Forest Fragmentation: The States of Our Forests & Prospects for Conservation
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Forest Fragmentation: The States of Our Forests & Prospects for Conservation

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    Forest Fragmentation: The States of Our Forests & Prospects for Conservation Forest Fragmentation: The States of Our Forests & Prospects for Conservation Presentation Transcript

    • Forest Fragmentation:The State of Our Forestsand Prospects forConservation Maile C. Neel
    • Taryn Sudol Nikolaus AndersonSustainableDevelopment and Norton-BrownConservation HerbariumProgramThanks to Prince George’s County for access to tree canopy and Green Infrastructure data
    • The Three R’s : Representation, Redundancy and ResilienceThe 3 R’s rest on of the premise thatbiodiversity conservation is about space – space in which species go about the activities that allow them to shelter, feed and breed. Shaffer and Stein (2000) Our Precious Heritage
    • Three R’s : Representation, Redundancy and Resilience Represent sites that support species or processes of interest Include redundant sites to protect against catastrophic loss Choose sites that are resilient to disturbance Large Well connected to other sites
    • Photos from Buzzle
    • Fragmentation includes both habitat loss and isolation Extensive continuous habitatIncreasing Habitat Loss Reduced extent See incision into habitat Increased edge effects Perforation Additional reduction in area Yet more reduction in area More patches Isolation of small, remnant patches
    • Increasing Amount of AggregationIncreasing Amount of Habitat Neel et al. 2004, Landscape Ecology
    • You Are 146,171 acres totalHere 28,055 patches Mean Patch Size: 5.3 acres Median Patch Size: 0.3 acres Largest Patch: 6,690 acres 47% of land area in the county
    • 20000 15000Number of Patches 10000 5000 0 1 10 50 100 500 1000 3000 >5000 Patch Area (Acres)
    • National Land Cover Data Set Classification Developed Forested Agriculture Miles 0 1.75 3.5 7 10.5
    • Examples of treecanopy indeveloped areas
    • 106,063 acres total 9,818 patches Mean Patch Size: 10.8 acres Median Patch Size: 0.26 acres Largest Patch: 3,971 acresGreen InfrastructureTree Canopy in GI Miles 0 1.75 3.5 7 10.5
    • 7000 6000 5000Number of Patches 4000 3,456 patches are ≥1 acre 3000 2000 1000 0 1 10 50 100 500 1000 3000 >5000 Patch Area (Acres)
    • Only 1,006 patches haveany habitat farther than180 feet from an edge.
    • Graph Theoretic Approaches to Connectivity Assessment Links Patches Components: All individual patches (nodes) & Patches joined by links (edges) •Number of Components at a particular distance •Distance at which all nodes form one component •Number of nodes in the largest component
    • Three Sources of ConnectivityArea Within Continuous Patches Intra-Patch D A C B SizeMovement Between Patches that are Either a Source or Destination Flux D A C B Size of A and C and number of linksMovement Through Stepping Stone Patches Connector D A C B Number of links and size of A and C
    • Integral Index of Connectivity - IIC area number of links area of the landscape A D C B nlAC=2Equivalent Connectivity (ECIIC) – the area of one continuous habitatpatch that has the same value of IIC as the observed landscape.
    • Graph Theoretic Approaches to Connectivity Assessment 1) How large and extensive are networks of patches that would be accessible to an organism that could disperse a specified distance? 2) At what distances is the network most sensitive to changes in different aspects of connectivity? 3) How do individual patches contribute to different aspects of connectivity? Miles 0 0.45 0.9 1.8 2.7
    • 106,063 acres total 9,818 patches Only patches ≥ 1 acre 104,249 acres total 3,456 patchesGreen InfrastructureTree Canopy in GI Miles 0 1.75 3.5 7 10.5
    • 2000Number of Components 1500 1000 2300 ft - all patches form a connected network 500 0 0 2000 4000 6000 8000 Distance (feet)
    • Components at 200 feet 309 patches are N=851 in the largest component Miles 0 1.75 3.5 7 10.53,456 original patches
    • Components at 300 feet 1,945 patches are N=409 in the largest component Miles 0 1.75 3.5 7 10.53,456 original patches
    • Components at 500 feet 2,284 patches are N=179 in the largest component Miles 0 1.75 3.5 7 10.53,456 original patches
    • 45000ECIIC (Acres) 35000 When all patches are first connected, ECIIC= 38,657 acres 25000 15000 Total Acres: 104,249 0 2000 4000 6000 8000 Distance (feet)
    • Patch Importance and Network SensitivitySequentially remove eachpatchRecalculate all networkstatisticsChange in the networkvalues without a patchindicates its importance toconnectivitySum of changes across allpatches indicates networksensitivityChanges can be assessed as Total IIC Intra-patch Flux Connector
    • 2 Sum of varIIC acres  0e+00 1e+09 2e+09 3e+09 4e+09 5e+090200040006000 Total IIC8000
    • 2 Sum of varIIC acres  0e+00 1e+09 2e+09 3e+09 4e+09 5e+090200040006000 Total IIC Within Patch8000
    • 2 Sum of varIIC acres  0e+00 1e+09 2e+09 3e+09 4e+09 5e+090200040006000 Flux Total IIC Within Patch8000
    • 2 Sum of varIIC acres  0e+00 1e+09 2e+09 3e+09 4e+09 5e+090200040006000 Flux Total IIC Connector Within Patch8000
    • 2 Sum of varIIC acres  0e+00 1e+09 2e+09 3e+09 4e+09 5e+09050010001500 Flux Total IIC2000 Connector Within Patch
    • Components 200 feet 300 feet Miles Miles 0 1.75 3.5 7 10.5 0 1.75 3.5 7 10.5 N=851 N=409
    • Top ten ranked patches for intra-patch connectivity Miles 0 1.75 3.5 7 10.5300 foot distance
    • Top ten ranked patches for flux connectivity Miles 0 1.75 3.5 7 10.5300 foot distance
    • Top ten ranked patches for connector function ~12% loss in ECIIC value 18% loss in ECIIC value 21% loss in ECIIC value Miles 0 1.75 3.5 7 10.5300 foot distance
    • 34,233 acres total 3,160 patches32% of all canopy in GreenInfrastructure is protected
    • Intra-Patch Connectivity45% protected2 patches missing altogether
    • Flux Connectivity35% protected3 patches missing altogether
    • Connector Patches47% protected6 patches missing altogether