spatial ecology ii: landscapes
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Spatial ecology II: landscapes. Bio 415/615. Questions. 1. Landscape ecology is the study of spatial patterns… and what else? 2. What are three main agents of landscape pattern? 3. What is GIS? 4. What are two examples of a landscape element?. Landscape Ecology. Space: grain and extent. - PowerPoint PPT PresentationTRANSCRIPT
Spatial ecology II: landscapes
Bio 415/615
Questions
1. Landscape ecology is the study of spatial patterns… and what else?
2. What are three main agents of landscape pattern?
3. What is GIS?4. What are two examples of a
landscape element?
Landscape Ecology
Space: grain and extent
“Heterogeneity is not an annoyance that complicates experimental designs, it is a critical ingredient in explaining the stability of ecological systems.” – Robert O’Neill (2001)
Landscapes are heterogeneous!
Landscape Ecologyvs. Island Biogeography and
Metapopulation biology
• Islands, populations, patches vary• The matrix is not neutral• The patch-matrix contrast is low or
high• There are edge effects• There are corridors, stepping stones,
and barriers
Landscape ecology
Landscape ecology is the study of the causes, consequences, and dynamics of spatial pattern in ecosystems
Like conservation biology, it is a relatively new subfield (1980s).
Landscape
Landscapes are blocks of land that contain this spatial pattern
Landscapes are defined either by natural boundaries (watersheds, divides) or by political or management boundaries
So, how BIG is a landscape?“The view from a small airplane”
So, how BIG is a landscape?
REALLY ANY SCALE, but most oftenused to refer to areas 10 to 100 km2
(2,500 to 25,000 acres) or larger
Depends on the process in question!
Wiens & Milne 1989 in Landscape Ecology
Landscapes can be of any resolution (grain) or extent.
Wiens & Milne 1989 in Landscape Ecology
5 m
Landscapes can be of any resolution (grain) or extent.
GIS: THE tool of landscape ecology
Geographic information systems (GIS) are tools for capturing (GPS units), managing & analyzing (software products) data that are referenced to spatial coordinates on Earth (‘georeferenced’).
GIS example: lat-longTreats the Earth as perfect sphere, divides each hemisphere into 90 degrees (plus divisions of 60 minutes and 60 seconds).
At equator, distance between longitude lines is about 69 miles.
Syracuse:
45° 2' 53" N, 76° 6' 54" W
Robinson projection: note any treatment of the Earth in 2D must be distorted!
GIS example: Universal Transverse-Mercator (UTM)
60 (distorted) world zones; tropics distorted the least
Syracuse: zone 18N
Easting: 412194 E
Northing: 4988893 N
Why UTMs? Values are in meters.
Pattern & ProcessThe Landscape Ecology
Mantra
Pattern & ProcessThe Landscape Ecology Mantra
Spatial pattern affects ecological processes
. . . and . . .Ecological processes affect spatial
pattern
This is why landscape ecology is not simply the study of pattern (more akin to traditional geography).
Patterns: discrete and continuous
• Landscape ecology can be similar to metapopulations, in that landscape positions are discretized (made into homogeneous patches)
• Landscapes can also be treated in more continuous fashion (such as elevation or contour maps, ie a surface)
• Both types are used in a GIS
Example of landscape modeling as a continuous
surface• Modeling ground-level temperature
in mountainous terrain
Example: How landscapes control near-ground temperature
A landscape modelA landscape model: how temperatures can : how temperatures can be predicted by factors derived from GISbe predicted by factors derived from GIS
Level 1: Minimum Temp = β0+ β1synoptic + β2radiation +
β3cos(ωvt) + β4sin(ωvt) + β5synoptic x radiation + ε
Level 2: β0 = π00 + π01elevation + π0ilog(strdist) + π03log(tci)β1 = π10 + π11log(strdist) + π11elevation + π13log(tci)β2 = π20 + π21elevation + π22log(strdist)β3 = π30 + π31elevation + π32log(strdist) + π33log(tci)β4 = π40 + π41elevation + π42log(strdist) + π43log(tci)β5 = π50
Mapping fine-scale GSMNP Mapping fine-scale GSMNP temperaturetemperature
Run model for each pixel (about 4 million at 30 m grain)Run model for each pixel (about 4 million at 30 m grain)
Scales of variationScales of variation
Mean annual tempMean annual temp
Patches & patch dynamics
Process of patch change– Disturbance– Recovery from disturbance
(succession)• Feedback to disturbance rate!
Patch dynamics: Processes of change (a) within a patch, and (b) interactions among patches on the landscape
Patch: A relatively homogeneous area defined by some criterion
Patch dynamics
The importance of computer modeling to simulate patch dynamics
Landscape Metrics• Composition: Kinds of patches,
matrix, connections, barriers• Size & Shape
– Perimeter/area ratio, Edge length– Shape or boundary complexity
• Arrangement:– Connectedness, dispersion,
isolation– Adjacency, contrast
Example of Example of discretizing a discretizing a landscape:landscape:
Mt LeConteMt LeConte
Great Smoky Great Smoky Mts National Mts National ParkPark
S
W
Let’s take a Let’s take a look at a look at a landscape:landscape:
Mt LeConteMt LeConte
Great Smoky Great Smoky Mts National Mts National ParkPark
S
W
Let’s take a Let’s take a look at a look at a landscape:landscape:
Mt LeConteMt LeConte
Great Smoky Great Smoky Mts National Mts National ParkPark
PP
PP
PP
PP
PP
PP
SW
Patches
Patches
Beetle kills
Patches
Patches
Matrix
Patches
Barrier Matrix
Matrix
Patches
Barrier
Landscape ecology
Matrix
Patches
Barrier
Landscape ecology
Connectedness
Landscape Elements:
Patch Matrix Corridor
Chardon et al. 2003
Landscape Elements:
Patch Matrix Corridor
Chardon et al. 2003
Landscape Elements:
Patch Matrix Corridor
Chardon et al. 2003
Size, quality
Chardon et al. 2003
Connectedness,Distance
Chardon et al. 2003
CorridorStepping stoneBarrier
Chardon et al. 2003
CorridorStepping stoneBarrier
Chardon et al. 2003
CorridorStepping stoneBarrier
Chardon et al. 2003
Matrix, Ecological Contrast
Chardon et al. 2003
Landscape Metrics• Composition: Kinds of patches,
matrix, connections, barriers• Size & Shape
– Perimeter/area ratio, Edge length– Shape or boundary complexity
• Arrangement:– Connectedness, dispersion,
isolation– Adjacency, contrast
Edge Area• Size effects edge• Large areas have relatively shorter edge
lengths than small areas
6ha
3ha
3ha
2ha 2ha2haEdge = 980m Total Edge =
1697m
Total Edge = 1386m
The shape of a patch influences amount of edge
All edge
Core & edge
Turner et al. 1997: How fire size influences vegetation response in Yellowstone NP
Small burned patches
recovered faster than
large burned patches
Size of burned patches
Landscape Metrics• Composition: Kinds of patches,
matrix, connections, barriers• Size & Shape
– Perimeter/area ratio, Edge length– Shape or boundary complexity
• Arrangement:– Connectedness, dispersion,
isolation– Adjacency, contrast
Patches
Barrier Matrix
Central Smokies: low connectivity
Western Smokies: high connectivity?
BIOTABIOTA
TOPOGRAPHYTOPOGRAPHYSUBSTRATESUBSTRATE
AGENTS OF LANDSCAPE AGENTS OF LANDSCAPE PATTERNPATTERN
CLIMATECLIMATE
Landscape Flows
• What processes connect patches or different landscape positions?
Landscape Flows
• Animal Dispersal• Wind movement• Hydrologic flows• Nutrient cycling• Insect outbreaks• Fire
Dynamic landscape models describe flows between landscape positions over time, including how the environment (eg, soil moisture) influences biota (eg plant growth) and vice-versa.
Process creates pattern+ Fire often
increases heterogeneity*
* (But not always!)
Post-fire mosaic, 1994 Rattlesnake Fire, Chiricahua Mts., AZ
Process creates pattern
+ Fire often increases heterogeneity*
- Succession sometimes decreases heterogeneity** (But not always!)
Blue Mts, California, at two periods
Pattern also affects process
+/- Fire spread regulated by fuel mass, moisture, distribution (“flammability”)
+/- Wind, humidity influenced by vegetation type and structure