Fragmentation and Landscape

Landscape Ecology
Recently pioneered field of ecology- Last 30 years
Landscape- view from an airplane

Landscape Ecology- Branch of ecology that studies ecological patterns and processes at a large scale
Scale- Areas on an order of a few Km2, to state sized, to entire countries

Fragmentation- Process in which a continuous landscape is broken into smaller patches.
Patches- Areas of similar vegetation, sourrounded by different types of vegetation
Ex forest- patch Field- patch

Forest- patch

Fragmentation usually the result of disturbances
- natural causes of fragmentation
1) volcano 2) earthquakes 3) tidal wave 4) hurricanes 5) fires

Human caused fragmentation- agriculture, development of cities/suburbs, forestry

Patches Properties
1) size 2) shape 3) # of patches 4) arrangement

Landscape Ecology
Patternspatches
Processes fragementation results from disturbances

GPS
GIS- Geographic information system software- Arcmap
Satellite imagery.

Ecosystems- all the organisms in an area plus all the abiotic factors that those organisms interact with.

Abiotic Factors
Rainfall, temp, soils, rocks, fire

Productivity
1) Primary productivity- amount of CO2 that is transformed into organic carbon per unit are, per year.
- measure of photosynthetic activity
- measure of plant activity

Normally ecologists measure plant growth
- Measurements go from 5(deserts) to 10,000(tropical forests) kg of CO2 fixed per year per hectare

What factors affect primary productivity?
1) sunlight- insolation 2) rainfall/ precipitation 3) temperature
4) seasonality 5) soil/nutrients

2) Gross Primary Productivity- Measure of total carbon fixed (photosynthesis) by plants in an ecosystem

3) Net Primary Productivity- Total fixed carbon minus the energy lost to respiration
Measured by looking at changes in plant growth In an ecosystem

Plans use Photosynthesis make sugars
Respiration break the sugars down for ATP

Photosynthesis= respiration + grow
(sugars) (burn sugars) (Left over sugars)
Large variation in NPP

Abiotic Factors
1) NPP generally is higher in warmer climates
2) NPP is also generally higher in wetter sites, but there is a limit.

As rainfall increases NPP rises, but only to a point NPP

rainfall
3) Nutrients- can limit NPP. Generally, NPP is higher in richer soils

Explanation for the Asymptote:
1) In rainier sites, its is also cloudier
Reduces photosynthesis
2) Leaching of nutrients at really rainy sites may limit NPP as well

Measuring NPP
1) Grasslands- cut the vegetation at ground level
-dry it