M. Stephenson et al., EFFECTS OF EXPERIMENTAL AND CULTURAL LAKE ACIDIFICATION ON LITTORAL BENTHIC MACROINVERTEBRATE ASSEMBLAGES, Canadian journal of fisheries and aquatic sciences, 51(5), 1994, pp. 1147-1161
A simple method for the assessment of littoral benthic macroinvertebra
te (BMI) assemblages in lakes was developed at the Experimental Lakes
Area (ELA) in northwestern Ontario and applied to 64 lakes in central
Ontario. The presence (1) or absence (0) of BMI taxa was established a
t five sites on each lake, using a kick-and-sweep net technique. Summi
ng presence/absence scores across sites ranked the importance of each
taxon in each lake on a scale of 0 to 5. Relationships between the BMI
assemblages were assessed using nonmetric multidimensional scaling (N
MDS), based upon the Kendall's tau correlation matrix. Correlations be
tween NMDS dimension 1 and 2 scores and environmental variables identi
fied factors that may structure BMI assemblages. The BMI assemblages o
f three experimentally acidified and seven reference lakes at the ELA
were correlated strongly with lake pH. The BMI assemblage structure of
central Ontario lakes was predicted by lake area and sensitivity to a
cidification (NMDS dimension 1) and by lake elevation (NMDS dimension
2). The BMI assemblages of small or Ca-poor and acidic lakes include f
ewer oligochaetes, mayflies, and Cryptochironomus and Stictochironomus
(chironomids) and more Odonata, Trichoptera, Chironomus, Conchapelopi
a, Microtendipes, and Procladius (chironomids), and Crangonyx (Amphipo
da) than other central Ontario lakes.