| GEOGRAPHY: William D. Gosling |
"Characterization
of Amazonian forest and savannah ecosystems by their modern pollen
spectra"
Funding:
University of Leicester Studentship,
QRA New Research Workers' Award 2000
Supervisors: Dr.
Francis E. Mayle and Dr.
Nicholas Tate
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Pollen-based
palaeoecological reconstructions of Amazonia are fraught with difficulty, in
large part due to our poor understanding of the relationships between fossil
pollen spectra and their parent vegetation. Progress in resolving this problem
can only be achieved by determining the modern pollen signatures of present-day
Amazonian ecosystems, and the degree to which they can be distinguished from
one another.
To
this end, pollen traps have been set up by F. Mayle within the 5 distinct ecosystems
of Noel Kempff Mercado National Park in Amazonian Bolivia. This study area is
of particular interest due its high habitat diversity, straddling ecotones between
humid evergreen rainforests to the north, and dry semi-deciduous forests and
cerrado savannas to the south. The pollen traps have been set up within permanent
vegetation study plots for which there are highly detailed botanical inventories.
The traps are sampled on an annual basis over several years to determine inter-annual
variability in pollen production.
This
project provides a number of exciting and interesting problems which will have
to addressed, there are also other additional lines of research that could be
developed.
Developments
within the scope of this project
- The expansion
of the reference collection by obtaining material from the ecologically well
documented Noel Kempff National Park.
- The creation
of a web based tropical pollen reference image database. Current developments
can be viewed here.
- The preservation
of samples in traps needs to be investigated to determine if there are any
problems oxidisation due to the intense heat.
- Localisation,
customisation and fine tuning of sample preparation techniques is required
to develop the most successful method of extracting the pollen. Investigation
into the possibility of biasing of samples with different preparation techniques
should be carried out due to the diverse nature of the pollen grains robustness
and morphology.
- Comparative
studies between trapped pollen and pollen extracted from soil samples or surface
lake muds to define biases with depositional environment, variations in pollen
rain and taphonomic processes would be possible.
Limitations
- Relatively small
reference collections in relation to the diversity of the ecosystems.
- Dominance of
insect and animal pollinated plants meaning that their representation in traps
or sediments may not be consistent or dependant on other factors as yet undefined.
ie. An insect species which disperses a particular type of pollen may not
have an exactly overlapping ecological range with that of the plant.
- Relation of
fossil assemblages to the characteristic assemblages determined. The possibility
of palaeoecosystems being non-analogous with those of the present.
Long
term
- The production
of a database providing an index of the key pollen signatures of the present
day Amazonian regions, with the possibility of using extracted components
of this to explain non-analogous assemblages.
- The exciting
prospect of a long record at Laguna Bellavista would provide a significant
and important archive of Quaternary vegetational history of the low latitudes.
Publication
Stratergy
- Mayle, F.E.,
Burbridge, R., Killeen, T.J. & Gosling, W.D. Moraceae pollen as an
indicator of humid evergreen rainforest. The Holocene or Journal
of Biogeography & Ecology.
- Gosling,
W.D., & Mayle, F.E. Improved methodology for processing of pollen
from Amazonian pollen traps. The Holocene.
- Gosling,
W.D., Mayle, F.E., Tate, N., & Killeen, T. Pollen signatures of forest
and savannah ecosystems in Amazonian Bolivia (preliminary data). The Journal
of Ecology.
- Gosling,
W.D., Mayle, F.E., Tate, N., & Killeen, T. Characterisation of forest
and savannah ecosystems in Amazonian Bolivia by their pollen spectra. Ecological
Monographs.
- Mayle, F.E.,
& Gosling, W.D. A re-assessment of Late Quaternary vegetation change
in Amazonia in light of new surface pollen data. Ecology or Journal
of Biogeography.
Links
W. D. Gosling
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