Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
212 Cards in this Set
- Front
- Back
|
What is Succession?
|
is the sequential change in species composition in a given area
|
|
|
What time scale does succession occur over?
|
Can be rapid or gradual.
Can be viewed on the scale of days to thousands of years according to the case. |
|
|
Under a given climate vegetation systems will gradually mature, their soil (substrate) types will also gradually mature.
What is the overall result of this process? |
same end point
climax |
|
|
What did Gleason believe?
|
Stated that plants would respond individualistically to habitat change… communities would not necessarily return to precisely the same state after disturbance. No climax community.
|
|
|
How do species respond to change?
|
individualistically
|
|
|
Communities are _______ and will not always return to a predictable ________
|
superorganisms
equilibrium |
|
|
Common examples of succession?
|
Abandonment of field
Recovery after fire Recovery from pollution Post volcanic disturbance Colonization of a new riverbank Colonization of a storm-damaged reef |
|
|
What is the difference between primary and secondary succession?
|
Primary: colonization of a new surface. One that has never before supported life, e.g. a marine spit, a new volcanic cinder cone, a sunken ship.
Secondary: colonization of a surface that is already supporting life. A clear-cut forest, an unmowed lawn, a newly flooded marsh. |
|
|
What is an example of a changing landscape?
|
marine spits lengthening, swinging and breaking
atoll formations |
|
|
Is land really empty?
assum no plants/roots left |
no
Some soil fauna still present, though most fertile topsoil is lost. Soil mycorrhizal fungi still present. Seed bank still present. Additional seeds arrive by wind, or transported by animals or water. |
|
|
What is a pioneer?
|
The first species to arrive on bare ground are termed pioneers.
They grow fast, need full-sun, invest in seeds not structure, often live for <1 yr. Within a few weeks they will produce the next generation and die. Produce many tiny seeds, often transported by wind. Annuals reproduce once (semelparous) |
|
|
how are seeds of pioneers generally dispersed?
|
by wind
|
|
|
What's the difference between biennials and perennials?
|
Biennials grow in their first year and reproduce in their second year, then die. Bigger bodies than annuals, they outcompete annuals.
Perennials live many years, reproduce many times (iteroparous). Can invest in bodies and defenses. Fewer, but larger seed in each flowering than annuals. They outcompete biennials. |
|
|
What are characteristics of mid succession?
|
The pines form a canopy that provides shade in which oaks germinate.
Pines and other conifers are softwoods. Broad-leafed trees such as oak, sweetgum, cherry, maple, beech are hardwoods. Generally, the harder the wood the slower the tree grows. Pines live about 80-120 years. Pines cannot regenerate in shade. |
|
|
What are characteristics of early succession? How do late succession characteristics compare?
|
high light sat. intensity, low efficiency in low light, high photosyntetic rate, high respiration rate, high transpiration rate, numerous small seeds, large disersal distance, long seed viabilty,low root to shoot ratio, small mature size, low structural strength, fast growth rate, short life span
|
|
|
What is the relationship between seed weight, seedling survival and shade?
|
Small seeds, disperse easily, mass quantities produced, energetically cheap per seed, no carbohydrate storage, seedlings cannot survive shade, characteristic of early successional species.
Large seeds the opposite. |
|
|
See slide 27 ppt 6-1 for r-K strategies
|
see previous
|
|
|
Why does succession take so long?
|
Different plant species have different ecological requirements. A beech or live-oak needs shade as a seedling.
They also need soil moisture which means the soil must have a high organic content. Succession is also the development of soil and colonization by soil organisms. |
|
|
What's the relationship between soil maturity and succession?
|
Soil accumulates organic matter as succession proceeds.
Increased ability to hold moisture. Pioneer species are shaded out. |
|
|
What is net primary productivity?
|
NPP = GPP-respiration
NPP maximal in immature stages of succession. Mature phase has senescent trees |
|
|
What are the 3 models of succession and who is responsible for them?
|
Facilitation
Environment less suitable for early species but more suitable for late-successional spp; early successional species die out Inhibition Environment less suitable for establishment by all species Tolerance All spp equally capable of surviving (all are tolerant of the conditions). Faster colonizers will arrive first, but be displaced. Connell and Slatyer |
|
|
Example of facilitation
|
Shade provided by pines allows seedlings of broad-leaved trees to survive.
Growth of a plant with nitrogen-fixing symbionts on sandy (nutrient poor) soils, e.g. Alder woodlands enrich the soil sufficiently for other species to colonize. |
|
|
What was initially thought to be the cause of all succession?
|
facilitation
|
|
|
charcteristics of tolerance
|
All species could live at all stages of the succession, but differing dispersal abilities/adaptations ensures earliest stages occupied by pioneer-type species.
As succession proceeds fewer and fewer of the early successional species can tolerate the new conditions and so the system advances to a mature stage. |
|
|
charcteristics of inhibition?
|
Species mutually inhibit one another through competition.
System can only change when an individual dies and is replaced. What will influence that replacement? |
|
|
Why don't we normally talk about succession with regards to animals?
|
do not show as clear of patterns as plants, but some birds (Georgia old fields) do reflect maturation of the system
|
|
|
What are sources of natural disturbances and about how often do they occur?
|
Continental drift…… millions of years
Climate change………hundreds to thousands yrs Volcanic……………..decades to hundreds yrs Disease epidemics…..decades Fire………………… annual to centuries Freezes…………….. annual to decadal Storm………………. monthly to decadal |
|
|
What is the intermediate disturbance hypothesis and who came up with it?
|
Connell
At very low disturbance competitive exclusion limits diversity At very high disturbance harsh conditions limit diversity Highest diversity at moderate disturbance regimes |
|
|
What are some characteristics of crown fires?
|
Crown fires
Soil organics burn C ignites at 500 oC these temperatures can penetrate 1m into soil. |
|
|
What are characteristics of destructive fires?
|
Fire present for hours.
Plant rootstocks killed Severe erosion follows Large area burned, reduces source for recolonization. |
|
|
What kind of fires are not sever and why defines them?
|
Surface fires
High surface temperature, but at 2 cm depth <50 oC. Fire passes in 2-5 minutes. Many tall plants survive though scorched. Animals either flee or survive in burrows. Fire is uneven, often leaves unburned/lightly burned patches Roots remain, soil held. |
|
|
What are physical effects of fire?
|
Scorching of leaves reduces productivity
Reduction of live biomass Reduction of surface organics Ashing and oxidation of soil chemicals More soluble, more likely to be leached (solution). Loose ash easily washed away (suspension). Volatilization, loss of chemicals in smoke, 70% of nitrogen. |
|
|
How does fire shape flora and fauna?
|
Fire sensitive species are killed outright by fire.
Introduction of fire can change dominant species. If fire is occasional leads to secondary succession. If fire is frequent get a pyrophilic community adapted to fire. |
|
|
What are some plant adaptations for fire tolerance?
|
corky park that insulates from heat
root resprouting |
|
|
What are epicormic buds?
|
Epicormic buds: buds beneath the bark that sprout following fire.
Epicormic sprouting is a sign of general stress on a plant. |
|
|
Australian grass tress flower as a result of smoke exposure. Why?
|
Synchronizes flowering, so that insects pollinate all.
Burned area offers suitable habitat for seed to become established. Note grass trees themselves may or may not have burned (these ones did). |
|
|
Why is fire bad if too frequent?
|
ex S. Africa: Land on right burned too often and rare Proteas (shrubs) are missing
|
|
|
What was Hubbard brook?
|
Long term ecological research (LTER) site.
Experimental deforestation, succession suppression and burns of entire stream catchments. Effects measured in stream water. |
|
|
What were the nitrate and sulfate results of Hubbard Brook?
|
Nitrate and sulfate are strong acid anions, and their leaching acidifies the streams, but will leave the soil more basic.
NO3 and SO4 content of stream water following fires in their catchment |
|
|
why does fire increase nutrient leaching?
|
Nutrient flow from a burned area is elevated for 2-6 yrs post fire.
Oxidation of chemicals increases solubility, decreases acidity (increase of 2 pH units) Sulfate concentrations in ELA streams: mean monthly SO4 concentrations in the Northwest stream before and after the 1980 fire. |
|
|
What are some fire regimes that can alter a fire?
|
Roads acting as fire breaks.
Fire suppression Prescriptive burns |
|
|
Primary colonization...
|
Follows succession from pioneers to late successional, but all have to disperse and arrive there.
Distance from source and dispersal abilities are important: Can larvae survive long enough to be transported there? Can seeds be blown there? Can mammals swim there? Can birds fly there? |
|
|
Best way to study primary succession? Good examples?
|
Follow one location from disturbance to maturity, ex. Krakatau, Surtsey, Mt St Helens.
Select similar habitats at different times since similar disturbance, ex. Glacier Bay, building riverbank |
|
|
Characteristics of Glacier Bay,Alaska
|
Steadily retreating glacier since 1850s.
New land surface revealed…primary succession. Oldest succession where ice first retreated. |
|
|
Succession at Glacier Bay
|
Retreating glaciers expose new land surface of till.
Rate of retreat ca. 65 km in 200 years Succession follows broadly predictable path |
|
|
Nutrient Changes at Glacier Bay
|
The initial soil is nutrient poor.
Alder is an N-fixer, spruce and hemlock are not. “forest floor” reflects N in leaf and wood litter. Peak in forest floor N at the transition to spruce-hemlock. Soil N decline in the spruce-hemlock zone |
|
|
What is Fastie Ecology?
|
He showed that Alder may actually slow the succession through competition.
The succession to Sitka Spruce was much faster in the sites deglaciated in the 1780s-1840s than the later sites. And hemlock has not begun to grow at any site that initiated after 1840. |
|
|
What are abiotic and biotic trends on mature and early succesion?
|
Abiotic and biotic trends are fairly even for mature systems
IN early succession abiotic influences impact biotic influences more than vis versa |
|
|
Spruce dispersal in Fastie Ecology
|
Spruce starts to invade the southern end of the valley by 1840, but does not reach the northern end until 2000.
Not facilitation but rate of migration, which is tolerance. |
|
|
Krakatau Island Case
|
Krakatau is an island group in Indonesia.
A volcanic eruption sterilized the islands in 1883. 2000 times the power of the bomb dropped on Hiroshima Generated tsunami that killed 36,000 people 100 m thickness of new ash coated the islands…new land surface. A natural laboratory. Colonization of plants and animals documented since 1884. |
|
|
Krakatau after the eruption
|
1884: no plant life found, some blue-green algae growing on ash.
1896: there were some coastal shrubs, scattered grasses and shrubs in the interior. 1908: Interior a “parkland” of grasses and clumps of trees. |
|
|
Krakatau primary succession
|
1928-1932: forests close over the grassland.
1979-1992: forests changing in species composition. Earliest trees now 60-80 years old. |
|
|
Dispersal mechanism in Krakatau
|
At first wind and sea dispersed species.
Later trees dominated by bird and bat dispersed species. Large pigeons and bats regularly move between islands and mainland Wind dispersal still brings orchids and ferns. |
|
|
Species diversity increase on Krakatau...how?
|
Plant species continue to colonize the islands.
New plants provide new opportunities for animals. Animals cannot colonize until primary producers (plants) are present. |
|
|
How does structure change the process of succession?
|
As succession proceeds the physical structure of the vegetation becomes more complex, offering more niches. Trunk-cavities, vines, larger limbs.
The more layers in the canopy the higher the animal diversity. Offer different feeding opportunities: Trunk-cavities provide nest sites for birds and insects. Vines provide food, cover and nest sites. Dead wood for decomposers. Larger limbs better attachment sites for epiphytes. |
|
|
Sursey, Iceland vs Krakatau
|
fewer plants have arrived in 40 years
|
|
|
Walker and Chapin 1987
|
Processes occur simultaneously so can’t always be grouped into alternative models
Relative importance of these processes Hypothesize the conditions under which each major successional process might be most important |
|
|
What are the different lake formations?
|
Beaver
Ox-bow Crater Faulting/warping Landslides Moraine-dammed Kettle hole Man-made |
|
|
beaver pond
|
Beavers are major shapers of northern landscapes as they fell trees to create dams.
|
|
|
OX-bows
|
Abandoned meander channels. Commonest type of lake formation in Amazonia. Found wherever a river meanders across a nearly flat plain.
All are “young” lakes (<4000 yrs) as river will re-enter them. |
|
|
crater lakes
|
Crater lakes form in volcanic cones, or where volcanoes explode and leave a lowered cone, a caldera.
Only in volcanic areas such as the Rockies and Andes |
|
|
faulting/warping
|
Lake Titicaca, Peru/Bolivia
formed by warping of Andes due to plate techtonics |
|
|
reservoirs
|
Most of US rivers are now dammed to provide hydroelectric power, or to regulate discharge.
Downstream loss of natural hydroperiod. Barriers to salmon migration |
|
|
zones in lakes
|
Littoral: very productive lake edge. Ends where there is insufficient light to support photosynthesis: compensation level.
Limnetic zone: open water above the compensation level Benthic: the bed of the lake below the compensation level. Profundal: open water below the compensation level. |
|
|
mid-winter cycle of a temperate lake
|
Surface of lake is ice-covered. 4oC is the densest water, so ice floats.
O2 is high in most of the lake as cold water can hold a lot of O2. Near bed O2 depleted by respiration. |
|
|
spring/fall cycle of lake
|
Lake is warming or cooling rapidly.
Complete mixing top to bottom. Mixing can be sudden as bottom water flips to the surface (overturn). O2 and nutrients dispersed throughout water column. |
|
|
summer cycle of lake
|
Surface of the lake is warm and rich in O2.
A thermocline is the layer where temperature falls abruptly..16oC in 1-2 m! Beneath the thermocline the water is cold and lacks oxygen |
|
|
summer stratification in a lake
|
The epilimnion is warm and less dense than other layers so it floats above them.
Metalimnion is the zone where temperature and O2 profiles change rapidly. The zone of rapid temperature change is the thermocline. The hypolimnion is very dense and does not mix with epilimnion. |
|
|
nutrient status of lake
|
Lakes that drain nutrient rich areas, e.g. they are likely to have more nutrients than those draining rocks such as granite.
The open water of a lake rich in nutrients is eutrophic. A lake poor in nutrients is oligotrophic. A eutrophic lake looks green or brown, an oligotrophic lake looks blue or brown. Eutrophic green or brown comes from the color of algae or from humic and tannic acids. Oligotrophic blue comes from deep penetration of light (i.e. few algae) A eutrophic lake looks green or brown, an oligotrophic lake looks blue or brown. Eutrophic green or brown comes from the color of algae or from humic and tannic acids. Oligotrophic blue comes from deep penetration of light (i.e. few algae) |
|
|
summer eutrophic lake
|
High nutrient availability.
Epilimnion very productive. Epilimnion blocks light to Hypolimnion. Epilimnion supplied with O2 from air. High BOD in hypolimnion as cells decompose. Hypolimnion anoxic. Fish almost all in epilimnion. |
|
|
summer oligotrophic lake
|
Low nutrient availability.
All lake unproductive Light penetrates hypolimnion allowing plants to grow and photosynthesize on lake bed. Hypolimnion supplied with oxygen from plants on lake bed. Epilimnion supplied from air. Fish throughout lake. |
|
|
Jordan Lake, NC Case
|
Large reservoir formed in mid 80s by damming a forest stream.
Phosphorus is the commonest limiting nutrient in temperate freshwater. (Nitrate in subtropical and tropical waters). Why does P peak in July? Data are for 3 yrs. Note cyclic changes in Nitrate is opposite to Ammonium (why?) |
|
|
What is a seiche?
|
In large lakes (and oceans) prevailing wind.
Wind induced standing wave is a seiche. When wind dies down, water flows back and overcompensates, so large changes on shoreline Midpoint of lake level unchanged (see-saw motion) ex Lake Michigan |
|
|
Why do we get fish kills?
|
Warm water -> O2 concs will be low.
In eutrophic system the hypolimnion is already anoxic. Epilimnion has O2 because of photosynthetic production of O2. Algal blooms dying and decomposing sets up large BOD. During night there is no photosynthetic production of O2but respiration continues. If no wind to stir O2 into the surface of the water, on a warm night in August/September lakes can become completely anoxic...fish die. |
|
|
How are fish bioindicators?
|
Some fish have narrow ecological tolerances and therefore are biological indicators of conditions.
Trout and salmon require high D.O., lake must be oligotrophic. Will also favor cool water. Why? Catfish and carp can live in low D.O., often in very eutrophic conditions. |
|
|
Lakes don't last forever, so how old are they?
|
In geological terms lakes are transient features in a landscape.
The oldest lakes in the African Rift are about 5 million years old. If formed by the last ice-age they may be 10,000 to 14,000 years old (many midwestern lakes). In Florida most lakes are about 4000 years old. |
|
|
What is hydrarch succession?
|
Pool gradually fills with peat.
Trees start to invade edge of marsh. When completely filled with peat trees cover entire surface. A wetland hollow develops a surrounding peat, lake may fill in but the site remains wet. |
|
|
phyto plankton and lake productivity
|
Algae bloom spring and fall.
Bloom causes nutrient limitation in summer. |
|
|
What are diatoms?
|
Composed of silica
Two halves (hence di-atom) They can be attached to substrate, often in chains. Reproduce asexually….keep getting smaller, or sexually return to “normal” size. Raphinid |
|
|
what are planktonic diatoms?
|
Free-floating diatoms that can form chains.
Often planktonics are araphinid. Ratio of planktonic: attached diatoms is used as a proxy measure for water depth. |
|
|
how do alkalinity and salinity affect diatoms?
|
Diatoms have relatively narrow tolerances to ranges of salinity, PH, alkalinity.
|
|
|
Rivers and streams
|
Confluence of rivers points downstream
1st, 2nd, and 3rd order rivers. (branching) Rivers change in character as they become larger. |
|
|
first order stream
|
They have no tributaries
Often fast flowing (> 0.5 m /sec)…fast enough to carry everything < 5mm. Pebbly bottom Nutrients derived from input of terrestrial organics, e.g. leaves, twigs. |
|
|
What defines a small, fast stream?
|
Periphyton mat made up of diatoms, cyanobacteria, watermoss and green algae, may coat some rocks (this is what makes river rocks super slippery).
Periphyton is an important source of primary productivity…equivalent to phytoplankton in a lake. |
|
|
Large stream?
|
Larger, deeper stream, broader channel, more volume and energy but slower flow.
Sandy bottom very unproductive...no place for periphyton to attach. |
|
|
Sluggish river?
|
Muddy bottom
As sediment of terrestrial origin is deposited. Phytoplankton in water column add to productivity. |
|
|
Flood plain?
|
Rivers regularly rise above their banks. Flood an area much greater than actual river.
Ecological importance is deposition of fertile alluvium in adjacent floodplain. Filling of temporary ponds with river water. Amphibians reproduce without fish. |
|
|
What causes annual variation in river level?
|
snowmelt, summer rains, hurricanes, wet/dry season
|
|
|
What are things organisms have to cope with in regards to low water flow?
|
low O2, high temps
|
|
|
Coping with high flow?
|
Scouring, silt
|
|
|
What's a bog body?
|
body preserved in a bog
|
|
|
Elling Woman
|
12yrs later a second body was found about 80 m from Tollund man.
A ~25 yr old woman Hung |
|
|
What is a water table?
|
Water table is where the soil is saturated. Usually below ground, but in a wetland may be at the surface.
|
|
|
What is an aquifer
|
porous rock where water is held
|
|
|
WHat is the aquclude?
|
impermaeable layer preventing downward movement
|
|
|
Why is biological oxygen demand a big deal?
|
The more organisms and the more decomposition the higher the BOD. If demand is greater than free oxygen, the system goes anoxic.
all decomposition needs oxygen |
|
|
What is chemical oxygen demand?
|
Reduced chemicals will scavenge free O2 from atmosphere...that’s why rust forms (Fe2 O2 ->Fe2 O3).
In air O2 is plentiful, so most chemicals are in their oxidized rather than reduced state. In water many chemicals are reduced and therefore deplete free O2 rapidly. Combination of COD and BOD can cause bottom water of lake, and soil of wetland to be anoxic. |
|
|
How does oxygen exchange work?
|
When soils are waterlogged reduced minerals scavenge free oxygen very rapidly.
When oxygen is exhausted the next most reactive oxidized chemical is stripped of its oxygen. Free Oxygen is taken up within 24 hours Nitrate is reduced to Ammonia Sulfate is reduced to hydrogen sulfide. Thoroughly reduced environments are rich in hydrogen sulfide (rotten egg gas) and |
|
|
HOw does the chemical profile in flooded soil change?
|
The deeper part of the profile is flooded for more time.
The upper part of the profile may rarely become saturated. |
|
|
What is the hydroperiod?
|
The time that a wetland is inundated, or that its soils are saturated with water.
Hydroperiod is very variable between wetlands and is an important determinant of wetland type |
|
|
how does plant rooting change oxygenated zone?
|
Only soil surface is oxidized in flooded environments.
Plant growth is very slow unless roots receive O2. Most plant roots are confined to the oxidized layer. A few roots will penetrate the partially reduced layer. |
|
|
what is waterlogged?
|
Waterlogging is when the airspaces of a soil fill with water.
|
|
|
Oxygen diffues how much faster through air than water?
|
10,000
|
|
|
What is an aquifer
|
porous rock where water is held
|
|
|
What is an aquifer
|
porous rock where water is held
|
|
|
WHat is the aquclude?
|
impermaeable layer preventing downward movement
|
|
|
WHat is the aquclude?
|
impermaeable layer preventing downward movement
|
|
|
Why is biological oxygen demand a big deal?
|
The more organisms and the more decomposition the higher the BOD. If demand is greater than free oxygen, the system goes anoxic.
all decomposition needs oxygen |
|
|
Why is biological oxygen demand a big deal?
|
The more organisms and the more decomposition the higher the BOD. If demand is greater than free oxygen, the system goes anoxic.
all decomposition needs oxygen |
|
|
What is chemical oxygen demand?
|
Reduced chemicals will scavenge free O2 from atmosphere...that’s why rust forms (Fe2 O2 ->Fe2 O3).
In air O2 is plentiful, so most chemicals are in their oxidized rather than reduced state. In water many chemicals are reduced and therefore deplete free O2 rapidly. Combination of COD and BOD can cause bottom water of lake, and soil of wetland to be anoxic. |
|
|
What is chemical oxygen demand?
|
Reduced chemicals will scavenge free O2 from atmosphere...that’s why rust forms (Fe2 O2 ->Fe2 O3).
In air O2 is plentiful, so most chemicals are in their oxidized rather than reduced state. In water many chemicals are reduced and therefore deplete free O2 rapidly. Combination of COD and BOD can cause bottom water of lake, and soil of wetland to be anoxic. |
|
|
How does oxygen exchange work?
|
When soils are waterlogged reduced minerals scavenge free oxygen very rapidly.
When oxygen is exhausted the next most reactive oxidized chemical is stripped of its oxygen. Free Oxygen is taken up within 24 hours Nitrate is reduced to Ammonia Sulfate is reduced to hydrogen sulfide. Thoroughly reduced environments are rich in hydrogen sulfide (rotten egg gas) and |
|
|
How does oxygen exchange work?
|
When soils are waterlogged reduced minerals scavenge free oxygen very rapidly.
When oxygen is exhausted the next most reactive oxidized chemical is stripped of its oxygen. Free Oxygen is taken up within 24 hours Nitrate is reduced to Ammonia Sulfate is reduced to hydrogen sulfide. Thoroughly reduced environments are rich in hydrogen sulfide (rotten egg gas) and |
|
|
HOw does the chemical profile in flooded soil change?
|
The deeper part of the profile is flooded for more time.
The upper part of the profile may rarely become saturated. |
|
|
HOw does the chemical profile in flooded soil change?
|
The deeper part of the profile is flooded for more time.
The upper part of the profile may rarely become saturated. |
|
|
What is the hydroperiod?
|
The time that a wetland is inundated, or that its soils are saturated with water.
Hydroperiod is very variable between wetlands and is an important determinant of wetland type |
|
|
What is the hydroperiod?
|
The time that a wetland is inundated, or that its soils are saturated with water.
Hydroperiod is very variable between wetlands and is an important determinant of wetland type |
|
|
how does plant rooting change oxygenated zone?
|
Only soil surface is oxidized in flooded environments.
Plant growth is very slow unless roots receive O2. Most plant roots are confined to the oxidized layer. A few roots will penetrate the partially reduced layer. |
|
|
how does plant rooting change oxygenated zone?
|
Only soil surface is oxidized in flooded environments.
Plant growth is very slow unless roots receive O2. Most plant roots are confined to the oxidized layer. A few roots will penetrate the partially reduced layer. |
|
|
what is waterlogged?
|
Waterlogging is when the airspaces of a soil fill with water.
|
|
|
what is waterlogged?
|
Waterlogging is when the airspaces of a soil fill with water.
|
|
|
Oxygen diffues how much faster through air than water?
|
10,000
|
|
|
Oxygen diffues how much faster through air than water?
|
10,000
|
|
|
What is an aquifer
|
porous rock where water is held
|
|
|
WHat is the aquclude?
|
impermaeable layer preventing downward movement
|
|
|
Why is biological oxygen demand a big deal?
|
The more organisms and the more decomposition the higher the BOD. If demand is greater than free oxygen, the system goes anoxic.
all decomposition needs oxygen |
|
|
What is chemical oxygen demand?
|
Reduced chemicals will scavenge free O2 from atmosphere...that’s why rust forms (Fe2 O2 ->Fe2 O3).
In air O2 is plentiful, so most chemicals are in their oxidized rather than reduced state. In water many chemicals are reduced and therefore deplete free O2 rapidly. Combination of COD and BOD can cause bottom water of lake, and soil of wetland to be anoxic. |
|
|
How does oxygen exchange work?
|
When soils are waterlogged reduced minerals scavenge free oxygen very rapidly.
When oxygen is exhausted the next most reactive oxidized chemical is stripped of its oxygen. Free Oxygen is taken up within 24 hours Nitrate is reduced to Ammonia Sulfate is reduced to hydrogen sulfide. Thoroughly reduced environments are rich in hydrogen sulfide (rotten egg gas) and |
|
|
HOw does the chemical profile in flooded soil change?
|
The deeper part of the profile is flooded for more time.
The upper part of the profile may rarely become saturated. |
|
|
What is the hydroperiod?
|
The time that a wetland is inundated, or that its soils are saturated with water.
Hydroperiod is very variable between wetlands and is an important determinant of wetland type |
|
|
how does plant rooting change oxygenated zone?
|
Only soil surface is oxidized in flooded environments.
Plant growth is very slow unless roots receive O2. Most plant roots are confined to the oxidized layer. A few roots will penetrate the partially reduced layer. |
|
|
what is waterlogged?
|
Waterlogging is when the airspaces of a soil fill with water.
|
|
|
Oxygen diffues how much faster through air than water?
|
10,000
|
|
|
What defines a small, fast stream?
|
Periphyton mat made up of diatoms, cyanobacteria, watermoss and green algae, may coat some rocks (this is what makes river rocks super slippery).
Periphyton is an important source of primary productivity…equivalent to phytoplankton in a lake. |
|
|
Large stream?
|
Larger, deeper stream, broader channel, more volume and energy but slower flow.
Sandy bottom very unproductive...no place for periphyton to attach. |
|
|
Sluggish river?
|
Muddy bottom
As sediment of terrestrial origin is deposited. Phytoplankton in water column add to productivity. |
|
|
Flood plain?
|
Rivers regularly rise above their banks. Flood an area much greater than actual river.
Ecological importance is deposition of fertile alluvium in adjacent floodplain. Filling of temporary ponds with river water. Amphibians reproduce without fish. |
|
|
What causes annual variation in river level?
|
snowmelt, summer rains, hurricanes, wet/dry season
|
|
|
What are things organisms have to cope with in regards to low water flow?
|
low O2, high temps
|
|
|
Coping with high flow?
|
Scouring, silt
|
|
|
What's a bog body?
|
body preserved in a bog
|
|
|
Elling Woman
|
12yrs later a second body was found about 80 m from Tollund man.
A ~25 yr old woman Hung |
|
|
What is a water table?
|
Water table is where the soil is saturated. Usually below ground, but in a wetland may be at the surface.
|
|
|
What is the aquiclude?
|
impermeable layer preventing downward movement
|
|
|
.biological oxygen demand?
|
All decomposition requires oxygen, all animals require oxygen to breathe
Continuous demand for oxygen from living things. Not important in air as oxygen is plentiful and diffuses rapidly. Not so underwater. The more organisms and the more decomposition the higher the BOD. If demand is greater than free oxygen, the system goes anoxic. |
|
|
Chemical oxygen demand?
|
Reduced chemicals will scavenge free O2 from atmosphere...that’s why rust forms (Fe2 O2 ->Fe2 O3).
In air O2 is plentiful, so most chemicals are in their oxidized rather than reduced state. In water many chemicals are reduced and therefore deplete free O2 rapidly. Combination of COD and BOD can cause bottom water of lake, and soil of wetland to be anoxic. |
|
|
How does oxygen exchange work?
|
When soils are waterlogged reduced minerals scavenge free oxygen very rapidly.
When oxygen is exhausted the next most reactive oxidized chemical is stripped of its oxygen. Free Oxygen is taken up within 24 hours Nitrate is reduced to Ammonia Sulfate is reduced to hydrogen sulfide. Thoroughly reduced environments are rich in hydrogen sulfide (rotten egg gas) and methane. The combination of these is flammable “marsh gas”. |
|
|
how does the chemical profile change in flooded soil?
|
The deeper part of the profile is flooded for more time.
The upper part of the profile may rarely become saturated. |
|
|
What is the Hydroperiod?
|
The time that a wetland is inundated, or that its soils are saturated with water.
Hydroperiod is very variable between wetlands and is an important determinant of wetland type |
|
|
Oxygen diffuses through air ___________ faster than water
|
10,000 times
|
|
|
What is a wet land?
|
An area that has water to within 10 cm of its surface for at least one week during the growing season.
A water body less than 1 m deep. |
|
|
Florida wetland?
|
Test A: > 50% Obligate aquatic vegetation AND Hydric soil characteristics OR Hydrologic indicators
Test B: Obligate + Facultative wet > 80% (Upland<20%) AND Hydric soil characteristics OR Hydrologic indicators |
|
|
What are the different types of wetlands?
|
Bottomland hardwood
Riveraine Mangrove Saltmarsh Fen Prairie pothole Bog |
|
|
bottomland hardwood
|
Valley bottoms, usually associated with river.
Maples, cypress, tupelo are typical. Flooding may only be for a few weeks each year. Nutrient rich soils. Rarely, if ever, burn. Rapid loss for farming and housing. |
|
|
riveraine
|
Can be any kind of wetland flanking a river, or in the case of the Everglades the wetland is the river.
Sawgrass marshes very nutrient poor water,but very fertile soils when drained, burn, almost continuously flooded. Rapid loss to agriculture. |
|
|
mangrove
|
Tropics and subtropics
3 spp. of mangrove in US, red, white and black. Australia has 27 spp. Estuarine/coastal locations. Salt adaptations such as leaf excretion of salt. Essential fish habitat. Very productive systems, will burn. Rapid loss to settlement and aquaculture. |
|
|
Saltmarsh
|
temperate equivalent of mangrove
|
|
|
Fen
|
Spring fed so water-table and chemistry determined by local groundwater.
Often alkaline (pH 8) Flowing water is oxygenated, high productivity, high species diversity. May burn. Loss due to deep land drainage lowering aquifer. |
|
|
prairie pot-hole
|
Formed by blocks of ice embedding in till and melting to leave hollow.
Millions of these lakes & wetlands in mid-west. 75% of US ducks nest in these wetlands. Many are ephemeral, fed by snow melt and spring rain. Very productive agricultural land if drained |
|
|
bog
|
Water in bog has no supply other than rainwater (ombrotrophic).
Bog water is acidic, nutrient poor with low DO. Low productivity Very productive if drained. |
|
|
what does a bog profile look like?
|
Floating mat grows out across surface. Trembles.
Peat can be >30 feet thick. Sphagnum moss is important constituent of flora and when dead of peat. Mined for peat. |
|
|
What wetland types are nutrient rich?
|
fens, saltmashes, mangroves
|
|
|
Which wetlands are nutrient deserts?
|
bogs, blackwater streams (Florida streams)
|
|
|
What are adaptations to live at low O2?
|
Pneumatophores
Cypress knees Aerenchyma Oxidized root margin Lenticels Swollen base of trunk |
|
|
What are pneumatophores and cypress knees?
|
Aerial portions of plant root.
Act like snorkels allowing O2 to enter plant even when surface of wetland is covered in water. Vaseline coating of knees reduced O2 concs. in plant. |
|
|
What does aerenchyma?
|
Aerenchyma are large air-filled cells in the stem and roots of a plant. Gas can flow freely along them.
Allows rapid transfer of O2 from aerial to submerged portion of plants. |
|
|
What causes swollen base and lenticels?
|
Increasing trunk surface area as close to rootzone as possible increases ability to absorb O2 and transfer it to roots..hence swollen trunk bases in wetlands.
Lenticels are pores on the trunks of trees that increase rate of gas exchange. |
|
|
How have some plants adaptation to low N?
|
Carnivory common in very nutrient poor settings, e.g. sundews, Venus fly trap, bladderwort and pitcher plants.
All trap insects and then dissolve them with digestive enzymes. Lots of nitrogen in a fly. |
|
|
What causes vulnerability to nutrients?
|
If nutrients are added to a system adapted to low nutrient conditions it allows a new set of species to live there. The nutrient-poor condition specialists are replaced by invasive generalist species, such as cat-tails that form monotypic stands.
Thus, nutrient enrichment of wetlands is a major threat to wetland species diversity. |
|
|
How are the Everglades being stressed by pollution?
|
Very important agricultural region is the Everglades Agricultural Area.
Groves and farming dump water into the northern Everglades. Everglades is a phosphate limited system. Water contains high quantities of phosphate c. 200 ppb, whereas Everglades water should be 6-8 ppb |
|
|
What damage was caused by a hunter when he fired into a ANWAR pipeline?
|
$3.5 millon leak
|
|
|
What percent of birds between 40 and 50 degrees breed then go south for winter?
|
95%
|
|
|
Why is fat important for gird migration?
|
energy source, water is metabolic by-product, resists low temps, easy storage.
Organs reorganized for this purpose |
|
|
What determines migration timing in birds?
|
internal clocks responding to day length and weather
birds move when conditions favor flying (tailwinds, low air turbulence, no rain) |
|
|
What are advantages of night migration?
|
more stable atmosphere
easier thermoregulation potentially lower predation |
|
|
How does day migration work?
|
Large soaring birds (hawks, storks, pelicans) use thermals to help fly
|
|
|
What was Hawk Mountain?
|
60 yr observational data Atinson 1996
|
|
|
What was the sooty shearwater study?
|
Shaffer 2006
19 tagged birds recorded location, sst, dive depth tags stayed on for avg 268 days narrow central pacific flyway following productivity w/3 northern feeding grounds (japan, CA and Alaska) traveled 910 +/- 186 km per day |
|
|
Sooty shearwater diving took place in what zone?
|
95% took place in highly productive regions. Almost no feeding in tropical seas
|
|
|
How does migration change relative to productivity?
|
Northward (no breed) shift in hemisphereic productivity
southward preceds hemispheric swich has pairs have to form on south breed ground w/enough time to lay egg and hatch chick in time of maximum food availability |
|
|
How far do long distance migrations birds travel?
|
30,000 miles each year
600,000 miles over their entire lives |
|
|
What organism does multigenerational migration?
|
monarch butterflies
100 million monarchs migrate south to roost in Mexico hatch in N. America, winter in Mexico, reproduce/die in N. America |
|
|
what animals have short migrations?
|
amphibians (frogs moving from forest to open)
|
|
|
how is migration different from dispersal/
|
regular roundtrip event, not one way
|
|
|
What is diurnal-nocturnal migration?
|
vertical migration of plankton in water column to avoid visual predators
|
|
|
What is biogeography?
|
study of distribution and abundance of species in relation to their environment through space and time
|
|
|
What is an example of range limit?
|
seed eater who may be range limited by deep snow
Eastern Phoebe thermal limit when temps fall below -4C |
|
|
How do new species arise?
|
genetic isolation (allopatry)
|
|
|
When species move to an island, how does dispersal work?
|
sp. travel to island then may or may not speciate
|
|
|
What is vicariance?
|
one pop divided by an event. Geneflow reduced to point where speciation occurs
ex rise of mountain chain or formation of desert |
|
|
WHat were Wallace's Zoogeographic realms?
|
1876 depiction of how vicariance happened amoung the continets
|
|
|
What do modern biogeographic realms refelct?
|
evolutionary history
based after Newton and Dale 2001 |
|
|
What was the great faunal interchange of 2-3 million years ago?
|
bunch of animals from north america moved to south america and vice versa
|
|
|
What are some animals that moved from N. Am to S. Am?
|
Elephant, lama, fox, wart hog
|
|
|
What are some animals that moved from S. Am to N. Am?
|
Armadillo, ground sloth Capybara...all originally from north, moved south, then north again
|
|
|
Why did most taxa not migrate?
|
filter, getting over the desert of Mexico
going into the change, there were more N Am mammals that S. Am |
|
|
What happened once they migrated?
|
Adaptive radiation caused an explosion of diversity in A. Am
|
|
|
Were mid ocean islands evidence of collapsed bridges?
|
potentially. plate tectonics
|
|
|
What and where is Wallace's line?
|
Far East meets Australasia
line where there is no longer crossover between species of the two geographic areas |
|
|
Why do we study island?
|
simple microcosm
representative evolutionalry processes more evident than on main land |
|
|
What is special about landbridge islands?
|
exist for shorter period of time, so might see some drawfing but not full speciation
|
|
|
What is dispersal/
|
blind and therefor dangerous,behaviour adjsutmetns are needed that reduce costs
|
|
|
What is one way movement of an animal called?
|
dispersal
|
|
|
Why dispers?
|
reduce competition
genetic diversity avoid temporal chagnes in environment |
|
|
three stages of dispersal?
|
leaving, traveling, settling
|
|
|
Types of dispersal?
|
natal, breeding
|
|
|
natal dispersal?
|
move ind. from its place of birth to an area where it first breeds
|
|
|
breeding dispersal?
|
move individ. between two successive breeding ares
|
|
|
Ways and definitions of disersal
|
active (control where they go)
passive (dispersed by external factors like wind) |
|
|
what are costs of dispersal?
|
increased mortality (predators)
competition uncertain carrying capacity (move to sink area) |
|
|
exploratory excursion?
|
indiv compare potential success elsewhere with potential success in present location
|
|
|
conspecific cues?
|
dispersing ind. us presents of conspecifics as indirect cue of habitat quality
|
