Effect * of species 1 on species 2 - + + - Effect of species 2 on species 1 COMPETITION MUTUALISM...
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Transcript of Effect * of species 1 on species 2 - + + - Effect of species 2 on species 1 COMPETITION MUTUALISM...
Effect * of species 1 on species 2
-
+
+
-Effect ofspecies 2
on species 1
COMPETITION
MUTUALISM
PREDATION
PREDATION
* On per capita growth rate
• Trophic Mutualisms• Protective Mutualisms• Dispersive Mutualisms
I. By Function:
Two ways to Classify Mutualisms
Obligate: species are so dependent on their mutualistic relationship that cannot live in its absence.
e.g., symbionts lichens leaf-cutter ants & fungustermites and gut fauna
Facultative: species can live without their mutualistic partner e.g., oxpeckers cleaner-wrasse many diffuse mutualists
Diffuse Mutualisms: Mutualistic interactions that where the“partner” can be one of any species, e.g., pollinators, seed dispersers.
Two ways to Classify Mutualisms
II. By relationship of mutualists for one another:
Trophic Mutualisms – involve a mutual exchange of energy/nutrients – specialized to the point of obligates
Lichens
Mycorrhizal fungi
Nitrification processes carried out only by specialized bacteria
NH3 NO2- NO2
- NO3-
Nitrosomonas (soil)Nitrosoccus (marine)
Nitrobacter (soil)Nitrococcus (marine)
Denitrification processes carried out only by specialized bacteria,such as Pseudomonas denitificans
NO3- NO2
- NO
Nitrogen fixation offsets Denitification and is accomplished by free-livingbacteria, such as Azotobacter, symbiotic bacteria, such as Rhizobium occurring in rootsof legumes, and cyanobacteria.
Nitrogen-fixing bacteria in root nodules of soybeans
Protective Mutualisms – involve an exchange of protection from predators/parasites often for an exchange of resources
Alarm Calling• prey-2 predator
Tree hopper-ant mutualisms
#alarm signals before and after predatorcontact
Dispersive Mutualisms – involve an exchange of a reproductive service often for an exchange of resources
Magnificent Hummingbird
BANFF NATIONAL PARK: Friendly Relations Between Clark’s Nutcracker and Whitebark Pine
Seed Dispersal
Experimental tests of mutualisms
Janzen’s study of Psuedomyrmexand the bullshorn acacia.
Beltian bodies
A comparison of acacia with ants and those with ants removed
Growth (cm) by
bullshorn acacia
Survival (%) by
bullshorn acacia
• 2000 interactions/day w/queue
• Eat parasites (coop) & mucosal tissue/scales (defect)
• The latter leads to client “jolt” so an observable cue
Jolts are predictors:
• 12-18/min among biting cleaners• 2-3/min among coop cleaners
Do clients image score?
• If previous client ends w/conflict (jolt/chasing): 100% bystanders (queue) depart• w/o conflict 100% approach
Audience effects?
• 17 vs. 6 cleaners spp showed (-) relationship between jolts and bystander presence
And also observed in Sergeant major
Virola surinamensis 7Tetragastris panamensis 12Virola sebifera 6Caesearia corymbosa ** 22Gurarea glabra 19Didymopanax morototoni 37Miconia argentea 46
Plant species Avian frugivores
** Considered a Keystone species by Howe (1977) because it bears a fruit crop for 10 week period including December, the time of lowest fruit production in La Selva forest
Keystone Mutualists (Eco Eng, Foundation Spp)
Chestnut-mandibled Toucan
Eats huge quantities of seeds, but a poor disperser. Toucans however depend on Casearia seeds in December when all their preferred foods are gone.
Disappearance of key fruit would push the tityra, the toucan, and other species to local extinction. Without its main disperser, Casearia, Virola (primarily dispersed by the Chestnut-mandibled toucan), and other treesdependent on these birds for dispersal would slowly lose their competitive position and diversity would slowly erode away in the tropical rain forest in La Selva.
The only known dependable disperser for Casearia seeds. Like the toucan, itappears to have no alternative food to eat in December.
Alternative *forms* of mutualisms
(1) Physical Ecosystem Engineers (after Jones et al. 1997)
What does a tree do in the forest?
- living and dead tissues are eaten by animals (+,-) - competes with other plants for water and nutrients (-,-)
- branches, bark, roots, and leaf surfaces make shelter, resting locations, and living space- small pools for organisms are created where water gets channeled into crotches- soil cavities that from when roots grow provide places to live and cache food- leaves and branches cast shade, reduce the impact of rain and wind, moderate temperature extremes, and increase humidity in the under story and soil - root growth aerates the soil, alters its texture, and affects the infiltration of water
And more…..
Jones et al. called these modifications ecosystem engineering
And there are many, many, many examples.
Some almost trivial, such as plants creating shade??
Others are very obvious….
Sometimes it’s the non-living structure left behind that providesthe benefit, other times it may benew structures created as a resultof an animal’s activity.
And EE have bothpositive and negativeeffects on individualSpecies or the