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EVS 430 Fall 2008
Dr. Rotenberg
Review Sheet – Midterm
Hi Tropical Environment Folks,
Please use this review sheet as a check-list for
terms and ideas that we’ve covered so far. Be
sure to begin studying NOW! Remember, the
exam will have some multiple choice, but the
rest will be short-answer-essay questions that
you will need to answer from this material.
Good Luck and Happy Studying!!
J.R.
Where are the tropics – Forest map
http://www.unep-wcmc.org
Major Environmental
Problems in Tropics
Deforestation
Cattle Ranching
Overpopulation/Resettlement of People
Mining Activity
Mercury Pollution
Timber Harvesting
Economics
Poverty, war, social inequality >>
Environmental degradation
Tropical Deforestation - definition
Why Tropical Deforestation?
Main reason = Economics
Short-term profits over long-term gain
without a foundation of sound economic and
ecological policy.
Economics and High Population growth
result in a labor force increasing more
rapidly than the economy >> Promotes
deforestation
Deforestation in Amazonia (Brazil)
Extent of Deforestation
Causes:
Road building (BR-364 in Rondonia)
Cattle Ranching
Resettlement of People
Mining Activity and Mercury Pollution
Timber Harvesting
Deforestation in Central America
Extent of Deforestation
For What?
Pastureland, Cattle Ranching, Various
agriculture, Monoculture plantations of
pine, oil palms, rubber
(More statistics on pp. 16-17 Schroth)
Anthropogenic Change
Deforestation from Space – satellite photos
Effects of Deforestation
Road building, Cattle Ranching,
Resettlement of People, Mining Activity and
Mercury Pollution, Timber Harvesting
Forest Fragmentation, Loss of Biodiversity
Regional and Global Climate Change,
Introduced Species, Exploitation of Natural
Environments, Hunting, Loss of Env.
Services
Deforestation in Brazil and the above
(ie., road building, cattle ranching etc.)
Economic Effects of Tropical Deforestation
And money $$$
Ecological Effects of Habitat Fragmentation in
the Tropics
Biodiversity – Lower? Higher?
Genetic diversity and endemic species, coadaptation
Edge Effects
How far into fragment? 50m? 100? 500m?
(figure 2.2, p 40)
Tropical Forest Types
Lowland evergreen Forest, Semi-evergreen
Forest, Seasonal Dry Forest, Montane
Forests (Cloud Forest), Jungle – aka:
disturbed, successional, secondary forest,
Flooded Forest – Amazon Basin,
Thornwoods, Mangroves
Other Tropical Habitats:
Savannas, Coral Reefs & Atolls, Tropical
Oceans
Tropical Climate
Sunlight, Trade winds, Ocean Currents, El
Niño, Seasonality
Climatic variations – know why they occur
Greatest annual energy input
Least amount of annual variation
Tropics and Global climate influence
Seasons and Earth’s orbit and tilt
Population Trends, Poverty, and Economics in
the Tropics
Population numbers
Large cities
Urban problems
Poverty and Poverty rates
Causes of Poverty
Education
Tourism
Valuating the Global Environment
Neoclassical Economists
Ecological / Environmental Economists
Ecosystem Valuation
Harmful External Costs and
Full-Cost Pricing
Does Economic Growth Always Aid the
Environment?
Obstacles to Sustainable Economic Growth
Ecology Basics
Photosynthetic strategies
Populations
Intrinsic Rate of Increase (r)
Carrying Capacity (K)
Population Growth Models
Exponential & Logistic growth
Density-dependent/independent
population control
Competition
Competitive Exclusion
Predation
Succession
Theory of Island Biogeography
“Islands in a sea of Pasture”
Area Effects – size/area relationships
Small vs. Large fragments
Distance Effects
Isolation of fragments – organisms with
phobias
Metapopulations
Small isolated subpopulations – gene flow
Tropical Terms
Biodiversity – defined
Structural diversity
High Biodiversity
Measured in number of species/hectare
1 hectare = 2.471 acres
High Biodiversity - Examples
Why does the tropics have so many species?
Vegetative Complexity – layers
Forest Structure
Physiognomy = structure
Floristics = species
Bole = trunk
Tropical Tree Characteristics
Stature-Height, Buttresses and Prop Roots,
Trunks and Crowns
Crown Architecture
Sympodial, Monopodial
Leaf Growth
Monolayered, Mulilayered
Leaf Shape
Simple – Compound, Leaflets, Palmate
– Pinnate, Drip-tip, See Page 79 - figure
41
Flower Growth and Type
Flower once/year, Cauliflory,
Shape/type attracts pollinators- list
EVS 430 Fall 2008 Dr. Rotenberg
Fruit Growth and Type
Inflorescence, Size, Seed dispersal by
animals, Seed predation, Wind dispersal
Special Plant types
Epiphytes - Bromeliads, Orchids
Lianas (Vines), Strangler Figs, Palms
Physiognomy (Structure), Floristics,
Species, Vegetative complexity, Light Gap
How a Rainforest Functions – Productivity
Productivity - defined
Productivity is measured in Biomass
Biomass –defined
Gross primary productivity (GPP) - defined
Net primary productivity (NPP) = GPP- R
Tropical Productivity facts
Rainforests are at least 2x as productive as
northern coniferous forests.
Rainforests produce approximately 50 billion
tons of dry organic matter annually compared to about 15 bill tons for temperate
forest!
46% of the worlds’ living terrestrial carbon is
stored in rainforests. --- Biochemical
cycling!!
Productivity graph – compares most to least
productive habitat types – Where are
tropical habitats compared to others?
Why is rainforest productivity high?
Longer growing season
Nearly constant temperature
Frost-free
Life history traits and surviving the winter.
Productivity is high but poor soils
Most tropical soils are nutrient-poor.
Nutrients are stored in the biomass of plants
and animals of the forest.
Nutrients are efficiently conserved
Nutrient/Chemical cycling
Essential soil nutrients:
Phosphorus, Nitrogen, Calcium,
Magnesium, and Potassium
Phosphorus and Nitrogen necessary in
formation of nucleic acids (DNA/RNA).
Magnesium essential component of
chlorophyll molecule.
READ pp. 48-49 Pathway of calcium atom.
Water Cycling and effects
Transpiration- defined
Water stressed plants – dry season
Various adaptations to reduce water loss
Water effects
Leaching, soil acidity and accumulation of
H+ ions (more H+ means lower pH)
How do tropical plants cope with poor nutrient
soils?
Where’s the nutrients necessary for the
rainforest? -- living plant tissues (biomass)
Tropical Soil Types
EVS 430 Fall 2008
Ultisols, Oxisols, Alfisols
What happens to tropical soils when the
rainforest is cleared?
Laterization, Soil fertility, Oligotrophic and
Eutrophic soils
Nitrogen fixation
READ pp.55-56 on how legumes acquire
gaseous nitrogen with the help of the
bacteria Rhizobium
Forest Restoration - El Eden Ecological
Reserve, Mexico
Mycorrhizal fungi experiment
Primary vs. Secondary Forest
Secondary Forests –ex: Tikal Forest
READ about Successional plants pp.69-74
Movie: “Medicine Man”
NOTES
Dr. Rotenberg