COMMUNITY ECOLOGY MODULE 2.3

Community ecology

the study of all the populations (plants,
animals, and other species) living and interacting in an area

Habitat

the physical environment in which individuals of a
particular species can be found

Niche

the unique role a species plays in its community,
including how it gets its energy and nutrients, what habitat
requirements it has, and with which other species and parts
of the ecosystem it interacts

Niche specialist

species with very specific habitat or
resource requirements that restrict where it can live

Niche generalist

a species that occupies a broad niche
because it can utilize a wide variety of resources

Food chain

a simple, linear path starting with a plant (or
other photosynthetic organism) that identifies what each
organism in the path eats

Food web

a linkage of all the food chains together that
shows the many connections in the community

Producers

an organism that converts solar energy to
chemical energy via photosynthesis
EX: plants, some bacteria, some protists

Consumers

an organism that obtains energy and nutrients
by feeding on another organism
EX: animals, fungi, some protists, some bacteria

Indicator species

a species that is particularly
vulnerable to ecosystem perturbations and that,
when we monitor it, can give us advance warning
of a problem

Trophic levels

feeding levels in a food chain

Detritivores

consumers (including worms, insects,
and crabs) that eat dead organic material

Decomposers

organisms such as bacteria and fungi
that break organic matter all the way down to
constituent atoms or molecules in a form that plants
can take back up

Species diversity

the variety of species in an area; includes
measures of species richness and evenness

Species richness

the total number of different species in a
community

Species evenness

the relative abundance of each species in
a community

Resilience

the ability of an ecosystem to recover when it is
damaged or perturbed

Ecotones

regions of distinctly different physical areas
that serve as boundaries between different communities

Edge effect

the change in species diversity that occurs
due to the different conditions that either attract or
repel certain species at an ecotone

Keystone species

a species
that impacts its community
more than its mere
abundance would predict,
often altering ecosystem
structure
EX: gopher tortoise

Symbiosis

a close biological or ecological relationship between
two species

Mutualism

a symbiotic relationship among individuals of two
species in which both parties benefit +/+

Commensalism

a symbiotic relationship among individuals of
two species in which one benefits from the presence of the
other but the other is unaffected +/0

Parasitism

a symbiotic relationship among individuals of two
species in which one benefits and the other is negatively
affected +/-

Predation

species interaction in which one individual, the
predator, feeds on another, the prey +/-

Competition

species interaction in which individuals are
vying for limited resources -/-

Intraspecific competition

same species

Interspecific competition

different species

Resource partitioning

a strategy in which
different species use
different parts or
aspects of a resource
rather than compete
directly for exactly the
same resource

Restoration ecology

the science that deals with the repair of
damaged or disturbed ecosystems

Ecological succession

progressive replacement of plant (and then
animal) species in a community over time due to the changing
conditions that the plants themselves create (more soil, shade, etc.)

Primary succession

ecological succession that occurs in an
area where no ecosystem existed before, such as on bare rock
with no soil

Pioneer species

plant species that moves into an area
during early stages of succession; these are often r-species

Secondary succession

ecological succession that occurs in an
ecosystem that has been disturbed; occurs more quickly than
primary succession because soil is present