http://www.unece.org/env/documents/2010/eb/wge/ece.eb.air.wg.1.2010.14.e.pdf and
ftp://ftp.mnp.rivm.nl/cce/outgoing/EmpCLBackgrDocuments
Overview of empirical critical loads for nitrogen deposition (kg N ha-1 yr-1) to natural and semi-natural ecosystems (column 1), Classified according to EUNIS (column 2), as originally established in 2003 (column 3), as revised in 2010 (column 4).The reliability is qualitatively indicated by ## reliable; # quite reliable and (#) expert judgement (column 5). Column 6 provides a selection of effects that can occur when critical load are exceeded. Finally, changes with respect to 2003-values are indicated in bold
|
Ecosystem type |
EUNIS- code |
2003 kg N ha-1yr-1 and reliability |
2010 kg N ha-1yr-1 |
2010 Reliability |
Indication of exceedance |
|
Marine habitats (A) |
|||||
|
Mid-upper saltmarshes |
A2.53 |
|
20-30 |
(#) |
Increase in dominance of graminoids |
|
Pioneer and low-mid saltmarshes |
A2.54 and A2.55 |
30-40 (#) |
20-30 |
(#) |
Increase in late-successional species, increase in productivity |
|
Coastal habitat (B) |
|||||
|
Shifting coastal dunes |
B1.3 |
10-20 (#) |
10-20 |
(#) |
Biomass increase, increase N leaching |
|
Coastal stable dune grasslands (grey dunes) |
B1.4 a |
10-20 # |
8-15 |
# |
Increase tall graminoids, decrease prostrate plants, increased N leaching, soil acidification, loss of typical lichen species |
|
Coastal dune heaths |
B1.5 |
10-20 (#) |
10-20 |
(#) |
Increase plant production, increase N leaching, accelerated succession |
|
Moist to wet dune slacks |
B1.8 b |
10-25 (#) |
10-20 |
(#) |
Increased biomass tall graminoids |
|
Inland surface water habitats (C) |
|||||
|
Softwater lakes (permanent oligotrophic waters) |
C1.1 c |
5-10 ## |
3-10 |
## |
Change in the species composition of macrophyte communities, increased algal productivity and a shift in nutrient limitation of phytoplankton from N to P |
|
Dune slack pools (permanent oligotrophic waters) |
C1.16 |
10-20 (#) |
10-20 |
(#) |
Increased biomass and rate of succession |
|
Permanent dystrophic lakes, ponds and pools |
C1.4d |
|
3-10 |
(#) |
Increased algal productivity and a shift in nutrient limitation of phytoplankton from N to P |
|
Mire, bog and fen habitats (D) |
|||||
|
Raised and blanket bogs |
D1 e |
5-10 ## |
5-10 |
## |
Increase in vascular plants, altered growth and species composition of bryophytes, increased N in peat and peat water |
|
Valley mires, poor fens and transition mires |
D2 f |
10-20 # |
10-15 |
# |
Increase in sedges and vascular plants, negative effects on bryophytes |
|
Rich fens |
D4.1 g |
15-35 (#) |
15-30 |
(#) |
Increase in tall graminoids, decrease in bryophytes |
|
Montane rich fens |
D4.2 g |
15-25 (#) |
15-25 |
(#) |
Increase in vascular plants, decrease in bryophytes |
|
Grasslands and tall forb habitats (E) |
|||||
|
Sub-atlantic semi-dry calcareous grassland |
E1.26 |
15-25 ## |
15-25 |
## |
Increase in tall grasses, decline in diversity, increased mineralization, N leaching; surface acidification |
|
Mediterranean xeric grasslands |
E1.3 |
|
15-25 |
(#) |
Increased production, dominance by graminoids |
|
Non-Mediterranean dry acid and neutral closed grassland |
E1.7 b |
10-20 # |
10-15 |
## |
Increase in graminoids, decline of typical species, decrease in total species richness |
|
Inland dune pioneer grasslands |
E1.94b |
10-20 (#) |
8-15 |
(#) |
Decrease in lichens, increase in biomass |
|
Inland dune siliceous grasslands |
E1.95b |
10-20 (#) |
8-15 |
(#) |
Decrease in lichens, increase in biomass, increased succession |
|
Low and medium altitude hay meadows |
E2.2 |
20-30 (#) |
20-30 |
(#) |
Increase in tall grasses, decrease in diversity |
|
Mountain hay meadows
|
E2.3 |
10-20 (#) |
10-20 |
(#) |
Increase in nitrophilous graminoids, changes in diversity |
|
Moist and wet oligotrophic grasslands |
|
|
|
|
|
|
|
E3.51 |
15-25 (#) |
15-25 |
(#) |
Increase in tall graminoids, decreased diversity, decrease of bryophytes |
|
|
E3.52 |
10-20 # |
10-20 |
# |
Increase in tall graminoids, decreased diversity, decrease of bryophytes |
|
Moss and lichen dominated mountain summits |
E4.2 |
5-10 # |
5-10 |
# |
Effects upon bryophytes or lichens |
|
Alpine and subalpine acid grasslands |
E4.3 |
10-15 |
5-10 |
# |
Changes in species composition; increase in plant production |
|
Alpine and subalpine calcareous grasslands |
E4.4 |
10-15 |
5-10 |
# |
Changes in species composition; increase in plant production |
|
Heathland, scrub and tundra habitats (F) |
|||||
|
Tundra |
F1 |
5-10 # |
3-5 |
# |
Changes in biomass, physiological effects, changes in species composition in bryophyte layer, decrease in lichens |
|
Arctic, alpine and subalpine scrub habitats |
F2 |
5-15 (#) |
5-15 |
# |
Decline in lichens, bryophytes and evergreen shrubs |
|
Northern wet heath |
F4.11 |
|
|
|
|
|
|
F4.11e,h |
10-20 (#) |
10-20 |
# |
Decreased heather dominance, decline in lichens and mosses, increase N leaching |
|
|
F4.11e,h |
10-25 (#) |
10-20 |
(#) |
Transition from heather to grass dominance |
|
Dry heaths |
F4.2 e; h |
10-20 ## |
10-20 |
## |
Transition from heather to grass dominance, decline in lichens, changes in plant biochemistry, increased sensitivity to abiotic stress |
|
Mediterranean scrub |
F5 |
|
20-30 |
(#) |
Change in plant species richness and community composition |
|
Forest habitats (G) |
|||||
|
Fagus woodland |
G1.6 |
|
10-20 |
(#) |
Changes in ground vegetation and mycorrhiza, nutrient imbalance, changes soil fauns |
|
Acidophilous Quercus-dominated woodland |
G1.8 |
|
10-15 |
(#) |
Decrease in mycorrhiza, loss of epiphytic lichens and bryophytes, changes in ground vegetation |
|
Meso- and eutrophicQuercus woodland |
G1.A |
|
15-20 |
(#) |
Changes in ground vegetation |
|
Mediterranean evergreen (Quercus) woodland |
G2.1 |
|
3-7 |
(#) |
Changes in epiphytic lichens |
|
|
|
|
|
|
|
|
Abies and Piceawoodland |
G3.1 |
|
10-15 |
(#) |
Decreased biomass of fine roots, nutrient imbalance, decrease in mycorrhiza, changed soil fauna |
|
Pinus sylvestriswoodland south of the taiga |
G3.4 |
|
5-15 |
# |
Changes in ground vegetation and mycorrhiza, nutrient imbalances, increased N2O and NO emissions |
|
Pinus nigra woodland |
G3.5 |
|
15 |
(#) |
Ammonium accumulation |
|
Mediterranean Pinuswoodland |
G3.7 |
|
3-15 |
(#) |
Reduction in fine root biomass, shift in lichen community |
|
Spruce taiga woodland |
G3.A i |
10-20 # |
5-10 |
## |
Changes in ground vegetation, decrease in mycorrhiza, increase in free algae |
|
Pine taiga woodland |
G3.B i |
10-20 # |
5-10 |
# |
Changes in ground vegetation and in mycorrhiza, increase occurrence of free algae |
|
Mixed taiga woodland with Betula |
G4.2 |
|
5-8 |
(#) |
Increased algal cover |
|
Mixed Abies-PiceaFagus woodland |
G4.6 j |
|
10-20 |
(#) |
|
|
Overall |
|
|
|
|
|
|
Broadleaved deciduous woodland |
G1 k,l |
10-20 # |
10-20 |
## |
Changes in soil processes, nutrient imbalance, altered composition mycorrhiza and ground vegetation |
|
Coniferous woodland |
G3 k,l |
10-20 # |
5-15 |
## |
Changes in soil processes, nutrient imbalance, altered composition mycorrhiza and ground vegetation |
|
|
|
|
|
|
|
a) For acid dunes, use the 8-10 kg N ha-1 yr-1 range, for calcareous dunes use the 10-15 kg ha-1 yr-1 range.
b) Use the lower end of the range with low base availability; use the higher end of the range with high base availability.
c) This critical load should only be applied to oligotrophic waters with low alkalinity with no significant agricultural or other human inputs. Use the lower end of the range for boreal and alpine lakes, use the higher end of the range for Atlantic softwaters.
d) This critical load should only be applied top waters with low alkalinity with no significant agricultural or other direct human inputs. Use the lower end of the range for boreal and alpine dystrophic lakes.
e) Use the high end of the range with high precipitation and the low end of the range with low precipitation; Use the low end of the range for systems with a low water table, and the high end of the range for systems with a high water table. Note that water table can be modified by management.
f) For D2.1 (quaking fens and transition mires): use lower end of the range (#).
g) For high latitude systems: use lower end of the range.
h) Use the high end of the range when sod cutting has been practiced; use the lower end of the range with low intensity management.
i) In 2003 presented as overall value for boreal forests.
j) Included in studies which were classified into G1.6 and G3.1.
k) In 2003 presented as overall value for temperate forests.
l) For application at broad geographical scales.