Plant Seed Dispersal Strategies: BIOC37H PDF

BIOC37H: Plants: Life on Edge 1-6. Reproduction Hydrochory Pollination (1-4) Seed dispersal (5-6) Myrmecochory Exozoochory Endozoochory Barochory (+) Anemochory...

BIOC37H: Plants: Life on Edge 1-6. Reproduction Hydrochory Pollination (1-4) Seed dispersal (5-6) Myrmecochory Exozoochory Endozoochory Barochory (+) Anemochory Special Ballistochory DIYS case: fire dispersal  Along big tropical rivers Hydrochory Along (tropical) sea shores Hard seed case Air pocket to float 3. Seed dispersal syndromes: b. water Coco de mer: the world’s largest seed! https://www.youtube.com/watch?v=sJgZz9k4FeU 7.12-9.15 3. Seed dispersal syndromes: b. water Hydrochory+: Splash seed dispersal https://youtu.be/b7K9UGFVxTk Perfect angles of Golden saxifrage open ovary walls to harvest maximum impact of rain drop Mitrewort 3. Seed dispersal syndromes: b. water Myrmecochory Forest spring flowers in ON rely heavily on myrmecochory 3. Seed dispersal syndromes: d. Ant dispersal Exozoochory Hooks & barbs of seeds near soil level (passing mammals) 3. Seed dispersal syndromes: e. External “hitchhiking” ‘Evil’ ☺ exozoochory https://www.youtube.com/watch?v=8ZLv3xAjH3Q&t=2s 3. Seed dispersal syndromes: e. External “hitchhiking” Endozoochory Advertisement of ripeness: color change, sugar Swallowed pebbles in bird stomachs (‘teeth’) Necessary scaring of seed Muscular stomach walls to grind food coat to germinate (in a nutritious pile of dung) 3. Seed dispersal syndromes: f. Internal “hitch-hiking” Barochory ‘plus’ Big, fat-rich seeds: great winter food! Seeds fall from the plant when ripe (heavy, large), typically landing close to parent plant Seeds are picked up for collection (and hence dispersal) by animals 3. Seed dispersal syndromes: g. Gravity dispersal Barochory: later dispersal through scatter hoarding Yellow-pine chipmunk Kuhn and Vander Wall. 2009. West. North Am. Nat. 69: 309-318 3. Seed dispersal syndromes: g. Gravity dispersal No seed dispersal adaptation In many small, especially r-selected weeds Mass-produce often tiny, cheap seeds “Hope for the best” → a few will make it to good sites Parents often annuals → ok for offspring to not disperse (inherit spot, no competition) 3. Seed dispersal syndromes: g. Gravity dispersal BIOC37H: Plant Form & Function 1-6. Reproduction Pollination (1-4) Seed dispersal overview Seed mass per dispersal syndrome, overview Nothing Unassisted Barochory Myrmecochory Myrmecochory Endozoochory Endozoochory Average Exozoochory Exozoochory Anemochory Anemochory Leishman et al. 2000. In: Fenner (ed.) Ecology and Regeneration in Plant Communities 3. Seed dispersal syndromes Seed dispersal syndromes, mid latitudinal trees Stand-in for S ON Barochory Herb layer? Mediterranean Mediterranean 5% 5% Modified from Howe and Smallwood.1982. Annu. Rev. Eco.l Syst. 13: 201-228 3. Seed dispersal syndromes Seed dispersal syndromes, herbs Ontario’s forests, Exo/endo herbaceous plants Ants: largest single animal disperser group 60% of herb seeds ant- dispersed Modified from Handel et al. 1981. Bull. Torr. Bot. Club 108: 430-437 3. Seed dispersal syndromes Seed dispersal 1. Reasons for (and against) seed dispersal 2. Variation in seed size 3. Seed dispersal syndromes 4. Seed dispersal distances 5. Long distance dispersal 6. Dispersal in time Dispersal without & with adaptations Without adaptations With adaptations 4. Dispersal distances Typical dispersal distances (wind, exo/endozoochory) Exo/endozoochorous trees trees In both cases, most seeds: deposited close-by With wind-dispersed seeds, average travel distance: generally much further than with animals Clark et al. 1999. Ecology 80: 1475-1494 4. Dispersal distances Hydrochory: Splash seed dispersal distance Plant-size dependent Mostly < 1m → enough distance given small stature of splash-seed dispersed plants Nakanishi. 2002. Ecological Research 17: 663-671 4. Dispersal distances Ballistochorous dispersal distance Plant-size dependent Mostly < 5m → enough distance given small stature of ballistochorous plants Narbona et al. 2005. Amer. J. Bot. 92: 510-516 4. Dispersal distances Myrmecochorous dispersal distance Blood- root seed Mostly < 10 m Gomez and Espadaler. 1998. J. Biogeogr. 25: 573-580 4. Dispersal distances Exozoochorous dispersal distances 1 Animal size dependent 2 1 3 What the heck? 2 Gotta get rid 3 4 of this! 4 5 5 6 6 7 14.9 vs 5 m 7 Kiviniemi and Telenius. 1998. Ecography 21: 108-116 4. Dispersal distances Endozoochous dispersal distances Complex, dependent on Gut passage time (animal size) Home range Migrating? Migrating ducks Pakeman. 2001. J. Biogeogr. 28: 795-800 Charalambidou et al. 2003. Funct. Ecol. 17: 747-753 4. Dispersal distances Typical dispersal distances