APS 124 Gareths Lectures Flashcards
(49 cards)
What is meant by a complementary distribution?
Where two species fill similar niches but in different parts of an environment
E.g. Crowberry vs dogwood in the UK
Similar plants but dogwood more common in south and crowberry common in south
What are the three factors that determine species distribution?
Climactic factors - global and regional patterns of distribution
2 physiographic factors - landscape more local scale
- e.g. Lapse rate -6.5 degrees for 1000 meter increase in altitude
- aspect - direction of a slope will effect the tree line
3 edaphic factors
- soil factors
Plant anchorage, water and nutrients
Define resource
Commodity that a organism consumes
Why do acidic soils often have less plant biomass?
Increases abundance of toxic ions
What are the six forms of interaction between species
Competition = both lose out
Facilitation= one species gains from another whilst having no detriment to the second species
3) parasitism = one species gains at the expense of another
4) mutualism = both benefit
5) commencsalism - similar to facilitation e.g. Bacteria living on you (no harmful)
6) ammensalism - no one benefits but one loses out e.g. Algal blooms in water
Define indirect competition
Normal competition where both organisms are competimg for the same shared resource
What is direct competition
A direct antagonism between plant soecies e.g. Strangling or parasitism
Differntiate between hemi and haloparasitic organisms
Hemi will have some chlorophyll e.g.witch weed
Halo parasitic - fully parasitic no chlorophyll e.g. Dodder
Define allelopathy
Chemical inhibit one plant by another via a release into the environment
Nitrogen depostion can be wet or dry and reduced or oxidised
Give an example of each combination
Dry oxidised - Nitrous oxide N20
Wet oxidised - No3 - (nitrate)
Wet reduced - NH4+ ammonium
Dry reduced - NH3 ammonia
What are the two major sources of anthropgenic nitrogen?
Fossil fuel combustion - NOx (oxidised emissions)
Agriculture - NHy (reduced emissions)
What is the UK N budget, how much do we export to Europe?
700 ktonnes per years
Export 321 tonnes
What are three factors effecting nitrogen deposition?
Distance from source - oxidied forms have larger dispersal distances than reduced forms
Surface roughness - faster on rough surfaces (woodland rougher than grassland)
Rainfall - more rainfall = more deposition
Describe the seeder feeder effect
A feeder cloud - orographic feeder sits above the hill and gathers pollution
Seeder cloud moves above and rains through the orographic cloud hence releasing all the pollution
Where are some N depostion hotspots? Why?
Brecon beacons and Peak District
- both agricultural land but very near industrial cities
Describe how eutrophication due to nitrogen depostion poses an ecological threat
Nitrogen accumulates in the soil and enables more nitrophillus species to grow = compeitive exclusion
Why does increased nitrogen deposition cause more acidic soil?
Depletes the quantity of cations in the soil
Increases the number of toxic metals
Is direct toxicity from nitrogen a big problem ecologically?
No
Eutrophication in dutch chalk lands caused which plant to expand?
Brachypodium pinnatum
What is the current average nitrogen deposition and what effect will this have on species richness? What about in peak district?
17kg per hectare
Reduce richness by 4/5 species
30kg per hectare
Recuce richness by half
Describe how nitrogen depositon is effecting the ecosystem service of providing clean drinking water
Looked at monoliths - rain water through monoliths Measured how much nitrogen left the soil 65-75% retained in calcareous grassland 37-16% retained acidic grassland Hence nitrogen is being kept in the water - worse quality for drinkng
How much will nitrogen depostion have increased by 2050?
Doubled
Nitrogen deposition is the ____ greatest
3rd
The ____ world biodiveristy hotspots make up ______ of the worlds global surface but contains ______ of global biodiversity
38
2.4
43
