Presentation on theme: "HOW MUCH IS ENOUGH? Conservation planning at multiple scales Mark Anderson, PhD Director of Conservation Science Eastern U.S. Conservation Region The Nature."— Presentation transcript:
HOW MUCH IS ENOUGH? Conservation planning at multiple scales Mark Anderson, PhD Director of Conservation Science Eastern U.S. Conservation Region The Nature Conservancy 31 October 2004 Land Trust Alliance Rally
Critical Concepts Ecosystem Function: How big does an example of a feature have to be? Replication and Redundancy: How many examples do we need to protect? Sources and Sinks: What is the role of the protected example in relationship to the surrounding landscape?
Minimum Dynamic Area: Big enough to absorb, buffer and benefit from catastrophic disturbances expected over centuries Species Area Requirements: Big enough to ensure long-term persistence of species that need or thrive under interior forest conditions
Disturbance Example Forest - In 300 Years: -15 Fires -4 Hurricanes -7 Windstorms -Infestations -Blight -Disturbances the Rule, Not the Exception
Critical Concepts Most disturbances are small and frequent Large infrequent catastrophic disturbances leave lasting impacts on the landscape Disturbance is distributed in patches of varying severity
Average Number of Breeding Bird Pairs per 99 Acres Adapted from Haney,J.C. and C.P.Schaadt.1996.Functional role of eastern old- in promoting forest bird diversity. In M.B.Davis (ed.) Eastern old-growth forests: prospects for rediscovery and recovery. Island Press. Washington DC.
The portfolio depicts the critical examples of ecosystems and population occurrences. Which strategies and how much area are needed to protect those features is the subject of localized efforts, referred to as conservation area planning.