study of landscape structure and processes
heterogeneous area composed of several ecosystems, or distinctive patches
Visually distinctive patches
e.g. forests, meadows, bogs, streams, parks, industrial districts, etc.
What is unique about landscape ecology?
highly interdisciplinary (often involves bio, eco, geo, hydro, social sciences, and humanities.)
-historically included humans and their influences.
-multiple spatial scales
size, shape, composition, number, and position of patches (landscape elements) in landscape
relatively homogeneous area that differs from surroundings
-patches in landscape form a mosaic=landscape
background mosaic that is most spatially continuous
Structure of landscapes in Ohio
Bowen & Burgess published quantitative analysis
-focus on structure of forest patches.
physical and biological transitional habitat between two ecosystems (or patches)
-can be a physical and biological mix of the two ecosystems
-often support species from both habitats and those unique to the ecotone.
describes distinct ecological conditions and higher species richness in ecotones compared to either ecosystems.
area of mathematics, used to quantify structure of natural shapes
-ex: perimeter estimates of a complex shape depend on the size of measuring device
Fractal describes phenomenon...
that seem to have a fractional rather than integer dimension
-the length of a coastline has fractal dimension between 1&2
-the length will seem longer the smaller the unit used to measure.
pop of many species occur in spatially isolated patches, with significant exchange of individuals.
transitional habitat between 2 ecosystems or patches
edge effects in patches
higher sp. diversity
hydrological flow system (hfs)
position of lakes in relation to each other + input/output of H2O
What kind of input to lakes at the upper end of hfs get?
lower levels get precipitation, surface water, + groundwater
during drought, which lakes in hfs drop more?
upper level lakes
where in hfs is [ion] higher in drought?
lower level lakes b/c [ion] high in groundwater but not ppt so ions aren't being diluted
which lakes in hfs have highest yr-yr variability in water level?
upper level lakes b/c fed by ppt.
how do ecosystems relate to landscapes?
can be contained within them
homogenous area that differs from surroundings
patches combined together
most dominate patch (background)
Ex: in konza prarie, matrix is grass
high patch shape index
elongated patches more edge habitat
Ex: 1.6 is high -> washington
what kinds of sp. live in ecotones?
-those unique to the ecotones (edge sp.)
-sp. from patches on both sides (interior sp.)
fractal geometry of landscapes
perimeter of complex shape depends on measuring device
Ex: large ruler misses nooks + crannies + makes length seem shorter
how to calculate the fractal dimension
what is the main thing that influences movement in metapopulations?
what do they do to pop.?
patches connected by corridors
-increase pop. density in patches
what is the primary source of landscape structure?
Ex: sedimentation volcanoes
bajadas (alluvial piedmont)
sloping plains @ base of mountains where erosion takes place as mountains uplift.
what kinds of soils are found on bajadas?
1.9 mya early pleistocene
10^(5) ya m-1 pleistoceine
11k ya halocene
young soil characteristics
-no B horizon
-low clay + CaCo3
old soil characteristics
where was highest plant diversity found on sonoran transects?
on unstable erosional slopes (early pleistocene)
what kind of alluvial deposits happen during wet periods?
red soil from iron oxides
change physical environ. to influence landscape structure
(Ex: humans, termites, afr. elephants, kang. rats, beavers)
what climate is prone to fires?
what does fire supression results in?
-fire less frequent but larger
-visually distinctive patch as seem from avoce (streams, parks, forests
Bowen + Burgess ohio forest landscapes
-forest cover area
-# forest patches
Index to describe patch shape: compares P to circle w/ same A
-spatially isolated patches that exchange ind.
-all belong to one big pop.
-rate of movement influenced evolution
diffendorfer habitat fragmentation study
-created diff. degrees of habitat framentation
-mean, squared dirt. quantifies home range
-ind. in small patches moved farther
soil layers in sonoran desert transect
-clay increases w/age
-CaCO3 increases w/age
material eroded from mountains + deposited on bajadas by floods
what does habitat fragmentation do to sp.?
can have - impact on sp persistence
Hanski butterfly metapopulation
-pop size increasing w/patch A
-pop. density decreases w/ patch A
-isolated patches had low densities