raster layer indicates the level of protection for all lands contained in the **Protected Areas Database of the United States (PAD-US)**: from highly protected in darker greens to not protected in grey. An example of highly protected land would be a national forest; an example of not-protected land would be a recreation area or other low-protection designation. Areas without a color on the map are not tracked in PAD-US and usually correspond to urban, agriculture, or other forms of privately exploited lands. In the least-cost analysis, the highest PAD-US protection levels are assigned the lowest movement cost, so medium- and high-protection areas function as anchor habitat in the corridor network.

How this corridor model was built in ArcGIS Pro

This map is the result of implementing Esri’s Learn ArcGIS project “Build a Model to Connect Mountain Lion Habitat” in ArcGIS Pro. The core of the workflow is an ArcGIS Pro ModelBuilder model that chains Spatial Analyst tools into a reproducible, parameterized corridor-analysis pipeline.

Study area and core habitats. Start from an Esri-provided ArcGIS Pro project containing the Los Angeles study area and polygon features for core mountain lion habitats. Elevation, land cover, roads, and PAD-US protection status are reviewed and selected as corridor criteria.
Pre-processing in ModelBuilder. In a “Prepare data” group, analysis inputs are derived using tools such as Rasterize Features and Euclidean Distance or Distance Accumulation (for roads), and a terrain ruggedness surface is computed from the elevation DEM using Focal Statistics with the RANGE statistic. All rasters are snapped to a common cell size, extent, and alignment using the ArcGIS Pro environment settings so they can be combined cleanly.
Cost surface generation. In a “Create cost surface” group, each criterion (distance to roads, land cover, PAD-US protection status, ruggedness) is normalized to a comparable scale using Rescale by Function, Reclassify, or Raster Calculator. A weighted linear combination is then applied via Weighted Sum or similar overlay tools to produce a single composite cost raster where low values correspond to easy movement for lions and high values approximate barriers.
Least-cost corridor extraction. The composite cost surface and core habitat polygons are fed into the Optimal Region Connections tool to compute least-cost paths between regions, returning a primary “Mountain_Lion_Paths” line network and optional neighbor-to-neighbor alternatives. These paths define the backbone wildlife corridor(s) spanning the study area.
Evaluation and export. The resulting cost surface and corridor network are symbolized in ArcGIS Pro, checked against roads and land-use conflicts, and then exported and tiled for web visualization using Mapbox GL JS (the maps at the top of this page).

The entire workflow is encapsulated in an ArcGIS Pro ModelBuilder model (schematized below). ModelBuilder groups preprocessing, cost-surface creation, and least-cost path extraction into modular sub-models that can be re-run or modified without rebuilding the analysis from scratch.

ArcGIS Pro ModelBuilder diagram for mountain lion corridor analysis — **ModelBuilder diagram.** The left-hand group handles data preparation and feature-to-raster conversion (for example, rasterizing roads and computing elevation-derived terrain metrics). The central group builds the composite cost surface by rescaling and reclassifying distance-to-roads, land cover, ruggedness, and protection status, then combining them with a weighted overlay. The right-hand group uses the resulting cost raster and core habitat features as inputs to *Optimal Region Connections*, producing a least-cost corridor network that is later evaluated and exported for web visualization.