Community Ecology Chapter 7. The flying fox Keystone species in tropical rainforest Pollinates...
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Transcript of Community Ecology Chapter 7. The flying fox Keystone species in tropical rainforest Pollinates...
Community Ecology
Chapter 7
The flying fox
Keystone species in tropical rainforest Pollinates plants while drinking nectar Spreads seed of fruit eaten Mutualistic relationship with durian fruit Help regenerate open areas through
seed dispersal (80-90% new seed) Decline in numbers from deforestation
and hunting
Dispersal of diversity
Groups are arranged either in clumps (most common), uniformly, or randomly
Edge effects are ecotones where different species may live. Usually different microclimate than adjoining areas
Largest Biodiversity
Tropical rainforest Coral reefs Deep sea Tropical lakes Also considered species rich
Tropical dry habitats Temperate shrublands (chaparral)
Biodiversity continued
Most diversity near equator Higher availability of resources Less evolutionary time High diversity leads to higher diversity More pressure from disease and parasites Speciation higher than background
extinction
Diversity in marine systems
Higher diversity near 2000 meters and on bottom More stable away from surface Lack of nutrients below 2000m Abundant nutrient on bottom and variation
of habitats
Pollution lowers diversity (never would have guessed that)
Diversity on Islands
The bigger the more diverse
The farther from mainland the less diverse
Nonnative species
Also called alien, exotic and introduced Generally have no natural predators so
population goes unchecked, seriously damaging the ecosystem
Often introduced by accident Cargo from foreign areas Pets and house plants that “escape” “Natural” migration due to climate changes
Prime players
Indicator species – serves as an early warning that an ecosystem is declining Birds – low birth rates, thin shells, birth defects
Keystone species – a species that contributes greatly to an ecosystem even though they may not dominate in numbers Seed dispersal/pollination (birds) Habitat modification (beaver) Efficient recycling of matter
Species interaction
Intraspecific competition – competing with your own species
Interspecific competition – competing with another species
Compete over food, shelter, space, breeding, etc.
Dibs, I saw it first!
Interference competition – when two or more species try to limit access to a resource (some humming birds defend particular trees)
Exploitation competition – when one group uses a resource faster than another (can lead to competitive exclusion principle (one dies out))
How to avoid competition
Resource partitioning – using a limited resource at different times, in different places or different ways
Think about how similar all birds are, but through evolution have developed different feeding patterns (beaks)
Fig. 8.9, p. 182
Black skimmerseizes small fishat water surface
Flamingofeeds on minuteorganismsin mud
Scaup and otherdiving ducks feed onmollusks, crustaceans,and aquatic vegetation
Louisiana heron wades intowater to seize small fish
Brown pelican dives for fish,which it locates from the air
Avocet sweeps bill throughmud and surface water in search of small crustaceans,insects, and seeds
Oystercatcher feeds onclams, mussels, and other shellfish into which it pries its narrow beak
Dowitcher probes deeplyinto mud in search ofsnails, marine worms,and small crustaceans
Herring gull is atireless scarialavenger
Ruddy turnstone searchesunder shells and pebblesfor small invertebrates
Knot (a sandpiper)picks up worms andsmall crustaceans leftby receding tide
Piping plover feedson insects and tinycrustaceans on sandy beaches
Predator-Prey relationship
Needed to keep gene pool strong Slow, sick, less agile, etc. “weak” are
more easily caught, and are therefore removed from the gene pool. This strengthens the remaining population
Symbiotic interactions
3 types of symbiosis – parasitism, mutualism, and commensalism
Parasitism – one species (parasite) feeds on another organism (host) by living in or on the host.
Parasites help promote biodiversity by controlling population size (eliminates the weak)
Mutualism
Two organisms (different species) interact and both benefit from the relationship
Examples Clownfish/Anemones Tickbird/Rhinoceros Protozoan/Termites
Fig. 8.13, p. 187
Commensalism
Two species interact, one benefits and the other is unaffected.
Some trees have mosses or epiphytes growing on them
Fig. 8.14, p. 187
Succession
Primary succession – takes place on new rock or lifeless ground
Mosses/lichen begin to turn rock to soil Small fast growing plants take root (weeds) Larger plants grow in the nutrient enhanced
soil Trees immigrate in from birds Mature ecosystem (forest) climax community
Secondary succession
Same as primary except in an area that once had life, but was ruined during a catastrophe (fire, flood, farming, etc.)
Fig. 8.17, p. 190
Early SuccessionalSpecies
RabbitQuailRingneck pheasantDoveBobolinkPocket gopher
MidsuccessionalSpecies
ElkMooseDeerRuffled grouseSnowshoe hareBluebird
Late SuccessionalSpecies
TurkeyMartinHammond’sFlycatcherGray squirrel
WildernessSpecies
Grizzly bearWolfCaribouBighorn sheepCalifornia condorGreat horned owl
Ecological succession
Sustainability
What maintains an ecosystem Inertia or persistence – ability of a
system to resist disturbances Constancy – keep population level
stable Resilience – ability to bounce back from
a disturbance
Thank you, have a nice day
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