HOW MUCH IS ENOUGH? Conservation planning at multiple scales Mark Anderson, PhD Director of...

HOW MUCH IS ENOUGH? Conservation planning at

multiple scales

Mark Anderson, PhDMark Anderson, PhDDirector of Conservation ScienceDirector of Conservation Science

Eastern U.S. Conservation RegionEastern U.S. Conservation RegionThe Nature ConservancyThe Nature Conservancy

31 October 200431 October 2004Land Trust Alliance RallyLand 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?

How large does a forest have to be?

How large does a forest have to be?

• 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

DisturbanDisturbanceceExample Forest - Example Forest - In 300 Years:In 300 Years:-15 Fires15 Fires

-4 Hurricanes4 Hurricanes-7 Windstorms7 Windstorms-InfestationsInfestations-BlightBlight-Disturbances Disturbances the Rule, Not the Rule, Not the Exceptionthe 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

Severe Damage

Patch

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

Severe Damage

Patch

- 25% in Early - 25% in Early Successional Successional StateState

- 50% Medium 50% Medium AgedAged

- 25% in Mature 25% in Mature StateState

DisturbanDisturbanceceHow much larger How much larger than the severe than the severe damage patch?damage patch?

Breeding habitat for forest interior species

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

Average Breeding Territory x 25

0 5000 10000 15000 20000 25000 30000 35000 40000 45000

Many Warblers

Scarlet tanager

Eastern wood pewee

Spruce Grouse

Nashville Warbler

Black & White Warbler

Pileated woodpecker

Sharp-shinned Hawk

Saw whet owl

Area sensitive songbirds*

Rusty blackbird

Northern goshawk

Barred owl

Broad-winged hawk

American marten

Acres

Minimum tract size for area sensitive birdsfrom Robbins et al. 89, Hamel 92

SPECIES summer tanager black-throated blue

veery cerulean warblerkentucky warbler northern parula

acadian flycatcher canada warblerblue-gray gnatcatcher louisiana waterthrushscarlet tanager black and white warbler

hairy woodpecker worm-eating warblerovenbird red-shouldered hawk

american bittern piliated woodpeckerwhite-breasted nuthatchred-eyed vireo

rose-breasted grosbeakwood thrush

tufted titmousegreat-crested flycatcherred-bellied woodpecker

*unknown sizes:american redstart, brown creeper, chestnut -sided warbler, hermit thrush, hooded warbler,least flycatcher, mourning warbler

0 2 5 25 50 100 500 1000 2000 3000 4000 // 6000

Size in acres

SALT MARSH

100 acres

200 acres

50 acres

Black Duck

SALT MARSH SIZE

Clapper RailSeaside sparrowWillet?

Savannah SparrowSharp tailed Sparrow Sedge Wren

LeastBittern

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)

Critical Concept

• Replication across Gradients

• Redundancy to spread risk

GEOLOGY

TOPOGRAPHY

ELEVATION

ROADS

ECO-SYSTEMSHOUSINGDENSITY

DATA EXAMPLES

Ecological Land Units (Geology, Topography and Elevation)

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

Initial Minimum Goals

• The number of viable occurrences needed in the Ecoregion is a function of restrictedness and scale

Matrix Large Patch Small PatchRestricted 20 30Limited 15 25Widespread 10 15Peripheral 5 5

DYNAMIC PORTFOLIO• Matrix Forest• Patch Communities & Species• Aquatic networksOptimum solution, alternatives not shown

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

Source

SinkSink

Sink

Sink

Dispersal Pressure

DISPERSAL PRESSURE

RESERVE

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.

N - DIMENSIONAL PINBALL

“Softening” the matrix between cores

Amplification& Buffering ofCore effects

Snowmelt Wind disturbances

Movement Hydrologic Cycles

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.