Regional Connectivity Modeling

Overview

California Fish and Game Code section 1932(b) directs the California Department of Fish and Wildlife (CDFW) to “Develop and maintain a spatial data system that identifies those areas in the state that are most essential for maintaining habitat connectivity, including wildlife corridors and habitat linkages.

The California Essential Habitat Connectivity project (CEHC; Spencer et al. 2010 (PDF)) was the first effort to identify natural landscape blocks and associated linkages at a statewide scale. The CEHC was a broad-scale analysis identifying linkages between natural habitat blocks 10,000 acres or larger statewide, based on landscape intactness but not considering species-specific movement needs. The CEHC report identified the need to develop focal species based, fine-scale linkage models at the regional scale.

In 2018, the California Biodiversity Initiative Roadmap (PDF) directed CDFW to develop an updated statewide habitat connectivity map. Following the recommendation in the CEHC report, CDFW has prioritized the development of regional focal species based, fine-scale linkage models, working toward a wall-to-wall statewide map of focal-species based, fine-scale linkages. To update the statewide connectivity map, CDFW compiled CEHC linkages and existing regional linkage models, along with additional statewide models [Conservation Biology Institute’s Terrestrial Landscape Intactness dataset (Degagne et al. 2016), The Nature Conservancy’s Omniscape model (TNC and CSP 2018)], into the Areas of Conservation Emphasis (ACE) Terrestrial Connectivity dataset. This dataset summarizes several different connectivity values by ACE hexagon (2.5 square miles) and serves as a spatial reference library of connectivity studies. The ACE Terrestrial Connectivity map depicts connectivity conservation importance statewide based on the best available data across multiple studies. CDFW updates this dataset with new connectivity studies as they become available.

The spatial data developed by CAU scientists is available for viewing and download in the CDFW spatial data library: the Biogeographic Information and Observation System (BIOS). The primary BIOS Viewer can be launched from the first button below. Additional configurations of BIOS have also been organized with select data layers on particular topics or projects preloaded in the table of contents. Statewide and region-specific connectivity data products can be accessed through additional buttons below.

Spatial Data and Connectivity Viewers

Getting Started in BIOS 6 (PDF)

Next Steps

CDFW continues to prioritize the completion of regional linkage analyses. Currently, approximately 2/3 of California falls within the footprint of one or more regional linkage analyses conducted by CDFW or external partners. Filling in the remaining “gaps” in coverage is a high priority for CDFW staff. This effort would facilitate effective action by managers and other practitioners at local and regional scales and improve the accuracy and utility of the ACE terrestrial connectivity dataset, furthering the goals outlined in both the Biodiversity Initiative Roadmap and the Fish and Game Code.

To this end, CDFW is in the initial stages of planning and/or developing several regional, fine scale, species-specific analyses for portions of the state identified as priority areas and/or those with recent, high-quality vegetation maps:

• A large portion of Northeastern and North-Central California, encompassing the area identified at the Northeastern California Connectivity Symposium (Penrod 2020 (PDF)).
• The Southern Sierra Nevada Foothills ecoregion, complementing the Northern Sierra Nevada Foothills analysis (PDF) completed by CDFW in 2015. As part of this updated analysis, the Northern foothills will be revisited and reanalyzed with finer spatial resolution, creating a contiguous linkage dataset spanning the entire Sierra Nevada foothills region.
• The north coast of California, encompassing the area recently mapped by CDFW’s Vegetation Classification and Mapping program (VegCAMP).

Beyond filling in gaps in coverage in the existing connectivity map, CDFW intends to continue conducting fine-scale, climate-wise linkage analyses as new data become available and California’s landscape and climate continue to change, ensuring that practitioners have access to the most current high-quality data to inform critical decisions about the State’s biodiversity now and into the future.

References

• Spencer, W.D., P. Beier, K. Penrod, K. Winters, C. Paulman, H. Rustigian-Romsos, J. Strittholt, M. Parisi, and A. Pettler. 2010. California Essential Habitat Connectivity Project: A Strategy for Conserving a Connected California (PDF). Prepared for California Department of Transportation, California Department of Fish and Game, and Federal Highways Administration.
• Degagne, R., J. Brice, M. Gough, T. Sheehan, and J. Strittholt. 2016. Terrestrial Landscape Intactness 1 km, California. Conservation Biology Institute, December 2016.
• Krause, K. and M. Gogol-Prokurat. 2014. Guidance Document for Fine-Scale Wildlife Connectivity Analysis (PDF). California Department of Fish and Wildlife, Biogeographic Data Branch, Conservation Analysis Unit, December 2014.
• The Nature Conservancy (TNC), California Chapter and Conservation Science Partners (CSP). 2018. TNC Omniscape Connectivity Web Map. 

Contact

• ConservationAnalysis@wildlife.ca.gov