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HOW MUCH IS ENOUGH? Conservation planning at multiple scales Mark Anderson, PhD Director of Conservation Science Eastern U.S. Conservation Region The Nature.

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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:

1 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

2 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?

3 How large does a forest have to be?

4 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

5 Disturbance Example Forest - In 300 Years: -15 Fires -4 Hurricanes -7 Windstorms -Infestations -Blight -Disturbances the Rule, Not the Exception

6 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

7 Severe Damage Patch

8 Severe Damage Patches in Pisgah Forest NH (from Foster 1988b) Severe Damage Patch

9 - 25% in Early Successional State -50% Medium Aged -25% in Mature State Disturbance How much larger than the severe damage patch?

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11 Breeding habitat for forest interior species

12 Ave breeding territories x 25 (sources Gill et al. 2004, DeGraff and Yamasaki 2002, *Robbins 1989.)

13 Minimum tract size for area sensitive birds from Robbins et al. 89, Hamel 92 SPECIESsummer tanagerblack-throated blue veerycerulean warbler kentucky warblernorthern parula acadian flycatchercanada warbler blue-gray gnatcatcherlouisiana waterthrush scarlet tanagerblack and white warbler hairy woodpeckerworm-eating warbler ovenbirdred-shouldered hawk american bitternpiliated woodpecker white-breasted nuthatch red-eyed vireo rose-breasted grosbeak wood thrush tufted titmouse great-crested flycatcher red-bellied woodpecker *unknown sizes:american redstart, brown creeper, chestnut -sided warbler, hermit thrush, hooded warbler, least flycatcher, mourning warbler // 6000 Size in acres

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16 SALT MARSH 100 acres 200 acres 50 acres Black Duck SALT MARSH SIZE Clapper Rail Seaside sparrow Willet? Savannah Sparrow Sharp tailed Sparrow Sedge Wren Least Bittern Black Rail MINIMUM DYNAMIC AREA ? Nutrient turnover, Flushing, Organic matter accumulation, transformations & storage Short –eared Owl SIZE (models, literature) CONDITION (Ground survey, Corroborating EOs) LANDSCAPE CONTEXT (GIS metrics, threat maps)

17 Critical Concept Replication across Gradients Redundancy to spread risk

18 GEOLOGY TOPOGRAPHY ELEVATION ROADS ECO- SYSTEMS HOUSING DENSITY DATA EXAMPLES

19 Ecological Land Units (Geology, Topography and Elevation)

20 Ecological Land Units were used to insure we identified forest blocks over all landscape types

21 Initial Minimum Goals The number of viable occurrences needed in the Ecoregion is a function of restrictedness and scale

22 DYNAMIC PORTFOLIO Matrix Forest Patch Communities & Species Aquatic networks Optimum solution, alternatives not shown

23 Source Sink Dynamics (Net exporters of juveniles based on habitat specific fitness) Source Sink

24 Dispersal Pressure DISPERSAL PRESSURE RESERVE

25 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.

26 N - DIMENSIONAL PINBALL

27 Softening the matrix between cores Amplification & Buffering of Core effects

28 SnowmeltWind disturbances Movement Hydrologic Cycles

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30 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.


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