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In the Netherlands a monitoring programme is in operation to map the effects of ammonia pollution with epiphytic lichens. The method is presented here and the results are statistically correlated with abiotic data. The abundance of nitrophytes on Quercus robur appears to be a useful parameter. Detailed spatial patterns of ammonia pollution can be obtained with lichens. To avoid interference, it is important to consider other influences, for example dust, climate, exposure, age of the trees and other pollutants.
31(1): 9-20 (1999)
Article No.
Available online at on IDE^-L
M. van HERK*
Abstract: In the Netherlands a monitoring programme is in operation to map the
effects of ammonia pollution with epiphytic lichens. The method is presented here
and the results are statistically correlated with abiotic data. The abundance of
nitrophytes on
Quercus robur
appears to be a useful parameter. Detailed spatial
patterns of ammonia pollution can be obtained with lichens. To avoid interference,
important to consider other influences, for example dust, climate, exposure, age
of the trees and other pollutants. [, 1999 The British Lichen Society
Since the 1950s lichens have often been used to map sulphur dioxide (SO2) air
pollution in the Netherlands (Barkman 1958; de Wit 1976). During recent
decades a progressive recovery of species sensitive to SO2 took place (van
Dobben 1993), due presumably to the falling levels of SO2. Now there are
several records of species that had not been seen for nearly
century (van Herk
& Aptroot 1996). There are even species new to science that were absent
before (Aptroot & van Herk 1998).
Some changes, however, do not fit within the spatial patterns and temporal
changes in SO2. In the course often years a spectacular increase in nitrophytic
species has taken place in all parts of the country with a high cattle density (van
der Knaap 1984; de Bakker 1987; van Dijk 1988). In these areas the trees
have become covered with such species as
This phenomenon is especially apparent
on trees with acid bark
on which nitrophytes were absent or
scarce before. In the same period several acidophytes, for example Evernia
prunastri, Hypogymnia
and Pseudevernia furfura-
rapidly decreased (van Dijk 1988; van Herk 1990). A large number of
stations formerly covered with these species are now totally devoid of them.
Outside the areas with intensive cattle breeding these changes are less
Air pollution with ammonia (NH3) is considered to be the most important
cause of these changes. In the Netherlands the correlation between ammonia
and lichens has been studied repeatedly. Correlations are reported by de
Bakker & van Dobben (1988), van Dijk (1988), de Bakker (1989), Aptroot
van Herk (e.g. 1990, 1991, 1993, 1995, 1996), van Dobben (e.g.
1993) and van Dobben
Wamelink (1992). In Belgium (Vlaanderen)
*Lichenologisch Onderzoekbureau Nederland, Goudvink 47, NL-3766 WK Soest, The
0024-2829/99/010009+12 S30.00/0 © 1999 The British Lichen Society
the effects of ammonia have been studied by Hoffmann (1993). In Great
Britain effects of intensive cattle breeding have been reported from Devon
(Benfield 1994).
Field observations show a clear relationship between the distance from a
livestock farm and the abundance of nitrophytes on trees (Fig. 1A-C). Some
of the species are more dominant, whereas other species are present only in
small quantities in the immediate surroundings of the farms, for example
Phaeophyscia nigricans, Candelariella aurella and Caloplaca holocarpa (Fig. 2).
Very polluted sites show a striking resemblance to epilithic vegetation of
calcareous substrata such as concrete. Even
medians and
Caloplaca decipiens
have been found at such stations on trees.
The transition zone surrounding a livestock farm is usually more or less
compressed at the west side and a little elongated at the east side, indicating
that westerly winds are more frequent. The effects are definitely not caused
only by slurry. Even in woods small branches at the tops of trees are now
covered with Physcia tenella and Xanthoria polycarpa.
The atmospheric behaviour of ammonia supplies an explanation for the
close transitions. At 100 m distance from a source, c. 10% of the ammonia is
deposited and at 1000 m this is c. 20% (Asman & van Jaarsveld 1990a).
However, the greater part of the ammonia disappears into the atmosphere
close to the source so gradients of ammonia concentrations may be abrupt at
ground level.
Until 1980 epiphytic nitrophytes on acid bark were largely confined to
farmyards, present in small quantities on trees surrounding dunghills. There
was no indication that gaseous ammonia was important for their occurrence,
only the direct influence of dung was apparent. At the end of the 1970s most
farmers switched over from a heavy solid straw-mixed product to liquid
manure. This switch might be an important cause of the observed changes, as
already suggested by Benfield (1994).
A few studies on bark chemistry demonstrate that the effects of ammonia on
nitrophytes are not primarily caused by the increased availability of nitrogen
(de Bakker
van Dobben 1988; van Herk 1990). More important is the rise
in bark pH, caused by the adsorption of NH3. In areas with a high cattle
density the pH of the Common Oak
pH 4-5, can
rise to c. 6-5. At pH 6-5 most acidophytes are replaced by nitrophytes. The
term, ' nitrophytic ' assumes that such species require some form of nitrogen.
However, a high pH seems to be a more direct reason for their occurrence. A
better name should be ' neutrophytic ' but this name is already used for
another ecological group. Real neutrophytic lichens (indifferent species), for
example most Parmelia and Ramalina species seem not to be affected
significantly by ammonia, although a slight positive reaction on ammonia
might be possible.
The Netherlands is one of the most polluted parts of Europe with respect to
ammonia. Ammonia is especially a huge problem in regions with acid sandy
In large areas of the Netherlands the emission values exceed 10 000 kg
NH3 km
2 year
~ *
(Asman & van Jaarsveld 1990a). Surprisingly ammonia
contributes to about 45% of the total acidification in the Netherlands.
Although ammonia is not acid in
nitrification transforms most of the
* NIW 4-5
NIW 1-2
•NIW 3-4
NIW 0-1
NIW 2-3
jwith oaks
with oaks
1. Spatial patterns in a hypothetical area with four livestock farms. A. Topography; B. Quantity of nitrophytes (NIW) on trees (all
C. Reconstruction of ammonia pollution isolines based on nitrophytes.
Physcia tenella
Xanthoria polycarpa
Physcia adscendens
Xanthoria candelaria
Xanthoria parietina
Caloplaca holocarpa
Candelariella aurella
Phaeophyscia nigricans
Rinodina gennarii
Candelariella vitellina
Lecanora dispersa (incl. L. hageni)
Phaeophyscia orbicularis
Candelariella reflexa
Physcia caesia
Physcia dubia
High threshold
Low threshold
2. Schematic reaction of several nitrophytic species to ammonia pollution in the Netherlands based on
observations on
The degree of pollution at which a species appears is called the threshold. Most of the
species become more common at a higher ammonia pollution.
1999 Ammonia pollution in the Netherlands—van Herk 13
ammonia into nitric acid (HNO3) after deposition. As far as is known, this
process only takes place in the soil, not on the bark of trees (van Dobben
Not all emitted ammonia appears to be deposited unchanged.
Some ammonia reacts in the atmosphere with acids, leading to the deposition
of, for example, ammonium sulphate [(NH4)2SO4], thus part of the emitted
ammonia will be transformed into ammonium (NH4+).
Regional ammonia and ammonium concentration and deposition calcu-
lations are available by means of mathematical models based on cattle density
(Asman & Jaarsveld 19906). Figure 3A, B shows the ammonia and ammo-
nium concentrations based on these calculations. Real measurements of
ammonia and ammonium are only acquired at a limited number of stations
because the costs are very high.
To fill a gap in our knowledge of ammonia pollution, most of
authorities charged with reducing their pollution have taken the initiative to
map parts of their territory using
From 1989 onwards every year a part
of Holland has been mapped using nitrophytes and acidophytes. This
information is now used to take measures; for example, state-aided removal of
livestock farms from the surroundings of nature reserves.
Materials and Methods
The imponant role of bark pH as an intermediate factor requires that the effects of ammonia are
mapped with only one tree species, preferably one with acid bark. Therefore only
Quercus robur
used. A limited area (province of Utrecht) has been mapped with several different tree species in
order to investigate the effect of the tree species used. Some tree species have been compared by
means of regression analyses (Table 1).
At the moment about 5500 sampling sites, each consisting often trees, have been investigated,
on average one site per 4 km2, covering about half of the Netherlands (Fig. 4). Sampling sites are
at least at a 100 m distance from a livestock farm. Only straight and exposed trees, without low
branches or shrubs in front, are used. Usually wayside trees are suitable. During subsequent years
additional regions will be mapped. Although all epiphytic lichens have been examined, only
selected results on nitrophytes and acidophytes are considered here.
To achieve the mapping an integrated parameter was designed, the NIW (' Nitrofiele Indicatie
Waarde '). The NIW is defined as the mean number of nitrophytes found on the bark of one
Species covering more than
dm2 count as double. The following species are considered
to be nitrophytes: Caloplaca citrina, C. holocarpa, Candelariella aurella, C. reflexa, C. vitellina,
C. xanthostigma, Lecanora muralis, L dispersa s. lat. (inc. L. hageni), Phaeophyscia orbicularis,
nigricans, Physcia adscendens, P. caesta, P. dubia, P. tenetta, Rinodina gennarii, Xanthoria
candelaria, X.
X. parietina and X. polycarpa. Note that common species present on all
trees add much more to the NIW (2 points) than species present in small numbers on one out of
ten trees only (0-1 point), thus quantity is an important element in the NIW. All common
nitrophytes are used; only a few nitrophytes for which interference with sulphur dioxide is
suspected (e.g.
Candelaria concolor)
have been omitted.
The above calculation has also been carried out with acidophytes, mainly to investigate whether
acidophytes reveal matching results. The species united into the AIW (' Acidofiele Indicatie
Waarde ') are Cetraria chlorophytta, Chaenotheca ferruginea, Cladonia (all species taken together),
Evemia prunastri, Hypocenomyce scalaris, Hypogymnia physodes, H. tubulosa, Lecanora aitema, L.
L. pulicans, Lepraria incana
Parmelia saxatilis,
ambigua, Placynthidla icmalea, Platismatia glauca, Pseudevemia furfuracea, Trapeliopsis flexuosa,
(all species taken together). At all sites the NIW and AIW have been
calculated and both NIW and AIW have been used to produce detailed maps by means of linear
To investigate statistical significance, the NIW was related by means of multiple regression to
several abiotic parameters,
ammonia air concentration, ammonium air concentration, sulphur
isolines 2.0 6.0 10.0 14.0 18.0isolines3.0 4.0 5.0 6.0 7.0
3. Ammon,a (A) and ammonium (B) ah' concentrate in the Netherlands in 1988 (,gm
[source: National Institute of Public
Health and Environmental Protection (RIVM)].<
1999Ammonia pollution
the Netherlands—van Herk 15
Nitrofiele Indicate Waaide
i 0.5-1
[_1I] 1.5-2.9
Built-up areas
No dala
Ammonia pollution
in the
Netherlands derived from
Quercus robur (NIW).
concentration, the structure
the landscape, distance from livestock farms, distance
from maize fields, the girth
the trees,
the geographical position
the Netherlands.
allows comparison
their abundance
nitrophytes. Both tree species yield
deposition values
do not
exceed, respectively,
1000 and
500 mol ha~
Furthermore, with both tree species there
is a
dose-response relationship
and the
explained variance
There was insufficient data from
Salix, Tilia
dose-response relationship
but the explained variance
only small, which means that factors other than
ammonia might dominate
results. Tilia
do not
dose-response relationship
at all.
1. Calculated linear
for the abundance of
(NIW) on Quercus robur and
Populus x canadensis against ammonia (NHJ deposition values (after van Herk 1996)*
Linear model: Y = a+bXExplained variance Degrees of freedom Probability level
= - 2-1 x 0-0020 NH,
= - 1-5 x 0-0028 NH,
*Dependent variables: Nitrofiele Indicatie Waarde with Quercus robur (NIW
) and Nitrofiele
Indicatie Waarde with Populus x canadensis (NIW
). Independent variable: ammonia deposition
values (molha
2. Multiple
with the abundance of
on Quercus robur (NIW) as
variable and nine
parameters as independent variables (after van Herk 1995)*
In model
Girth of trees
Maize fields
Livestock farms
Regression coefficient
+ 0-2373
+ 0-0028
+ 0-0042
Not in model
Sulphur dioxide
*A total of 2349 sampling sites throughout the Netherlands were analysed. A variable enters the
model when F-Enter is at least 4-00 (corresponds to /><0-05). The contribution of the variables
on the left-hand side ('in model') is significant (.P<0-05). No significant contribution to the
model could be proved for the variables on the right-hand side (' not in model'). Dependent
Nitrofiele Indicatie Waarde (NIW). Explained variance
47-l%, degrees of free-
^Explanation of variables:
mean ammonia (NH
) air concentration per 5x5 km
(ug . m~
) [taken from the
National Institute of Public Health and Environmental Protection (RIVM)];
mean ammonium (NH
) air concentration per 5x5 km
(|ig . m~
) (taken from
girth 0/wees=girth of the sampled trees (dm);
roughness ' of the landscape, parameter to express to what rate the landscape causes
turbulence and dilution (taken from RIVM);
maize fields=presence of maize fields in the surroundings (—m distance);
farms=presence of livestock farms in the surroundings (—m distance);
sulphur dioxide=mean SO
air concentration per 5x5 km
(n . m~
) (taken from RIVM);
X-co-ordinate/Y-co-ordinate=^West-Rast/l>lorth-So\ith position in the Netherlands.
Other calculations (Table 2) make clear that Q. robur is very useful
for mapping ammonia. Unfortunately, Q.
is absent or sparse in the
western part of the Netherlands. Investigations are being carried out to
find whether
is an appropriate alternative in areas where
not occur.
Figure 4 shows the abundance of nitrophytes in the area mapped so far.
Detailed patterns of NIW are notable; areas with high and low values are
situated close to each other. The overall similarity of the spatial patterns of
NIW and the ammonia air concentration (Fig. 3A) is striking. There is not
only a good correspondence concerning the polluted areas (e.g. Gelderse
1999 Ammonia pollution in the Netherlands—van Herk 17
Vallei) and the cleaner areas (e.g. Drenthe). The size and position of the
smaller polluted regions like Friese Wouden and Kempen is also clearly
visible. It was not attempted to map individual livestock farms, although
clusters of big farms are often visible in Fig. 4. The pattern derived from the
lichen composition (Fig. 4) is obviously much more detailed than the pattern
calculated using cattle density (Fig. 3A). Therefore, the lichen method is
much more informative.
The similarity between the NIW and the ammonium air concentration
(Fig. 3B) is only slight. Multiple regression confirms this. The ammonia air
concentration contributes considerably to the explained variance of the NIW,
but the contribution of the ammonium air concentration is not significant
(Table 2). The explanation is that ammonium has no effect on bark pH. Thus,
only the effects of ammonia are visible with nitrophytes because ammonia
gives rise to an increase in the pH. The increased nitrogen availability caused
by ammonium apparently has no effect on the occurrence of nitrophytes, as
already concluded in connection with bark chemistry. Neither has nitrogen
oxide (NOX), emitted mainly by traffic, any effect on the occurrence of
nitrophytes (statistical calculation not presented).
The presence of livestock farms in the surroundings adds considerably to
the variance (Table 2). Both parameters ' ammonia ' and ' livestock farms ' are
good for 43% explained variance. The remaining four variables with a
significant contribution in Table 2 add only 4%.
Maize fields are usually spread heavily with slurry. The presence of
maize fields, however, has only a slight effect on the presence of nitrophytes
(Table 2). Perhaps only sources of ammonia with a continuous character have
a clear effect, as maize fields are spread with slurry only once or twice a year.
More important is the structure of the landscape. Very open ' windy'
landscapes with only exposed trees yield more nitrophytes than landscapes
with many hedges, bushes and ' hidden ' rows of trees. In the last case the
ammonia is probably spread over a lot of objects resulting in a dilution effect.
An important cause of interference is the age of the trees. The NIW appears
to be higher on young (slender) trees (see below). Nitrophytes (NIW) and
acidophytes (AIW) appear to have oppositing behaviour (r=
Thus, on trees with high NIW values, AIW values are usually low
and vice versa.
There are also other differences in behaviour between nitrophytes and
acidophytes. Multiple regression shows that acidophytes are sensitive to both
ammonia and ammonium (whereas nitrophytes react only to ammonia). This
phenomenon is confirmed by field observations. At a lot of stations acido-
phytes (e.g. Hypogymnia physodes and Pseudevernia furfuracea) have disap-
peared on a large scale without any or only a small increase of nitrophytes.
This is especially the case at some distance from the well-known areas with a
high cattle density. (Fig. 3A) but within the areas for which a high ammonium
deposition is calculated (Fig. 3B). This suggests that (at least some) acido-
phytes are not only sensitive to a rise of the pH, but also sensitive to an
increase in the ammonium content of the bark. Competition with other
lichens, for instance increasing nitrophytes, is in most cases not an important
reason for their disappearance.
The abundance of epiphytic nitrophytes can be used effectively to map spatial
patterns of ammonia pollution. Lichens have the advantage that very detailed
maps can be produced at relatively low costs. Only (expensive) direct
measurement of the ammonia air concentration reveals comparable detailed
information. At this moment permanent measurements are carried out at
about 100 lichen monitoring stations by a Dutch institute for technical
research (TNO). For this purpose special measuring tubes were developed,
which can be suspended from a monitored tree. Once a month these tubes
are collected and the mean ammonia concentration during the preceding
month can be calculated. In the near future a comparison between lichen
composition and these ammonia air concentrations will be carried out. These
calculations are important for a further validation of the detailed patterns of
ammonia pollution observed with nitrophytic lichens (Fig. 4).
In other countries, on other substrata, or under other circumstances the
occurrence of nitrophytes may be less obviously linked to nitrogenous
emissions. The way in which nitrophytes react to the pH of the substratum
means that the observations cannot be compared with the straight reaction of
lichens to SO2. Interference from other factors, which might even be dominant
must be considered. To avoid interference it is important to consider the
influence of other factors such as climate, dust, the age of the trees, other
pollutants, dogs, bark wounds, and salt spray. Each of
will be discussed.
Climate is considered to be an important interfering factor. Within the
Netherlands a slight shift in climatic conditions is evident, from dry in the
South and East to slightly wetter near the coast and in the North. Some species
are more drought resistant (Xanthoria parietina, Physcia adscendens), whereas
other species are slightly more common in areas with higher precipitation
Within the area studied the effect of the climate as
a whole is probably negligible on the NIW. However a slight shift along
the Y-co-ordinate is apparent (Table 2), which might be due to climatic
Epiphytic nitrophytes also occur on the base of trees on calcareous soils,
especially under dusty circumstances. As most of the soils in the Netherlands
are non-calcareous and oligotrophic, dust is probably only a minor cause of
interference in the area studied. In countries with a very dry climate, drought
and dust might be dominant factors, preventing the use of nitrophytes as
indicators of ammonia pollution.
The age of the trees investigated appears to be important. Multiple
regression shows that on old trees fewer nitrophytes occur than on young trees
with the same NH3 pollution (Table 2). On young trees the NIW is about 0-7
NIW unit higher than on old
To avoid interference, trees with only slight
differences in age should be compared.
Nitrophytes are also common on trees polluted by dogs. In built-up areas it
is sometimes difficult to find ' clean ' trees. A practical solution might be not
to use the base of trees since such pollution generally reaches no higher than
50 cm. Near bark wounds nitrophytes are also common, especially on
and Fagus. Trees with bark wounds should be avoided.
1999 Ammonia pollution in the Netherlands—van Herk 19
However, on Q.
usually very few nitrophytes are to be found near bark
wounds. Finally, salt spray causes some influence in coastal areas, but the
effects seem to be restricted to a few kilometres along the coast.
Table 2 shows that there appears to be no effect of
on the NIW: in areas
with a high SO2 concentration there is no ' deficit' of
If the (not
significant) effect is calculated in a regression equation, the effect appears to be
only 0-01 unit, thus negligible. It is surprising that SO2 levels have no effect
on the spatial pattern of nitrophytes on oaks (NIWQu) in the Netherlands.
At the moment the SO2 level is very low; even in the most polluted areas
the concentration now rarely exceeds 30
3. It is likely that SO2 is not
limiting the occurrence of common nitrophytes any more. Furthermore no
effect of SO2 on the pH of the bark of Q.
could be traced (van Herk
Even trees in the centre of cities with only
Lecanora conizaeoides
appeared to have the same pH as trees in large woods with lush
pH 3-9). Only the effect of ammonia on the pH is apparent. However, the pH
of tree species with neutral bark may be influenced by SO2 levels. A
calculation carried out with
shows that this indeed seems to be the
Multiple regression with SO2 and NH3 on NIWPo shows a just
significant (but not dominant) effect of SO2 (van Herk 1997).
A sensitivity scale based on separate species has not been used to estimate
ammonia pollution, although clear differences in the species response exist
(Fig. 2). It is obvious that in the area studied the total quantity of nitrophytes
and acidophytes (NIW and AIW) at sampling sites are useful and sufficient
indicators. The use of separate species as indicators of pollution zones has the
disadvantage that a shift in response of a single species can disrupt the scale
Such a shift could be caused by spatial differences of other pollutants,
the climate or the ecology, as stated for X. parietina in connection with
I am grateful to Dr A. Aptroot and L. Spier for discussions on this subject and useful comments
on the manuscript. Furthermore, I am grateful to the provincial administrations of Groningen,
Friesland, Drenthe, Overijssel, Gelderland, Utrecht and Noord-Brabant for making this research
possible and giving me the opportunity to publish this paper.
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Accepted for publication 16 January 1998
... 2003, Marmor et al. 2017). The progressive eutrophication of the environment over the past few decades in Europe caused that the differences between lichen compositions on the bark of various deciduous species are becoming blurred in polluted areas (van Herk 1999, van Herk et al. 2003, Liška & Herben 2008, Spier et al. 2010. Roadside trees in NE Poland still constitute a specific habitat for lichens and this fact should be encouragement to well-targeted landscape management that aims to protect valuable environmental resources, including epiphytes. ...
... However, oaks as roadside trees are not characterised by an aboveaverage diversity of epiphytes and does not constitute an exceptional refuge for lichens in the Masurian Lakeland region. Presumably, this may be related to the change of oak bark parameters under the influence of habitat conditions characteristics for the transformed agricultural environment ( van Herk 1999, van Herk et al. 2003, Spier et al. 2010. This is partially reflected in our results; oak individuals, in terms of lichen compositions, are positioned close to trees considered less acid-barked and more nutrient-rich (Fig. 4). ...
... Large deposition of nitrogen compounds in agriculture and rural areas can considerably change the composition of epiphytic lichens, especially in the case of trees with naturally low bark pH ( van Herk 1999van Herk , 2001. Mineral fertilisers and manure constitute two main nitrogen inputs to agricultural land (Asta et al. 2002, Marschner & Rengel 2007. ...
Kubiak, D. & Osyczka, P. 2019. Tree avenues as reservoir for epiphytic lichens in deforested landscapes. – Herzogia 32: 398 – 420.Old tree avenues are a disappearing traditional element in European landscapes. Roadside trees constitute an important habitat for many groups of organisms and support the maintenance of biodiversity in deforested areas, but they are often neglected in conservation strategies. This study describes and analyses the conservation value of planted trees along rural roads in NE Poland for epiphytic lichens. A total of 105 trunks of seven deciduous tree species were examined. Lichen species inventories were assembled for trunks at a height up to two meters from the ground. A total of 99 lichen species was recorded. Lichen species richness and cover were dependent primarily on tree species. Diameter of trees was not significantly correlated with the number of species. Ulmus laevis and, to a lesser extent, Fraxinus excelsior and Acer platanoides, were be the most valuable tree species in terms of lichen species richness. Quercus robur as a roadside tree did not have above-average species numbers. Lichen species with a preference for eutrophicated or alkaline bark occurred in their largest numbers on Populus nigra agg. Betula pendula hosted the largest number of species avoiding eutrophication. Each tree species had its own set of exclusive lichens and hosted taxa which are red-listed in Poland; however, no single tree species alone guarantees preservation of the entire range of epiphytic lichens on roadside trees in the study area. Since tree avenues, especially those composed of multiple species, provide a suitable habitat for various rare and endangered lichens, potentially high conservation value should always be attributed to this element of local landscapes in low pollution areas.
... Hoofddoel was het vaststellen van de mate waarin Overijssel met ammoniak verontreinigd was, en de ruimtelijke verdeling daarvan. Het Overijsselse meetnet is na de start herhaald in 1994 ( van Herk, 1995), 1999), 2005(van Herk, 2006 en 2015 ( . Steeds zijn alleen de zandgronden opgenomen. ...
... Dit gegeven is belangrijk omdat het een verklaring geeft voor het feit dat de hoeveelheid ammoniakminnende korstmossen op eiken (de hoogte van de NIW) in gebieden met een SO 2 -vervuilingsgeschiedenis ongeveer even veel voorkomen als in gebieden die deze geschiedenis niet gekend hebben. Dit is nu zo, en dat was begin jaren '90 ook al zo ( van Herk, 1999). Dit komt doordat er bij eiken in beide situaties een initieel vergelijkbare schors-pH is. ...
... (Grof)gebogen schildmos Imshaugia aleurites 0,1 0,1 0,0 0,0 0,0 0,0 Dennenmos Jamesiella anastomosans 0,0 3,5 5,2 6,1 7,2 6,1 Aspergekorst Lecanactis abietina 0,0 0,0 0,1 0,1 0,1 0,1 Maleboskorst Lecania cyrtella 0,0 0,0 0,0 0,0 0,0 0,3 Boomglimschoteltje Lecania naegelii 0,0 0,0 0,0 0,0 0,0 0,6 Rookglimschoteltje Lecania rabenhorstii 0,0 0,0 0,0 0,0 0,3 0,0 Steenglimschoteltje Lecanora aitema 0,3 0,1 0,1 0,1 0,0 0,0 Dennenschotelkorst Lecanora argentata 0,6 0,6 1,3 1,6 2,7 2,2 Bosschotelkorst Lecanora barkmaniana 0,0 1,5 9 1,5 1,5 1,3 0,7 0,7 1,0 Groot takmos Ramalina lacera 0,0 0,3 0,3 0,3 0,4 0,6 Waaiertakmos Ramalina pollinaria 0,0 0,1 0,1 0,1 0,1 0,1 Sierlijk takmos Rinodina oleae 0,0 0,1 0,0 0,0 0,3 0,6 Donkerbruine schotelkorst Rinodina pityrea 0,0 0,0 0,0 0,0 0,6 0,0 Blauwe mosterdkorst Sporodophoron cretaceum 0,0 0,0 0,0 0,0 0,0 0,3 Witkring Strangospora pinicola 0,0 3,2 5,8 4,7 2,0 1,2 Gew. muggenstrontjesmos Trapeliopsis flexuosa 0,0 0,0 0,0 0,0 0,0 0,3 Blauwe veenkorst Trapeliopsis granulosa 0,9 0,9 1,7 1,2 0,8 1,5 Lichte veenkorst Tuckermanopsis chlorophylla 0,1 0,1 0,0 0,0 0,0 0,0 Bruin boerenkoolmos Usnea hirta 1,0 0,7 1,0 0,3 0,0 0,0 Bleek baardmos Varicellaria hemisphaerica 0,0 0,0 0,1 0,1 0,0 0,0 Boskringkorst Violella fucata 0,6 0,6 0,3 0,3 0,3 0,6 Trilzwamkorst Xanthoparmelia verruculifera 0,0 0,0 0,1 0,1 0, Bijlage 4. De NIW in 1994, 1999, 2005 en 2020 als functie van het type weg waarlangs de monsterpunten gelegen zijn (n= resp. 486, 497, 307, 152 en 248). ...
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Epiphytic lichens are monitored in the province of Overijssel in The Netherlands since 1989. This report deals with the results of the 6th round, carried out in 2020. All lichen species abundance changes over this period are calculated and discussed. Maps are provided, showing changes of the abundances of nitrophytes (expressed as NIW). Trends are calculated over all investigated years. Changes of NIW indicate that ammonia air pollution (NH3) has decreased since 1999, especially in agricultural areas due to clean air policy. However, very recently (> 2015) the NIW has increased again slightly, indicating a stagnation of the improvement. In built-up areas the NIW has increased over the whole period, probably due to car exhausts (ammonia emissions from catalytic converters and the application of AdBlue). Species with a sensitivity to ammonia (many acidophytes, expressed as AIW) are decreasing all the way since the start in 1989 due to a continuing deacidification of tree bark (ammonia has basic properties). This is a cumulative process, and will at its best only slow down at lower ammonia levels. Return of acid of bark properties (and acidophytes) at low ammonia levels is unlikely. Climate change is another important driving force for species abundance changes. Many atlantic species have increased. Indicator values for temperature have increased over the whole period, and similarly values for continentality have decreased.
... According to indicator species analysis, it was found that X. parietina and A. punctata indicated the lichen community composition of NNB. X. parietina is a nitrophytic species (Ruoss, 1999;Van Herk, 2001;Munzi et al., 2014) and its presence decreases in non-nitrogen-rich ecosystems (Van Herk, 1999;Munzi et al., 2014). Another nitrophytic species, A. punctata (Hauck, 2010) prefers organic and inorganic salts (Hafellner and Casares-Porcel, 2003) and, therefore, is resistant to air pollution and inorganic fertilizers (Smith et al., 2009). ...
... In addition, it was determined that the lichen community composition of AG is strongly related to P. orbicularis. This specie is extremely tolerance to nitrogen and dust (Ellenberg et al., 1992;Van Herk, 1999;Stapper and Kricke, 2004;Larsen et al., 2007), shows positive correlation with high amount of NO in terms of x frequency and number of individuals (Larsen et al., 2007). Furthermore, P. orbicularis has the highest eutrophication tolerance (according to ) among all species identified in the park. ...
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Epiphytic lichens are biological indicators, which can give information about the environmental changes of the ecosystem. The differences in richness and community compositions of lichens can indicate the environmental quality of their location. This study was done in order to examine the possible differences in richness and in community composition of lichens that may have occurred in the research area, Kurşunlu Waterfall Nature Park and surroundings. Kurşunlu Waterfall Nature Park and surroundings was divided into 4 sections; natural area near brook, natural pine forest area, planted pine forest area and agricultural greenhouses area. The study was planned to focus on epiphytic lichens living on Pinus brutia Ten. trees. European Guideline, which is a standardized method to assess lichen diversity (LDV) on tree bark for monitoring environmental stress, was used for monitoring quality of four different environmental conditions with lichens. In order to determine the differences of lichen community composition of these four conditions, some statistical analyses were performed. Lichen richness of planted pine forest area was found poorer and statistically different than the other areas. In addition, the lichen community composition of natural pine forest area was found significantly different than the agricultural greenhouse area and the natural area near brook, partly different than the planted pine forest area. Statistical evaluations indicate that the natural pine forest area had natural or semi-natural habitat characteristics and there was no or less eutrophication in this region. Also it showed that other areas were affected by the presence of human damage and eutrophic pollution load in the environment. This eutrophic pollution load was related to non-ecological agriculture applications around the park. This study proves that epiphytic lichens change their community composition by adapting to changes in environmental conditions. Also this study showed that lichens are strong indicators of environmental quality.
... 70% within 20-30 m: Davies et al., 2007). There are indications that lichen diversity and development in GBG might be influenced by nitrogen deposition: (1) the presence of the nitrophyte Candelariella xanthostigmoides (albeit in very small quantity) on many mature and young trees, and on lignum; (2) the rarity of Parmelia saxatilis s. lat., which is usually a prominent member of the Pseudevernietum furfuraceae association (James et al., 1977) but is also sensitive to nitrogen pollution (van Herk, 1999;Will-Wolf et al., 2015); and (3) the luxuriance on some young trees, and significant presence on some mature trees, of Parmelia sulcata s. lat., which, though not considered to be a nitrophyte, appears to be quite tolerant of nitrogen pollution (Davies et al., 2007;Smith et al., 2009). If nitrogenous pollutants are inhibiting lichen colonisation and growth in GBG and other Glasgow parks, then the ongoing switch from hydrocarbonfuelled to electrical vehicles bodes well for the future of these organisms throughout the city. ...
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A total of 62 lichen taxa was found during a survey of Glasgow Botanic Gardens, Scotland conducted in 2018-20. This adds 54 taxa to the previous list of 14 recorded in the Gardens. Twelve lichen species have not been previously recorded in Glasgow and two - Catillaria nigroclavata and Verrucaria dolosa - are new to VC77 (Lanarkshire). Factors affecting the distribution and diversity of lichens in the Gardens are discussed.
... Ihre Indikatoreigenschaften sucht man sich in verschiedenen Verfahren zunutze zu machen, um die räumliche Abstufung von Belastungen zu erkennen (z. B. Natho 1964, Hawksworth & Rose 1970, van Herk 1999, Larsen et al. 2006. Durch Einrichtung von Dauerbeobachtungspunkten läßt sich ferner auch die zeitliche Entwicklung solcher Belastungen verfolgen (Zimmer 2000, Kirschbaum et al. 2002, Franzen-Reuter et al. 2006, Janssen et al. 2007, Kirschbaum et al. 2010. ...
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In the Euroregion Neiße, epiphytic macrolichen vegetation had become destroyed nearly totally due to industrial air pollution, in particular SO2 and fly-ash, until the end of the 20th century. Meanwhile reimmigration takes place. We compared historical and current lichen flora of two areas whose previous lichen flora is well documented. In the area with reference collections from around the year 1800 (Meffersdorf/Unięcice in the Iser Mts.) the decline in species number is higher than in the area with reference collections from around the year of 1900 (Rothwasser/Czerwona Woda in the Görlitzer Heide forest). This is explained by the presence of ancient woodland species among the specimens collected in the Iser Mts. around 1800, whereas they were widely absent in the Görlitzer Heide forest already around 1900. In both areas, the historical records include species with very low toxitolerance, which were not found now. Apart from these species groups, species numbers are nearly equal now compared with the historical data in both areas. However, species composition has changed by about 40 %. Impact of climate change cannot be shown, which might be influenced by the fact that data on quantitative shifts are not available. Observed qualitative changes might be accidentally in the case of rare or inconstant species. But probably they also reflect the considerable changes in structure and tree species composition of the forests. For more precise conclusions, further monitoring should be based on a sufficient number of monitoring sites, which are ecologically characterised and precisely located, and the abundancies of the species should be noted. However, in order to further use the historical data for comparison purposes, in the historically better studied areas also in future a complete documentation of the species also outside the monitoring sites should be done.
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Alien tree species have been introduced to Europe and often used as roadside trees. Currently, preference is given to species that are adapted to urban climate and drier conditions. Native epiphytic lichens are adapted to local tree species; however, little is known whether a shift toward more alien roadside trees would affect the diversity of epiphytic lichens within cities. We considered three genera of roadside trees that are common in Hamburg (Germany) Acer, Tilia, and Quercus, each with a native and an alien species per genus. Species numbers, frequency and diversity of epiphytic lichens were assessed and compared. Tree locations were grouped according to three classes of increasing traffic volume as a proxy for air pollution. Mean bark pH values have been recorded for each tree individual. The species pairs Quercus robur/rubra and Acer platanoides/saccharinum showed significant differences in the diversity and abundance of lichens, with the alien species showing lower values. The species pair Tilia cordata/tomentosa did not show any significant differences. The number of nitrogen-tolerant lichen species differed little among all tree species. Lichen species richness decreased with increasing traffic volume for all tree species pairs, thus demonstrating the inhibiting effect of traffic on the occurrence of lichens. Bark pH differed little between the species pairs yet high traffic volume resulted in an increased bark pH. In conclusion, two out of three alien species had negative effects on lichen diversity. Further tree species should be assessed to better estimate the effect of alien roadside trees on lichen diversity.
Species composition and ecology of the epiphytic lichens collected on 31 species of the trees and shrubs at the rural settlements and their surrounding area were studied. In total 71 lichens species including 25 species on the fruit and berry crops were found. On many trees, even in forests the variety of species of lichens is strongly depleted. This is especially true for rural settlements, razing places, keeping and running cattle. Bryoria and Usnea species at the rural settlements and their surrounding area were not found. It was shown that G. scripta is a pioneer species on the speckled alder under the conditions of relatively strong shading and humidity.
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Epiphytic lichens are monitored in the province of Zeeland in The Netherlands since 1997. This report deals with the results of the 5th round, carried out in 2019. All lichen species abundance changes over this period are calculated and discussed. Detailed maps are provided showing the changes of the abundances of nitrophytes (expressed as NIW) over the five investigated years. NIW is used as indicator of ammonia pollution. Changes of NIW indicate that ammonia air pollution has decreased since 2006 in several agricultural areas due to clean air policy. In built-up areas with much traffic NIW increased, probably due to car exhausts (catalytic converter and application of AdBlue). The same holds for some industrial areas. There was no significant change since 2006 of the average NIW in Zeeland as a whole. Climate change is another important driving force for species abundance change. Many atlantic species have increased. Indicator values for temperature have increased, and values for continentality have decreased.
Question Biodiversity surveys of epiphytic bryophytes and lichens on standing trees are mostly restricted to the lowermost 2 m, since sampling above this level is time‐consuming and therefore expensive. However, sampling only the stem base is likely to result in underestimation of forest epiphyte diversity, because microclimate and physico‐chemical site conditions, both of which vary with height above the ground, play important roles for poikilohydric organisms. We investigate variation in epiphyte diversity and composition along the vertical gradient in forests and discuss factors that may potentially account for height‐dependent distribution patterns. Location Montane primeval beech forest Havešová in the Carpathians, eastern Slovakia. Methods Ten circular plots, each 500 m², were selected randomly in an area severely affected by windfall. Epiphytes were sampled along the stems of recently uprooted trees, from base to the canopy. Mean Ellenberg indicator values (EIV) for light, moisture, acidity and nitrogen availability were used as surrogate variables for environmental interpretation of compositional patterns for sampling segments of 2 m along the stem. Results By sampling only the lowest 2 m, 10% of the total bryophyte and 48% of the lichen species would have been missed. We detected systematic patterns of compositional variation for both groups along the vertical gradient. While pleurocarpous mosses and liverworts were mostly restricted to the stem base, acrocarpous mosses and crustose lichens occurred along the stem almost to the top. Foliose and fruticose lichens were concentrated at intermediate heights and the upper canopy. Patterns of variation in EIVs suggested that increasing light availability, decreasing moisture and increasing inputs of acidic and nitrous substances are responsible for the compositional shifts along the vertical gradient. Conclusions Sampling only the stem base implies severe underestimation of the epiphyte diversity in temperate broad‐leaved forests. The middle and the upper parts of tree stems have distinctive compositions of epiphytic cryptogams, because microclimate and physico‐chemical site factors vary with elevation above the ground. This article is protected by copyright. All rights reserved.
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[pp. 70, many figs.; 84 appendices, coloured maps]
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[pp. 25, 2 fig. 2 tab.; 6 appendices, 174 distribution maps]
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Lecanora barkmaneana, a sorediate corticolous lichen belonging to the Lecanora subfusca group, is described as a species new to science on the basis of numerous sterile collections. It is known so far as only from the Netherlands, where it often grows on roadside trees. it seems to be spreading rapidly at nutrient-rich sites.
Lecanora barkmaneana, a sorediate corticolous lichen belonging to the Lecanora subfusca group, is described as a species new to science on the basis of numerous sterile collections and two richly fertile collections. It is known so far only from the Netherlands, where it often grows on roadside trees. It seems to be spreading rapidly at nutrient-rich sites.
[pp 57, many figs, maps, tables; 20 appendices]
24 fig. 3 tab. 8 bijl. 119 fig.