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2002/2003
Phytochemical diversity
A technique for chiral separation of individual monoterpenes
has been developed along with a sampling protocol for extraction
of whole pine needles. These innovations facilitate rapid
processing of large numbers of small samples to a high degree
of resolution. The variation in absolute concentration of
total monoterpenes within individual trees, is about 10%;
this knowledge has been used to improve the efficiency of
sampling of pine needles. Despite their volatility, levels
of monoterpenes in needles seem to decline slowly with age
in attached needles and litter. MTPs have also been quantified
in the roots of pine seedlings and in litter and soil. Root
concentrations are 40% of those in shoots. Results support
the hypothesis that, MTPs occur at locations and in concentrations
that are likely to influence ecosystem processes. Both roots
and litter are a potential source of soil MTPs.
Ecological processes
Spatial variation in vegetation dynamics
Initial results suggest that post-dispersal seed, and
seedling survival is very low. Ground vegetation diversity
in the vicinity of individual trees is positively related
to chemical diversity of the trees themselves, which are highly
variable. This novel result indicates the importance of ‘chemodiversity’
as a determinant of ecosystem diversity, raising the possibility
that conservation management should take place at the genotype
rather than the species level. Only about a third of trees
produced seed in 2003, and the consistency of this between
years, needs to be assessed before its possible significance
to tree fitness can be ascertained.
Spatial variation in tree crown insect
herbivores
Population performance of pine
loopers was assessed by enclosing larvae onto foliage of 30
trees of contrasting phenotypes. Mortality of the larvae was
very high, and the experiment is to be repeated using larger
sample sizes. Data on Pine looper moth success from early
instar caterpillars to pupae are being compared with terpene
and phenolic profiles of each pine tree, the physical attributes
of needles and crown and the landscape context of each tree.
The fall of arthropods, their frass and damaged plant material,
and associated litter fall from tree crowns was assessed via
regular sampling, at least monthly, of 45 sets of collection
funnels. These samples are currently being identified but
initial results show that the insect related material represents
ca. 1% of fallen material in autumn, whereas it was 8% of
material in early summer. A less frequent sampling regime
should be sufficient in 2003. Although pine aphids are abundant,
honeydew trapping yielded relatively little honeydew; an analytical
protocol is being developed which distinguishes different
sugars of aphid and plant origin.
Quantification of mycorrhizal diversity
of pine
Species richness curves for mycorrhizal morphotypes were
produced from 40 soil cores taken around 5 trees of contrasting
terpene chemotype. Thirty four morphotypes were identified
and the species richness curve suggested this sampling frequency
was sufficient to assess the population. The identity of mycorrhiza
is being confirmed by sequencing the ITS region of extracted
DNA. A method for the identification of the host tree from
these root tips was developed to link host pine genotype to
mycorrhizal diversity using pine specific microsatellite markers.
A protocol for exposing mycorrhizal cultures
to monoterpenes was tested using five ectomycorrhizal (EcM)
isolates. Initial results suggest that EcM fungi grown in
culture are selectively inhibited by different monoterpenes.
These initial experiments resulted in an improved microcosm
design to be used in future experiments to test a wider range
of species.
Quantification of microbial community
structure
Soil sampling to measure spatial variation in microbial
community structure around 5 trees of contrasting chemotype
was completed in September. Soil chemical analysis is complete
and the analysis of microbial phospholipid fatty acid profiles
is partially complete. Soils have been archived at minus 80
degrees C for future extraction of the DNA and quantification
of the fungal diversity. The development of the microsatellite
approach to genotype root fragments will enable the statistical
analysis to link these data with pine chemoptype.
Spatial Ecology
Spatial model of biodiversity
All available data relating to the spatial variation
of biodiversity at different levels, on the main study site,
have been collated. Initial analyses show no spatial autocorrelation
among MTP concentrations in different trees sampled on a 200m
grid. Emphasis of spatial analyses will therefore shifted
from "landscape" to the more "local" inter-relationship
between maternal pines and variations in terpene chemistry
of offspring saplings.
2004/2005
Phytochemical diversity
Analysis of pine needles of groups of
known half-sibs germinated in the laboratory, and putative
groups of half-sibs sampled in the field at Balmoral and Mar
lodge estates, showed large variation between individuals in
monoterpene concentrations only a relatively small
proportion of which can be attributed to family differences.
Extraction, appropriate hydrolysis and analytical methods
for pine terpenoids and phenolics were optimised, and
revealed that Scottish Scots pine Pinus sylvestris
subspecies scotica shows an unusual phytochemistry,
for the genus. It is characterised by a low proportion of
oxygenated terpenes, of which only bornyl acetate occurs in
quantities of up to 5% of total monoterpene concentration.
Caryophyllene is the major sesquiterpene in the subspecies.
For phenolic metabolites, prodelphinidin-based condensed
tannins make up the largest proportion with the flavonol
quercetin, a major phenolic for the genus Pinus,
occurring only in trace amounts.
Ecological processes
Spatial variation in vegetation dynamics
The small mammal population sizes and species diversity
associated with contrasting ground vegetation was measured
in October 2003 using a mark-recapture Longworth trapping
program. The small mammal population was dominated by bank
voles, and wood mice were also present. The vegetation
structure and species richness at each of 12 small mammal
sampling sites was also measured, but no close associations
were seen between vole numbers and particular vegetation
characteristics.
In order to investigate seedling mortality in relation to
maternal chemotype, seed was collected during March 2003.
However, the germination success for the collected seed was
less than 50%, as compared with at least 80% for the
previous year, and therefore insufficient seedlings were
produced from the required mothers, to allow completion of
the planned experiment. Further seed was collected in March
2004, and germinated for the experiment which will now be
run in the summer of 2004.
Increment cores were collected in March 2004, from all
mature pines in the project’s initial sampling grid of 150
original trees, and in excess of a further 500 trees in
seven, 1ha plots.
Spatial variation in tree crown insect herbivores
The sampling of arthropods and needles and other materials
falling from the crowns of 45 pine trees to the woodland
floor was completed in October 2003, representing continual
sampling from April 2002. Primary sorting of plant and
arthropod material from all trees on each sampling date has
been completed. Arthropods have been sorted to guilds and
identified as far as possible for 17 of the 32 sample dates.
The average mass of plant material per funnel was 0 g
(April) to 12 g (October) compared with an arthropod mass of
0.005 g (February) to 0.10 g (September). The monoterpene
composition of pine trees was a significant factor
determining the spatial variation in the distribution of
arthropods by guild, after effects of altitude were taken
into account. More phytophages were found in the crowns of
pine trees with higher concentrations of beta-pinene.
A second bioassay was successfully undertaken on 30 pine
trees with different monoterpene mixtures using pine looper
moth (Bupalus
piniarius)
caterpillars. Length gain of caterpillars was greater in
trees with higher concentrations of camphene and sabinene
and lower concentrations of beta-phellandrene and
gamma-terpinene.
Evidence of ant trails was investigated on the target 45
pine trees. Monthly 30-minute counts were made of descending
ants and laden ants were collected and their loads
identified. Replete ants (those dilated through carrying
aphid honeydew) were also counted. Activity of ants peaked
in July-August 2003, slightly earlier than the cooler year
in 2002. Journeys to collect honeydew of pine aphids reached
a peak of 3000 journeys each half-hour by August 2003.
Quantification of mycorrhizal diversity of pine
Data analysis has been completed for the initial sampling
effort to assess the effect of contrasting pine chemotype on
ectomycorrhizal (EcM) diversity. All root fragments were
identified by microsatellite analysis and the associated EcM
fungi identified by ITS RFLP and sequencing. This work has
been written up and submitted for publication.
Additional EcM fungal isolates have been sub-cultured in
preparation for setting up further experiments to test the
tolerance of EcM fungi to terpenes in pure culture.
Pine seedlings have been germinated and microcosms have been
prepared to investigate the effects of pine chemotype on EcM
fungi. The difficulty in obtaining sufficient seedlings of
each different chemotype has resulted in this experiment
changing slightly. The microcosms have been prepared using
soil collected from the Ballochbuie field site to act as
natural EcM inoculum for the seedlings. The microcosms have
been prepared and set aside to allow time for the fungi to
colonise the seedlings. We will then investigate the effects
of needle litter patches of different chemotype on the
external mycelium of EcM fungi.
Quantification of microbial community structure
The extraction of PLFAs is complete and the data is
currently being analysed. Depending on this analysis higher
resolution analysis, using DNA extraction and
fingerprinting, will be done.
Litter decomposition assays were undertaken in both
microcosms and in a field trial. The laboratory microcosm
tested the effect of litter from trees of contrasting
chemotype on the soil microbial community structure and rate
of N mineralisation. The presence of green litter (rich in
monoterpenes) inhibited N mineralisation but there was no
significant difference between chemotypes. Soil sampling
from core trees was postponed until autumn 2004 and a
preliminary, additional field experiment was undertaken
instead using a standard litter type placed in different
positions around six replicate trees of two chemotypes (high
and low carene). Both litter decomposition and wood
decomposition is being measured and the soil sampled to
determine differences in microbial community composition.
Spatial Ecology
Spatial model of biodiversity
We have analysed MTP variation as a function of
environmental variation and found no significant
environmental explanatory factors. The best explanation for
MTP variation may well be the isolation-by-distance genetic
model, which we have successfully developed to predict MTP
patterns. We have added to our earlier finding that MTP
variation is spatially unstructured at the >200m scale by
collecting and analysing finer-scale data on needle MTP
variation within seven 1 ha plots. This involved spatial
mapping of a further 500 (approx) trees, and was linked to
determination of their ages. Within these plots we do indeed
find some spatial structuring of MTP’s at smaller spatial
scales. In addition, preliminary analysis of our
mother-offspring plots shows patchiness associated with
putative mother trees but this spatial structuring force may
be relatively weak once additional differential survival and
predation of age-structured seedlings is investigated.
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Johnstone, J., Dennis, P., Iason, G., Beaton, J. and Jacob,
A.
Formica aquilonia foraging patterns in a Scots pine
forest. Poster presentation to the Royal Entomological
Society Meeting 'Ecology and Evolution of Social Insects',
London, October 2002.
Saari, S.K., Alexander, I.J., Campbell, C.D., Russell, J.
and Anderson, I.C.
Do
individual host trees support different communities of
ectomycorrhizal fungi? - - The Fourth International Conference on Mycorrhizae (ICOM4),
Montreal,
Canada, 10th-15th August 2003.
Iason G, Lennon J, Thoss, V, Dennis P, Pakeman R, Campbell
C, Saari S, Anderson I, Chapman S, Beaton J, Stockan J, Sim
D & *Alexander, I.
Does individual variation in phytochemistry determine associated
biodiversity and processes in a natural Scots pine ecosystem?
Oral presentation to British Ecological Society Annual Meeting,
Manchester, September 2003
Lennon, JJ et al. Spatial structure
in chemical ecology and biodiversity within native Scots Pine
forest. Oral presentation to British Ecological Society
Annual Meeting, Manchester, September 2003.
Iason, G.,
Lennon, J., Thoss, V., Pakeman, R., Dennis, P., Campbell,
C., Saari, S., Anderson,
I., Chapman, S., Beaton, J., Johnstone, J., Sim, D., and Alexander, I.
Does individual variation in phytochemistry determine associated
biodiversity and processes in a natural Scots pine
ecosystem? British
Ecological Society Conference,
Manchester
Metropolitan University, 9-11 September 2003.
Iason G, Thoss V, Lennon J, Dennis P,
Pakeman R, Campbell C, Saari S, Anderson I, Chapman S,
Beaton J, Stockan J, Sim D & *Alexander, I. Does individual
variation in phytochemistry determine associated biodiversity
and processes in a natural Scots pine ecosystem? Research
Seminar, University of Joensuu, Finland November 4th 2003.
Stockan, J., Dennis, P., Thoss, V. and Beaton, J.
Effects of pine tree chemistry on insect herbivore
diversity and distribution. Oral presentation to the
Royal Entomological Society's North Region Meeting on
Insects and Trees, Myerscough College, Lancashire, 25
February 2004.
Iason, G, Lennon J, Thoss, V., Pakeman
R, Dennis P, Campbell C, Saari S, Anderson I, Chapman S, Beaton
J, Johnstone J, Sim D & *Alexander, I.
Does individual variation in phytochemistry determine associated
diversity and processes in a natural Scots pine ecosystem?
Poster presentation to Gordon Research Conference on Plant-Herbivore
Interactions, Ventura California, 1-5 March 2004.
Iason, G, Lennon J, Thoss, V., Pakeman
R, Dennis P, Campbell C, Saari S, Anderson I, Chapman S, Beaton
J, Johnstone J, Sim D & *Alexander, I. Does individual
variation in phytochemistry determine associated diversity
and processes in a natural Scots pine ecosystem? Poster
presentation to Conference on Terrestrial Environmental Change
in the highlands and Islands,: From Mountain Summits to Coasts.
Inverness, 26-28 March 2004.
Iason G, Lennon J, Thoss V, Dennis P,
Pakeman R, Campbell C, Saari S, Anderson I, Chapman S,
Beaton J, Stockan J, Sim D & *Alexander, I. Chemical ecology
of Scots pine woodlands. Oral presentation to the Native
Woodland Discussion Group, Deeside, Scotland, 3-5 June 2004
Iason G., Dennis P, Lennon J, Thoss, V,
Pakeman R, Campbell C, Saari S, Anderson I, Chapman S, Beaton
J, Stockan J, Sim D & *Alexander, I. The role of variation
between trees in phytochemistry in determining associated
diversity in a natural Scots pine ecosystem. Oral presentation
at The Ecology and management of large Native pinewoods: past,
present and future. British Ecological Society Forest Ecology
Group, 14-16 June 2004.
Stockan, J., Dennis, P., Thoss, V., Iason, G. and Beaton, J.
Phytochemistry of Scot's pine as a driver of spatial
heterogeneity in insect herbivore and broader diversity in a
native forest landscape. Poster presentation to
the International Association of Landscape Ecology
conference on Landscape Ecology of Trees and Forests ,
Cirencester, 21-24 June 2004.
Dennis,
P., Stockan, J., Thoss, V., Lennon, J. and Beaton, J.
Spatial heterogeneity in monoterpene concentrations of
native pine as a driver of insect herbivore distribution and
abundance. Oral paper to the national meeting of the
Royal Entomological Society, York University, 21-23 July,
2004.
Stockan, J., Dennis, P., Thoss, V., Iason, G. and Beaton, J
.Phytochemistry
of Scot's pine as a driver of spatial heterogeneity in
insect herbivore and broader diversity in a native forest
landscape. Landscape
ecology of trees and forests. Proceedings of the twelfth
annual IALE (UK) conference,
Cirencester, UK, 21-24 June 2004. Pp340-343.
Dennis, P., Stockan, J., Thoss, V., Iason, G., Lennon, J.
and Beaton, J.
Spatial heterogeneity in monoterpene concentrations of
native pine as a driver of insect herbivore distribution and
abundance. Oral presentation to the XXII International
Congress of Entomology, Brisbane, Queensland, Australia,
15-20 August, 2004.
Dennis, P., Stockan, J., Thoss, V., Beaton, J., Lennon, J.
and Iason, G.
Spatial
heterogeneity in monoterpene concentrations of native pine
as a driver of insect herbivore distribution and abundance.
Oral presentation to the British Ecological Society,
Annual Meeting, Lancaster University, 7-9 September 2004.
Thoss, V., Iason, G., Dennis, P., Lennon, J., Pakeman, R.,
Campbell, C., Saari, S., Anderson, I., Chapman, S., Beaton,
J., Stockan, J., Sim, D. and Alexander, I.
Individual
variation in Scots pine phytochemistry and its effects on
associated ecological processes in a Caledonian forest. PSNA
and ISCE 2004 Meeting, Chemical Ecology and Phytochemistry
in Forest Ecosystems. Oral paper.
Iason, G., Lennon, J., Thoss, V., Pakeman, R., Dennis, P.,
Campbell, C., Saari, S., Anderson, I., Chapman, S., Beaton,
J., Stockan, J., Sim, D. and Alexander, I.
Does individual variation in phytochemistry determine associated
diversity and processes in a natural Scots pine ecosystem?
Science for Biodiversity, Scottish Biodiversity Forum's
Action Plan and Science Group, Edinburgh, 11 March 2005.
Pakeman, R.J., Beaton, J., Thoss, V., Lennon, J., Sim, D.
and Iason, G
Phytochemistry of Scots pine contributes to understorey
assemblage structure.90th
ESA Annual Meeting / IX Intecol Congress, Montreal, 8-12
August 2005.
Stockan,
J., Dennis, P., Thoss, V., Beaton, J., Elston, D.
Phytophagous insects of Scots Pine: Do tree genetics
determine herbivore diversity? Oral presentation to
Royal Entomological Society Annual Meeting, Sussex, 12-14
September 2005.
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Saari, S. K.,
Russell, J., Campbell, C. D., Alexander, I. J. and Anderson, I. C.
2004. Pine microsatellite markers allow roots and
ectomycorrhizas to be linked to individual trees. New
Phytologist165 (1):295-304, 2005.
Saari, S. K.,
Russell, J., Campbell, C. D., Alexander, I. J. and Anderson, I.
C. 2004. Pine microsatellite markers allow roots and
ectomycorrhizas to be linked to individual trees. New
Phytologist165
(1):295-304, 2005.
Iason,
G.R., Lennon, J., Pakeman, R., Thoss, V., Beaton, J., Sim, D.
and Elston, D.
Does chemical composition of individual Scots pine trees
determine the biodiversity of their associated ground
vegetation? Ecology
Letters, 8, 364-369.
Thoss,
V. and Byers, J.A.
Monoterpene chemodiversity of ponderosa pine in relation to
herbivory and bark beetle colonization.
Chemoecology.
In press.
Pakeman,
R.J., Beaton, J.K., Thoss, V., Lennon, J.J., Campbell, C.D.,
White, D. and Iason, G.R.
The extended
phenotype of Scots pine (Pinus sylvestris) structures the
understorey assemblage.
Ecology.
SUBM.
O'Reilly-Wapstra,
J., Iason, G. and Thoss, V.
The
role of genetic and chemical variation of Pinus sylvestris
seedlings in influencing slug herbivory.
Journal of Ecology.
SUBM.
Dennis,
P., Stockan, J., Thoss, V., Elston, D.A. and Iason, G.I.
Evidence for effects of genotypic diversity via monoterpene
composition on phytophagous insects of a native Scot's pine
forest.
Oecologia.
SUBM.
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