Lecture 6: Rangeland Ecology/Succession

Question 1

Ecology

Answer 1

The study of relationships among organisms, and between organisms and their environment

Question 2

Population ecology

Answer 2

Autecology, individual organisms and populations

Question 3

Community ecology

Answer 3

Synecology, deals with complex groups of organisms, for example the plant community, and their relationship to other organisms, for example herbivores, as well as their environment.

Question 4

Population

Answer 4

A group of individuals of the same species living in a given area at the same time

Question 5

Species

Answer 5

A population or group of populations whose members have the potential in nature to interbreed and produce fertile offspring

Question 6

Environment

Answer 6

Total surroundings of an organisms, including other plants and animals, and those of its own kind.

Question 7

Habitat

Answer 7

Place where a plant or animal can live

Question 8

Community

Answer 8

A group of interacting plants and animals inhabiting a given area

Question 9

Association

Answer 9

A kind of plant community represented by stands that occur in places where environments are so similar that there is a high degree of floristic uniformity in all layers of the plant community

Question 10

Dominant

Answer 10

Plant species or species groups, which by means of their number, coverage, or size, has considerable influence or control upon the conditions of existence of associated species

Question 11

Ecosystem

Answer 11

The biotic community and its abiotic environment functioning as a system

Question 12

Four characteristics of ecosystems

Answer 12

• web of interactions and interdependencies
• synergy
• stability
• diffuse boundaries

Question 13

Abiotic components

Answer 13

Non living components of the ecosystem on which living organisms depend. This includes parent material, climate, topography, and natural disturbances

Question 14

Biotic components

Answer 14

The living organisms in an ecosystem. Producers, consumers, decomposers, and manipulators.

Question 15

Succession

Answer 15

Implies a sequence in time or space. Directional change in species composition, community structure, and function over time and space

Question 16

Primary succession

Answer 16

Sequence of plant communities on a new site, previously devoid of plants. Examples include volcanic eruptions, glacial retreat, sand dunes. Grasses are common in early succession.

Question 17

Secondary succession

Answer 17

Describes the change in plant communities after a disturbance, on a site which already had plants and soil. For example, grazing and fire. This is the progressive modification of soil, micro-climate, and vegetation. Plant traits and dominance play a key role.

Question 18

Primary succession graph

Answer 18

Bare ground–> serial stage–> serial stage–> climax

Question 19

Secondary succession graph

Answer 19

Seral stage–>earlier serial stage–> serial stage–> climax

Question 20

Autogenic (biotic) succession

Answer 20

Vegetation changes due to the activities of the organisms themselves

Question 21

Allogenic succession

Answer 21

Vegetation change due to environmental conditions and environmental change or external factors

Question 22

Stress gradient hypothesis

Answer 22

Facilitation occurs in stressful environments. Competition occurs in productive environments,

Question 23

Stability: Resistance

Answer 23

The ability of the system to withstand a perturbation

Question 24

Stability: Resilience

Answer 24

The speed at which a disturbed system returns to equilibrium after a perturbation

Question 25

Stability: Inertia

Answer 25

The tendency of s community to continue to occupy a specific range site, even after conditions have changed to favour a new community

Question 26

Seres

Answer 26

Intermediate stages in the development of a climax plant community

Question 27

Retrogression

Answer 27

Changes within the plant community away from climax due to a disturbance

Question 28

Community unit hypotheses

Answer 28

Clements,

Question 29

Individualistic hypothesis

Answer 29

Gleason

Question 30

Facilitation

Answer 30

Each seral community changes the site for the next community, similar to relax fluoristics

Question 31

Tolerance

Answer 31

Which species have the ability to survive the longest

Question 32

Inhibition

Answer 32

Some species will inhibit the development of others

Question 33

Clements 6 stages of primary succession

Answer 33

Nutation, migration, establishment, competition, reaction, stabilization