Transcript of Forest Fragmentation: The States of Our Forests & Prospects for Conservation
- 1. Forest Fragmentation:The State of Our Forestsand Prospects
forConservation Maile C. Neel
- 2. Taryn Sudol Nikolaus AndersonSustainableDevelopment and
Norton-BrownConservationHerbariumProgramThanks to Prince Georges
County for access to tree canopy and Green Infrastructure data
- 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. 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. Photos from Buzzle
- 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. IncreasingAmount ofAggregationIncreasing Amount of Habitat
Neel et al. 2004, Landscape Ecology
- 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. 2000015000Number of Patches10000500001 10 50 100 500
10003000 >5000 Patch Area (Acres)
- 10. National Land Cover Data Set Classification Developed
Forested Agriculture Miles0 1.75 3.5 7 10.5
- 11. Examples of treecanopy indeveloped areas
- 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. 700060005000Number of Patches4000 3,456 patches are 1
acre3000200010000 1 10 50 100 500 1000 3000 >5000 Patch Area
(Acres)
- 14. Only 1,006 patches haveany habitat farther than180 feet
from an edge.
- 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. 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. 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. 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. 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. 2000Number of Components 1500 10002300 ft - all patches
form a connected network 500 002000 40006000 8000Distance
(feet)
- 21. Components at 200 feet309 patches areN=851 in the
largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
- 22. Components at 300 feet1,945 patches areN=409in the
largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
- 23. Components at 500 feet2,284 patches areN=179in the
largestcomponentMiles 0 1.75 3.5 7 10.53,456 original patches
- 24. 45000ECIIC (Acres)35000 When all patches are first
connected, ECIIC= 38,657 acres2500015000Total Acres: 104,2490
20004000 6000 8000 Distance (feet)
- 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. 2 Sum of varIIC acres 0e+00 1e+09 2e+09 3e+09 4e+09
5e+090200040006000 Total IIC8000
- 27. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+09 4e+09
5e+090200040006000 Total IIC Within Patch8000
- 28. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+09 4e+09
5e+090200040006000FluxTotal IICWithin Patch8000
- 29. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+094e+09
5e+090200040006000FluxTotal IICConnectorWithin Patch8000
- 30. 2 Sum of varIIC acres 0e+00 1e+09 2e+093e+094e+09
5e+09050010001500FluxTotal IIC2000ConnectorWithin Patch
- 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. Top ten ranked patches for intra-patch connectivity Miles0
1.75 3.5 7 10.5300 foot distance
- 33. Top ten ranked patches for flux connectivity Miles0 1.75
3.5 7 10.5300 foot distance
- 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. 34,233 acres total3,160 patches32% of all canopy in
GreenInfrastructure is protected
- 36. Intra-Patch Connectivity45% protected2 patches missing
altogether
- 37. Flux Connectivity35% protected3 patches missing
altogether
- 38. Connector Patches47% protected6 patches missing
altogether