environmental gradients Flashcards
what are examples of environmental gradients?
• particle size
• salinity
• vertical: emersion/depth
• wave exposure
• latitude/temperature
• anthropogenic disturbance
what life is present on rocky shores?
epifauna and flora
what life is present on cobbles and shingles?
unstable and lifeless, no macrobiota
what life would be present in salt marshes, mangroves, seagrasses and sandy beaches?
infauna, epifauna and macrophytes
What adaptations would be present in plants in anoxic sediments?
Prop roots - enable gas exchange out of sediment using lenticels
Pneumatophores – roots that stick up out of surface and do gaseous exchange
MANGROVES IN MUDDY SHOREs
What are halophytes?
Plants adapted to growing in saline conditions, e.g. mangroves in muddy shores or terrestrial plants in salt marshes
What is true of mangroves in muddy shores?
Serves as coastal erosion protection
Sediment accretion
Infaunal communities present
What are infaunal communities?
Aquatic animals that live in the substrate of a body of water and which are especially common in soft sediments
What is true of sandy beaches?
(in terms of sediment)
- Physical substrate is shifting and unstable
- Substance disturbance by waves
What is true for fauna on sandy beaches?
- Burrow to avoid stresses and predation
- Fauna rely on imported food
- Low primary production
What is the intermediate disturbance hypothesis?
Predicts that the highest diversity will occur at levels of moderate disturbance.
What are Sousa’s (1979) notes on the intermediate disturbance hypothesis?
Size of boulders, mobility and their diversity – boulders with intermediate disturbance had highest number of species
What are Connell’s (1978) notes on the Intermediate disturbance hypothesis?
Low or high diversity is bell shaped from frequent and rare, large or small, etc.
What is true of rocky shores?
- Physical substrate is hard and stable
What is true of fauna on rocky shores?
- Organisms visible
- Living on top of substrate: epifauna, epifloral, not to be confused with epibiont
- Abundant and small – unusually large specimens on West Coast of USA
- Sessile or sedentary