30. Landscapes Flashcards
landscape
A heterogeneous (diverse, mixed, varied) area consisting of distinct patches (landscape elements - organized in a mosaic-like pattern)
landscape ecology
the study of the relationship between spatial pattern and ecological processes over a range of scales
processes that create landscapes
- geological processes
- climate
- organisms
- fire
landscape structure
Describes the size, shape, composition, number and position of patches (landscape elements) in a landscape - influences processes such
as the flow of energy, materials, and species
distributions across a landscape
edge effects
impacts to the adjacent ecosystem caused by changes in the physical environment along its edge, reduced habitat area, and by isolation
habitat fragmentation and corridors
Landscape structure, especially the size, number, and distance between patches, can influence the movement of organisms between potentially suitable habitats.
examples of landscape elements
mountains, meadows, streams, parks, residential, industrial
why is landscape ecology different
- Involves researchers from multiple disciplines.
- Included humans and human influence from beginning.
- Uses multiple scales
geological processes that create landscapes
– Volcanism
– Sedimentation
– Erosion –> streams create v-shaped valleys
climate creating landscapes
- Ice Ages –> glaciers create u-shaped valleys, glacial retreat leads to primary succession
–Global Warming
organisms that create landscapes
–Humans
– Beavers
fire creating landscapes
– Lightning-caused
– Fire suppression
glacial ages
periods of variable cool and warm global temperatures that can last for millions of years
glaciations
cold periods lasting about 60,000- 90,000 years within a glacial age
interglacial period
relatively short warm periods (10,000-40,000 years) that occur between glaciations in a glacial age
glacier
a body of dense ice that can move under its own weight
talus
large rock piles pushed aside and left behind by glaciers
glacial till
mixed (boulders, clay, rocks) material left by glaciers
moraine
piles of till either pushed aside or left behind by glaciers
drumlin
hills created when glaciers pass over moraines
eskers
narrow ridges of debris left behind by glacial streams
kettle
lake created by a piece of detached glacier melting into a depression
glacial refugia
areas that occur within the extent of the glacial landscape that remained uncovered by glaciers
nunatak
a type of glacial refugia, in which a mountain peak was surrounded but not covered by continental glaciers
example of humans creating landscapes - Veluwe Region, Netherlands
- Pre-human: Forest
- 800-1100 CE: Heathlands and agriculture
- 1100-1800 CE: Sand
- 1800-now: Forest plantations to reduce sand drifts
example of beavers creating landscapes - Kabetogama Peninsula, Minnesota USA
- Pre-colonization: 60-400 million beaver individuals
- Colonizing fur trappers: almost extinct
- 20th century onwards: beaver recovery
example of fire and fire suppression creating landscapes - Southern California and Baja California
• Frequent fires from lightning
• Dry summers, oil-rich vegetation
• Fire suppression in SoCal, but allowed to burn in
Baja = lower median fire area
patch
a relatively homogenous area that differs from it’s surroundings
matrix
element within the landscape that is the most spatially continuous
measuring landscape structure
of forest patches
avg. patch size
% cover of forest
Avg patch shape
patch quality: shape
S≅1 ➔Circular
S>1 ➔Less circular
scale is important because the closer you zoom in, the greater the detail that can be measured
edge effects: Amazon rainforest
- Environment along forest edges hotter and drier,
with higher intensity of solar radiation. - Tree mortality higher at edges and overstory decreases while understory vegetation increases.
• Decreased diversity of many animal groups.
habitat fragmentation
the division of previously intact habitat into several
isolated patches, typically due to human
development and resource extraction
corridors
some sort of strip of habitat connecting similar
habitat types patches across a landscape - can help
mitigate the effects of habitat fragmentation
- not all corridors work - good corridors must be
developed in areas that the targeted organisms naturally use
habitat corridors: fish ladder
a structure designed to allow fish the opportunity to migrate upstream over or through a barrier to fish movement
