L2 Factors that influence species distributions: dispersal and habitat selection Flashcards
Species could survive outside of its current range but is absent because…
-It cannot get there (dispersal)
-It does not recognize it as suitable habitat (habitat selection)
Species could not complete its life cycle outside of its current range because of…
-Interactions with other organisms (Predation, disease competition, mutualism, symbiosis)
-Impacts of physical and chemical factors (eg. temperature, light, moisture)
How can dispersal can happen gradually
-Dispersal by diffusion: (sea otters)
-Gradual recolonization of suitable habitat after population crash due to hunting
What is a jump dispersal?
When individuals move across large distances, often crossing unsuitable habitat and establish a population in a new area
Can humans cause dispersal of species?
Yes and cause introduction of exotic species to new areas
-Some introduced species become established and interfere with human activities- pest species
What are some issues associated with Salvinia molesta?
-Extremely high growth rates
-Interferes with drainage and irrigation
-Taints drinking water supplies
-Blocks cooling water intake pipes
-Interferes with navigation
-Provides habitat for disease vectors
What are some successful criteria for biological controls?
-Are host specific
-Life cycle is synchronous with pest species
-High intrinsic rates of increase
-Able to survive when few prey are available
-Have great searching ability
What is essential for biological control programs to work?
Must be informed by sound understanding of the ecology of the biocontrol species and its potential impacts on the ecosystem
What is the definition of a habitat?
Any area where a particular species can live
What is habitat quality?
Some habitats promote better rates of growth/survival/reproduction than other
-
