habitat interspersion – Leopold’s Law of Interspersion

1. habitat interspersion – Leopold’s Law of Interspersion

3. Human Land Use Practices

4. History of Landscape Ecology • “European School” • roots back to those of ecology • typing, classifying, naming • landscape architecture, planning, designing • “American School” • young = early 1980’s • focus on natural systems • theory & models, some field experiments

5. What is Landscape Ecology? • Meta-analysis of papers in Landscape Ecology (Wiens 1992) – 1st 5 yrs of journal • Most studies are large scale (landscapes are big) • Most studies are descriptive or conceptual • Experiments difficult to conduct, thus modeling • Emphasis on vegetation pattern / land use pattern • Humans = impt. part of systems

6. What is Landscape Ecology? • Hobbs (1997) – 2nd 5 years of Landscape Ecology • Less descriptive studies • More “methods” and modeling studies, no expts. • More quantitative / statistical analysis (spatial stats)

7. Structure Function Emergence of Landscape Ecology ? Equilibrium View ? ? ?

8. Structure Function Emergence of Landscape Ecology Dynamic View

11. Long Temporal Scale Short Fine Coarse Spatial Scale Ecological Scaling: Scale & Pattern • Acts in the “ecological theatre (Hutchinson 1965) played out across various scales of space & time • To understand these dramas, one must select appropriate scale Speciation Extinction Species Migrations Secondary Succession Windthrow Fire Treefalls Recruitment

12. American Redstart American Redstart Least Flycatcher Least Flycatcher Ecological Scaling: Scale & Pattern Regional Scale (thousands of ha) Local Scale (4 ha plots)

13. Ecological Scaling: Definitions • Ecological scale & cartographic scale are exactly opposite • Ecological scale = • Cartographic scale =

14. Ecological Scaling: Components of Scale • Grain = finest component of environment that can be differentiated up close • Extent = range at which a relevant object can be distinguished from a fixed vantage point Extent Grain Coarse Fine Scale

15. Ecological Scaling: Components of Scale • )

16. Identifying the “Right” Scale(s) • No clear algorithm for defining • Autocorrelation & Independence • Life history correlates • Dependent on objectives and organisms • Multiscale analysis! • e.g., Australian leadbeater’s possum

17. Multiscale Analysis • Species-specific perception of landscape features : scale-dependent • e.g., mesopredators in Indiana • Modeling species distributions in fragmented landscapes

18. Spatial and Temporal Ecology of Raccoons

19. Gehring and Swihart. 2003. Biological Conservation 109:283-295

20. Brown and Litvaitis. 1995. Canadian Journal of Zoology 73:1005-1011

21. Hierarchy Theory • Lower levels provide mechanistic explanations • Higher levels provide constraints

22. Scale & Hierarchy Theory • Hierarchical structure of systems = helps us explain phenomena • Why? : next lower level • So What? : next higher level • minimum 3 hierarchical levels needed

23. Constraints (significance) Level of Focus (level of interest) Components (explanation)

24. Landscape Pattern • Landscape Components (attributes of features or spatial elements) landscape are comprised of: - corridors - patches - matrix

25. Landscape Pattern • Landscape Components (attributes of features or spatial elements) landscape are comprised of: - corridors - patches - matrix • Composition • Configuration • Connectivity Relative to landscape spatial elements….

26. How much of the area is comprised of each type of spatial element? How are spatial elements arranged in space? How do these attributes change through time?

27. How does one quantify landscape pattern? How do biotic communities interact with pattern?

28. Landscape Pattern Patch-Corridor-Matrix Model • Patch – • Corridor • Matrix –

32. Landscape PatternPatches Defining patches using vector data • Digitizing = delineating polygon patches using remotely-sensed data (e.g., DOQ) based on visual interpretation of patch boundaries; subjective, but ground truthing needed DOQ Vector Coverage

33. Landscape PatternPatches Defining patches using raster data • Satellite sensor = delineating pixel-shaped patches based on spectral signatures; aggregating cells based on shared attributes DOQ Raster Coverage

34. Landscape Pattern Patches • Patch boundaries meaningful only when referenced to particular scale & phenomenon; resolution impt., gradients or discrete boundaries?

36. Landscape Pattern Corridors • Definition based on function….. • Habitat – increase connectivity by providing breeding habitat…facilitate gene flow • Facilitated Movement – increase connectivity by facilitating dispersal, migration, and/or range shifts • Barrier or Filter – prohibit (barrier) or impede differentially (filter) movements

37. Landscape Pattern Corridors Facilitated Movement Corridors

38. Landscape Pattern Corridors Facilitated Movement Corridors • Selectivity (s): degree of discrimination of possible pathways • Resistance (k): survival cost per unit time spent in corridor • Velocity (v): avg rate of movement through • Final evaluation = immigration rate

39. Landscape Pattern Corridors Barriers & Filters

40. Landscape Pattern Matrix • Most abundant • Highest connectivity