Chapter 18: Community Dynamics Flashcards
The gradual and seemingly directional change in community structure through time
(temporal changes in community structure)
succession
The series of successional stages on a given site that lead to a terminal community
sere
Following a series of stages;
A point in a continuum of vegetation through time
seral stage
Plant species characterized by: high dispersal rates, ability to colonize disturbed sites, short life span, and shade intolerance
early successional/pioneer species
Long-lived, shade-tolerant plant species that supplant early successional species
late successional species
Vegetational development starting on a new site never before colonized by life
primary succession
Development of vegetation after a disturbance
secondary succession
Groups of sites within the same area that are in different stages of succession
chronosequences
A theory of plant succession and community dynamics developed by Frederic Clements;
The community is viewed as a highly integrated superorganism and the proves of succession represents the gradual and progressive development of the community to the ultimate, or climax stage;
The process was seen as analogous to the development of an individual organism
monoclimax hypothesis
A hypothesis proposed by Frank Egler;
The process of succession at any site is dependent on which species get there first;
Succession is individualistic and dependent on the particular species that colonize the site and the order in which they arrive
initial floristic composition hypothesis
States that early successional species modify the environment so that it becomes more suitable for later successional species to invade and grow to maturity;
In effect, early-stage species prepare the way for late-stage species, facilitating their success
facilitation model
Involves strong competitive interactions;
As long as it lives and reproduces, the first species maintains its position;
The species relinquishes it only when it is damaged or dies, releasing space to another species
inhibition model
Holds that later successional species are neither inhibited nor aided by species of previous stages;
Later-stage species can invade a newly exposed site, establish themselves, and grow to maturity independently of the species that precede or follow them
tolerance model
Self-generated
autogenic
Refers to successional change brought about by a change in the physical environment
allogenic
