Climate Change: Defining Reference Conditions and Restoring Freshwater Ecosystems - Climate Change Impacts on Freshwater Ecosystems - page 212

2000
1950
1900
1850
1800
1750
pre 1740
Historical record
Plant macrofossil record
Pollen record
Figure 9.3 Comparison of the historical (crosses) and macrofossil records (bars) for
several taxa selected on the basis of their presence as sedimentary remains in a core
from Loch Leven (Salgado et al . 2009).
site-specific reference conditions (e.g. Guilizzoni et al . 2006; Taylor et al . 2006;
Bennion & Battarbee 2007).
The approach is illustrated in Fig. 9.4 by a comparison of the remains of a
range of biota (diatoms, plant macrofossils and zooplankton ephippia) in 20 year
increments from the surface (~ AD 1980-2000) and reference samples (~ AD
1700-20) of dated sediment cores from Groby Pool (see above). The ecological
reference condition is one of benthic diatom dominance ( Fragilaria spp.), a
relatively diverse submerged aquatic plant community (e.g. Characeae including
Nitella and Chara, Myriophyllum spp. (both spicatum and alterniflorum),
Utricularia vulgaris agg.) and plant-associated Chydoridae. In contrast, the surface
sample is dominated by planktonic forms of diatoms (e.g. Stephanodiscus
parvus ) and zooplankton ( Bosmina and Daphnia spp.) and elodeid macrophytes