top-down control. (Modsat er når trophic levels er kontrolleret af produktiviteten og abundance af populationer i trophic levels under dem - bottom-up control).
an amphibian laying eggs in all possible habitats. (Fundamental niche - the range of environmental conditions tolerated by a species defines its fundamental niche).
(Realized niche - the fundamental niches modified by species interactions - community structures reflects this).
a trade-off among species with respect to competitive ability and stress tolerance. (This trade-off can result in patterns of zonation across the landscape where variations in resource availability exist).
apparent competition.
(Occurs when two species that do not compete with each other for limited resources affect each other indirectly by being prey for the same predator).
Spatial changes in community structure are referred to as zonation.
The biological structure of a community is first constrained by the environmental tolerances of the species (fundamental niche), which are then modified through direct and indirect interactions with other species (realized niche).
As we move across the landscape, variations in the phsycal environment alter (ændrer) the nature of both these constrains on species distribution and abundance - giving rise to patterns of zonation