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Species Interactions Important in determining – population dynamics community composition landscape spatial pattern ecosystem function T. Kittel, W. Bowman.

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Presentation on theme: "Species Interactions Important in determining – population dynamics community composition landscape spatial pattern ecosystem function T. Kittel, W. Bowman."— Presentation transcript:

1 Species Interactions Important in determining – population dynamics community composition landscape spatial pattern ecosystem function T. Kittel, W. Bowman Univ of Colorado

2 General Categories Assigned by effect on the two individual organisms interacting: +, + = mutualismN 2 fixation, mycorrhizae +, 0 = commensalismNurse plants –, 0/+ = amensalismAllelopathy –, + = parasitism herbivory / predation –, – = competitionIntra & interspecific Think about these interactions in the context of species geography! Can be more complicated than direct interactions of 2 individuals  mediated through a 3 rd individual or species soil microbes, herbivores influence competitive interactions

3 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

4 “The Forgotten Pollinators” Rufous Hummingbird Monarch Butterfly White-winged Dove Arizona-Sonoran Desert Museum Lesser Long-nosed Bat “Nectar corridors” Sequence of flowering plants Long–distance migratory pollinators Threatened – habitat loss Keystone species

5 moss v. lichen Atlantic Forest, Brazil B. Commensalism ( +,0) Plant-Plant 1) Vines 2) Epiphytes Bromeliads Orchids Cacti Ferns Lichen Moss Algae Staghorn fern

6 Exceptions – Commensalism goes  to Mutualism –  Lichen with cyanobacteria: N leaching, benefit to tree  goes bad –  Competition Strangulation Overtopping  Detrimental overburden Strangler fig

7 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

8 2) Nurse plants Saguaros under Palo Verde Desert annuals under shrubs A. Commensalism – continued Piñon pine under Sagebrush

9 Plant - animal commensalism – Habitat Oropendola nests, Roraima Brazil Titi monkey, São Paulo Brazil Red-footed Booby in Mangrove Galápagos Is. Iran Jaya's People of the Trees nesting roosting hunting for other animals shelter from other animals

10 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

11 D. Parasitism ( –,+ ) Dodder (Cuscuta) – stem parasite no chlorophyll = holoparasite

12 Coral root orchid - Corallarhiza maculata root parasite on pines

13 Mistletoe – stem parasite differing degrees of chlorophyll with chlorophyll = hemiparasite w/o  holoparasite Arceuthobium americanum Carpellate plant on Pinus contorta Arceuthobium cyanocarpum Staminate plant (left) and carpellate plant (right) on Pinus ponderosa Dwarf mistletoe – holoparasite

14 Broadleaf (Hairy) mistletoe - hemiparasite Phoradendron tomentosum on hackberry (Celtis laevigata), preferred host

15 More hemiparasites: Indian paintbrush – Castilleja spp. Root parasite

16 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)

17 Landscape spatial patterning (con’t) if amensalism occurs, should be pushed away from each other  giving an even distribution Larrea tridentata - Creosote

18 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

19 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

20 Keystone species Presence of a species determines community structure disproportionately to population size

21 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


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