habitat interspersion – Leopold’s Law of Interspersion

Human Land Use Practices

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

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

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)

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

Emergence of Landscape Ecology Structure Function Dynamic View

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 Temporal Scale Spatial Scale Fine Short Coarse Long Speciation Extinction Species Migrations Secondary Succession Windthrow Fire Treefalls Recruitment

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

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

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 Fine Coarse Scale

Ecological Scaling: Components of Scale )

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

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

Spatial and Temporal Ecology of Raccoons

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

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

Hierarchy Theory Lower levels provide mechanistic explanations Higher levels provide constraints

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

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

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

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….

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?

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

Landscape Pattern Patch-Corridor-Matrix Model

Landscape Pattern Patches 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

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

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

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

Landscape Pattern Corridors Facilitated Movement Corridors

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

Landscape Pattern Corridors Barriers & Filters

Landscape Pattern Matrix Most abundant Highest connectivity