Conserving wildlife biodiversity in a land of roads

Dale SteeleCalifornia Department of Fish and Game

Species rarity and richnessin the United States

Based on Precious Heritage, Stein et al. 2000. Used by permission.

High

Low

California is UNIQUE

Climate + Geology = Speciation = Endemism

High biological diversity

> 6000 species of plants> 1400 species of

animals, including fish> 1300 vegetation types> 2000 types of distinct

plant associations

Species at risk in California

> 400 Listed plants > 200 Listed animals > 200 Species of Special Concern> 1000 Sensitive plants (CNPS)

California highway facts• About 15,000 miles of state highways • More than 23.4 million registered vehicles • Annual vehicle miles traveled exceeds 280 billion• Road density averages 1.2 mile/square mile• Highways, streets and adjacent right-of-way total

about 20 million acres • Roads equal about 1 % of the total US land area

Biological concerns• About a fifth of the US land area directly affected

by the road network• Roads generally reduce population size and

increase the risk of population extinction of sensitive species

• Considerable time lag before the full impact to wildlife and natural communities can be seen

• No systematic records of wildlife mortality on US roads

• Direct loss of habitat • Decrease quality of adjacent habitat• Habitat fragmentation• Roadkills• Impede animal movements

Successful wildlife crossing decreases significantly as roads are upgraded to accommodate greater traffic volume. Smaller populations may result, with a greater potential of genetic problems and increased chance of local extinction.

More ecological effects

More info needed• Roadkill data spotty and limited • Baseline effects of roads on wildlife,

effectiveness of existing mitigation, and priority locations for additional studies not known

• Little known about long-lasting ecological effects in terms of reduced mobility, increased isolation, and/or splitting of gene pools

• Especially important to determine critical road density at which a population can no longer persist

Strong environmental laws• California Endangered Species Act (CESA)• California Environmental Quality Act (CEQA)• Natural Community Conservation Planning Act

(NCCPA)

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Conservation planning• Ecosystem level

– Multiple species– Natural communities– Ecological

processes– Common as well as

rare species• Science-based• Interconnected reserve

systems

Species selection• Degree of threat or endangerment• Endemism• Highly restricted habitat• Surrogates for ecological processes• Adequacy of inventory/monitoring

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Priorities for planning

• Rapidly-urbanizing regions

• Working landscapes• Collaborative

partnerships• Public support• Funding

Long-term goals• Species recovery• Ecosystem function• Landscape conservation• Compatible land use planning • Statewide resource inventory