1,721,330 research outputs found
Introduction [Options for ammonia mitigation: guidance from the UNECE Task Force on Reactive Nitrogen]
No full textBeyond nitrogen critical loads – is there a role for the ‘Ecosystem Services’ approach?
No full textThis paper considers the extent to which indicators of critical load exceedance capture the potential
impacts of changes in nitrogen deposition on ecosystem services. It shows that there are significant
links between nitrogen deposition and a large range of ecosystem services. There is potential for
indicators to be adapted to provide more specific qualitative information for Natura 2000 sites of
the implications of critical load exceedance for ecosystem services.
For the provision of ecosystems goods (e.g. food, fuel, fibre) and water quality and erosion
regulation, it is likely that quite specific information can be provided on the effects of nitrogen
deposition. For others, such as pollination and cultural services, the implications for ecosystem
services are likely to depend on the specific changes in species composition that are found in
specific habitats and sites. The issue of climate regulation has been identified as a critical ecosystem
service, but this effect is not currently considered explicitly in setting critical loads, and given the
complexity of the potential effects of nitrogen deposition on different greenhouse gas fluxes, it
seems impractical to include this in any simple assessment of effects of critical load exceedance.
There are ecosystem services where exceedance of the established empirical critical load for
nitrogen input can be a positive outcome, for example, increases in more nitrophilous species
increasing productivity in certain grassland types and increased grass growth stabilising coastal
dunes, and hence enhancing erosion regulation. An ecosystems approach would therefore have
value in informing the prioritization of conservation management practices in areas with high
nitrogen deposition, depending on the ecosystem service that is most valued at any particular site.
However, given that the cause and effect relationships underlying important ecosystem services are
often complex and not sufficiently understood, more data and research is needed to provide specific
guidance on potential conservation priorities
Executive summary [Options for ammonia mitigation: guidance from the UNECE Task Force on Reactive Nitrogen]
No full text
Evaluation of nitrogen indicators on ombrotrophic acid bogs: observations from a nitrogen manipulation study.
No full text• Among Natura 2000 ecosystems, ombrotrophic bogs/peatlands are likely to be one of the
most sensitive to reactive N deposition.
• This paper briefly examines methods of evaluating species, growing on an ombrotrophic
bog, to different N forms using a case study from Whim bog to illustrate peatland vegetation
response to wet and dry N deposition.
• Vegetation cover data are used to examine typical N indicators in terms of species richness,
diversity, functional group response, Ellenberg indicator values, species cover and National
Vegetation Classification (NVC).
• In addition an ordination technique is applied to the data and principal response curves
(PRC) generated to examine temporal community response to the N deposition.
• The N indicators tested here of species richness, diversity, Ellenberg indicator values and
NVC were insensitive to the apparent effects of the N deposition treatments. This is despite
significant responses at both the species and community levels detected using a weighted
cover index and PRC.
• In addition responses varied with N form and particular functional groups e.g. species from
the ericoids or Sphagnum show differential responses: Calluna responds negatively to
ammonia whereas Vaccinium myrtillus and Empetrum nigrum have responded positively,
the hummock forming S.capillifolium is negatively affected by N while the wetter loving S.
fallax increased in response to N additions.
• The results emphasise that indicators represent a range of sensitivities and a considered
approach to the choice of indicator needs to be applied with reference to the ecosystem
under question and form of nitrogen applied.
• Future research efforts should concentrate on developing predictive indicators with
sufficient sensitivity to show species level change that can be used to detect and predict loss
of important peatland species or groups
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