Ecological Principles

Front 1

ability of an ecosystem to recover from disturbance

Back 1

resilience

Front 2

List 3 ways ecological disturbances differ

Back 2

-intensity

-frequency and return interval

-adaptation of ecosystem

-synergism with other disturbances

-(also): distribution and size, predictability, etc.

Front 3

a regular progression of communities replacing each other on a site until a relatively permanent climax community is established

Back 3

succession

Front 4

early-successional, generalist organisms with short lifespans, large numbers of offspring, and good dispersal capabilities

Back 4

r-selected species

(r: rodents)

Front 5

later-successional organisms with fewer offspring but higher survival rates

Back 5

K-selected

(K: killer whales)

Front 6

What is Clements' view of succession?

Back 6

1. Specific sequence of plant communities occurs on a given site

2. Each community prepares the site for subsequent invaders

3. At the end of the sequence is a stable climax community

Front 7

When early successional species alter the environment to make it more favorable for the establishment of later-successional species-most common in highly disturbed ecosystems

Back 7

Facilitation

9ex: manzanita trees providing shade for redwood seedlings

Front 8

When early successional species alter the environment to make it less favorable for the establishment of later-successional species

Back 8

inhibition

Front 9

What are 2 components of alternative models of succession?

Back 9

1. Trajectory of the ecosystem depends on the composition of species that establish first and modify the system (Gleason)

2. Succession is modified by environmental gradients

Front 10

mosaic of two or more ecosystems that exchange organisms, energy, water and nutrients

Back 10

landscape

Front 11

Island Biogeography Theory

Back 11

1. Number of species at equilibrium is a function of island size (i.e.: larger islands have more species; smaller islands will have fewer species)

2. Rate of immigration is a function of distance from mainland (i.e.: nearer islands have higher immigration/colonization)

Front 12

What is one problem with small population sizes?

Back 12

low genetic diversity, which results in:

-weak and infertile offspring

-loss of evolutionary flexibility

Front 13

Name 3 more problems with small populations?

Back 13

-High demographic stochasticity: variations in individual death and birth rates more important when there are fewer individuals

-Susceptibility to environmental stochasticity: small populations more likely to be affected by random environmental variations

-at low population densities individuals

may not be able to find mates or be pollinated

Front 14

What are edge effects?

Back 14

the smaller the patch size the larger the ratio of edge to interior habitat (mostly applies to forests)

Front 15

changes in the abundance or distribution of species caused directly by the physical conditions near the edge (vegetation structure and plant and animal distribution)

Back 15

direct biological edge effects

Front 16

changes in species interactions near the edge--predation, competition, herbivory

Back 16

indirect biological edge effects

Front 17

a set of geographically isolated subpopulations that are interconnected by gene flow and colonization, often consist of one or more core populations that are persistent and a number of satellite populations

Back 17

Metapopulation

Front 18

reproduction > mortality

Back 18

source habitat

Front 19

reproduction < mortality

Back 19

Sink population

Front 20

What are two strategies to encourage movement between habitat patches?

Back 20

1. corridors

2. stepping stone populations

Front 21

intentionally moving individuals of a species outside their present range in response to changing climactic conditions

Back 21

Assisted migration/translocation