Summary of Nutrient Nitrogen Critical Loads from Noordwijkerhout Workshop June 2010

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

 

 

 

 

 

 

  • Molinia caeruleameadows

     

  • E3.51

    15-25 (#)

    15-25

    (#)

    Increase in tall graminoids, decreased diversity, decrease of bryophytes

     

  • Heath (Juncus) meadows and humid (Nardus stricta) swards

     

  • 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

     

     

     

     

     

  • 'U' Calluna-dominated wet heath (upland moorland)

     

  • F4.11e,h

    10-20 (#)

    10-20

    #

    Decreased heather dominance, decline in lichens and mosses, increase N leaching

     

  • 'L' Erica tetralixdominated wet heath (lowland)

     

     

  • 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.

    This page was accessed on Monday, November 12, 2018 20:38