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Seed dispersal

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**1. Seed Dispersal Mechanisms:**

– Wind dispersal
– Abundant seed production enhances likelihood of landing in suitable sites
– Some plants adjust morphology for controlled diaspore detachment
– Cody and Overton (1996) observed reduced dispersal in island Asteraceae
– Wind crucial for riverbank and wetland colonization
– Weedy species use unique mechanisms like tumbleweeds and Physalis fruits

– Water dispersal
– Aquatic and terrestrial species employ hydrochory for dispersal
– Seeds can travel long distances, especially waterproof fruits
Mangrove trees create islands through water dispersal
– Effective for plant migration and species spread

– Animal dispersal
– Epizoochory and endozoochory (zoochory) mechanisms
– Birds and mammals key dispersers aiding in migration and genetic diversity
– Rapid spread of invasive species possible
Myrmecochory involving ants benefits both ants and plants
– Melittochory with bees documented in a few plant species

– Gravity dispersal
– Barochory uses gravity for seed dispersal
– Heavier fruits fall aiding dispersal
– Examples include apples, coconuts, and passionfruit
– Leads to further dispersal by water or animals

– Explosion dispersal
– Ballochory involves explosive ejection of seeds
– Force from turgor pressure or hygroscopic tensions
– Examples include Arceuthobium spp., Geranium spp., and Hura crepitans
– Witch hazel uses ballistic dispersal without explosive mechanisms

**2. Importance of Seed Dispersal:**

– Biodiversity maintenance
– Ecosystem resilience
Plant population dynamics
– Habitat restoration
– Genetic diversity preservation

**3. Human Impact on Seed Dispersal:**

– Unintentional seed transport by humans
– Higher mobility compared to animals
– Spread of invasive species through human dispersers
– Cars as unintentional seed transporters
– Risks associated with deliberate methods like seed bombing

**4. Ecological Significance of Seed Dispersal:**

– Essential for migrations and biodiversity maintenance
– Contribution to Janzen-Connell hypothesis and recruitment limitation
– Influences diversification rates in plant groups
Fruit morphs allow seeds to adapt to environments
– Variability in dispersal distances affecting seed characteristics

**5. Research and Conservation Efforts on Seed Dispersal:**

– Long-distance dispersal studies
– Genetic consequences of forest regeneration
– Secondary seed dispersal effects
– Primate role in seed dispersal
– Implications of animal-mediated dispersal

Seed dispersal (Wikipedia)

In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living (biotic) vectors such as birds. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the dispersal mechanism and this has important implications for the demographic and genetic structure of plant populations, as well as migration patterns and species interactions. There are five main modes of seed dispersal: gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus. These modes are typically inferred based on adaptations, such as wings or fleshy fruit. However, this simplified view may ignore complexity in dispersal. Plants can disperse via modes without possessing the typical associated adaptations and plant traits may be multifunctional.

Epilobium hirsutum seed head dispersing seeds
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