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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.
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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
Landscapes are heterogeneous! “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)
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 often used 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 Landscapes can be of any resolution (grain) or extent. 5 m
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-long Treats 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 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
A landscape model: how temperatures can be 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 temperature Run model for each pixel (about 4 million at 30 m grain)
Scales of variation Mean annual temp
Patches & patch dynamics Process of patch change • Disturbance • Recovery from disturbance (succession) • Feedback to disturbance rate! Patch: A relatively homogeneous area defined by some criterion Patch dynamics: Processes of change (a) within a patch, and (b) interactions among patches on the landscape
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 discretizing a landscape: Mt LeConte Great Smoky Mts National Park
Let’s take a look at a landscape: Mt LeConte Great Smoky Mts National Park S W
Let’s take a look at a landscape: Mt LeConte Great Smoky Mts National Park S W
P SW P P P P P
Patches Beetle kills
Matrix Patches
Matrix Barrier Patches
Matrix Patches Landscape ecology Barrier
Matrix Patches Landscape ecology Barrier Connectedness
Landscape Elements:PatchMatrixCorridor Chardon et al. 2003
Landscape Elements:PatchMatrixCorridor Chardon et al. 2003
Landscape Elements:PatchMatrixCorridor 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 3ha 3ha Total Edge = 1386m 6ha 2ha 2ha 2ha Edge = 980m Total Edge = 1697m
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