VSF 2010 Report - Nabo

zone but values decline towards the top of the zone. Cyperaceae values remain constant
throughout the zone at around 20%. Charcoal concentration values are exceptionally low in
this zone.
LPAZ Vat-5 (C. 1890 – 2008)
Percentage pollen values for this upper zone are marked by increases in pollen concentration
values (Figure 4) which reflect changes in the peat composition with peat beginning to dry
out. Betula, Poaceae and Equisetum increase throughout the zone, in contrast to reduced
values in Lactuaceae, Potentilla and Cyperaceae. Charcoal concentration values also show an
increase towards the top of the zone.
Discussion
The formation of the wet meadow dated to 890-1020 AD lies within the traditional landnám
timeframe, and is considered to post-date the settlement of Vatnsfjörður. The pollen evidence
presented here suggests that since the early developmental stages of the wet meadow species
composition has not varied considerably. Poaceae (grasses) has dominated the species
assemblage, remaining at a relatively stable and high percentage value until the present day.
Various herb species have grown alongside Poaceae, although in much smaller quantities and
never dominate the species assemblage. It is suggested that the habitat type of a wet, grass
rich meadow once established persisted until the present day. Here it is proposed that to
maintain this grass rich meadow would have required some form of management to prevent
the encroachment or dominance of other species such as Cyperaceae (sedges). Management
could have been either through removal of the vegetation for fodder or through grazing. The
herb species diversity would also indicate that there has been some form of management
again to maintain this modest level of diversity. Additional evidence of management on site
is from micromorphological analysis of soil from the meadow which showed micro-horizons
of midden type material spread over the meadow, likely as a manuring strategy to cope with
the inherently infertile land (Barclay 2008); this practice might have aided the maintenance of
enhanced levels of Poaceae throughout the period of occupation. The pollen evidence would
suggest that after c. 1420 AD there is slight reduction in diversity perhaps indicating a change
in management but that after c. 1775 AD there is a marked reduction in diversity. It is
proposed that this marked reduction in diversity at c. 1775 AD is in response to a change in
management or land use with perhaps a move to greater intensity of the meadow area for
grazing rather than for fodder use.
The timing of the establishment of the wet meadow and the above evidence for
management of the meadow would suggest that this meadow is anthropogenic in origin,
created just after settlement of the Vatnsfjörður site. The creation of this meadow would
have been through the extension of a naturally occurring wetland area on the site (Figure 1)
and would have exploited the raised beach ridge to effectively create a larger wetland area.
What is less clear from the pollen analysis is if the water table at the site was maintained in
terms of irrigation or if once peat began to accumulate and drainage was impeded that the wet
meadow was self sustaining. Aquatic taxa (Figure 3) are present in low values throughout the
profile and would suggest that wet conditions persist. In addition the continued accumulation
of peat also requires wet anaerobic conditions to allow for the preservation of organic
material.
Concentration values of larger charcoal fragments (>50 µm) remain constant
throughout the profile. This would indicate that the overall changes in charcoal concentration
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