Species Interactions - Niwot...
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Species Interactions Species Interactions Important in determining – • population dynamics • community composition • landscape spatial pattern • ecosystem function T. Kittel, W. Bowman Univ of Colorado
Transcript of Species Interactions - Niwot...
Species InteractionsSpecies Interactions
Important in determining –
•
population
dynamics•
community
composition•
landscape
spatial pattern •
ecosystem
function
T. Kittel, W. BowmanUniv of Colorado
Presenter
Presentation Notes
Species Interactions Important in determining species life history Each interaction requires allocation of resources to facilitate/defend against population dynamics community composition landscape spatial pattern Clumped if beneficial interaction (drawn together) Uniform if antagonistic - to be revisited at the end ecosystem function So roles at every level of plant ecology (ecophysiological, in addition to those above) Can you explain (or give examples of) how interactions play a role at each level?
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
Presenter
Presentation Notes
I. General Categories Assigned by the effect it has on the two individual organisms interacting: +, + = mutualismN2 fixation, mycorrhizae +, 0 = commensalismNurse plants - , 0/+ = amensalismAllelopathy -, + = parasitism, herbivory, predation -, - = competitionIntra & interspecific Interactions can be more complicated than direct interactions between 2 individuals can be mediated (mitigated, aggravated) through a third individual or species soil microbes, herbivores can 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
Presenter
Presentation Notes
A. Mutualism (+, +) Plant-Microbe Mycorrhizae – plant+fungi N-fixation – plant+bacteria (incl cyanobact) Lichen - algae or cyanobacteria(bluegreen algae)+fungi Plant-Animal Pollination Insects Birds - Hummingbirds – highly specialized Ecuador, a center of h’bird diversity Bats - Mucuna holtonii (fabaceae) <http://www2.mcdaniel.edu/Biology/botf99/flowernew/flowerstructure.htm > =Tropical vine, night pollinated. Lower concave petal = acoustic mirror – for guiding bats Fruit dispersal Defense Ants [+woody plants = “myrmecophytes”- Barbour et al p 140] – Cecropia: nest sites (internodes with access points), food bodies Ants: defense against other insects, vines <http://www.evergreen.edu/ants/ANTPLANTS/CECROPIA/Cecropia.html> Photos: rhinoceros hornbill eating Strangler Figs <http://www.vulkaner.no/t/indo/intro.html> (Borneo's Stranger Fig Trees', National Geographic Magazine April.1997, Foto© Tim Laman) Cecropia: http://www.alexanderwild.com/Ants/Taxonomic-List-of-Ant-Genera/Azteca/9321705_K2VsV/1/641418403_VoUZK/Medium
“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
Presenter
Presentation Notes
“The Forgotten Pollinators” Rufous Hummingbird White-winged Dove Lesser Long-nosed Bat Monarch Butterfly Long-distance migratory pollinators Threatened – habitat loss Keystone species – at the landscape level! Native Plants, characteristic of these landscapes, are having increasingly to compete with invasive spp for pollinators. So both native plant communities and pollinators are threatened. “Nectar corridors” Sequence of flowering plants along migration routes. These are then migratory “stepping stones” which are ‘breaking up’, if you will, by habitat loss. Notes: The forgotten pollinators http://www.desertmuseum.org/pollination/introduction.html http://www.sare.org/sanet-mg/archives/html-home/11-html/0289.html
moss v. lichenAtlantic Forest, Brazil
B.
Commensalism
(+,0)
Plant-Plant
1) Vines
2) Epiphytes
•
Bromeliads•
Orchids•
Cacti
•
Ferns•
Lichen•
Moss•
Algae
Staghorn fern
Presenter
Presentation Notes
A. Commensalism (+,0): Epiphytes – plant-plant commensalism Common taxa Bromeliads – Tillandsia - Spanish moss Orchids Cacti Ferns Lichen – note that moss and lichen compete for space here moss wins if forest conditions generally moist, lichen if dry Moss Algae Derive no nutrients (mineral or organic) directly from host plant, only take aerial habitat Must gather water and nutrients from precipitation (bromeliad ‘tanks’) – key habitat for many insects (mosquitos) and rare tree frogs Some get water from air humidity (lichen, & to some extent bromeliad Spanish moss – absorptive tissue) Vertical stratification of epiphytes (Fig 7.2, Barbour et al.) Photos: Red lichen: Elian (SEE-U Br, 04-I)
Exceptions –
Commensalism
goes
to Mutualism –
Lichen with cyanobacteria: N leaching, benefit to tree
goes bad –
Competition
•
Strangulation •
Overtopping
Detrimental overburden
Strangler fig
Presenter
Presentation Notes
Exceptions Mutualism – Lichen with cyanobacteria N leaching, benefit to tree Detrimental overburden Commensalism gone wrong … later if community of epiphytes weighty enough, breaks branch (or more) Competition Strangler fig – epiphyte sends down aerial roots that grow to form an open ~closed casing of the trunk, restricting further growth of the host tree. At the same time overtopping the canopy, shading out the host. Eventually the host dies, but the root casing is strong enough to support the now fig tree. Overtopping next slide – light and other resources Photo Strangler fig – Plant Ecology text, fig 10.7a
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 USCelastrus orbiculata
Presenter
Presentation Notes
Some epiphytes may switch to competitors later as they grow e.g. Kudzu, “vine that ate the south” Notes: http://www.cptr.ua.edu/kudzu/ http://www.cptr.ua.edu/kudzu/ : “During the Great Depression of the 1930s, the Soil Conservation Service promoted kudzu for erosion control. Hundreds of young men were given work planting kudzu through the Civilian Conservation Corps. Farmers were paid as much as eight dollars an acre as incentive to plant fields of the vines in the 1940s. ” http://www.nps.gov/plants/alien/fact/pumo1.htm : ECOLOGICAL THREAT: Kudzu kills or degrades other plants by smothering them under a solid blanket of leaves, by girdling woody stems and tree trunks, and by breaking branches or uprooting entire trees and shrubs through the sheer force of its weight. Once established, Kudzu plants grow rapidly, extending as much as 60 feet per season at a rate of about one foot per day. This vigorous vine may extend 32-100 feet in length, with stems 1/2 - 4 inches in diameter. Kudzu roots are fleshy, with massive tap roots 7 inches or more in diameter, 6 feet or more in length, and weighing as much as 400 pounds. As many as thirty vines may grow from a single root crown.
2) Nurse plants
•
Saguaros under Palo Verde
•
Desert annuals under shrubs
A. Commensalism –
continued
•
Piñon pine under Sagebrush
Presenter
Presentation Notes
2) Nurse plants Saguaros under Palo Verde Desert annuals under shrubs Piñon pine under Sagebrush Can lead to crowding out ‘host’: leads to competition for moisture dead Palo Verde’s under Saguaro’s
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
Presenter
Presentation Notes
Plant-animal commensalism “endless” examples of non-detrimental animal use of plants Habitat – nesting, roosting, hunting, shelter, Photos: Oropendola nests - Bruce (Duke Univ) Tree house <http://www.vulkaner.no/t/indo/intro.html> (c) George Steinmetz Booby – Gwen Kittel
C. Amensalism (–
, 0/+)
Allelochemical Interactions
•
Plant–Plant
•
Allelopathy
Larrea tridentata - Creosote
•
Plant–Animal
•
Herbivory defensesBig 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
Presenter
Presentation Notes
C. Amensalism (– , 0 or +) Allelochemical Interactions – most commonly cited examples of amensalism inhibition via release of metabolic by-products Difficult to show Plant-Plant Allelopathy, secretions of plant inhibitors Larrea tridentata Sunflowers Big Sage sagebrush? Expected because of high aromatics we associate with sagebrush Shown in lab results, not demonstrated in field! Salt Cedar (Tamarisk) – salt accumulation in leaves, which when dropped increase soil salinity around tree. Plant-Animal Herbivory defenses Plant-Decomposer Litter composition soil pH Acidic soils under conifers shift to soil fungi Neutral soils under temperate deciduous forest favoring soil bacteria Plant leakage of organic and inorganic compounds vs. mutualistic effects of plant chemicals Photos & notes - Sunflowers <http://www.its-about-time.com/htmls/ab/abch1_47.html> “Allelopathy benefited the sunflower growing in the wild. It reduced competition for nutrients, �water, and sunlight. However, allelopathy works against sunflower crops. Sunflower crops �must be rotated to avoid buildup of the "poison" in the soil.” Sagebrush? Apparently not shown in field <http://fwp.state.mt.us/insidefwp/fwplibrary/sagebrushbulletin.asp> Allelopathy Definition: The suppression of growth of one plant species by another due to the release of toxic substances (Webster 1983). Big sagebrush foliage contains chemical properties capable of producing allelopathic affects (Schlatterer et al. 1969; McCahon et al. 1973; Kelsey et al. 1978). The allelopathic affects observed under laboratory conditions include the retardation of plant growth and prevention of seedling germination. Native grass species growing under the canopy of big sagebrush. (Photo by FWP) While allelopathic properties of big sagebrush have been reported in laboratory situations, the effect of this phenomena under natural field conditions has not been demonstrated. Observations made by Hoffman et al. (1977) illustrate the problem of applying laboratory results to natural field situations. They reported: "not all examples of germination inhibition under laboratory conditions can be supported by correspondingly favorable observation in the field." They found the aqueous extracts of big sagebrush litter inhibited germination of such species as western wheatgrass (Agropyron smithii), pellitory (Parietaria pennsylvanica), spurge (Euphorbia podperae), rough pennyroyal (Hedeoma hispida), and yarrow (Achillea millefolium). Yet, they noted those same species are often abundant directly under or very near big sagebrush shrubs. In fact, well-developed grass and forb understories are commonly associated with big sagebrush stands on ranges that have proper grazing management practices. Kelsey and Everett (1992) have conducted extensive research on the phenomena of allelopathy. They report that the importance of allelopathy in the ecology of sagebrush shrublands has not been demonstrated to date. They concluded that allelopathy "is probably not the single most important cause of changes in plant patterns, succession, productivity, or plant response to management."
D. Parasitism
(–,+)
Dodder (Cuscuta) –
•
stem parasite•
no chlorophyll = holoparasite
Presenter
Presentation Notes
D. Parasitism (–,+) Dodder (Cuscuta) Stem parasite has no chlorophyll =holoparasite
Coral root orchid - Corallarhiza maculataroot parasite on pines
Presenter
Presentation Notes
Coral root orchid - Corallarhiza maculata root parasite on pines: holoparasite
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
Presenter
Presentation Notes
Mistletoe – stem parasite different spp. with differing degrees of chlorophyll with chlorophyll = hemiparasite – ‘green mistletoe’ (Phoradendron sp) hi psn, nearly independent, little-zero photosynthate from host does draw water w/o = holoparasite – ~Dwarf mistletoe (Arceuthobium spp, as here) minimal photosynthesis of its own. [ref: Barbour et al. p. 136] Dwarf mistletoe Photos D. L. Nickrent.
Broadleaf (Hairy) mistletoe -
hemiparasite
Phoradendron tomentosumon hackberry (Celtis laevigata), preferred host
Presenter
Presentation Notes
Broadleaf (Hairy) mistletoe – hemiparasite Phoradendron tomentosum on hackberry (Celtis laevigata), preferred host Photos <http://www.sbs.utexas.edu/mbierner/bio406d/images/pics/vis/phoradendron_tomentosum.htm >
More hemiparasites:
•
Indian paintbrush –
Castilleja spp.•
Root parasite
Presenter
Presentation Notes
More hemiparasites: Indian paintbrush – Castilleja spp. Root parasite – e.g. on shrubs, including reported with N-fixing Lupinus (yellow arrow) <http://www.findarticles.com/p/articles/mi_m2120/is_n4_v79/ai_20793926> Notes: <http://www.calacademy.org/research/botany/wildflow/names/05186f.htm> Applegate's Indian Paintbrush Castilleja applegatei (Scrophulariaceae) Applegate's Indian Paintbrush is a green root-parasite that taps into the water and nutrient supply of neighboring shrubs. It is actually called a hemiparasite because it can grow independently. Many hemiparasites take up a contact relationship with their hosts immediately after seed germination. Although they are green and capable of fixing appreciable amounts of carbon via photosynthesis, they grow poorly under these circumstances. Studies have shown that as soon as a hemiparasite makes contact with a host, growth rate improves greatly and the plant becomes much more vigorous. DISTRIBUTION: Meadows and dry open forest or scrub throughout Calif.; 300-3600 m.
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 association they should occur closer together (clumped)
than predicted by chance (random)
Presenter
Presentation Notes
II. Inference of species interactions in the field: spatial patterning If species interactions are important to plant species it should be reflected in the spatial patterns of individuals (inter and intraspecific) if mutualisms among plant species occur, should be a positive association they 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
Presenter
Presentation Notes
II. if amensalism occurs, should be pushed away from each other giving an even distribution
Landscape spatial patterning (con’t)
•
Under competition –
competitive exclusion leads to •
range separation •
niche partitioning
Non-overlapping geographic ranges of fivespecies of large kangaroo rats
Presenter
Presentation Notes
Fig from Biogeography, 2nd ed.
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
Presenter
Presentation Notes
Amazonian tree – exhibiting the diversity of plants that grow as epiphytes. Low on the trunk are Arums and Philodendrons - with heart-shaped leaves. On the middle and upper branches cluster groups of orchids, bromeliads and ferns. The long roots (right) dangling from the crown probably belong to philodendrons. -- Photo: T.Kittel
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
Presenter
Presentation Notes
Plants are engaged in interactions with a wide range of other taxa Plant-plant, plant-microbe, plant-animal integral part of the species’ Life History strategies – Require allocation of resources, That have positive, detrimental, or neutral effects on themselves and the other organism that define the relationship, course, and allocation requirements Ranging from mutualism (+,+), commensalism (+,0) to amensalism (–,0/+) And several manifestations of (–,–): parasitism, competition, herbivory The nature of these doesn’t necessarily stay the same with time: Can switch with time ‘commensalism gone bad’: e.g., competition And are often altered by the presence of a 3rd species for better or worse e.g., competition for pollinators Are reflected in spatial patterns on a landscape ‘pulling in’ each other in clumped, or ‘pushing away’ uniform difficult to demonstrate in field
