Download Succession in boreal bryophyte communities

Succession in boreal bryophyte communities –
the role of microtopography and post-harvest
bottlenecks
by
Martin Schmalholz
Plants & Ecology
Plant Ecology
Department of Botany
Stockholm University
2008/03
Succession in boreal bryophyte communities –
the role of microtopography and post-harvest
bottlenecks
Licentiate thesis
by
Martin Schmalholz
Supervisors:
Kristoffer Hylander and Ove Eriksson
Plants & Ecology
Plant Ecology
Department of Botany
Stockholm University
2008/03
Plants & Ecology
Plant Ecology
Department of Botany
Stockholm University
S-106 91 Stockholm
Sweden
© Plant Ecology
ISSN 1651-9248
Printed by Solna Printcenter
Cover: Clear-cut covered with the grass species Deschampsia flexuosa, Lesjöfors, eastern
Värmland.
Summary
Clear-cutting forestry can be considered to be the most important disturbance agent in the
Fennoscandian boreal forest, where both effective fire and insect suppression have reduced
the influence of natural disturbances considerably. Most conservational attention has been
devoted to understand and mitigate the detrimental effects associated with the clear-cutting
event. The first study of this thesis explores the successional trajectory of boreal bryophyte
communities in search of other bottlenecks than the initial clear-cut disturbance. A bottleneck
is here defined as a period with distinct retrogressive succession, where the ongoing
reorganization process towards the mature forest community reverts due to decrease in
abundance or local extinctions of mature forest species. Furthermore, we hypothesized that
high grass cover following timber harvest, high litter cover during canopy closure and
shortage of dead wood in the young forest would induce bottlenecks in three different
bryophyte guilds. We did not find clear evidence of any bottleneck in species composition
occurring during the recovery process for each of the three guilds. One reason for this pattern
might be that the expected high values in needle cover during canopy closure and distinct
decrease in dead wood in the young forest was not very pronounced. The retrogressive
tendency found in the epilitic guild between 35-50 years after clear-cutting might be related to
the infavorable light regime in the dense stands prior to first thinning. The epixylic guild
displayed a gradual recovery during the first 50-60 years after clear-cutting. During the last 30
years of succession however, this guild was found to be constrained by the amount of large
diameter logs (>25 cm) with sites with higher amount of woody debris displaying continued
development and sites depleted of coarse woody debris displaying retrogressive tendencies.
In the second study, we investigate the potential influence of microtopography on bryophyte
post-harvest recovery. Microtopography, in this study expressed as boulder cover, was
hypothesized to increase the initial clear-cutting resistance through providing sheltered
microsites where drought-sensitive bryophytes may survive the clear-cut phase. We analyzed
the importance of boulder cover on both initial resistance and the subsequent recovery rate for
species density, composition and abundance change of single species. We found boulder-rich
stand to have a higher density of closed-canopy species throughout the whole rotation cycle
than compared to boulder-poor stands. We can not rule out the possibility that this result is
due to the fact that boulders actually enhance the clear-cutting resistance by providing
drough-sensitive species with “safe-sites” in which species can survive and from which
subsequent recolonization can occur. Due to the absence of convergence over time in species
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density, we belive that the effect of boulders may be in its effect on forest floor micro-sites
and microclimatic heterogeneity. For species utilizing exposed substrates, recovery was not
significantly affected by boulder cover, although the response surface for both composition
and density suggest a higher resistance and a higher recovery rate.
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Sammanfattning
Denna avhandling omfattar två olika studierna som båda syftar till att utforska och undersöka
återhämtningsprocessen hos mossamhällen i boreal kulturskog efter kalavverkning. I den
första studien undersöktes förändringen i artsammansättning över tiden för tre olika
mossguilder; mark-, block- och vedarter. Många studier har visat att skogskryptogamer
påverkas negativt av kalavverkning, ett faktum som kan härledas till att många kryptogamer
saknar effektiv vattenreglering och därigenom blir mer känsliga för de mer torra och varma
mikroklimat som råder på hygget. Naturvårdsåtgärder på beståndsnivå inom skogsbruket har
följaktligen nästan helt fokuserat på denna ”flaskhals” under rotationscykeln som det enda
tillfälle då skyddsvärda och artrika kryptogamsamhällen slås ut eller decimeras. Ett normalt
skogsbestånd genomgår i regel ett antal stadier som potentiellt kan tänka påverka
mossamhället negativt. I den första studien i denna avhandling undersöktes mossuccessionen
efter kalavverkning med avseende på förekomsten av ytterligare flaskhalsar utöver den initiala
kalavverkningen. Vi var intresserade av att undersöka effekten av initialt hög grästäckning,
hög täckningsgrad barrförna samt brist på död ved under ungskogsfasen. Vi fann inga
distinkta flaskhalsar i mossuccessionen för de tre undersökta guilderna, vilket motiverar den
nuvarande fokusen på kalhyggesfasen inom den skogliga naturvården. Mark- och vedguilden
genomgick en gradvis förändring i artsammansättning över tiden medan blockarterna
uppvisade en stor variation mellan bestånden. Sammansättningen av dödvedsarter var starkt
korrelerat med mängden grov ved (>25 cm i diameter) under de sista 30 åren, vilket indikerar
att denna guild är starkt begränsad av mängden tillgängligt substrat under denna del av
rotationscykeln.
I studie två undersökte vi hur mikrotopografisk heterogenitet påverkar återhämtningen av
mossamhället efter kalavverkning. Mikrotopografi i boreal skog beskriver markens
”knölighet”, dess grad av ojämnhet och styrs i hög utsträckning av mängden konvexa/konkava
elements såsom block, lågor och gropar. I denna studie har vi dock valt att fokusera på
betydelsen av block. I skuggan av stora stenblock kan mortaliteten i bottenskiktets
mossamhälle i samband med kalavverkning tänkas vara mindre jämfört med mer exponerade
partier. Dessa fläckar med överlevande individer från samhället innan störning brukar kallas
refugier och har visat sig påverka återhämtningshastigheten i många ekosystem. Vi
undersökte blockens betydelse med statistiska modeller samt med en tredimensionell
visualiseringsgraf för markmossor samt arter på upphöjda substrat. De statistiska modellerna
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gav få signifikanta samband medan de tredimensionella graferna emellertid antydde att
blockighet var en viktig förklaringsvariabel för vissa arter i mossamhället. De
tredimensionella graferna (responsytorna) antydde att mossor på upphöjda substrat har högre
initiala överlevnad och en snabbare återhämtning. Dessa indikationer kunde emellertid inte
bekräftas av våra statistiska modeller och bör därför tolkas med ett visst mått av försiktighet.
För markmossorna verkar arttätheten vara konstant högre i blockrika skogar. Detta samband,
som var signifikant, antyder dels en högre initial överlevnad samt en mer divers
markmossflora i blockrika bestånd generellt. De är troligt att de blockrika skogarna erbjuder
en större mängd mikrohabitat i sprickor och gropar mellan blocken och av den anledningen
kan hysa fler arter generellt under rotationscykeln.
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Introduction
Disturbances are ubiquitous features of most natural and human influenced ecosystems,
continuously remodeling the composition of plant communities and resetting secondary
succession (Pickett et al. 1989, Johnson and Miyanishi 2007). Naturally occurring
disturbances such as wildfires, insect outbreaks and storms usually vary in frequency, extent
and intensity within landscapes resulting in a mosaic mixture of disturbed and unaffected
habitats. Antropogenic disturbances, such as forestry practises, are on the other hand
characterized by the low degree of spatial varition in both frequency and intensity. Although
more uniform, the ecological responses to these homogenious disturbances will vary
according to environmental heterogeneity and the species composition in the affected
community. Succession in boreal forest understory communities is highly idiosyncratic with
few generalities and many exceptions (Hart and Chen 2003). The majority of studies
conducted on both post-fire and post-harvest succession are “snapshot”-studies, assessing the
immediate effects on plant communities, usually vascular plants, neglecting other important
groups such as bryophytes.
Forestry and bryophytes in the boreal forest
Forestry practices in the Fennoscandian countries have historically been intense and both fire
and insect outbreaks have been successfully suppressed (Esseen 1997). Approximately 85%
of the forest land in Sweden is today managed exclusively for extraction of timber and pulp
(Anon. 2007). The disturbance regime prevailing in productive spruce dominated forest in
Sweden is characterized by clear-cutting, ground preparation, pre-commercial thinning and
one or two commercial thinning where stems are extracted for production of pulp or timber.
Natural wildfires are scarce, only 0.01% of the forest area burns every year due to highly
efficient fire suppression (Granström 2001). The transition from the natural fire-dominated
disturbance regime to the silvicultural disturbance regime have resulted in a substantial loss of
both within and among stand structural heterogeneity with old-growth forests surrounded by
vast expanses of clear-cuts and young forests. At the same time, a growing awarness of the
ongoing rapid decline in biodiversity have spurred the development of a more restrictive
legislation. The new Forestry Act in Sweden from 1993 stipulates that equal importance
should be given to timber extraction as to conservation (Anon.2006). The pronounced
fragmentation of the boreal forest in Fennoscandia has lead forest ecologists and managers to
realize that the quality of the matrix must be improved. Several studies have shown that
young managed forests can support cryptogam species previously regarded as confined to old5
growth forest conditions (e.g. Rudolphi et al. in prep.).This result indicates that the capacity of
managed “matrix” forest stands might actually support species previously imagined to be
exclusive to old-growth conditions. Most research has been directed towards the standreplacing phase, assessing the impact of clear-cutting or the benefits of leaving living (i.e.
“green-trees”) and/or dead trees during final felling operations. These adjusted management
practices utilizes a coarse-grained approach to conservation and often aims at mimicking
patterns or structures generated through natural disturbances. Bryophyte communities are
known to have strong influence on the functioning of the boreal forest ecosystem, (Steijlen et
al. 1995, De Luca et al. 2002). Apart from influencing nutrient and moisture levels, closedcanopy bryophyte communities are species rich (e.g. Berglund and Jonsson 2001) and provide
important habitats for detrivorous invertebrates (Merrifield and Ingham 1998). Closed-canopy
bryophytes are severely disrupted by clear-cutting disturbance (e.g. Hannerz and Hånell 1997,
Jalonen and Vanha-Majamaa 2001).
Ecological memory and resilience of bryophyte communities
The concept of resilience has been utilized in various ecological contexts since it first was
introduced by Holling in 1973. Resilience is currently beeing used in two quite different ways
in the ecological litterature. The traditionally view of resilience describe the ability of a
certain ecological system to cope with and reorganize after a disturbance and has been termed
equilibrium or engineering resilience (Gunderson 2000). Ecological resilience, in contrast,
acknowledges the possibility of several alternative stable states in ecosystems and describes
the amount of disturbance that a system can absorb a state shift occurs. Due to the difficulties
in quantifying ecological resilience, the more robust and easily interpretable concept of
engineering resilience has historically been prefered. In this thesis I will stick to the traditional
definition when discussing the recovery of bryophytes after clear-cutting.
Resistance and recovery is usually considered to be two important components of engineering
resilience describing the initial change in composition and species density and the subsequent
rate of return (Halpern 1988). The recovery pattern of plant communities has traditionally
been explained by distance to the nearest propagule sources, such as closest unaffected habitat
(e.g. Glenn-Levin 1992, Fastie 1995). During the last two decades, ecologists have started to
appreciate the importance of initial resistance, i.e. surviving species, during the reorganization
of new communities (e.g. Franklin 1985). These patches have been termed refugia (e.g. Sedell
1990) and have been shown to be frequent in some lotic systems experiencing periodic flow
disturbances (Matthaei et al. 2000). Several papers have found that refugia can affect recovery
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rates through providing internal recolonization sources or through facilitating the
establishment of incoming propagules that otherwise would fail to establish (Franklin et al.
1985, Gjerlöv et al. 2003, Panzer 2003). The importance of refugia have recently been
incorporated into the concept of ecological memory that described the pattern of surviving
species and structures necessary for recoloniation such as substrates, i.e. internal memory, as
well as the distribution of potential dispersal sources in the adjacent unaffected part of the
landscape, i.e. external memory, (Bengtsson et al. 2003). In the second paper we investigate
the imporance of one aspect of internal memory, i.e. surviving species, during the recovery
process.
Aims with the thesis
1) Although the emphasis on clear-cutting effects might seem intuitive given the disruptive
impact on forest bryophytes, additional bottlenecks might occur. The purpose with the first
paper in this thesis was to provide data on bryophyte succession and assess to what extent
post-harvest bottlenecks occur. More specifically, we wanted to understand the impact of the
following three potentially hostile stand conditions; (1), high initial grass cover (2), high litter
cover in young stands prior to thinning and (3),the decline in coarse woody debris in the
young forest, on bryophyte communities recovery after a clear-cut disturbance.
2) The aim with the second study was to investigate the influence of microtopograhic
structure on the bryophyte recovery process following clear-cutting. We used boulder cover as
a proxy for microtopograhic structure. Since bryophytes are poikilohydric, i.e. lack the ability
to regulate their own waterbalance, and are known to be negatively affected by clear-cutting,
we hypothesized that they might be able to survive a clear-cutting phase in the shade of large
boulders. Ultimately, the question that we wanted to explore in this study is to what extent
microtopograhic structures can influence the resilience of bryophyte communities by
mitigating the initial resistance and/or increasing the recovery potential.
Methods
Study 1 and 2
Study area
The two studies included in this thesis were performed in the Bergslagen region of the three
provinces Västmanland, Dalarna and Värmland during the summer and autumn 2007. The
forest landscape in Bergslagen has been exploited for timber extraction since the beginning of
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the 13th century due to the large charcoal demands by the mining industry. Stand regeneration
by clear-cutting became the most common logging method earlier (>200 years ago) in this
region than in other parts of Sweden (Nilsson 1996). The coniferous forest is dominated by
Norway spruce, Picea abies. L, on mesic to moist soil and by Scots pine, Pinus sylvestris.
L,on dry soils with nutrient poor soils and on peat producing wetlands. The yearly
precipitation in the area lies between 800-1100 mm with increasing precipitation from east to
west. The highest postglacial coastline is situated at ~170-180 m above sea level, usually well
below the location of most study sites. Mean temperature for January is -7 and +14 degrees
Celsius for July (Raab and Vedin 1999). Most of the forest land in this region is owned by the
two large forest companies Bergvik Skog AB and Sveaskog.
Stand selection and sampling design
For practical reasons we chose to work with the two large landowners in the area (Bergvik
Skog AB and Sveaskog). We used the well known chronosequence method to investigate the
temporal pattern in bryophyte succession. In this method a sequence with stands of different
ages is constructed and supposed to represent the successional trajectory of a hypothesized
stand. This space-for time substitution will always introduce additional variation in the
response variables that is not related to age, due for example to local stand conditions. This
variation can be minimized if strict selection criteria are used when choosing among objects
to include. When choosing among forest stands the following five criteria’s were used; 1.
slightly poor to moderate productivity (i.e. site index G22-G28 according to Hägglund and
Lundmark 1999), 2. mesic moisture conditions (i.e. dry and wet sites omitted), 3. tree species
composition dominated by Norway spruce (>50 % basal area) and less than 15 % deciduous
trees, 4. regeneration after traditional clear cutting and 5. low to intermediate cover of
boulders (paper 1 only). A field visit of each stands was also conducted in order to assess the
suitability. Approximately 1/3 of all stands were excluded from further data collection. Data
was collected using 0.1 ha, sample plot (50x20m). We chose this plot size since we wished to
include as many species as possible from the stand species pool. Each plot was divided into
ten 10x10 m subplots, enabling frequency counts between 1-10 to be obtained for each
occurring species. The plots were located in a representative part at least 25 m from the stand
edge.
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Data collection
We collected data belonging to three categories: 1. general stand variables, i.e. stem basal area
and canopy cover, 2; predictor variables; grass-and littercover and CWD-surface area (study
1) and boulder cover (study 2), 3; response variables; species composition, density and
abundance (cover and frequency) (study 1 and 2). Each subplot was inventoried for all
bryophyte species. Samples of bryophytes that could not be identified in field were collected
for later identification using a light microscope. To ensure effective data collection the
following taxa were treated as one taxon l: Dicranum fuscescens/flexicaule, Plagiothecium
laetum/curvifolium, Chiloschyphus pallescens/polyanthus, Cephalozia lunulifolia/affinis and
Bryum sp. The nomenclature follows Hallingbäck et al. (2006). In study 1 we classified
species in three groups depending on main habitat preference; 1. epigeeics, i.e. forest floor
living species, 2. epilitics, rock and boulder living species and 3. epixylics, i.e. dead wood
living species. In study 2, we chose to omit obligate epilitic species, since they are affected by
boulder cover as a substrate, and obligate epiphytes. When analyzing the impact of
microtopography on species composition we classified species into one of the two groups,
epigeeics or species on exposed substrates. The latter group comprises both obligate epixylics
and facultative epiphytes, utilizing tree-bases as a substrate. For species density, species that
were considered to be favored or at least indifferent to clear-cutting were omitted.
Statistical analysis
Due to the exploratory approach in the first study we chose to work with robust nonparametric methods not depending on particular model assumptions such as linearity or
normally distributed variables. To investigate the general patterns in species composition over
time density and species abundance within the three bryophyte guilds, we performed locally
weighted scatterplot smoothing (LOWESS)-regressions with a narrow window-width (f=0.5).
We used the site scores of a two-dimensional non-metric multidimensional scaling (NMDS)
ordination (using Bray-Curtis distance measure for frequency values) as a measure of species
composition. The three selected guilds were; epigeeic, epilitics, and epixylics. These were
chosen since we hypothesized they would display different degree of susceptibility to the
three potenially hostile stand conditions. Finally, Spearman correlations were performed in
order to test hypothesis about bottlenecks during certain critical age intervals. All statistical
analyses were performed in R 2.4.0 (R development Core Team 2007).
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In study 2 we chose to visualize our data with three-dimensional response surface. This
approach facilitated our understanding of the potential interaction between the two predictors
of interest, i.e. stand age and boulder cover and was used as a compliment to our statistical
models. Furthermore, Generalized Additive Models (GAM) was used to evaluate if and how
boulders affect our response variables. As predictors in the models we used the logarithm of
boulder cover and a smooth function of stand age. The product of the logarithm of boulder
cover and the logarithm of stand age was included as a third predictor to be able to detect
possible interaction effects. Site ordination scores from a one-dimensional NMDS-analysis
were used for species composition using relative Sørensen dissimilarity index on frequency
data in the statistical program PCord (McCune and Mefford 1999).
Results and discussion
Study 1
We found no clear evidence of any bottleneck in species composition during the post-harvest
recovery of the forest floor guild. Neither grass nor litter cover was found to disrupt the
compositional recovery in the epigeic or epilitic guild as we hypothesized. The forest floor
guild, mainly composed of long-lived pleurocarps, was more or less recovered 40-45 years
after clear-cutting. The three most dominant species within this guild, i.e. Hylocomium
splendens, Pleurozium schreberi and Dicranum majus, all displayed clearly non-monotonic
recovery pattern with P.schreberi and D.majus having distinct peaks in the young forest, i.e.
during the first 50 years. H. splendens instead showed a gradual increase during the first 3040 years followed by a period with haltered recovery between 40 and 60 years after clear
cutting and thereafter increasing again. This dynamic change in abundance is an interesting
finding since they occur after maximum bryophyte cover was attained, implying competitive
interactions as an important structuring factor in this guild. In the epilitic guild, species
composition displayed a small retrogressive tendency around 30-50 years after clear-cutting.
Since the majority of species in this group are drought-resistant and thriving in semi-shaded
light conditions, e.g. Racomitrium microcarpon, Paraleucobryum longifolium and Hedwigia
ciliata, we believe these species to be disfavored by the very shady conditions prevailing in
Norway spruce stands prior to first thinning. The recovery process in the epixylic guild did
not seem to be severly affected by the extreme low values of CWD during the first 60 years.
The gradual change away from the initial clear-cut composition might be explained by the
development of a favorable microclimate during canopy closure. Instead we found that the
area large logs (>25 cm in diameter) was strongly correlated with species composition during
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the last 30 years of recovery. Stands with low amounts of large logs exhibited retrogressive
tendencies becomming more similar in composition to the clear-cut stands. The response in
abundance of the species within this guild differed, with some species showing slow recovery
followed by a strong decline during the last 30 years of succession, e.g. Blepharostoma
trichophyllum, and some species displaying fast recovery, e.g. Tetraphis pelludia and
Ptilidium pulchellum. In addition to micro-site limitations it is possible that some species of
liverworts can be negatively affected by the changed microclimate in the newly thinned stands
between 45-55 years or by a second thinning around 65-75 years.
Study2
The general response of the forest floor guild was somewhat different between the two
measure responses, i.e. species composition and density. We found the forest floor guild to
have a higher density of closed-canopy species confined to mature forests throughout the
whole rotation cycle in boulder-rich stands. This implies that boulders might affect the
resistance to clear-cut disturbance by enhancing the initial survival and perhaps by having
higher forest floor micro-sites and microclimatic heterogeneity. The recovery of Hylocomium
splendens was found to be significantly affected by boulder cover. According to the response
surface the recovery rate but not the initial resistance was higher in the boulder-rich forests.
One possible reason for this faster recovery might be a higher establishment success on the
microclimatically more heterogeneous forest floor of the boulder-rich sites. Dicranum majus
seems to recover equally well independent of boulders during the first half of the rotation
cycle. On the other hand boulders affected the late seral trajectory, in that boulder poor forests
supported much denser populations of D.majus compared to boulder-rich stands. The effect of
boulder cover on the recovery of species utilizing exposed substrates was not statistically
significant, although the response surface for both composition and density suggest a higher
resistance and a higher recovery rate. The same pattern was evident for Barbilophozia
attenuata at least during the first half of the cycle. During the later part boulders seems to
have a negative influence on the recovery of this species.
Conclusion and future ideas
The two major goals with this thesis were to describe the post-harvest bryophyte succession in
boreal forests and to investigate the impact of microtopographic structure and three
potentially hostile stand conditions. Our results suggest that bryophyte succession is a gradual
process for both epigeeic species and epixylic species and perhaps partly non-monotonic for
11
epilitic species. Our three-dimentional response surface indicates that microtopographic
structure might be important, although we need a larger data set before solid conclusions can
be drawn. Some management practices, especially thinning, that were not considered in these
studies, might also introduce additional variation in our response variables. In moderately
productive spruce-dominated stands in south-central Sweden, thinning is usually carried out at
two occasions reducing stem densities with as much as 30-35%. It is possible that the canopy
break-up during thinning could induce compositional changes in the bryophyte community
through alterations in microclimatic parameters. Species relying on a stable moist and shaded
microclimate might be negatively affected and species depending on semi-shaded conditions
might increase. It is perhaps also possible that the field layer response due to the increased
light levels could affect the composition of the forest floor guild.
Recent studies indicate that bryophyte recolonization might be depending on the regional
propagule source rather than a local source, from a nearby stand (e.g. Hylander unpublished).
In southern and south-central Sweden the landscape is in many places dominated by clear-cuts
and young forest. Thus, one interesting objective for the future is to evaluate the influence
stand age distribution on a landscape scale for the local post-harvest recovery. It is possible
that landscape structure is important for species that commonly reproduces sexually and that
disperese by spores.
Acknowledgement
I would like to thank Kristoffer and Ove for excellent supervision during my first two years,
Juha Loenberg for helping me with fieldwork and Börje Pettersson and Rune Andersson at the
forest companies Bergvik Skog AB and Sveaskog for providing me with stand data.
12
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invertebrates during disturbance in a NEW Zealand stream. Journal of North
American Bentholological Society 19: 82-93.
McCune, B. and Mefford, M.J. 1999. PC-ORD. Multivariate analysis of ecological data.
Version 4.0. MjM Software, Gleneden Beach, Oregon, USA.
Merrifield, K. and Ingham, R.E.1998. Nematodes and other aquatic invertebrates of
Eurhynchium oreganum of Marys Peak, Oregon coast range.
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Nilsson, NE. 1996. Editor in Skogen, 2th edition. Sveriges National Atlas (SNS).
Panzer, R. 2003. Importance of In Situ Survival, Recolonization and Habitat Gaps in the
Postfire Recovery of Fire -Sensitive Prairie Insect Species. Natural Areas Journal 23:
14-21.
Pickett, S.T.A., Kolasa, J., Armesto, J.J. and Collins, L. 1989. The ecological concept of
disturbance and its expression at various hierarchial levels. Oikos 54:129-136.
Raab, B. and Vedin, H. 1999. Editors in Klimat, sjöar och vattendrag. Svensk National Atlas
(SNS)
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Foundations for Statistical Computing, Vienna, Austria.
Rudolphi, J., Gustafsson, L. and Berglund T. Old-growth forest and lichens in young boreal
production forests. In prep.
Sedell, J.R., Reeves, G.H., Hauer, F.H., Stanford, J.A. and Hawkins, C.P. 1990. Role of
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Steiljen, I., Nilsson, MC. and Zackrisson, O. 1995. Seed regeneration of Scots pine in boreal
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Serien Plants & Ecology (ISSN 1651-9248) har tidigare haft namnen "Meddelanden från
Växtekologiska avdelningen, Botaniska institutionen, Stockholms Universitet"
nummer 1978:1 – 1993:1 samt "Växtekologi". (ISSN 1400-9501) nummer 1994:1 –
2003:3.
Följande publikationer ingår i utgivningen:
1978:1 Liljelund, Lars-Erik: Kompendium i matematik för ekologer.
1978:2 Carlsson, Lars: Vegetationen på Littejåkkadeltat vid Sitasjaure, Lule Lappmark.
1978:3 Tapper, Per-Göran: Den maritima lövskogen i Stockholms skärgård.
1978:4: Forsse, Erik: Vegetationskartans användbarhet vid detaljplanering av
fritidsbebyggelse.
1978:5 Bråvander, Lars-Gunnar och Engelmark, Thorbjörn: Botaniska studier vid
Porjusselets och St. Lulevattens stränder i samband med regleringen 1974.
1979:1 Engström, Peter: Tillväxt, sulfatupptag och omsättning av cellmaterial hos
pelagiska saltvattensbakterier.
1979:2 Eriksson, Sonja: Vegetationsutvecklingen i Husby-Långhundra de senaste
tvåhundra åren.
1979:3 Bråvander, Lars-Gunnar: Vegetation och flora i övre Teusadalen och vid Autaoch Sitjasjaure; Norra Lule Lappmark. En översiktlig inventering med anledning av
områdets exploatering för vattenkraftsändamål i Ritsemprojektet.
1979:4 Liljelund, Lars-Erik, Emanuelsson, Urban, Florgård, C. och Hofman-Bang,
Vilhelm: Kunskapsöversikt och forskningsbehov rörande mekanisk påverkan på
mark och vegetation.
1979:5 Reinhard, Ylva: Avloppsinfiltration - ett försök till konsekvensbeskrivning.
1980:1 Telenius, Anders och Torstensson, Peter: Populationsstudie på Spergularia marina
och Spergularia media. I Frödimorfism och reproduktion.
1980:2 Hilding, Tuija: Populationsstudier på Spergularia marina och Spergularia media.
II Resursallokering och mortalitet.
1980:3 Eriksson, Ove: Reproduktion och vegetativ spridning hos Potentilla anserina L.
1981:1 Eriksson, Torsten: Aspekter på färgvariation hos Dactylorhiza sambucina.
1983:1 Blom, Göran: Undersökningar av lertäkter i Färentuna, Ekerö kommun.
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1984:1 Jerling, Ingemar: Kalkning som motåtgärd till försurningen och dess effekter på
blåbär, Vaccinium myrtillus.
1986:1 Svanberg, Kerstin: En studie av grusbräckans (Saxifraga tridactylites) demografi.
1986:2 Nyberg, Hans: Förändringar i träd- och buskskiktets sammansättning i
ädellövskogen på Tullgarnsnäset 1960-1983.
1987:1 Edenholm, Krister: Undersökningar av vegetationspåverkan av vildsvinsbök i
Tullgarnsområdet.
1987:2 Nilsson, Thomas: Variation i fröstorlek och tillväxthastighet inom släktet Veronica.
1988:1 Ehrlén, Johan: Fröproduktion hos vårärt (Lathyrus vernus L.). - Begränsningar och
reglering.
1988:2 Dinnétz, Patrik: Local variation in degree of gynodioecy and protogyny in Plantago
maritima.
1988:3 Blom, Göran och Wincent, Helena: Effekter of kalkning på ängsvegetation.
1989:1 Eriksson, Pia: Täthetsreglering i Littoralvegetation.
1989:2 Kalvas, Arja: Jämförande studier av Fucus-populationer från Östersjön och
västkusten.
1990:1 Kiviniemi, Katariina: Groddplantsetablering och spridning hos smultron, Fragaria
vesca.
1990:2 Idestam-Almquist, Jerker: Transplantationsförsök med Borstnate.
1992:1 Malm, Torleif: Allokemisk påverkan från mucus hos åtta bruna makroalger på
epifytiska alger.
1992:2 Pontis, Cristina: Om groddknoppar och tandrötter. Funderingar kring en klonal
växt: Dentaria bulbifera.
1992:3 Agartz, Susanne: Optimal utkorsning hos Primula farinosa.
1992:4 Berglund, Anita: Ekologiska effekter av en parasitsvamp - Uromyces lineolatus på
Glaux maritima (Strandkrypa).
1992:5 Ehn, Maria: Distribution and tetrasporophytes in populations of Chondrus crispus
Stackhouse (Gigartinaceae, Rhodophyta) on the west coast of Sweden.
1992:6 Peterson, Torbjörn: Mollusc herbivory.
1993:1 Klásterská-Hedenberg, Martina: The influence of pH, N:P ratio and zooplankton
on the phytoplanctic composition in hypertrophic ponds in the Trebon-region, Czech
Republic.
1994:1 Fröborg, Heléne: Pollination and seed set in Vaccinium and Andromeda.
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1994:2 Eriksson, Åsa: Makrofossilanalys av förekomst och populationsdynamik hos Najas
flexilis i Sörmland.
1994:3 Klee, Irene: Effekter av kvävetillförsel på 6 vanliga arter i gran- och tallskog.
1995:1 Holm, Martin: Beståndshistorik - vad 492 träd på Fagerön i Uppland kan berätta.
1995:2 Löfgren, Anders: Distribution patterns and population structure of an economically
important Amazon palm, Jessenia bataua (Mart.) Burret ssp. bataua in Bolivia.
1995:3 Norberg, Ylva: Morphological variation in the reduced, free floating Fucus
vesiculosus, in the Baltic Proper.
1995:4 Hylander, Kristoffer & Hylander, Eva: Mount Zuquala - an upland forest of
Ethiopia. Floristic inventory and analysis of the state of conservation.
1996:1 Eriksson, Åsa: Plant species composition and diversity in semi-natural grasslands with special emphasis on effects of mycorrhiza.
1996:2 Kalvas, Arja: Morphological variation and reproduction in Fucus vesiculosus L.
populations.
1996:3 Andersson, Regina: Fågelspridda frukter kemiska och morfologiska egenskaper i
relation till fåglarnas val av frukter.
1996:4 Lindgren, Åsa: Restpopulationer, nykolonisation och diversitet hos växter i
naturbetesmarker i sörmländsk skogsbygd.
1996:5 Kiviniemi, Katariina: The ecological and evolutionary significance of the early life
cycle stages in plants, with special emphasis on seed dispersal.
1996:7 Franzén, Daniel: Fältskiktsförändringar i ädellövskog på Fagerön, Uppland,
beroende på igenväxning av gran och skogsavverkning.
1997:1 Wicksell, Maria: Flowering synchronization in the Ericaceae and the Empetraceae.
1997:2 Bolmgren, Kjell: A study of asynchrony in phenology - with a little help from
Frangula alnus.
1997:3 Kiviniemi, Katariina: A study of seed dispersal and recruitment of plants in a
fragmented habitat.
1997:4 Jakobsson, Anna: Fecundity and abundance - a comparative study of grassland
species.
1997:5 Löfgren, Per: Population dynamics and the influence of disturbance in the Carline
Thistle, Carlina vulgaris.
1998:1 Mattsson, Birgitta: The stress concept, exemplified by low salinity and other stress
factors in aquatic systems.
18
1998:2 Forsslund, Annika & Koffman, Anna: Species diversity of lichens on decaying
wood - A comparison between old-growth and managed forest.
1998:3 Eriksson, Åsa: Recruitment processes, site history and abundance patterns of plants
in semi-natural grasslands.
1998:4 Fröborg, Heléne: Biotic interactions in the recruitment phase of forest field layer
plants.
1998:5 Löfgren, Anders: Spatial and temporal structure of genetic variation in plants.
1998:6 Holmén Bränn, Kristina: Limitations of recruitment in Trifolium repens.
1999:1 Mattsson, Birgitta: Salinity effects on different life cycle stages in Baltic and North
Sea Fucus vesiculosus L.
1999:2 Johannessen, Åse: Factors influencing vascular epiphyte composition in a lower
montane rain forest in Ecuador. An inventory with aspects of altitudinal distribution,
moisture, dispersal and pollination.
1999:3 Fröborg, Heléne: Seedling recruitment in forest field layer plants: seed production,
herbivory and local species dynamics.
1999:4 Franzén, Daniel: Processes determining plant species richness at different scales examplified by grassland studies.
1999:5 Malm, Torleif: Factors regulating distribution patterns of fucoid seaweeds. A
comparison between marine tidal and brackish atidal environments.
1999:6 Iversen, Therese: Flowering dynamics of the tropical tree Jacquinia nervosa.
1999:7 Isæus, Martin: Structuring factors for Fucus vesiculosus L. in Stockholm south
archipelago - a GIS application.
1999:8 Lannek, Joakim: Förändringar i vegetation och flora på öar i Norrtälje skärgård.
2000:1 Jakobsson, Anna: Explaining differences in geographic range size, with focus on
dispersal and speciation.
2000:2 Jakobsson, Anna: Comparative studies of colonisation ability and abundance in
semi-natural grassland and deciduous forest.
2000:3 Franzén, Daniel: Aspects of pattern, process and function of species richness in
Swedish seminatural grasslands.
2000:4 Öster, Mathias: The effects of habitat fragmentation on reproduction and population
structure in Ranunculus bulbosus.
2001:1 Lindborg, Regina: Projecting extinction risks in plants in a conservation context.
2001:2 Lindgren, Åsa: Herbivory effects at different levels of plant organisation; the
individual and the community.
19
2001:3 Lindborg, Regina: Forecasting the fate of plant species exposed to land use change.
2001:4 Bertilsson, Maria: Effects of habitat fragmentation on fitness components.
2001:5 Ryberg, Britta: Sustainability aspects on Oleoresin extraction from Dipterocarpus
alatus.
2001:6 Dahlgren, Stefan: Undersökning av fem havsvikar i Bergkvara skärgård, östra
egentliga Östersjön.
2001:7 Moen, Jon; Angerbjörn, Anders; Dinnetz, Patrik & Eriksson Ove: Biodiversitet i
fjällen ovan trädgränsen: Bakgrund och kunskapsläge.
2001:8 Vanhoenacker, Didrik: To be short or long. Floral and inflorescence traits of Bird`s
eye primrose Primula farinose, and interactions with pollinators and a seed predator.
2001:9 Wikström, Sofia: Plant invasions: are they possible to predict?
2001:10 von Zeipel, Hugo: Metapopulations and plant fitness in a titrophic system – seed
predation and population structure in Actaea spicata L. vary with population size.
2001:11 Forsén, Britt: Survival of Hordelymus europaéus and Bromus benekenii in a
deciduous forest under influence of forest management.
2001:12 Hedin, Elisabeth: Bedömningsgrunder för restaurering av lövängsrester i Norrtälje
kommun.
2002:1 Dahlgren, Stefan & Kautsky, Lena: Distribution and recent changes in benthic
macrovegetation in the Baltic Sea basins. – A literature review.
2002:2 Wikström, Sofia: Invasion history of Fucus evanescens C. Ag. in the Baltic Sea
region and effects on the native biota.
2002:3 Janson, Emma: The effect of fragment size and isolation on the abundance of Viola
tricolor in semi-natural grasslands.
2002:4 Bertilsson, Maria: Population persistance and individual fitness in Vicia pisiformis:
the effects of habitat quality, population size and isolation.
2002:5 Hedman, Irja: Hävdhistorik och artrikedom av kärlväxter i ängs- och hagmarker på
Singö, Fogdö och norra Väddö.
2002:6 Karlsson, Ann: Analys av florans förändring under de senaste hundra åren, ett
successionsförlopp i Norrtälje kommuns skärgård.
2002:7 Isæus, Martin: Factors affecting the large and small scale distribution of fucoids in
the Baltic Sea.
2003:1 Anagrius, Malin: Plant distribution patterns in an urban environment, Södermalm,
Stockholm.
20
2003:2 Persson, Christin: Artantal och abundans av lavar på askstammar – jämförelse
mellan betade och igenvuxna lövängsrester.
2003:3 Isæus, Martin: Wave impact on macroalgal communities.
2003:4 Jansson-Ask, Kristina: Betydelsen av pollen, resurser och ljustillgång för
reproduktiv framgång hos Storrams, Polygonatum multiflorum.
2003:5 Sundblad, Göran: Using GIS to simulate and examine effects of wave exposure on
submerged macrophyte vegetation.
2004:1 Strindell, Magnus: Abundansförändringar hos kärlväxter i ädellövskog – en
jämförelse av skötselåtgärder.
2004:2 Dahlgren, Johan P: Are metapopulation dynamics important for aquatic plants?
2004:3 Wahlstrand, Anna: Predicting the occurrence of Zostera marina in bays in the
Stockholm archipelago,northern Baltic proper.
2004:4 Råberg, Sonja: Competition from filamentous algae on Fucus vesiculosus –
negative effects and the implications on biodiversity of associated flora and fauna.
2004:5 Smaaland, John: Effects of phosphorous load by water run-off on submersed plant
communities in shallow bays in the Stockholm archipelago.
2004:6 Ramula Satu: Covariation among life history traits: implications for plant
population dynamics.
2004:7 Ramula, Satu: Population viability analysis for plants: Optimizing work effort and
the precision of estimates.
2004:8 Niklasson, Camilla: Effects of nutrient content and polybrominated phenols on the
reproduction of Idotea baltica and Gammarus ssp.
2004:9 Lönnberg, Karin: Flowering phenology and distribution in fleshy fruited plants.
2004:10 Almlöf, Anette: Miljöfaktorers inverkan på bladmossor i Fagersjöskogen, Farsta,
Stockholm.
2005:1 Hult, Anna: Factors affecting plant species composition on shores - A study made in
the Stockholm archipelago, Sweden.
2005:2 Vanhoenacker, Didrik: The evolutionary pollination ecology of Primula farinosa.
2005:3 von Zeipel, Hugo: The plant-animal interactions of Actea spicata in relation to
spatial context.
2005:4 Arvanitis, Leena T.: Butterfly seed predation.
2005:5 Öster, Mathias: Landscape effects on plant species diversity – a case study of
Antennaria dioica.
2005:6 Boalt, Elin: Ecosystem effects of large grazing herbivores: the role of nitrogen.
21
2005:7 Ohlson, Helena: The influence of landscape history, connectivity and area on
species diversity in semi-natural grasslands.
2005:8 Schmalholz, Martin: Patterns of variation in abundance and fecundity in the
endangered grassland annual Euphrasia rostkovia ssp. Fennica.
2005:9 Knutsson, Linda: Do ants select for larger seeds in Melampyrum nemorosum?
2006:1 Forslund, Helena: A comparison of resistance to herbivory between one exotic and
one native population of the brown alga Fucus evanescens.
2006:2 Nordqvist, Johanna: Effects of Ceratophyllum demersum L. on lake phytoplankton
composition.
2006:3 Lönnberg, Karin: Recruitment patterns, community assembly, and the evolution of
seed size.
2006:4 Mellbrand, Kajsa: Food webs across the waterline - Effects of marine subsidies on
coastal predators and ecosystems.
2006:5 Enskog, Maria: Effects of eutrophication and marine subsidies on terrestrial
invertebrates and plants.
2006:6 Dahlgren, Johan: Responses of forest herbs to the environment.
2006:7 Aggemyr, Elsa: The influence of landscape, field size and shape on plant species
diversity in grazed former arable fields.
2006:8 Hedlund, Kristina: Flodkräftor (Astacus astacus) i Bornsjön, en omnivors påverkan
på växter och snäckor.
2007:1 Eriksson, Ove: Naturbetesmarkernas växter- ekologi, artrikedom och
bevarandebiologi.
2007:2 Schmalholz, Martin: The occurrence and ecological role of refugia at different
spatial scales in a dynamic world.
2007:3 Vikström, Lina: Effects of local and regional variables on the flora in the former
semi-natural grasslands on Wäsby Golf club’s course.
2007:4 Hansen, Joakim: The role of submersed angiosperms and charophytes for aquatic
fauna communities.
2007:5 Johansson, Lena: Population dynamics of Gentianella campestris, effects of
grassland management, soil conditions and the history of the landscape
2007:6 von Euler, Tove: Sex related colour polymorphism in Antennaria dioica.
2007:7 Mellbrand, Kajsa: Bechcombers, landlubbers and able seemen: Effects of marine
subsidies on the roles of arthropod predators in coastal food webs.
22
2007:8 Hansen, Joakim: Distribution patterns of macroinvertebrates in vegetated, shallow,
soft-bottom bays of the Baltic Sea.
2007:9 Axemar, Hanna: An experimental study of plant habitat choices by
macroinvertebrates in brackish soft-bottom bays.
2007:10 Johnson, Samuel: The response of bryophytes to wildfire- to what extent do they
survive in-situ?
2007:11 Kolb, Gundula: The effects of cormorants on population dynamics and food web
structure on their nesting islands.
2007:12 Honkakangas, Jessica: Spring succession on shallow rocky shores in northern
Baltic proper.
2008:1
Gunnarsson, Karl: Påverkas Fucus radicans utbredning av Idotea baltica?
2008:2
Fjäder, Mathilda: Anlagda våtmarker i odlingslandskap- Hur påverkas
kärlväxternas diversitet?
23