Species Interactions Important in determining – population dynamics community composition...
-
Upload
gavin-hines -
Category
Documents
-
view
215 -
download
0
Transcript of Species Interactions Important in determining – population dynamics community composition...
Species InteractionsSpecies Interactions
Important in determining –•population dynamics•community composition•landscape spatial pattern •ecosystem function
T. Kittel, W. BowmanUniv of Colorado
General Categories
Assigned by effect on the two individual organisms interacting:
+, + = mutualism N2 fixation, mycorrhizae
+, 0 = commensalism Nurse plants
– , 0/+ = amensalism Allelopathy
–, + = parasitism herbivory / predation
–, – = competition Intra & interspecific
Think about these interactions in the context of species geography!
Can be more complicated than direct interactions of 2 individuals
mediated through a 3rd individual or species • soil microbes, herbivores influence competitive
interactions
A. Mutualism (+, +)
Plant-Microbe
•Mycorrhizae•N–fixation•Lichen
Rhinoceros Hornbill eating Strangler Fig fruits, Borneo
Mucuna holtonii, Central America
Plant-Animal
•Pollination
•Insects•Birds
• Hummingbirds•Bats
•Fruit dispersal
•Defense•Ants
Azteca Ants on Cecropai, Panama
“The Forgotten Pollinators”Rufous Hummingbird
Monarch Butterfly
White-winged Dove
Arizona-Sonoran Desert Museumwww.desertmuseum.org/pollination/
Lesser Long-nosed Bat
“Nectar corridors”•Sequence of flowering
plants
Long–distance migratory pollinators•Threatened – habitat loss•Keystone species
moss v. lichenAtlantic Forest, Brazil
B. Commensalism (+,0)
Plant-Plant
1) Vines
2) Epiphytes
•Bromeliads•Orchids•Cacti
•Ferns•Lichen•Moss•Algae
Staghorn fern
Exceptions – Commensalism goes
to Mutualism –
Lichen with cyanobacteria: N leaching, benefit to tree
goes bad –
Competition
• Strangulation • Overtopping
Detrimental overburden
Strangler fig
Pueraria montana var. lobata
Kudzu – “the vine that ate the south”
• Introduced 1876 from Asia• Planted for soil conservation 1930’s
Oriental Bittersweet
• Vine, introduced from e. Asia• Invasion in eastern US
Celastrus orbiculata
2) Nurse plants
• Saguaros under Palo Verde
• Desert annuals under shrubs
A. Commensalism – continued
• Piñon pine under Sagebrush
Plant-animal commensalism – Habitat
Oropendola nests, Roraima Brazil
Titi monkey, São Paulo Brazil
Red-footed Booby in MangroveGalápagos Is.
Iran Jaya's People of the Trees
• nesting• roosting• hunting for other animals• shelter from other animals
C. Amensalism (– , 0/+)
Allelochemical Interactions
•Plant–Plant•Allelopathy
Larrea tridentata - Creosote
• Plant–Animal • Herbivory defenses
Big sagebrush with native bunchgrasses growing under
canopy
Difficult to show in field
• Plant–Decomposer• Litter composition soil pH soil biota:
Conifer low pH fungi favored, Temperate Deciduous neutral
bacteria• Plant leakage of compounds detrimental to soil biota
D. Parasitism (–,+)
Dodder (Cuscuta) –
•stem parasite•no chlorophyll = holoparasite
Coral root orchid - Corallarhiza maculata root parasite on pines
Mistletoe –
•stem parasite•differing degrees of chlorophyll
•with chlorophyll = hemiparasite•w/o holoparasite
Arceuthobium americanumCarpellate plant on Pinus contorta
Arceuthobium cyanocarpumStaminate plant (left) and carpellate plant (right) on Pinus ponderosa
Dwarf mistletoe – holoparasite
Broadleaf (Hairy) mistletoe - hemiparasite
Phoradendron tomentosum on hackberry (Celtis laevigata), preferred host
More hemiparasites:
•Indian paintbrush – Castilleja spp.
•Root parasite
Inference of species interactions on the landscape
• If species interactions are important to plant species – Should be reflected in the spatial patterns of individuals (inter and intraspecific)• if mutualisms among plant species occur, should be a
positive associationthey should occur closer together (clumped) than predicted by chance (random)
Landscape spatial patterning (con’t)
• if amensalism occurs, should be pushed away from each other giving an even distribution
Larrea tridentata - Creosote
Landscape spatial patterning (con’t)
• Under competition – competitive exclusion leads to • range separation • niche partitioning
Non-overlapping geographic ranges of five species of large kangaroo rats
Within–canopy distribution
Amazonian tree –
The long roots dangling from the crown probably belong to Philodendrons
On the middle and upper branches cluster groups of orchids, bromeliads, and ferns – including staghorn fern
Low on the trunk are Arums & Philodendrons with heart-shaped leaves
Keystone species
• Presence of a species determines community structure disproportionately to population size
Summary – Species Interactions
Plants and animals engaged in interactions with wide range of other taxa
Positive, detrimental, or neutral effects of one species on another
Reflected in spatial patterns – random vs. even vs. uniform
Reflected in community structure – Keystone species