Seed dispersal
- Dispersal (種子散布)
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The passive or active movement, usually one way and on any time scale, of organisms from their point of origin to another location where they may subsequently produce offsprings (e.g., insect larvae, fungal spores, or plant seed by wind; insect adults by flight; animals by walking or swimming).
Primary dispersal vs secondary dispersal
Primary seed dispersal
That means seeds dispersed by any dispersers, such as wind, animal, and gravity.
Secondary seed dispersal
The secondary dispersal occurs when seeds are moved elsewhre after the primary seed dispersal is completed.
- Evolution
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- Escape hypothesis (Janzen-Connell hypothesis): Seed dispersal reduces competition between the parent plant and the seeds and between the seedlings.
- Colonization hypothesis: Seed dispersal provides chances to immigrate new habitats.
- Suceession
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In the early stages of succession, e.g., soon after volcanic eruptions, species with long-distance seed dispersal, such as wind-dispersal, immigrate faster.
- Seed-dispersal types
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Table. Summary of seed dispersal types Dispersal vector Term Example Wind (*) anemochore Hypochaeris radicata, Polygonum sachalinense,
Picea marianaWater (+) hydrochore Phyllospadix iwatensis Animal zoochore endo-zoochore (active)
Prunus sargentii, Rhus trichocarpa ecto-zoochore (passive)
Arctium lappa, Juncus tenuis Self autochore Corydalis speciosa, Geranium spp., Impatiens balfourii, Oxalis corniculata (Gravity) balochore (Cf. cache) Quercus dentata *: species producing fine, such as Drosera spp. seeds are considered to be wind dispersal.
+: Most wetland species somehow utilize water for their seed dispersal. - Animal dispersal (動物散布)
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Classification based on the transporation means
ectozoochre
epizoochores (exozoochores): on surface such as skin
synzoochores: by mouths or toes
endozoochores: through body inside
Classification based on the vectors
mammaliochory: mammal
ornithochory: bird
chiropterochory: bat
mymecochory: ant
saurochory: reptile
ichthyochory: fish - Cache (隠匿散布)
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Seed cache is a kind of animal dispersals.
Although animals represented by rodents and birds that cache acorns under the ground surface, they often abandon to eat. When the seeds are left there, they can germinate and this means seed dispersed by animals.
- References
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- Jungle Crow (Corvus macrorhynchos) ハシブトガラス
- mast seeding 豊凶
- seedbank 埋土種子
- seed germination 種子発芽
- seed trap 種子トラップ