Biogeography: Patterns And Distribution

Front 1

Two forces underlying biogeographic distributions

Back 1

○ Colonization: the expansion of a reproducing population into a new area
§ Range: total area inhabited by a species
§ Habitat: the location in which an organism lives

Extinction: the elimination of a species from all or part of its range

Front 2

Spatial and temporal scale of distributions

Back 2

○ The importance of abiotic and biotic factors change with scale
○ The role of environmental and ecological factors is not constant across space and time
○ The uniqueness of place

Front 3

Scale and Spatial Patterns

Back 3

○ The dynamics of a given area is entirely dependant on its scale

Front 4

Temporal Patterns

Back 4

○ May look at population fluctuations for the same species at several locations over time

Front 5

factors required for colonization

Back 5

○ Capacity for dispersal
○ Conditions for dispersal
§ Under certain conditions any organism can be dispersed
○ Environmental conditions for dispersal
May be seen as
○ Physical limiting factors (Abiotic)
○ Ecological limiting factors (Biotic)

Front 6

Dispersal agents (mechanisms involved in dispersal)

Back 6

○ Abiotic
§ Wind (possibly foremost agent in abiotic dispersal)
§ Gravity
§ Water
○ Biotic (assisted by animals)
§ Phoresy: the transport of one organism by another organism
□ Attachment: when something sticks on a passerby
□ Ingestion/excretion
□ Cachement
○ Humans

Front 7

Capacity for Dispersal: Plant dispersal

Back 7

• Stolons: Above ground, horizontal shoots
• Rhizomes: below ground horizontal stems
• Seed crawling (burrowing): expansion and contraction of seed in response to changes in relative humidity

Dehiscence: seed ejection caused by high seed pod pressures

Front 8

Operational Environment

Back 8

(what are the factors that determine where and when organisms occur)
○ What environmental factors govern the distribution of a given species
○ What are the most important factors that define a distribution

Front 9

Qualities of climate that can act as limitng factors

Back 9

□ Solar radiation (latitudinal variation)
□ Air temperature
□ Atmospheric gases and particulate matter
□ Atmospheric humidity/moisture
□ Mechanical force

fire

Front 10

Edaphic factors that can act as limitng factors

Back 10

§ Soil moisture
§ Soil temperature
§ Soil chemical in liquid or solid phases
§ Soil gases

While edaphic factors are abiotic in a sense, they play such a vital role in distributions of living organisms, that the line becomes hazy

Front 11

○ Environmental factors of soil type

Back 11

§ Diagrams of pollens relating to out wash and till expose several factors over time often show inverse relationships
§ Differential reveals difference in vegetation in relation to texture and nutrient quality
§ Dolomite soils have a higher moisture content but lower nutrient content than snadstone
§ Looking at distributions of Ultramaphic rocks in PNW reveals plants that are adapted to soils that are toxic and low in nutrients

Front 12

○ Soil formation is a function of

Back 12

§ Climate
§ Parent material
§ Relief
§ Organisms
§ Time

Front 13

○ Vegetation is a function of

Back 13

§ Climate
§ Soils
§ Relief
§ Organisms
§ Time

Front 14

Niche

Back 14

All of the conditions needed for an organism to exist

Front 15

Ecological perspective of niche

Back 15

§ The functional role of a species in a community
§ The sum of the resources required by a species
□ Ecological requirements (abiotic and biotic) must be considered within theory

Multi-dimensional ("niche volume"

Front 16

○ Evolutionary Perspective of niche

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§ A niche is defined by individual species
§ No two species can occupy the same niche
§ Niche is a result of natural selection

Thinking about niche in terms of populations and resources

Front 17

○ Fundamental Niche

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§ The total range of physical conditions suitable for a particular species to exist

Front 18

○ Realized Niche

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§ The actual set of conditions (as modified by another species) occupied by a species

Front 19

Unfilled Niche

Back 19

§ If a niche is defined by an organism, does that niche exist following the extinction of that organism?
□ This is a fundamental question among biogeogrpahers because they ultimately do not know exactly what all of the requirements of a species is
§ Darwin's wedging
□ If there is a finite amount of space and a new organism is introduced it will either not fit or will displace existing organisms
□ Gradualism: is "niche packing"

Front 20

Neutral interactions

Back 20

Birds and soil fungus--there is no direct relationship

Front 21

Protocooperation

Back 21

tick birds and rhinos--neither bird or rhino needs the other but they both benefit from the other

Front 22

Mutualism

Back 22

ant and the acacia--completely obligatory, symiotic

Front 23

Commensialisms

Back 23

does not provide any great benefit for one but does for the other

Front 24

Amensalism

Back 24

positive for one but neutral for the other--where one species emits a chemical that hinders the growth of another

Front 25

Parasitism

Back 25

prolonged host consumption

Front 26

Predation

Back 26

killing and consumption

Front 27

Competition

Back 27

is strictly about resource competition
§ Exploitive: use efficiency
□ Example: soil moisture with grasses and shrubs
§ Interference: limits access to resources

Example: shading

Front 28

Coexistence

Back 28

sharing of common resources in a manner that reduces competition
§ Strategies of Coexistence
□ Different times
□ Different sources
□ Different period during the life cycle
® Can occur between different or same species

Front 29

Carrying Capacity

Back 29

Number of individuals that can be supported by the resources available in a given area

Front 30

Population Growth

Back 30

Change = births + immigration -deaths - emigration

Front 31

Range expansion

Back 31

□ Decline of local resources relative to population pressure
□ High resource availability beyond the normal range of the species

Front 32

Range Contraction

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□ Resource exploitation (where carrying capacity is exceeded)
□ Changing environmental conditions

Front 33

Autocology

Back 33

Ecology of individual species

Front 34

syncology

Back 34

Ecology of multiple species

Front 35

Adaptive zone

Back 35

area that supports an entire genus as opposed to being limited to species

Front 36

Ecological Amplitude

Back 36

the range of conditions in which a species can survive

Front 37

Ecological release

Back 37

occurs when one competitive organism is removed allowing the other to thrive

Front 38

Niche Overlap

Back 38

Where species niches overlap