Unit 7.3 - Tropical Forests* Flashcards
Comment on the use of satellite imagery to monitor the extent of tropical forests.
Landsat geostationary satellites will pass over any single point in the tropics once every 16 days. On each pass, it will record digital images of the landscape below, allowing any change in land use to be identified.
(+) wavelengths used can penetrate clouds
(+) digital images lend themselves to electronic data processing
Describe the extent and locations of the tropical forest biome and contrast the major tropical forest regions.
Tropical forests occur between the Tropics of Cancer and Capricorn (23 degrees N and S), and cover 6% of the Earth’s land area. They occur in three major regions:
- South America (neotropics): in some places, species of hebs and epiphytes may outnumber trees. Greatest number of species.
- Africa: fewest families, genera and species.
- Indo-Malaya: home to many conifer species.
List reasons why tropical forests form the most diverse biome on Earth.
Although covering only 6% of the land surface, tropical forests contain 50% of all species.
There are many theories as to why this is so, including:
- tropical forests have existed for a very long time, having escaped glaciation …
- refugia theory …
- current climatic conditions allow all-year-round availability of resources (bigger pie allows more slices) …
Distinguish between ‘species richness’ and ‘species diversity’ and describe the relationship between alpha, beta and gamma diversity and the geographical scales to which they relate.
- Species richness: the number of species.
- Species diversity: the number of species, and the number of individuals (abundance) of each species.
- Alpha diversity refers to the species richness of a single location.
- Beta diversity refers to the variation of habitats within a region.
- Gamma diversity refers to the species richness of a region.
- gamma diversity = alpha diversity x beta diversity
Explain how the large number of species within a tropical forest are able to coexist.
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Describe the effect of fragmenting a stand of tropical forest.
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Contrast the food webs of tropical forests with those of other biomes.
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Explain why animals use mimicry, and describe two different types of mimicry observed within tropical forests.
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Batesian mimicry: palatable species mimic unpalatable species.
Mullerian mimicry: several species of unpalatable species share markings, thereby reinforcing the warning message.
Compare the cycling and storage of nutrients within tropical forests with those of other biomes.
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Explain how forest fragmentation affects habitat conditions within the remaining fragments.
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Describe how a tropical forest can be sustainably managed for timber production.
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Explain why the conservation of genetic diversity within the tropical forest biome is important.
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