Disease Reveals the Predator: Sarcoptic Mange, Red Fox Predation, and Prey Populations
Source: Ecology, Vol. 75, No. 4 (Jun., 1994), pp. 1042-1049
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Ecology' 75(4), 1994, pp. 1042-1049
Z0 1994 by the Ecological Society of America
DISEASE REVEALS THE PREDATOR: SARCOPTIC MANGE,
RED FOX PREDATION, AND PREY POPULATIONS'
ERIK R. LINDSTROM, HENRIK ANDRtN,
BIRGER H6RNFELDT2,
PER ANGELSTAM, G6RAN
LARS JADERBERG, PER-ARNE
CEDERLUND,
LEMNELL,
BERIT MARTINSSON, KENT SKOLD, AND JON E. SWENSON
Grimso WildlifeResearchStation, Departmentof WildlifeEcology,
Swedish Universityof AgriculturalSciences,S-730 91 Riddarhyttan,Sweden
Abstract. An epizootic of sarcoptic mange was prevalent among Scandinavian red
foxes (Vulpes vulpes) during the late 1970s and 1980s. By substantially reducing the population density of foxes, the epizootic created a natural experiment on the importance of
fox predation for prey density. The fox population started to recover during the late 1980s.
We monitored the populations of the fox and its prey [voles (Cricetidae), mountain hare
(Lepus timidus), European hare (L. europaeus), Capercaillie (Tetrao urogallus), Black Grouse
(T. tetrix), Hazel Grouse (Bonasa bonasia), and roe deer (Capreolus capreolus)] throughout
the event, on a local (10l1102
kM2), a regional (104 kM2), and a national scale. Methods
included den counts, snap-trapping, pellet/dropping counts, counts of displaying birds,
young/adult ratio from incidental observations of deer, regional questionnaires, and national hunting records. The study revealed red fox predation as a crucial factor in limiting
the numbers of hares and grouse as well as fawns per doe of roe deer in autumn, and in
conveying the 3-4 yr cyclic fluctuation pattern of voles to small game. The classical view,
that predators take but a "doomed surplus" of their prey, was false for these species in
Scandinavia.
Key words: Bonasa;boreal;Capreolus;Cricetidae;cycles;Lepus;populationlimitation;predation;
Sarcoptes; Tetrao; Vulpes.
nized fluctuations in main and alternative prey popThe role of predation in limiting population density ulations (e.g., Cabot 1912, Cox 1936, Grange 1949,
of birds and mammals has been an intensively debated Hagen 1952, Lack 1954, Keith 1974, Hornfeldt 1978,
issue for at least a century (e.g., Lindstrbm et al. 1986). Angelstam et al. 1985, Summers 1986, Jirvinen 1990).
The view of P. Errington dominated discussions of The alternative prey hypothesis states that the alterpredation on small game species for many years; prey native prey (hares and grouse in Scandinavia) are limpopulations are limited by habitat constraints, and ited by predation during the decline of the cycle. The
predators take only a "doomed surplus" of the popu- hypothesis does not explain the cyclicality of the main
lation (Errington 1946). This hypothesis remained es- prey (3-4 yr cyclic voles and lemmings, Cricetidae, in
sentially untested for 40 yr (Romesburg 1981), and Sih Scandinavia). The cyclic main prey is considered the
et al. (1985:289) noted that ". . . virtually no studies "motor" of the system and need not be influenced at
all by predation. However, the evidence supporting the
have manipulated predators of vertebrate prey."
However, island populations of mountain hare (Lepus alternative prey hypothesis was primarily circumstantial, including the occurrence of synchronized cycles in
timnidus) may react strongly to the presence or absence
of predators (Angerbjdrn 1989), and recent experi- species with very different feeding ecology (Henttonen
1985, Pehrson 1985, Summers 1986, Jarvinen 1990),
mental reductions or exclusions of local predator popthe
occurrence of the predicted shift in the diet of predulations have brought into question the existence of a
"doomed surplus" in different vertebrates (Erlinge 1987, ators (Adamcik et al. 1978, 1979, Angelstam et al.
1984), and rates of predation on alternative prey that
Marcstrbm et al. 1988, 1989, Tapper et al. 1991, Gasvaried
as predicted (Keith et al. 1977, Angelstam 1983,
away et al. 1992). Furthermore, the hypothesis that
Angelstam
et al. 1984, Danell 1985, Myrberget 1985,
predation pressure on alternative prey varies in accorIn Sweden, two experiments have been
Jarvinen
1990).
with
dance
cyclic fluctuations of the main prey of the
predators (the alternative prey hypothesis) has been performed to test whether the predation-caused morrevived several times as an explanation of synchro- tality of the alternative prey was additive. Their results
(Lindstr6m et al. 1987, Marcstrdm et al. 1988, 1989)
agreed with the alternative prey hypothesis for mountain hare and forest grouse (Black Grouse, Tetrao tetrix,
' Manuscriptreceived 1 March 1993;revised 3 September
Capercaillie, 7. urogallus, and Hazel Grouse, Bonasa
1993; accepted 11 September 1993.
2 Departmentof AnimalEcology,UniversityofUmeA,S-901
bonasia). Yet, the generality of the conclusions still
87 UmeA,Sweden.
could be questioned.
INTRODUCrION
June 1994
FOX PREDATION
A large-scale natural experiment on the effects of red
fox (Vulpes vulpes) predation occurred with an epizootic of sarcoptic mange (Sarcoptes scabiel) in Scandinavian foxes. The mange mite, discovered in Sweden
for the first time in 1975, causes hair loss, skin deterioration, and ultimately death of the host (Mbrner and
Christensson 1984). Within a decade the mange spread
over mainland Sweden (Lindstrbm and Mdrner 1985),
reducing the number of foxes dramatically (Lindstrdm
1991, 1992; the number of foxes shot in Sweden declined by >70%, Anonymous 1963-1992). The fox's
prey includes voles, hares, grouse, and roe deer (Capreolus capreolus) (Englund 1965). If fox predation
limited the population density of any of these species,
the mange epizootic should have resulted in increased
prey densities. Furthermore, the epizootic should have
weakened or broken the assumed link between voles
on the one hand and hares and grouse on the other
(i.e., a varying predation pressure exerted by foxes
mainly feeding on the cyclically fluctuating voles). This
should have led to a lowered degree or even absence
of cycles in the hare and grouse populations. In the
present paper we examine the effects of the reduced
fox population on prey populations; density, fluctuation pattern, and reproductive success (fawns per doe
in autumn).
1043
ARCTIC
CIRCLE
OF MANGE
1975-76
ofmiln
GRIMap
andMomer1985)78
May eachyerdurig1941979-80
.: : - :
: :.............
Gec..s 1981cs
the number of Hazel it.u..,
198
METHODS
Grimsb Wildlife Research Area (140 kM2), located
in south-central
Sweden (59040'
N, 15025'
E; Fig. 1),
is dominated by coniferous forest and bogs (Angelstam
et al. 1982). Since the mid-1970s we have conducted
yearly counts or indexing of a selected set of birds and
mammals ("the small game community") in the area.
We snap-trapped voles (bank vole, Clethrionomys
glareolus, and field vole, Microtus agrestis) in early
May each year during 1973-1992, using - 1000 traps
set for three nights. The traps were set in 10 groups of
five traps along each of 20 diagonals of 100 x 100 m
squares systematically spread out over the research area.
The same diagonals were used each year. The traps
were checked and reset daily. Red fox litters were
counted during observations of all known dens in early
June 1973-1992 (100-200 dens). Together with incidental observations of young later in the summer, this
yielded minimum figures of the number of litters born
on the research area (Lindstrbm 1992). Mange first
appeared on the research area in 1982. More detailed
accounts of the fox population in the research area and
the effects of mange on Swedish foxes are given in
Lindstrbm and Mdrner (1985) and Lindstrbm (1989,
1991, 1992).
In early May 1977-1992, we counted the number of
pellets, droppings, and pellet groups of mountain hare,
woodland grouse, and roe deer on 173-498 plots sized
1 x 10 m and previously cleared in late autumn (October-November). The plots were spaced 100 m apart
along north-south oriented transects covering 25 km2
..
~~ ~ ~
. .
.. .
.
roeen dercinrerouctivrea
199.1). Wep obtief meinasurdo
Lnrom
duing autmn59719 ffo 992
succtes (frawn perdone)
inietlosevtoso
rede
beofdslyg
ntheresearch
area.Amnmmn
Bylthe GoseckswsotaffnatGnmslaWillifeiReearchSttin
lso esitumatedi
ararea
woldie research
ThveGrimsbth
the OreberofCaelGountsFg.1.Te county includesn large
as aeseacboreal forests.dMnge ap-d
agicltra
area wftel
attuemptol evaluate
Hane
inteaont inm1979.eI
peat nwred
aereactwe
the1)genrlt ofbthied reasults ofromteresearch
1971974-1992m
conucteds
(awns annua questionnardurimng
ofrom allrove the countyctoe
asingc1d0-355 hunrvterns
estimae populations changies ofvoesedafox mttounGroueae Grmoue andlif Capearchraii sinceatedpre
viou hunting season
(Fincreaseh soutabe rcldeclrgeas)
a-1
of1Mande
werwell asignedealufoests
Thecutuansweres
oealculated
repetedively, aondthe average I answr weremp
leve
hutingrecoardsaveail-e
Onthe
therresut arem
gneationa
ableu(Anonymousn1963-1992).nForrtheupresent7purpose
har
conerningmountai
datmal
weschsent analysethuner
foxuefro
released
Teandwr
the AC0,Y,
W-cunie
and
(area roughly coinciding with that covered by the mange
1044
TABLE 1.
ERIK R. LINDSTROM
ET AL.
Ecology,
Vol. 75, No. 4
Sample sizes in Figs. 2, 3, and 5.
Year
No. trap nights
Pellet plots
1973
1974
1975
1976
1977
1978
1979
1980
1981
3000
3000
3000
3000
2850
175
3000
208
3000
414
3000
383
3000
276
254
278
277
182
240
251
241
242
277
276
180
243
240
236
237
272
271
179
239
244
240
223
259
257
169
220
225
218
246
273
270
190
227
242
227
268
293
290
188
252
262
243
205
237
235
160
200
217
199
125
137
141
91
121
130
117
12
38
78
79
83
Questionnaire answers
Voles
Red fox
Mountain hare
European hare
Black Grouse
Hazel Grouse
Capercaillie
Doe observations
epizootic in 1977-1978; Fig. 1). These counties include
most of boreal Sweden, were exposed to mange at an
early point of the epizootic, and formed the core area
of sychronized 3-4 yr cycles (Angelstam et al. 1985).
All P values in this text are one-tailed because we
do not consider the alternative hypothesis that increased predation may increase the density of prey.
Ninety-five percent confidence limits are presented
when available and/or appropriate. Accompanying n
values are given in Table 1.
RESULTS
The number of red fox litters on the research area
tracked vole density during the 1970s (Fig. 2A, B). The
positive relationship between vole index and number
of fox litters persisted when mange appeared, but the
average number of fox litters declined to that previously experienced only during vole population lows
(for detailed analyses including other types of data, see
Lindstrdm 1989, 1991, 1992). During the last 3 yr
(1990-1992), the number of fox litters has returned to
the same level as before the mange. In the following
analyses, we have considered the fox population on the
research area as reduced by mange from winter 19821983 until autumn 1989. Regionally, this period was
extended to include the winter of 1981-1982. Unless
otherwise stated, fox density is measured by a dummy
variable attaining the values 1 (high) or 0 (low due to
mange).
The vole fluctuations did not seem to be affected in
any respect by the variation in fox numbers (Fig. 2A).
On the other hand, the indices of mountain hare and
grouse densities increased by 40-100% in connection
with the outbreak of mange (Fig. 2C-E). When foxes
recovered, these indices fell as low or lower than prior
to the epizootic (comparing periods of high and low
fox density; hare pellets: t = 4.34, P < .001; grouse
droppings: t = 3.05, P < .01; displaying Black Grouse:
t
3.21, P < .01). Hazel Grouse numbers exhibited
a similar decline late in the epizootic (Fig. 2E).
A multiple linear regression of the hare index against
the vole index the previous year and fox density showed
significant relationships with both independent variables (n = 16; R2 = 0.69; total F= 150, df= 2, 13, P
< .001; partial values: vole index F= 5.15, df= 1,
13, P < .05; fox density F= 24.7, df= 1, 13, P <
.001). We could not detect a disappearance of the synchrony between vole and hare fluctuations as mange
impacted the fox population, although the coefficient
of variation of the hare index was larger during years
of high fox densities (46.1) than during low densities
(34.3; the low number of years make a test of significance powerless). The density of Black Grouse likewise
followed the vole cycle before mange with a peak in
grouse density following the year after a peak in the
vole index (see also Angelstam et al. 1985). However,
we could not detect this relationship with the data from
the entire period for cocks or for droppings in similar
multiple regressions as for the hare (partial Fs for vole
index = 0.1 and 2.1, df = 1, 16 and 1, 13, respectively,
P > .05 in both cases). The only significant relationships were with fox density, as already noted. Furthermore, none of the barely distinguishable peaks in
Black Grouse density during the period of mange in
foxes followed a previous peak in vole density (Fig.
2E). Still, it should be noted that the declines in hare
and grouse densities during the late 1980s were initially
associated with a decline in the vole index during 19881989.
On the regional scale, we found relationships similar
to those found on the research area for voles, fox,
mountain hare, Black Grouse, and Hazel Grouse (Fig.
3). Also, the populations of European hare and Capercaillie increased and subsequently decreased as foxes
declined and returned (Fig. 3). Before mange, the fluctuations of both the fox and the mountain hare populations were synchronized with the vole cycle. Hence,
the questionnaire indices for mountain hare and fox
during 1974-1981 were positively related also to each
other (slope = 0.63 ? 0.75 [mean and 95% ci], R2
0.41, F= 4.2, df= 1,6, P < .05). After mange appeared,
the relationship turned into a negative one (1982-1992,
slope = -0.59 ? 0.40, R2 = 0.56, F = 11.5, df = 1,
9, P < .01). Similarly, on the national scale (Fig. 4)
TABLE 1.
1045
FOX PREDATION
June 1994
Continued.
Year
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
3000
173
3000
481
3000
483
3000
498
2850
488
3000
493
3000
498
3000
303
3000
495
3000
493
3000
496
281
336
332
207
283
268
283
303
355
353
232
302
296
302
302
356
349
238
307
291
293
301
310
310
216
267
254
258
293
294
315
217
269
258
260
269
250
291
190
258
245
249
265
239
272
185
248
235
239
247
219
253
171
235
218
225
264
249
277
181
250
236
239
242
242
252
173
229
227
220
237
237
245
168
220
222
218
48
117
125
81
62
40
65
36
26
37
32
the hunting records of the two species showed a significant positive relationship before mange (slope
1.81 ? 1.2, R2= 0.49, F = 11.4, df= 1, 12, P < .01,
n 14). After 1977 the relationship was negative (slope
+ 2.0, R2= 0.72,F= 30.1,df=
1, 12,P <
=-4.99
.0001,
n = 14).
In multiple regressions of data from the questionnaires, with hare and grouse indices as dependent vaniables and fox and vole indices as independent variables
over the entire 19-yr period, all hare and grouse indices
were significantly negatively related to the fox index
(df= 1, 16 in all cases): mountain hare (partial F
20.7, P < .001); European hare (partial F = 3.15, P <
.05); Black Grouse (partial F = 23.4, P < .00 1); Hazel
Grouse (partial F= 3.82, P < .05); and Capercaillie
(partial F= 17.4, P < .00 1). However, only two were
also significantly positively related to the vole index
(mountain hare, partial F for vole index = 18.2, df =
1, 16, P < .001; and Capercaillie, partial F = 3.61, df
1, 16, P < .05). In the case of the mountain hare,
simple regressions showed a significant relationship with
voles during years of high fox densities (n =11, R2 =
0.80, F = 36, df= 1, 9. P < .001), but not during years
of low fox densities (n = 8, R2 = 0.25, F = 2.5, df
1, 6, P > .05).
It is likely that the fox's primary effect on a roe deer
population is through the mortality of young fawns
(Cederlund and Lindstrbm 1983). After mange struck
the fox population (1983-1989), the number of fawns
observed per doe in autumn increased by 30% and the
average density index of deer increased 64% (Fig 5;
fawns per doe: t = 2.6, P < .05; deer pellet group counts:
t = 3.0, P < .01). On the other hand, there were no
returns to previous levels when foxes recovered. However, production of young has been shown to correlate
with the previous winter's weather in deer (Verme and
Ullrey 1984), and the winters 1989-1992 were exceptionally mild in south-central Sweden. We did not find
any relationship between the number of fawns per doe
and a crude measure of weather (snow depth in the
middle of February, partial F = 0.347, df = 1, 13, P
> .05; the multiple regression also included a nonsig-
nificant effect of mange through fox density, F = 2.4,
df= 1, 13, P > .05). However, when a delay of 1.5 yr
in the effect of snow depth was incorporated, the regression explained 48% of the variation in fawns per
doe (Fig. 6, total F 6.07, df= 2, 13, P < .05, partial
F for snow depth
7.87, P < .01; partial F for fox
density = 5.62, df= 1, 13, P < .05).
DISCUSSION
Our data indicate the importance of fox predation
to the small game community in two respects: (1) limiting of the average density of prey and (2) transferring
the cyclic fluctuation pattern of voles to hare and grouse
populations.
1. Average density.-All prey populations except
voles increased in density, both locally and regionally,
as mange struck the fox population. All but that of roe
deer returned to previous levels when the fox population recovered. The varying amplitude of the vole
cycle may be explained by variations in plant production (Hdrnfeldt et al. 1986) and snow depth during
winter (Lindstrbm and H6rnfeldt 1994).
In the case of mountain hare, our data come from
pellets accumulated between October and May. Hence,
one might argue that we have not excluded the possibility of late winter as a population density bottleneck. Thus breeding densities may still have been unaffected. However, there was no indication of any
influence of snow depth either during the winter of, or
the winter before, the hare index (partial F = 0.343
and 0.486, respectively, when adding snow depth as
an independent variable to the multiple regression of
hare index against vole index and fox density; df = 1,
12, P > .05 in both cases), irrespective of the fact that
the period of study included winters when a rich supply
of dwarf shrubs (Vaccinium spp.) were available from
autumn to spring as well as winters with deep snow
cover. Thus, intraspecific competition during winter
seemed improbable.
On the other hand, winter weather explained a significant portion of the variation in the reproductive
success of roe deer. The delayed effect of snow depth
1046
ERIK R. LINDSTROM ET AL.
Ecology, Vol. 75, No. 4
0
0i
Cl)
-50U~
80
D
o CE
U
0/
~~~~~~~~~~D
~~~~~~~~~~~0
-25 IE
0
40.
yi
-10W
0-1
.
.
.
.
. .
b~~~~~~~~~~~~
Z~~~~~~~~~~~~
z~~~~~~~~~~~~
~
~
~
N
~
10
-IJ
0
0-J
8-
LI
10,
Cn
Ui
><
0
5~
LL
0
z
D Z
OCE
M2-
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
YEAR
FIG. 2. Population fluctuations on the Grims6 Research Area: (A) voles, (B) fox litters, (C) mountain hare, (D) grouse,
(E) displaying Black Grouse cocks and number of Hazel Grouse cocks (LI). Shaded area indicates years of mange. Darker
shading indicates period of low fox densities as interpreted from the variation in number of fox litters. For n values, see
Table 1.
probably reflected a 1-yr postponement of puberty of
fawns that experienced a hard first winter. This is suggested by the low live masses of fawns during severe
winters (Cederlund and Lindstrbm 1983). Normally
roe deer females come into their first estrous in their
second summer, and after delayed implantation they
give birth to their first young at an age of 2 yr. However,
the effect of fox density on fawn production remained
significant also when winter weather was included in
the analysis.
2. Cycles.-In accordance with previous suggestions
(Danell and H6rnfeldt 1987, Marcstr6m et al. 1988,
1989) the cyclic cofluctuations of voles and small game
decreased (locally) or disappeared (regionally) as mange
June 1994
FOX PREDATION
COAPERCAILLIE
1047
'120000
/
30000
100000O.'
80000
=
0.3
1
0
120000
Cl
~~~~~~~~~~~
w
Cl)
LLi 60000cr
HAZELGROUSE
~~~~~~~~~~~~~~~~
=40000
.
z
z
20000
. . . . . .
196.5
1970
. . . .0
1975
19'80
1985
1990
YEAR
-0.3
FIG.4. Hunting records of red fox and mountain hare
from the area covered by the mangeepizootic in 1977-1978
(Anonymous 1963-1992, counties AC, Z, Y, X, and W).
Shaded area indicates period of mange.
{BLACKGROUSE
{EUROPEANHARE/
/
-1:
O.
S
HARE%
:IMOUNTAIN
RDFOX
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
et al. 1990). The more pronounced effect in the questionnaire indices vs. that in the results from the research area may be explained by the greater effect of
mange on the fox populations of the central agricultural
areas of the county than in its northern boreal parts
(Lindstrbm 199 1).
In particular, we interpret the positive correlations
between mountain hare and red fox density indices
(from questionnaires as well as hunting records) during
years of high fox density, and the negative correlations
during years of low fox density, as the hare population
being limited by predation during both periods. Total
predation is determined both by individual consumption and predator density. Before mange appeared, the
rate of hare predation was determined primarily by the
density and hence also consumption of main prey
(voles), as stated by the alternative prey hypothesis.
During the epizootic, the large decline and subsequent
increase in fox numbers had the overriding effect on
predation rates.
The large-scale field experiments needed to test predictions concerning the importance of predation in vertebrate communities are often too difficult or costly to
conduct. Hence, they have to be supplemented by correlative data of natural variation (Hansson 1989). The
YEAR
FIG. 3. Questionnaire indices to annual population changes
in Orebro County (Fig. 1). Average answer of "Iincrease"()
"stable" (0), or "decrease" (- 1). Shaded area inicates years
of fox mange. Darker shading indicates period of low fox
densities as interpreted from the fox index. For n values, see
Table 1.
1,0
30.8
r)
LU
0.6~~~~~~~~~~~
~~~~~~~~~~
:D
struck the fox population. The persisting covaniation
between hare and vole fluctuations in the research area
stil might have been conveyed by foxes, which never
were eradicated completely. It is also possible that other predators, such as pine marten (Alartes martes), stoat
(Mustela erminea), weasel (Mustela nivalis), European
badger (Meles meles), and buzzard (Buteo buteo) were
involved in synchronizing the fluctuations. The density
of pine martens increased when foxes decreased (Storch
3
CC 0.4
0
CL
U..
0.~~~~~~~~~~~~~0
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
YEAR
FIG.5. Counts of roe deer pellet groups(means and 95%
ci) and yearlynumberof fawns observed per roe deer doe in
autumn(Z) by the staffat Grimso Wildlife ResearchStation.
Shaded areasas in Fig. 3. For n values, see Table 1.
ERIK R. LINDSTROM ET AL.
1048
o
1.0
*
c
@0
n
Cl)
z 0.5
0
0
0
LL
0
0
20
40
60
80
100
120
SNOW DEPTH (cm)
FIG. 6. Fawns per doe in relation to depth of snow cover
in mid-February 1.5 yr earlier. 0 years with low fox densities
due to mange. 0 years of normal fox densities. Snow data
from the Swedish Meteorological and Hydrological Institute,
weather station Riddarhyttan.
natural experiment caused by the epizootic of sarcoptic
mange revealed red fox predation as a crucial factor in
the dynamics of the small game community in Scandinavia. The effects could be discerned on local, regional, and national levels.
In particular, the same reaction of the three grouse
species pointed to fox predation rather than habitat
changes, which is otherwise an important factor determining the long-term dynamics of these populations
(Swenson and Angelstam 1993). The reactions to habitat changes are different or even opposite in different
species. We conclude that the red fox plays a key role
in structuring the small game community in Scandinavia, primarily by keeping the densities of prey at low
levels, but secondarily also by conveying the cyclic 34 yr fluctuation pattern of voles to the hare and grouse
populations. However, in a pristine landscape, with
much less red fox habitat, fox predation may be of
minor importance. By opening up the forest, with clearcutting as the dominant management practice in forestry, man has created excellent habitat for the fox
(Christiansen 1979) at the same time as we have more
or less exterminated its natural enemies, such as wolves
(Canis lupus).
ACKNOWLEDGMENTS
We thank John Wiens for constructive criticism. Thanks
also to the great number of people involved in gathering the
data. The study was supported by the private foundations
"Olle och Signhild Engkvist stiftelser," and the Swedish Environmental Protection Agency.
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