Lecture 20: Ricklefs notes Ch. 25 and Ch. 27 pg. 574-576

Landscape ecology is looking at ecological factors more broadly.

Landscape: an area of many diverse habitat types
Landscape ecology: the study of the composition of landscapes and the spatial arrangement of habitats between them, and of how those patterns influence individuals, populations, communities, and ecosystems at different spatial scales

Legacy effects: long-lasting influences of historical processes (ex: eskers)
- Ancient human influences on soil can still be found today (ex: abandoned French farmland from Roman times)
Present Influences – fires (natural and those influenced by human uses of land), animals (beaver, alligator, humans are the most impressive – “ecosystem engineers”)

Remote sensing – collection of geographic information from a distance, or of landscape information based on photographs taken from airplanes or satellites
- Scientists are able to create digital maps of mountains, waterways,
GPS - satellite-informed location information, at least 4 satellites sending information can provide full information including latitude, longitude, and altitude
GIS- combines the remote sensing information and GPS location, brings together sets of geographic information, including maps of soils, elevations, land uses, water availability, plant and animal distributions

Example of the Swiss butterflies habitat being studied using the various GPS and other sensing technologies to make decisions about habitat protection.

Habitat fragmentation can affect species abundance and species richness
• Landscape can be fragmented by human activities or natural events
• Five effects:
o The total amount of the habitat decreases
o The number of habitat patches increases
o The amount of edge habitat increases
o The average patch size decreases
o Patch isolation increases
• Species can be affected
o Negative effects: too small to sustain populations, too isolated to receive colonists, may have issues with edge habitats
o Positive: spatial separation can promote species coexistence, greater to resilience to extinction by predation, edge species benefit
Habitat fragmentation and species abundance
• Edge specialists: species specialize to live the edge ecotone
• Example of ticks and Lyme disease increasing with fragmentation
Fragment Shape and species abundance
• Some species prefer areas with a higher proportion of edge
• Different fragmented shapes have a different amount of edge

Habitat Corridors: typically narrow strips of habitat that facilitate the movement of organisms between adjacent habitat fragments.
• Increase gene flow and genetic diversity within populations (counteract the negative effects of bottlenecking); allow for new colonists
• However, can also increase predator movement, competitors, and pathogens
• Stepping Stones: small intervening patches

Landscape Ecology and the Quality of the Matrix between Habitat Fragments:
A landscape can be thought of as a conglomeration of favorable habitat patches, favorable corridors, and inhospitable habitat matrix surrounding the patches.

Landscape context: the quality and spatial arrangement of the different habitats in the matrix
Edge context: the effect of the edge of a fragment on the different habitats of the matrix

Importance of Scale:
Different species have vastly different concepts of scale (think whale vs. butterfly)
Two elements: Grain – the degree of resolution of which one views the landscape
Extent – the size of the landscape of interest

Animals can vary their distance traveled by their daily activities. Some have seasonal, reproductive, or other sources of large variance.

Pages 574-576

Overexploitation – human activities can overly strip the land and inhibit its ability to reproduce. Eventually, we may run out of new places to go to and food shortages and its associated diseases. Our technology allows us to exploit at a much more intense rate then ever before.
-Clear-cutting tropical forests usually only provides a few years of harvest before the soil depletes its nutrients
-Tropical land often cleared to grow cash crops
Ways to reduce the problems:
-Limit exploitation of the resource population to the maximum sustainable yield
-Implement alternative sustainable uses of land
-increase agricultural intensity on land that will bear it
-improve the distribution of food from areas of production to areas of need

Species introduction – 50,000 non-native plants and animals introduced to the US
-Can displace or otherwise alter local biota
-Introduction or displacement of keystone species can have a big impact while some do not greatly impact the ecosystem

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