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Reduce landscape fragmentation

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Approach

EASTERN:
The fragmentation of contiguous forest habitats is a primary driver of biodiversity loss and reduced productivity through exposure to disturbance, obstruction of migration pathways, and overall lowered resilience (Fischer and Lindenmayer 2007). Protecting large areas from fragmentation will require a concerted effort to create partnerships, agreements, and other mechanisms for land protection and management across property boundaries. Strategic acquisition of high-priority conservation areas, conservation easements, certification programs, restoration projects, and other efforts to increase the size and connectivity of forest ecosystems will foster a landscape-level response to counter the widespread effects of climate change (Anderson et al. 2012, Millar et al. 2007, Spittlehouse and Stewart 2003). This approach may be facilitated by approach 5.4, which focuses on establishing new reserves. (1)

WESTERN:
The fragmentation of contiguous habitats is a primary driver of biodiversity loss and reduced productivity through exposure to uncharacteristic disturbance, obstruction of migration pathways, and overall lowered resilience (Fischer and Lindenmayer 2007, CA Dept. Fish and Wildlife 2015, Haddad et al. 2017). In many parts of California, the state’s forests and other ecosystems have been compromised due to increased urban development and expansion of the wildland-urban-interface, which constrains adaptation potential (Radeloff et al. 2005, Klausmeyer and Shaw 2009, Radeloff et al. 2018). Protecting large areas from development and fragmentation will require a concerted effort to create partnerships, agreements, and other mechanisms for land protection and management across property boundaries. Strategic acquisition of high-priority conservation areas, conservation easements, certification programs, restoration projects, and other efforts to increase the size and connectivity of ecosystems will foster a landscape-level response to counter the widespread effects of climate change (Spittlehouse and Stewart 2003, Millar et al. 2007). This approach may be complemented by approach 5.4, which focuses on establishing new reserves. (2)

Tactics

  • Using geospatial information to identify new and existing migration corridors (1, 2).
  • Restoring native vegetation and vegetation structure in degraded areas within the ecosystem matrix, especially in key linkage areas that join fragmented population cores (1, 2).
  • Establishing partnerships and coordinating acquisition of conserved forest lands or riparian areas to achieve common management goals (1, 2).
  • Establishing or expanding reserves adjacent to other forest blocks to form a connective network of a few large reserves, many small reserves along a climatic gradient, or a combination of large and small reserves close to each other.
  • Promoting or participating in conservation easement programs (e.g., Cal Fire CFIP) that retain vegetation cover and achieve landscape-scale connectivity (1, 2).
  • Establishing or expanding reserves adjacent to other habitat cores to form a connected network of a few large reserves, many small reserves along a climatic gradient, or a combination of large and small reserves close to each other (2).
  • Work with partner agencies (e.g., Cal Trans, NPS, USFS) to develop effective road-crossing structures that facilitate wildlife dispersal and minimize impacts from vehicle collisions, particularly in key habitat corridors (2).
  • Review system roads periodically and eliminate unneeded ones. Eliminate or restore user-created non-system roads, as appropriate (2).

Strategy Text

Species migration is a critical factor in the maintenance of ecosystem function in a changing climate, but fragmentation of landscapes and loss of habitat may restrict species movement and gene flow (Davis and Shaw 2001, Iverson et al. 2004a). Managing the landscape for connectivity may allow for easier species movement, reduce lags in migration, and enhance the flow of genetic material. The current rate of climate change coupled with contemporary land use, however, creates unique challenges to migration. Many species are not expected to be able to migrate at a rate sufficient to keep up with climate change and associated range shifts (Davis and Shaw 2001, Iverson et al. 2004a). Therefore, it may be beneficial to combine the approaches under this strategy with efforts to create refugia or relocate species (i.e., assisted migration). But connectivity may also increase movement of invasive species and insect pests, thereby increasing the need to prevent introduction of these species.

Citation

1. Swanston, C.W.; Janowiak, M.K.; Brandt, L.A.; Butler, P.R.; Handler, S.D.; Shannon, P.D.; Derby Lewis, A.; Hall, K.; Fahey, R.T.; Scott, L.; Kerber, A.; Miesbauer, J.W.; Darling, L. (2016). Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers, 2nd Edition. Gen. Tech. Rep. NRS-87-2. U.S. Department of Agriculture, Forest Service, Northern Research Station p. http://www.nrs.fs.fed.us/pubs/52760,
2. Swanston, C.W.; Brandt, L.A.; Butler-Leopold, P.R.; Hall, K.R.; Handler, S.D.; Janowiak, M.K.; Merriam, K.; Meyer,
M.; Molinari, N.; Schmitt, K.M.; Shannon, P.D.; Smith, J.B.; Wuenschel, A.; Ostoja, S.M 2020. Adaptation Strategies
and Approaches for California Forest Ecosystems. USDA California Climate Hub Technical Report CACH-2020-1.
Davis, CA: U.S. Department of Agriculture, Climate Hubs. 65 p.