Lecture 4- abiotic factors that limit species distribution

Question 1

What are the 3 main abiotic factors that affect species distribution?

Answer 1

1. Climate (temp, water availabilty, sunlight and wind)
2. Topography
3. soil

Question 2

What is climate and its 2 subdivisions?

Answer 2

Climate is the composite or generally prevailing weather in an area

1. Macroclimate- patterns on the global, regional and local level
2. Microclimate- very fine patterns, such as those encountered by the community of organisms underneath a fallen log

Question 3

What are important factors of temperature and water availability

Answer 3

• dominant factors affecting distributions of terrestrial biomes, affecting geographical ranges of organisms in these biomes
• more important is the balance between Temp and water availability.

Question 4

What are the 2 ways drought can occur?

Answer 4

1. Soil drought occurs when water is deficient( low precip, high temps)
2. Freeze drought occurs when low temps make water unavailable

Question 5

What is a widely used metric of surface water availability?

Answer 5

Precipitation / potential evapotranspiration (P/PET)

-The amount of incoming water (P) adjusted for water loss due to drying (PET)

Question 6

What does Evaporation include?

Answer 6

1. Evaporative water loss from soil and water surfaces, Plus

2. Water loss due to transpiration through plant stomata

Question 7

What is potential evapotranspiration?

Answer 7

The estimated rate of evapotranspiration that would occur given and unlimited supply of water. this is an index of drying power

Question 8

What 2 variables drive earth surface temperature variations?

Answer 8

1. incoming solar radiation (Insolation) compared to the equator, insolation at the poles occurs at more oblique angles during most of the year. temp is lower and more seasonally variable at the poles
2. Distribution of land and water
   compared to land, water cools/heats more slowly because it has a higher specific heat capacity. areas near large water bodies have lower daily and seasonal temp fluctuations

Question 9

What 4 effects do Temp and water availability have on species distributions?

Answer 9

1. Survival
2. Reproduction
3. Development of young
4. Interactions with other species (effects greater near the edges of a species range.

Question 10

How is knowing threshold levels beneficial to conservation?

Answer 10

Directing resources.
controlling species with abiotic factors
where will climate do your job for you?

Question 11

What 2 options do organisms have for dealing with local temp and water availability?

Answer 11

1. Simply tolerate them
2. ‘Escape’ them using adaptations
   - physical, psychological, behavioral

Question 12

What 2 ways does sunlight limit species distributions?

Answer 12

1. Indirectly through its effect on temperature and water availability
2. Directly through effects of light intensity and light quality on rates of photosynthesis.

Question 13

What is a specific trait that determines photosynthetic rate?

Answer 13

Photosynthetic pathway

-The chemical pathwa by which CO2 is converted to sugar.

Question 14

What are 3 types of photosynthetic pathways?

Answer 14

1. C3 plants- 20-25*, high water, low light
2. C4 plants- 30-35*, medium water, high light
3. CAM plants- 35* low water, medium light

Question 15

How does wind modify the effects of temp and water availability?

Answer 15

Increasing heat loss due to convection and water loss due to evaporation (mainly affecting plants)

Question 16

How does Topography affect species distributions?

Answer 16

mainly indirectly by modifying other abiotic factors:

1. Temp
2. Precip
3. Sunlight
4. Wind

Question 17

How do soil trait limit distribution?

Answer 17

1. Mineral and organic composition
2. pH
3. Physical structure (porosity, grain size)

plants can also influence these soil properties

Question 18

How does seasonality impact species distributions?

Answer 18

1. Seasonal variability of temp/light increase steadily toward the poles. many species migrate to higher latitudes to take advantage of resources made available by longer summer days
2. Lakes are sensitive to seasonal temp change, which results in turnover of water and associated nutrients

Question 19

How is the importance of abiotic factors to species distributions assessed?

Answer 19

1. Identify which life cycle stage (Egg, seed, juvenile, adult) is most sensitive to the variable
2. Then identify the tolerance zone to that variable (critical physiological limits)
3. Evidence that the variable may limit the species distribution exists if the variable is within this tolerance zone inside the species range, but is not within the tolerance zone outside the species range

Question 20

Common garden experiments can help assess whether ecotypes are:

Answer 20

Different genotypes (genetic differences between ecotypes) or 
Different phenotypes (no genetic difference between ecotypes)

Question 21

What are 2 estimated impacts of anthopogenic climate change on the ranges of terrestrial species?

Answer 21

1. Shift toward the poles/high altitude at a rate of 16.9km/decade
2. Shift towards higher elevations at a rate of 11m/decade

Question 22

What does a species ability to deal with climate change depend on?

Answer 22

1. Whether they can tolerate or adapt to climate changes or
2. Whether they can disperse to acceptable climates.

one caveat is that adaptation evolution rates or dispersal rates may not occur fast enough to keep pace with rates of anthropogenic climate change

Question 23

how is the range of chthamalus barnacles affected by both biotic and abiotic factors?

Answer 23

They are limited by 2 factors:

1. exposure to air (drying) in the upper intertidal
2. Competition for space with semibalanus barnacles in the lower intertidal.

Question 24

What are the effects of abiotic and biotic factors on the distribution of spectacled eiders.

Answer 24

Variable wind, pack ice, and prey dispersion affect the long term adequacy of protected areas for an arctic sea duck