1. 1. Forest Fragmentation:The State of Our Forestsand Prospects forConservation Maile C. Neel
2. 2. Taryn Sudol Nikolaus AndersonSustainableDevelopment and Norton-BrownConservationHerbariumProgramThanks to Prince Georges County for access to tree canopy and Green Infrastructure data
3. 3. The Three Rs : Representation, Redundancy and ResilienceThe 3 Rs rest on of the premise thatbiodiversity conservation is about space space in which species go about the activitiesthat allow them to shelter, feed and breed. Shaffer and Stein (2000) Our Precious Heritage
4. 4. Three Rs : 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 disturbanceLargeWell connected to other sites
5. 5. Photos from Buzzle
6. 6. Fragmentation includes both habitat loss and isolation Extensive continuous habitatIncreasingHabitat LossReduced 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
7. 7. IncreasingAmount ofAggregationIncreasing Amount of Habitat Neel et al. 2004, Landscape Ecology
8. 8. You Are 146,171 acres totalHere28,055 patchesMean Patch Size: 5.3 acresMedian Patch Size: 0.3 acresLargest Patch: 6,690 acres 47% of land area in the county
9. 9. 2000015000Number of Patches10000500001 10 50 100 500 10003000 >5000 Patch Area (Acres)
10. 10. National Land Cover Data Set Classification Developed Forested Agriculture Miles0 1.75 3.5 7 10.5
11. 11. Examples of treecanopy indeveloped areas
12. 12. 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 Miles0 1.75 3.5 7 10.5
13. 13. 700060005000Number of Patches4000 3,456 patches are 1 acre3000200010000 1 10 50 100 500 1000 3000 >5000 Patch Area (Acres)
14. 14. Only 1,006 patches haveany habitat farther than180 feet from an edge.
15. 15. Graph Theoretic Approaches to Connectivity Assessment Links Patches Components: All individual patches (nodes) & Patches joined by links (edges)Number of Components at a particular distanceDistance at which all nodes form one componentNumber of nodes in the largest component
16. 16. Three Sources of ConnectivityArea Within Continuous Patches Intra-Patch D ACB SizeMovement Between Patches that are Either a Source or Destination Flux D ACB Size of A and C and number of linksMovement Through Stepping Stone PatchesConnector D ACBNumber of links and size of A and C
17. 17. Integral Index of Connectivity - IICarea number of linksarea of the landscape A DCBnlAC=2Equivalent Connectivity (ECIIC) the area of one continuous habitatpatch that has the same value of IIC as the observed landscape.
18. 18. Graph Theoretic Approaches to Connectivity Assessment 1) How large and extensiveare networks of patchesthat would be accessibleto an organism that coulddisperse a specifieddistance? 2) At what distances is thenetwork most sensitive tochanges in differentaspects of connectivity? 3) How do individual patchescontribute to differentaspects of connectivity? Miles0 0.45 0.9 1.8 2.7
19. 19. 106,063 acres total 9,818 patches Only patches 1 acre 104,249 acres total 3,456 patchesGreen InfrastructureTree Canopy in GI Miles0 1.75 3.5 7 10.5
20. 20. 2000Number of Components 1500 10002300 ft - all patches form a connected network 500 002000 40006000 8000Distance (feet)
21. 21. Components at 200 feet309 patches areN=851 in the largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
22. 22. Components at 300 feet1,945 patches areN=409in the largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
23. 23. Components at 500 feet2,284 patches areN=179in the largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
24. 24. 45000ECIIC (Acres)35000 When all patches are first connected, ECIIC= 38,657 acres2500015000Total Acres: 104,2490 20004000 6000 8000 Distance (feet)
25. 25. 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 asTotal IICIntra-patchFluxConnector
26. 26. 2 Sum of varIIC acres 0e+00 1e+09 2e+09 3e+09 4e+09 5e+090200040006000 Total IIC8000
27. 27. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+09 4e+09 5e+090200040006000 Total IIC Within Patch8000
28. 28. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+09 4e+09 5e+090200040006000FluxTotal IICWithin Patch8000
29. 29. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+094e+09 5e+090200040006000FluxTotal IICConnectorWithin Patch8000
30. 30. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+094e+09 5e+09050010001500FluxTotal IIC2000ConnectorWithin Patch
31. 31. Components200 feet300 feetMiles Miles 0 1.75 3.5 7 10.5 0 1.75 3.5 7 10.5 N=851 N=409
32. 32. Top ten ranked patches for intra-patch connectivity Miles0 1.75 3.5 7 10.5300 foot distance
33. 33. Top ten ranked patches for flux connectivity Miles0 1.75 3.5 7 10.5300 foot distance
34. 34. Top ten ranked patches for connector function ~12% loss in ECIIC value 18% loss in ECIIC value21% loss in ECIIC value Miles0 1.75 3.5 7 10.5300 foot distance
35. 35. 34,233 acres total3,160 patches32% of all canopy in GreenInfrastructure is protected
36. 36. Intra-Patch Connectivity45% protected2 patches missing altogether
37. 37. Flux Connectivity35% protected3 patches missing altogether
38. 38. Connector Patches47% protected6 patches missing altogether