-
Quaternary Science Reviews, Vol. 6, pp. 29-40,1987. 0277-3791/87
$0.00 + .50 Printed in Great Britain. All rights reserved.
Copyright © 1987 Pergamon Journals Ltd.
CHIRONOMIDAE (DIPTERA) IN PALEOECOLOGY
Ian R. Walker Department of Biological Sciences, Simon Fraser
University, Burnaby, British Columbia, Canada V5A 1S6
A comprehensive review of chironomid paleoecology is provided,
with a discussion of relevant aspects of chironomid biology. The
systematics, ecology, morphology, and taphonomy of chironomids are
specifically addressed, as is the application of chironomid remains
in investigations of lake ontogeny, anthropogenic eutrophication
and acidification, paleosalinity, and paleoclimate.
INTRODUCTION
Although the attributes of fossil Chironomidae (non- biting
midges) as paleoecological indicators are rather well known within
the limnological community, their value is poorly known among
paleoecologists in general. According to Frey (1964), the earliest
report of the chitinous sedimentary remains of Chironomidae may be
attributed to Ekman (1915). Numerous sub- sequent reports (e.g.
Lundbeck, 1926; Gross, 1937; Brehm et al., 1948) have since been
compiled by Frey (1964), who considers the earliest attempt to
interpret such remains in terms of past conditions to be that of
Gams (1927). A decade thereafter, Andersen (1938) noted the
response of midge communities to Danish late-Pleistocene climatic
variations. Although Ander- sen's (1938) research 'seemed prophetic
of things to come' (Frey, 1964), the technique continued to develop
slowly.
In the half century to follow, fossil remains of chironomids
have been used to trace the paleo- productivity of lake systems
(e.g. Deevey, 1942; Stahl, 1959; Bryce, 1962), to assess
anthropogenic eutrophi- cation (e.g. Carter, 1977; Warwick, 1980;
Wiederholm, 1979; Wiederholm and Eriksson, 1979) and acidifi-
cation (Henrikson et al., 1982), and to monitor the impact of
salinity fluctuations (Paterson and Walker, 1974; Clair and
Paterson, 1976) and climatic variations (Walker and Mathewes, in
press) upon aquatic com- munities. In the present paper, I review
the present knowledge of chironomids in paleoecology, as well as
relevant aspects of the organisms' biology and ecology. My
objective is to convey information regarding the value of
chironomids in paleoecological-studies to the many Quaternary
scientists who are, as yet, unfamiliar with these insects.
Chironomid paleoecology has sig- nificantly advanced since the
earlier and less com- prehensive reviews provided by Frey (1964,
1976), Stahl (1969), and Hofmann (1979a).
BIOLOGY
The Chironomidae constitute a family of true flies (Diptera)
which are prominent as larvae in the bottom
communities of virtually all freshwater habitats. Upon hatching
from an egg (Fig. 1), the first instar larva begins a period of
growth which eventually necessitates the shedding of the
exoskeletal integument. Upon replacing this integument, the larva
then continues growth in its second instar. Two further episodes of
ecdysis (replacement of the exoskeletal wall) and growth follow,
defining the third and fourth larval instars. Although bearing a
well-developed, strongly- sclerotized head capsule, the elongate
soft-bodied larvae otherwise resemble maggots. As mature fourth
instar larvae, they vary from 1 to 30 mm in length (Oliver and
Roussel, 1983).
Lacustrine chironomid larvae inhabit the uppermost sediments of
both littoral and profundal (deep-water) environments, cling or
burrow into aquatic plants, tunnel in moist wood, or parasitize
other invertebrates (Oliver and Roussei, 1983). Similar habitats
are occupied in streams, and chironomid taxa are known to inhabit
littoral marine environments, water-logged soils, peats, and dung
(Oliver and Roussel, 1983). They are among the most ubiquitous of
insects.
The first instar larva of lacustrine midges are gener- ally
planktonic, allowing for dispersal of larvae to suitable
substrates. Larvae from habitats other than standing water, and the
later instars of lacustrine midges are largely sedentary. The first
instar is typically brief, with each later instar usually of
progressively longer duration. Although the first instar larvae may
derive some nourishment from the egg yolk, larvae feed on a variety
of materials including algae, organic detritus, macrophytes, and
other invertebrates (Oliver, 1971). Predation occurs among
free-living Tanypodinae and in genera of the Harnischia complex
(Chirono- minae), whereas most other chironomidS combine algae and
detritus to form their diet.
During the latter part of the fourth larval instar, the thoracic
segments expand, achieving a pre-pupal con- dition. Following
ecdysis, the chironomid enters the pupal stage in which morphology
is reorganized to that of the adult insect. Apart from the
Tanypodinae, almost all pupae are sedentary. The pupal stage is
brief, persisting a few days at most (Oliver, 1971).
At maturity, the pupa moves to the water surface,
29
-
30 I R . Walker
r
1st instar larva
th instar
FIG. 1. Chironomid life cycle. (Adapted from Borror et al . ,
1976.)
allowing emergence of the winged adult. Although mosquito-like,
adult chironomids seldom bear a pro- boscis, and do not share the
biting habit of mosquitoes. Persisting for a few weeks only, the
adult stage permits dispersal and reproduction.
The duration of the midge life cycle varies greatly among taxa,
and with habitat. Long life cycles typify arctic taxa, occasionally
extending to several years (Oliver, 1968; Butler, 1982; Hershey,
1985). In warmer climates several generations are common in a
single s e a s o n ,
CLASSIFICATION
Ten subfamilies constitute the Chironomidae. One subfamily, the
Telmatogetoninae, are all but com- pletely restricted to marine
environments. In Hawaii this family also inhabits freshwater
(Cranston, 1983). Three subfamilies are very rare, known only from
a small segment of the globe. The Chilenomyiinae, represented by a
single species, is known only from southern Chile (Brundin, 1983a).
The Buchonomyiinae include two species native to Europe and Asia
(S~ether, 1983). The Aphroteniinae, including four genera, are
known only from South America, South Africa, and Australia
(Brundin, 1983b). Such a distribution suggests that this primitive
group originated before the Mesozoic disintegration of Gondwanaland
(Brundin, 1965). An extinct Aphroteniinae tribe, the Electro-
teniini, records this subfamilies' former, more wide- spread
Cretaceous distribution, extending into Siberia (Kalugina, 1980).
Chironomidae are also known from Triassic deposits (Ashe,
1983).
Three subfamilies, the Orthocladiinae, Tany- podinae, and
Chironominae, constitute the great majority of taxa encountered in
lake sediments. The remaining subfamilies, Podonominae, Diamesinae,
and Prodiamesinae, are predominantly cold-stenothermous
taxa inhabiting temperate and montane to polar and alpine
climatic regions (Oliver, 1971).
Considerable confusion of chironomid systematics arose from two
early publications of Meigen (1800, 1803). According to Oliver and
Roussel (1983), Meigen proposed different names for the same
insects in each publication. Thus, the earlier names, including
Ten- dipes and Pelopia were replaced by Chironomus and Tanypus
respectively. The latter names were widely adopted before
rediscovery of the earlier publication. With this rediscovery, a
second system of nomenclature entered common use, but the
International Com- mission on Zoological Nomenclature ruled in
favour of the system established by Meigen's (1803) second
publication (Oliver, 1971). Consequently, Chir- onomus, and the
derived tribe, subfamily, and family designations are correct,
whereas the respective names derived from Tendipes, including the
family name Tendipediae, are not. Similarly, Tanypus and Tany-
podinae are preferred to Pelopia and Pelopiinae. These synonyms are
frequently encountered in recent literature.
Despite these difficulties, and others (Stahl, 1959; Ashe,
1983), the systematic treatment of chironomids is achieving
stability. A recent volume (Wiederholm, 1983) has reviewed the
systematic position of Holarctic Chironomidae, and is destined to
remain the standard for future investigations. Ashe (1983) has
prepared another monumental publication which has catalogued each
of the world's chironomid genera. Future research should rely
principally upon these volumes for a solid taxonomic base. This
should facilitate improved com- munication among ecologists,
paleoecologists, physi- ologists, and other persons investigating
chironomid biology.
Although the taxonomic keys of Wiederholm (1983) rarely permit
identification of fossil larval head cap- sules, reference to the
illustrations and diagnoses of
-
Chironomidae (Diptera) in Paleoecology 31
each genus usually do permit classification. Fortunate- ly, most
of the characters employed by systematists are borne on the head
capsule and consequently may be available to the paleoecologist.
Hofmann (1971a) provides keys and illustrations which should permit
identification of head capsules encountered in lake sediments.
Reference to other treatments (e.g. Oliver et al., 1978; Simpson
and Bode, 1980; Oliver and Roussel, 1983) may occasionally be
necessary. In any instance, recent systematic literature must be
con- sulted. Simpson (1982) has conveniently catalogued North
American systematic publications.
HEAD CAPSULE MORPHOLOGY
The chitinous head capsules of larval Chironomidae are abundant
and usually well preserved in freshwater sediments. The structure
of the head capsule varies greatly, however the greatest part of
this variation can be illustrated with reference to the subfamilies
Chir- onominae, Orthocladiinae, and Tanypodinae (Fig. 2). In this
paper, only those structures most important for subfossil diagnosis
will be discussed. The terminology employed for describing
anatomical features varies among publications. Here, I adopt the
standard nomenclature established by Sa~ther (1980), although I
will often present synonomous terms in parentheses following the
preferred term.
a ) / ) ~ ~ ~ 7~n:ir ~':nna ' / * . ' ~ ' ~ . ~ . se gmant
." • ~ d ~ r s ~ e n t a l
" ligula
The head capsules of Tanypodinae (Fig. 2a) are generally weakly
pigmented and somewhat elongate. The retracted first segment of
each antenna is often visible within fossil head capsules near the
anterior lateral margin. The proportions of the head capsule and
first antennal segment can be important characters for subfossil
diagnosis. A fork-shaped ligula is situated in a median anterior
ventral position. The ligula may become separated from head
capsules during burial or processing of fossil material. Variations
in the shape, number and colour of ligula teeth also aid identifi-
cation. The dorsomental teeth (paralabial teeth), lack- ing in the
tribe Pentaneurini, are, otherwise, situated laterally adjacent to
the ligula and will usually remain with the head capsule. In well
preserved material, one or both mandibles may be retained at the
antero-lateral margin.
The principal features facilitating identification of fossil
Chironominae (Fig. 2b) and Orthocladiinae (Fig. 2c) are the
ventromental (paralabial) plates and the teeth of the mentum
(hypostomial or labial plate). The mentum is situated in an
anterior median ventral position. The pair of ventromental plates
are situated laterally, adjacent to the mentum on either side. In
the Chironominae, the ventromental plates are very large and
usually conspicuously striated. Although fan- shaped in the tribe
Chironomini, laterally elongated, strap-shaped plates occur on the
Pseudochironomini and many members of another Chironominae tribe,
the Tanytarsini.
In the Orthocladiinae, the ventromental plates are always much
less conspicuous, and never striated. In many instances, these
plates are greatly reduced, vestigial structures. In all
Chironominae and Ortho- cladiinae the shape, number, and
arrangement of the mental teeth and characteristics of the
ventromental plates are critical diagnostic features. Most other
structures are normally lost from the head capsule.
b)
e)
- - - - mandibles
i i': en,a, plates
~' _. \----~ventromental ~ plates
FIG. 2. Prominent head capsule features (a) Tanypodinae, (b)
Chironominae, (c) Orthocladiinae.
TAPHONOMY
Head capsules are produced by each midge, during each larval
instar. Thus, a chironomid surviving to the fourth larval instar
will have produced four head capsules. A chironomid expiring prior
to attaining its fourth instar will produce fewer head capsules.
The head capsules subsequently preserved could include both those
shed with exuviae during ecdysis, and the remains of dead
larvae.
There exist, however, numerous reasons why the abundance of
fossil midge remains might not reflect the abundance of the living
larvae from which they were derived. Quality of preservation may
vary among taxa, among instars, and between head capsules derived
from expired insects and those shed as exuviae. As Iovino (1975: p.
41) has stated, 'If remains result only from expired individuals,
age distribution of the re- mains would vary with age specific
mortality.' Hof- mann (1971b) has observed that because pupae of
some chironomids, for example Chironomus, retain the
-
32 I.R. Walker
fourth instar's exuviae, this instar's head capsule may be blown
onto shore following emergence of the adult. Bivoltine and
multivoltine taxa produce more head capsules per season than
univoltine taxa of the same abundance. Redistribution of head
capsules might influence the concentration and composition of
fossil assemblages. Unfortunately, little study has yet been
devoted to these problems.
Iovino (1975) has investigated the composition of Chironomus
attenuatus exuviae by means of the chito- san-iodine test
(Campbell, 1929). Iovino (1975) deter- mined that first and second
instars usually dissolve the procuticle completely prior to
ecdysis, leaving only a thin, non-chitinous, epicuticular exuviae.
In contrast, third instar exuviae usually include chitin, and
fourth instars were chitinous almost without exception. Thus,
exuviae of early instars are much less durable than both those of
later instars and remains of expired larvae. This, in part, would
explain the great under-represen- tation of early instar head
capsules in lake sediments (Iovino, 1975). Such remains may also be
lost through the use of coarse sieves during processing (Walker and
Paterson, 1985). Similar tests for chitin should be repeated for
taxa other than Chironomus to assess whether Iovino's (1975)
results apply generally.
To avoid counting individual larvae twice, Carter (1977) and
D6vai and Moldovfin (1983) chose to base their analyses on fourth
instar remains only. Iovino (1975) presents data which questions
the ease with which instars may be separated. Also, if fourth
instar remains are blown ashore with the pupal exuviae of some
taxa, fourth instar head capsules may be under- represented in
sediments (Hofmann, 1971b).
Both lovino (1975) and Walker et al. (1984) have compared the
composition of chironomid life and death assemblages. In both
instances, a good correlation was evident. Walker et al. (1984) do
provide evidence suggesting that Procladius may be
under-represented in fossil material. Bryce (1962) and Roback
(197(1) have also suggested that Tanypodinae head capsules may be
poorly preserved.
Iovino (1975) demonstrates that some offshore dis- placement of
head capsules occurs, particularly in shallow lakes and from the
littoral to the sublittoral of stratified lakes. Wiederholm (1979)
and Brodin (1982) found large numbers of littoral chironomid
remains in profundal sediments of Lakes Washington and Vfixj6s- j6n
respectively. Chironomids characteristic of streams have also been
recorded in lake profiles (Warwick, 1980; Walker and Mathewes, in
press).
D6vai and Moldovfin (1983) report that head capsule preservation
was not as good in the high energy environment of a shallow
Hungarian lake as would be expected in deeper waters. They also
suggest that because chironomids may burrow to 15 cm depth in the
sediment, some extant taxa may not be well rep- resented in
sediments collected within 5 to 10 cm of the mud surface. Despite
the recent eutrophication of Lake Balaton, they report maximum
Chironomus concen- trations 15 cm below the sediment surface
I have noted that head capsules of planktonic first instar
larvae dominate sediments beneath a saline, meromictic basin of
White Lake, British Columbia. Unfortunately, first instar head
capsules differ greatly from those subsequently produced. Thus,
identification of first instars is rarely possible. The dearth of
head capsules in meromictic basins, also noted by Crisman (pers.
comm. 1984), suggests that little offshore dis- placement of head
capsules occurs in such lakes.
METHODOLOGY
Meticulous preparation, sorting, and identification of midge
remains is requisite for analysis of past com- munities. As
experienced chironomid paleoecologists will attest, these
procedures are extremely tedious. A carefully cleaned sample is
greatly appreciated when the sorting operation begins.
Small lakes in forested watersheds usually contain sediments
with a high organic content. My experience suggests that 1 or 2 ml
of wet sediment from such lakes provides 50 to 100 head capsules,
sufficient for analysis (Walker and Paterson, 1983; Walker and
Mathewes, in press). Inorganic sediments, such as those frequently
encountered in late glacial deposits, may yield much lower
concentrations.
However, head capsule concentrations vary greatly among sites.
Deevey (1942) has reported maximum concentrations of 68 head
capsules/ml at Linsley Pond, but according to Frey (1964), Deevey
(1955a) later encountered 1700/ml at Pyramid Valley, New Zealand.
The highest concentration yet reported, nearly 8000/ ml, was
tallied for Eight Lake, Alaska (Livingstone e¢ al., 1958). Stahl
(1959) reported concentrations of 6 to 65/ml. Sediments of the
Sch6hsee yield concentrations ranging from 0 to 260/ml (Hofmann,
1971b). Warwick (1980), for the Bay of Quinte, Lake Ontario,
describes concentrations varying from 4.6/ml at the sediment
surface to 124/ml at the 1.14 m depth. The range observed in
Warwick's (1980) study may result from several factors including
compression of the deeper sediments, recent increased sedimentation
rates, and changes in head capsule production.
Samples are usually deflocculated in 5 to 10% KOH prior to
analysis. In calcareous sediments, an acid wash (t0% HCI) may also
be necessary. Warwick (1980) emphasizes the delicate nature of
midge remains and the need for mild treatments. He recommends the
use of 8% KOH at 60°C for 30 minutes. Apparently, chitinous
structures may be bleached and deformed by high temperatures
(Warwick, 1980). It is important to remember that although
chitinous structures are very resistant, exuviae of early instars,
if present, may contain little or no chitin (Iovino, 1975). Also,
harsh treatment may disarticulate head capsule features.
Following the above chemical treatments, head capsules are
generally separated from finer debris by means of sieving.
Methodology varies, but a 100 ~m or finer sieve will retain most
head capsules and is recommended (Walker and Paterson, 1985).
Sub-
-
Chironomidae (Diptera) in Paleoecology 33
sequently, the residue is back-washed from the sieve into a
container and stored wet until the material is sorted. Unless
sorted shortly after sieving; preservation in 99% ethanol (Warwick,
1980) is advisable.
Sorting of wet residues may be accomplished in a petri dish,
watch glass, or Stender dish at magnifi- cations of 25 to 50 x
(Warwick, 1980). To limit the possibility of overlooking remains, I
prefer to sort head capsules from sediments at 40 to 50 x in a
Bogorov counting tray (Gannon, 1971). The particular Bogorov tray
which I employ includes 7 parallel grooves cut in a perspex plate.
The bottom width of each groove, 4.5 mm, corresponds to the field
of view, at 50 x, of a Wild M5 stereomicroscope. As remains are
located, each is transferred with forceps to coverslips for
mounting and identification.
Researchers should note that head capsules of some taxa,
especially the Orthocladiinae, readily split into two equal,
identifiable halves. Thus, it is important to count these fragments
as 1/2 head capsule. Head capsules bearing more than one half of
the mentum may conveniently be counted as whole head capsules, and
head capsules consisting of less than one half of the mentum may be
ignored. This splitting of the head capsules creates difficulties
in the application of con- ventional statistics. If the halves are
sedimented in- dependently, perhaps each half should be treated as
if representing an 'individual' for statistical purposes. If the
head capsules split within the sediment, or during processing, and
the head capsules remain in close proximity, they would be better
treated as halves.
Presentation of results varies among authors. Saw- toothed
figures similar to those of pollen diagrams are most common, yet
histograms convey the results equally well. In any circumstance,
figures convey information more readily than tables of data. Com-
puter programs for plotting pollen diagrams are easily adapted for
use with chironomid data.
More critical is the decision to present data as either
percentages, counts, or influx estimates. Percentages are limited
chiefly because changes in the relative abundance of one taxon may
result either from an actual change in its influx or a change in
the influx of one or more other taxa.
Count data are difficult for the reader to assess since the
counts at adjacent levels may not readily be compared unless
sedimentation rates remain constant. Readers are required to
perform the mental gymnastics necessary to standardize the data.
Interpretation of count data suffers from variations in
sedimentation rates and sample volume. Consequently, percentage
results are usually more convenient.
Ideally, influx rates for each taxon should convey the most
information. In practice, influx data are more informative only if
accurate measures of sedimentation rate are available. Influx
calculations frequently assume a constant sedimentation rate over a
broad sampling interval, yet it is likely that sedimentation rates
vary considerably in the short term. In calculating sedimentation
rates for surface cores, investigators
must carefully consider the effect of compaction on apparent
rates. Sediment focussing may have important effects (Davis et al.,
1984), especially during the early history of a lake. Periods of
rapid natural or anthro- pogenic environmental change may induce
abrupt changes in sedimentation. Periodic catastrophic events such
as forest fires and debris slides in the catchment may induce brief
but rapid episodes of sediment deposition. Inaccurate estimates of
sedimentation rates cause influx data to reflect these inaccuracies
rather than the varying abundance of chironomid taxa.
It is also possible, particularly in small lakes, that as the
lake shallows the changing sedimentary environ- ment may alter the
influx of chironomid remains without a change in a taxon's actual
abundance. A core might record a transition from a profundal stage
to a littoral environment. If chironomid remains tend to become
concentrated in the sublittoral, then peak concentrations in the
middle of a core could reflect this artifact (Walker and Mathewes,
in press).
Authors should cautiously consider how the data are to be
displayed, and how the changes can most accurately and honestly be
portrayed. Perhaps, in future, another form of presentation will be
attempted, providing rates of chironomid production. A simple cubic
relationship could be calculated between the width of a taxon's
head capsule and biomass of the living larva. More perplexing is
the task of quantifying each of the taphonomic processes regulating
which head capsules are deposited at a site, and which would
subsequently be preserved.
APPLICATIONS
Lake Ontogenetic Studies As indicated with my introduction,
midge remains
have been employed by paleoecologists with a variety of goals.
The earliest application (Gams, 1927) was for investigating the
natural ontogenetic processes which influence lake ontogeny via
nutrient supply. Such a goal may appear esoteric to many Quaternary
scien- tists, but is a theme central to much limnological theory,
and to paleolimnology as a science.
Early limnologists sought to classify lakes by a variety of
means. Prominent among early investigators were Einar Naumann and
August Thienemann. Borrowing terms which Weber (1907) had coined
for nutrient supply to bogs, Naumann (1919) categorized lakes
according to their phytoplankton productivity, providing the basis
for our present lake trophic classi- fication. Naumann (1919)
described two basic lake types, the highly productive or
'eutrophic' Baltic lakes and the unproductive or 'oligotrophic'
north European lakes. Hansen (1962) also credits Naumann (1917,
1918, 1920) with introducing the 'dystrophic', humic or brown-water
lake as a sub-type of the north European lakes.
Thienemann (1918, 1921) derived similar conclusions through his
attempts to classify lakes on the basis of dominant components in
their benthic fauna. Thiene-
-
34 I.R. Walker
mann (1921), accepting Naumann's (1919) terminol- ogy, described
oligotrophic Tanytarsus lakes, eutrophic Chironornus lakes, and
humic lakes in which both Chironomus and Corethra (now Chaoborus,
Chao- boridae) were prominent.
Brinkhurst (1974) provides an excellent review of subsequent
attempts to refine Thienemann's typology. The scheme of Brundin
(1949, 1956, 1958) describes several classes of temperature
stratified lakes: arctic Heterotrissocladius subpilosus lakes
(ultraoligo- trophic), subarctic and high boreal Tanytarsus-Hetero-
trissocladius lakes, boreal and montane Tanytarsus lugens lakes
(oligotrophic), Stictochironomus rosen- scholdii-Sergentia coracina
lakes (a transitional 'meso- trophic' type between oligotrophy and
eutrophy), Chironomus anthracinus and C. plumosus lakes
(eutrophic), and C. tenuistylus (dystrophic) lakes. Furthermore,
Brundin (1951) argued that oxygen microstratification at the
mud-water interface was a major determinant of the profundal
(deep-water) bottom fauna. Larger chironomid taxa, commonly
associated with more productive lakes, could better cope with a
micro-layer of O2-depleted water at the mud-water interface. Also,
such larvae (e.g. Chiron- omus) frequently possess hemoglobin.
Because lakes with higher productivity generally display greater
profundal oxygen deficiencies, a correlation exists among lake
productivity, oxygen deficit, and benthic fauna.
As Rodhe (1969) has emphasized, trophic categories are abstract
entities with overlapping ranges in be- tween. A continuum of lakes
among all of those described probably exists. This is apparent in
S~ether's (1975, 1979) analysis of benthic lake typology. He
describes 15 trophic categories, ranging from ultra- oligotrophy to
extreme eutrophy, in addition to the mesohumic and polyhumic types.
S~ether's (1975) analysis extends European benthic lake typology to
North America. He also describes atrophic range for each of many
chironomid taxa. Warwick (1975) and S~ether (1979) suggest that
food may be more critical than oxygen microstratification in
determining the benthic fauna of lakes.
Naumann (1919) had speculated that lakes should gradually become
less productive as a consequence of constant leaching of catchment
soils. Many limnol- ogists, however, have subsequently perceived
eutrophication, a gradual increase in lake productivity, as the
dominant, if not universal process. Whiteside (1983) traces this
perception tO 'The oft redrawn figure showing eutrophication
proceeding with community succession (Lindeman, 1942) and the early
work of Deevey (1955[b]) . . . ' . Deevey (1955b) had empha- sized
that the gradual infilling of lakes, by reducing the hypolimnetic
volume, could generate an O2-poor hypo- limnion. Regeneration of
phosphorous, from the sediments beneath the hypolimnion could then
produce a real increase in lake productivity. This process Deevey
(1955b) dubbed 'morphometric eutrophi- cation'.
Whiteside (1983) emphasizes the 'mythical' nature of a universal
trend towards eutrophy. Eutrophication had unfortunately become the
deus ex machina invoked by paleolimnologists to explain observed
changes in sedimentary sequences.
Several chironomid pateoecologists attempted to trace the
natural ontogenetic development of lakes. According to Frey (1964),
Gams (1927) was able to demonstrate that Eutanytarsus, abundant in
inter- stadial sediments of Lunzer Obersee, was later re- placed by
Bezzia (Ceratopogonidae) and Chironomus. Similarly, Deevey (1942)
describes evidence that an early Tanytarsus fauna at Linsley Pond
was first succeeded by Endochironomus and Glyptotendipes (his
description and illustration of 'Glyptotendipes" are more likely to
be that of Dicrotendipes), and sub- sequently by Chironomus. Frey
(1955) reported Eutanytarsus as initially abundant in L~ingsee,
Austria, but with Chaoborus (Chaoboridae) arriving later. Each of
these investigations could be interpreted as suggest- ing a natural
tendency to eutrophication.
However, Livingstone et al. (1958) suggest, on the basis of
large concentrations of chironomid remains (principally Corynocera
(as 'Dryadotonytarsus') and Tanytarsus) and other microfossils,
that Eight Lake in arctic Alaska may have experienced an early
eutrophic stage, becoming less productive as the lake tended to
dystrophy. At Myers Lake, Indiana (Stahl, 1959), an early
Sergentia-dominated fauna declined as Chaoboruz' increased. Stahl
(1959) argues that even in its early stages this lake may have
experienced 'moderate severe oxygen depletion', and that subsequent
changes arose from a reduction in hypolimnetic volume rather than
an increase in productivity.
Bryce (1962) also presents contrary results, indicat- ing an
early dominance by Chironomus at his Malham Tarn Moss site. Bryce
(1962) argues that marl de- position may have reversed the
ontogenetic process, causing the site to become more oligotrophic.
Stahl (1969) finds this conclusion unsubstantiated. Stahl's (1969)
remarks also question the reliability of detailed Russian
investigations (Lastochkin, 1949; Konstan- tinov, 1951) with
tenuous systematic analysis, recovery, and interpretation
techniques.
In southern Finland, Alhonen and Haavisto (1969) have noted an
early eutrophic stage subsequent to a lake's isolation from the
sea. Hofmann (1971b, 1979b) indicates that the eutrophic north
German Chironornus lakes were formerly oligotrophic Tanytarsus
lugens lakes. Lawrenz (1975) suggests that Green Lake, Michigan,
has always remained oligotrophic, although the fauna did respond to
a variety of factors including changes in sediment type, water
level, and climate. Chironomid succession in a dystrophic, bog lake
perhaps responded to natural increases in lake acidity more than to
Holocene trophic variations (Walker and Paterson, 1983; Walker et
al., 1985).
The above results suggest that broad generalizations regarding
lake ontogenetic patterns are unwarranted. The initial oligotrophic
condition suggested in early
-
Chironomidae (Diptera) in Paleoecology 35
lake sediments often relates to cold climatic conditions
prevailing at that time. Many lakes appear to achieve 'trophic
equilibrium' (Hutchinson and Wollack, 1940) during the Holocene. In
addition, Hofmann (1971b: p. 55; 1980) notes that Thienemann's
(1915) Tanytarsus lakes were originally characterized by a
misidentified species, later placed in Lauterbornia, and now recog-
nized to belong to Micropsectra. Since few paleoecol- ogists have
been able to distinguish among several Tanytarsini genera
(including Micropsectra), the genus Tanytarsus has been employed in
a broad sense incorporating taxa not characteristic of profundal
oligotrophic environments. Similarly, although Chiron- omus
anthracinus and C. plumosus are important indicators of eutrophy,
some Chironomus species may be abundant in dystrophic, or even
oligotrophic situ- ations.
Stahl (1969) has noted that chironomid paleoeco- logical
investigation sites had included unstratified lakes. The system of
benthic lake typology conceived by Thienemann (1915, 1918, 1921)
and Brundin (1956) was intended only for stratified lake
environments. Nevertheless, Warwick (1975) and S~ether (1979) have
argued that food may be more important than 02 microstratification
in determining the benthic fauna. If true, benthic lake typology
can be applied to shallow polymictic lakes.
Anthropogenic Eutrophication One of the major environmental
issues to concern
limnologists has been the problem of anthropogenic
eutrophication. Increased nutrient loading from urban and
agricultural land-use has dramatically increased the productivity
of some lakes, to the point where tremen- dous algal blooms foul
shorelines and produce anaero- bic conditions within the profundal
environment. In addition to the induced autotrophic production,
allochthonous inputs of sewage and other organic wastes compound
the de-oxygenation problem. One might argue that these lakes are
not 'dead' (as has been suggested for many such lakes); rather they
are too full of life!
Since chironomid communities respond dramatically to such
trophic alterations, their remains provide a detailed record of
eutrophication events. Thus, it is possible to determine man's
impact upon lake pro- cesses.
Goulden (1964) noted a recent shift in the midge fauna of
Esthwaite Water, following thousands of years of stable conditions.
The rapid increase in Chironomus abundance suggested that the lake
had experienced a period of eutrophication beginning with Norse
immi- gration and later deforestation. Similarly, Carter (1977)
described a shift from a Tanytarsus to a Chironomus- dominated
fauna. This change spanned the last 100 to 150 years with more
rapid change following the Second World War. Wiederholm (1979)
records less dramatic, but similar changes in the fauna of Lake
Washington.
Swedish investigations have identified a period of gradual
eutrophication in Lake M/il/iren preceding
rapid eutrophication between 1940 and 1950 (Wieder- holm and
Eriksson, 1979). Similarly, Brodin (1982) outlines a shift to
extreme eutrophy in Lake V[ixj6sj6n beginning in the early 1800s
and accelerating in the present century.
Certainly the most detailed paleoecological investi- gation of
anthropogenic eutrophication is that described by Warwick (1975,
1980). Warwick's (1980) analyses depict 2800 years of human impact
upon the Bay of Quinte, Lake Ontario, beginning with abor- iginal
land-use. He suggests that a slight increase in lake productivity,
ca. 500 B.C. to 300 A.D., 'probably is attributable to the
developing Hopewell culture.' (Warwick, 1980: p. 78). These
aboriginal people practiced extensive agriculture. A return to a
more oligotrophic condition characterizes the subsequent Algonkian
and Iroquois periods. A slight increase in productivity later began
with French contact, but ended with extensive logging by subsequent
British colonists in the early 1800s. Finally, rapid industrial
expansion and population growth, particularly during this cen-
tury, have produced the present eutrophic situation.
Warwick's (1980) analysis depicts the great potential of
subfossil Chironomidae as indicators of human impact upon aquatic
systems. Although the technique has been applied principally to
determining the impact of modern man, it may prove valuable in an
archaeo- logical context for determining the environmental
consequences of early land-use.
Acidification Studies Recent concern with regard to acidic
precipitation
and its impact upon aquatic communities has raised the
possibility of using chironomids to monitor these impacts as well.
Several recent studies document chironomid communities inhabiting
waters of different acidities (Roff and Kwiatkowski, 1977;
Wiederhoim and Eriksson, 1977; Mossberg and Nyberg, 1979; Raddum
and Sa~ther, 1981; Clair, 1982; Dermott, 1985; Walker et al.,
1985). Chironomidae are well rep- resented even in strongly-acidic
waters (pH 3.5 to 5.5). Chironomus, Phaenopsectra, Psectrocladius,
and Zalut- schia tend to be present in greater relative abundance
at low pH. As Wiederholm and Eriksson (1977) observed, the favoured
taxa tend to be large-bodied, having smaller surface areas relative
to volume. Con- sequently, it may be easier for large larvae to
maintain their internal pH balance. JernelOv et al. (1981) also
note that the increased buffering capacity afforded by hemoglobin
may favour hemoglobin-bearing larvae.
As yet paleolimnological studies documenting the impact of
acidification upon chironomid populations are few. Henrikson et al.
(1982) have examined recent anthropogenic impacts upon two Swedish
lakes. Clair (1982) has attempted a similar investigation. Walker
and Paterson (1983) have examined chironomid succession in a
naturally acidic system.
Henrikson et al. (1982) investigated the recent sediment of two
heavily-acidified (pH < 5), oligo- trophic lakes in southwestern
Sweden. The 15 cm long
-
36 I.R. Walker
cores were inferred to represent sedimentation begin- ning early
in the present century. The total abundance of Chironomidae is
reported to have since declined. Phaenopsectra and Psectrocladius
exhibit an increase on a relative basis. However, the Tanytarsini
appear to have been adversely affected. Curiously, Henrikson et al.
(1982) report Chironomus and Dicrotendipes as the present dominants
in Lake G~rdsj6n, yet neither are recorded from the surface
sediments. Perhaps this is a very recent change. The upper sediment
sample was 1 to 2 cm below the surface, possibly representing
sediments 10 to 20 years before the sampling data.
Henrikson et al. (1982) cite several factors as possible
influences upon the chironomid community, including pH, metal
mobilization, increased oxygen deficit, decreased decomposition,
changes in the algal flora, and altered predatory-prey
interactions. They also note that the midges which appear more
abundant in acidified lakes are taxa reported to be more common in
fish diets. Thus acidification, by eliminating fish, could favour
these taxa.
The investigation of bog lake succession at Wood's Pond in
Atlantic Canada (Walker and Paterson, 1983) spans the postglacial.
A late-glacial Tanytarsus-Hetero- trissocladius community is
succeeded by a Tanytarsus fauna in which Lauterborniella and
Stempellinella occur. Lauterborniella and Stempellinella are
reported to be sand-case building taxa (Coffman, 1978; Ferring-
ton, 1985) characteristic of clear-water, oligotrophic,
circum-neutral to weakly-acidic lakes (Beck, 1977; Raddum and
S~ether, 1981; Warwick, 1980). The eventual disappearance of these
taxa may be linked to slight increases in water acidity and humic
content, or to a disappearance of sand substrates as peatlands
enclosed the lake margin. Subsequently, Chironomus and
Monopsectrocladius, taxa common in small, strongly-acidic bog lakes
and peat pools (Walker et al., 1985) increase markedly. Although
the record had originally been interpreted as suggesting
acidification 2 to 3 ka BP, recent diatom analyses suggest that a
relatively high pH (>5.5) was maintained until at or about the
time of European settlement (Walker and Paterson, unpubl, data).
This is when Chironomus increased most abruptly. The high dissolved
organic content of the water indicates that these acids con-
tribute much of the present acidity. However, the coincident pH
drop and land-use changes suggest that man may have influenced
recent events in this lake. Perhaps logging and the subsequent
natural regener- ation of catchment forests favoured expansion of
the encircling bog.
Salinity The feasibility of using chironomids as indicators
of
the ionic content of saline waters is largely unexplored. Two
investigations linking midge distributions to salinity differences
among lakes are worthy of note.
The midge fauna of saline lakes in central British Columbia can
be divided into three distinct associ- ations, apparently related
to salinity. Cannings and
Scudder (1978) consider an association of Cricotopus abanus and
Procladius bellus as indicative of low salinity (mean conductivity
= 40 p~S/cm 25°C). Glypto- tendipes barbipes and Einfeldia pagana
dominate in highly productive lakes of moderate salinity (480 to
2770 ~S/cm). At high salinities (4000 to 12,000 ~S/cm) with
somewhat lower productivity, Tanytarsus gracilentus and
Cryptotendipes ariel prevail.
Conducting a similar study in western Victoria, Australia, Timms
(1983) provides data suggesting two groupings. Procladius spp. and
Chironomus duple,,: dominated in low salinity lakes (1 to 13 g/l).
Tanytarsus barbitarsus characterized lakes of higher salinity (13
to 200 g/l). Timms (pers. comm. 1984) has indicated his intention
to conduct similar work for the saline lakes in Saskatchewan,
Canada.
According to Stahl (1969), Konstantinov (1951) interpreted
chironomid stratigraphy at two sites in Kazakhstan as indicating
salinity variations, although it was unclear how this was
ascertained. Subsequently, only two chironomid paleoecological
studies have been conducted in relation to salinity. Clair and
Paterson (1976) record a salt-water intrusion, and the sub- sequent
rapid recolonization by midges of a marsh lake in Atlantic Canada.
Paterson and Walker (1974) examined salinity variations in an
Australian saline lake.
The investigation by Paterson and Walker (1974) illustrates that
subfossil midges have great potential as salinity indicators. An
early freshwater community including Chironomus duplex was replaced
by Tany- tarsus barbitarsus, indicating increasing salinity. Later
Procladius paludicola immigrated to the lake. A brief return of C.
duplex, peak numbers of P. paludicola, and lower sediment
conductivity later suggest a fresh- water interval. The
disappearance of C. duplex and high sediment conductivities imply a
subsequent return to the higher salinities.
Paleoclimate The relation of chironomids to climate is also
little
investigated, but is implicit to early benthic lake
classifications. Thienemann's (1918) Chironomus lakes were low
elevation Baltic sites, but his Tanytarsus lakes were described as
sub-Alpine. Similarly, Brundin described the ultraoligotrophic
Heterotrissocladius lakes as principally arctic~ whereas Tanytarsus
lugens lakes were common in temperate climates. Further- more,
Brundin (1958: p. 14) states, 'In a lake type system of the world
the ultraoligotrophic lake indicates one extreme of a climatically
based type series, where the ultraeutrophic equatorial lowland lake
forms the other extreme'.
Numerous climatic effects, direct and indirect, might influence
the chironomid fauna. As Brundin's (1958) statements imply, lake
productivity is partly related to climate. Higher temperature and
longer growing seasons facilitate greater biological activity and
pro- ductivity. Increased chemical weathering rates at high
-
Chironomidae (Diptera) in Paleoecology 37
temperatures yield higher nutrient levels. The catch- ment
vegetation, also climatically dependent, may significantly
influence nutrient flux in a watershed.
Climate may have direct effects upon midges. Many taxa
characteristic of ultra-oligotrophic and oligo- trophic lakes are
cold stenothermous. Williams et al. (1981) suggest 'that both
aquatic and terrestrial insects are good indicators of
macroclimate'. Most Chiron- ominae and Tanypodinae are
warm-adapted. The Orthocladiinae and Diamesinae are predominantly
cold-adapted. Cold-adapted taxa appear to grow prin- cipally in
winter; warm-adapted taxa grow rapidly through summer (Oliver,
1971). Emergence in cold- stenothermous taxa usually occurs
immediately follow- ing ice-melt (Oliver, 1968).
The duration of ice-cover and the interval between mixing
episodes will influence profundal oxygen deficits. Shallow lakes in
cold climates may experience pronounced oxygen depletion beneath
winter ice (Nagell and Brittain, 1977). Similar lakes without ice
cover would be continuously well-oxygenated. Warm monomictic lakes
will experience a long spring to autumn interval without renewal of
oxygen-depleted hypolimnetic water, as compared to dimictic lakes,
where both spring and fall overturns occur.
Andersen's (1938) early investigation of the Danish
late-Pleistocene midge fauna reveals that midges responded rapidly
to the known late-glacial climatic oscillations of Europe.
Corynocera (as Dryadotany- tarsus), Chironomus, and a group of
undetermined Orthocladiinae (including Heterotrissocladius?) were
prominent during the Older and Younger Dryas, but disappeared
during the intervening Aller0d phase.
It is unfortunate that Megard's (1964) analyses of Pleistocene
sediments in Dead Man Lake, New Mexico, did not include a more
thorough systematic analysis. Palynological results are interpreted
as in- dicating alpine conditions. Thus, the Pleistocene midge
fauna may have included cold-stenothermous taxa. Where recent
studies of post glacial succession have included thorough
systematic analysis, Heterotrisso- cladius, Corynocera, and members
of the Tanytarsus lugens community are prominent in the
late-glacial sediments (Giinther, 1983; Hofmann, 1971b, 1978,
1979b, 1983a, b, 1984, 1985; Walker and Paterson, 1983; Walker and
Mathewes, in press).
Late-glacial sediments of two small lakes in Atlantic Canada
include large numbers of Heterotrissocladius remains with
Paracladopelma (Walker and Paterson, 1983). This assemblage is
strikingly similar to that of Brundin's (1958) arctic
Heterotrissocladius subpilosus lakes. The peak abundance of this
fauna may relate to a particularly cold phase, which Mott (1985)
has been tempted to correlate with the European Younger Dryas. The
more organic basal sediments, in which Heterotrissocladius and
Paracladopelma are less com- mon, contain an anomolously high
representation of thermophilous pollen. These sediments could
relate to an earlier warm phase in which pollen from the
sparsely-vegetated, recently-deglaciated terrain was
mixed with pollen transported long distances by warm
south-westerly winds.
Similarly, Hofmann (1983a) noted that the faunal changes
observed in a shallow North German lake do not reflect trophic
conditions, but were related to climate and siltation. Walker and
Mathewes (in press, unpubl, data) derive similar conclusions for
lakes of coastal British Columbia, Canada. They demonstrate (Walker
and Mathewes, in press) that climatic infer- ences suggested by the
chironomid data correspond well to trends indicated by
pollen-climate transfer functions. They also note that a fauna in
which Heterotrissocladius was prominent seems to have been
widespread near the glacial margins.
These studies illustrate that chironomids may yield valuable
information for paleoclimatologists. The re- lationships between
midge taxa and climate are not well understood, and it is unlikely
that such environmental requirements will be as closely defined as
those relating climate and vegetation. However, where equivocal
interpretations of pollen data exist, Chironomidae may help to
clarify past conditions. An arctic lake possessing a normal
eutrophic fauna, or a small warm-temperate lake dominated by
Heterotrissocladius would be highly unusual.
Chironomidae, as adults, are capable of rapid dispersal. As with
Coleoptera (Birks and Birks, 1980; Morgan and Morgan, 1980),
Chironomidae may respond more rapidly to climate than is possible
for vegetation. Significantly, Paterson and Fernando (1970) have
noted that midge colonization of a reser- voir was essentially
complete within a single season!
SURFACE SPECTRA
Perhaps the greatest difficulty inherent to using midges as
paleoecological indicators is the limited ecological information
available for many taxa. This is perhaps less of a problem in
Europe than North America. Studies defining the ecological range of
chironomid taxa have proven very useful (S~ether, 1975, 1979; Beck,
1977; Timms, 1983; Mossberg and Nyberg, 1979; Walker et al., 1985).
However, because many of these studies are based upon few
collections per season, and since taphonomic processes may
influence the composition of subfossil associations, such studies
yield information not easily comparable to fossil data.
To overcome similar difficulties with fossil analyses,
palynologists and diatomists have examined large numbers of
subfossil remains from surficial sediments of extant lakes.
Comparison of fossil data with these modern samples from known
environments has greatly assisted interpretation of paleoecological
data. Similar work with chironomid surface spectra would establish
a more quantitative basis for chironomid investigations and greatly
enhance their paleoecological value. Cris- man (pers. comm. 1984)
has collected a large set of chironomid surface spectra from
Florida lakes. I have limited data regarding occurrence of
chironomid re-
-
38 I.R. Walker
mains in New Brunswick and British Columbia lakes in Canada. The
growing bank of such data should greatly assist future chironomid
paleoecological studies.
CONCLUSION
Subfossil Chironomidae have provided, and will continue to
provide significant information regarding past environments. To
date, such studies have per- mitted reconstruction of past trophic
variations, acidi- fication trends and salinity fluctuations.
Changes in chironomid communities appear also to reflect past
climatic change. The potential of Chironomidae in each of these
areas will, in future, be greatly enhanced by improved ecological
information, systematic knowl- edge, and extensive analyses of
surface spectra.
Acknowledgements - - I thank P.S. Cranston, Rolf Mathewes, Colin
Paterson, Geoff Quickfall, and Bob Vance for critically reviewing
this manuscript. This effort has been supported by the Natural
Sciences and Engineering Research Council of Canada through grant
A3835 to R. Mathewes, and a postgraduate scholarship held by the
author.
REFERENCES
Alhonen, P. and Haavisto, M.L. (1969). The biostratigraphical
history of Lake Otalampi in southern Finland with special reference
to the subfossil midge fauna. Bulletin of the Geological Society of
Finland, 40, 157-164.
Andersen, F.S. (1938). Sp/itglaziale Chironomiden. Meddelelser
Dansk geologisk Forening, 9,320-326.
Ashe, P. (1983). A catalogue of chironomid genera and subgenera
of the world including synonyms (Diptera: Chironomidae). Entomo-
logica scandinavica Supplement, 17, 1-68.
Beck, W.M., Jr. (1977). Environmental requirements and pollution
tolerance of common freshwater Chironomidae. U.S. Environ- mental
Protection Agency Report, Cincinnati, EPA/600/4-77/024: 1-26l.
Birks, H.J.B. and Birks, H.H. (1980). Molluscs, insects, and
invertebrates in Quaternary paleoecology. In: Quaternary Paleo-
ecology. Edward Arnold, London, 289 pp.
Borror, D.J., Delong, D.M. and Triplehorn, C.A. (1976). An
introduction to the stud)' of insects. Holt, Rinehart &
Winston, Toronto, 852 pp.
Brehm, V., Krasske, G. and Krieger, W. (1948). Subfossile
tierische Reste und Algen im Schwarzsee bei Kitzbfihel.
Osterreichische botanische Zeitschrifi, 95, 74-83.
Brinkhurst, R.O. (1974). The Benthos of Lakes. MacMillan Press,
London.
Brodin, Y. (1982). Paleoecological studies of the reccnt
development of Lake V~ixj6sj6n. IV. Interpretation of the
eutrophication process through the analysis of subfossil
chironomids. Archiv fiir Hydro- biologie, 93,313-326.
Brundin, L. (1949). Chironomiden und andere Bodenticrc dcr
Stidschweden Urgebirscen. Report of the Institute of Freshwater
Research, Drottningholm, 30, 1-914.
Brundin, L. (1951). The relation of Oe microstratification of
the mud surface to the ecology of the profundal bottom fauna.
Report of the Institute of Freshwater Research, Drottningholm, 32,
32-44
Brundin, L. (1956). Die bodenfaunistischen Seetypen und ihre
Andwendbarkheit auf die Stidhalkugel. Zugleich ein Theorie tier
produktionbiologischen Bedeutnng der glazialen Erosion. Report of
the Institute of Freshwater Research, Drottningholm, 37,
186-235.
Brundin, L. (1958). The bottom faunistical lake type system and
its application to the southern hemisphere. Moreover a theory of
glacial erosion as a factor of productivity in lakes and oceans.
I/erhandlungen der internationalen Vereingung lheoretische und
angewandte Limnologie, 13,288-297.
Brundin, I.. (1965). On the real nature t)f tranantarctic
lelationships. f-voluziorl. 19, 496-505.
Brundin, L. (1983a). Chitenomyia paradoxica gen. n., sp. n. and
Chilenomyiinae, a new subfamily among the Chironomidae (Diptera).
Entomologica scandinavica, 14, 33-45.
Brundin, L. (1983b). Two new aphrotenian larval types from Chile
and Queensland, including Anaphrotenia lacustris n. gen., n. sp.
(Diptera: Chironomidae). Entomologica scandinavica, 14, 415-
433.
Bryce, D. (1962). Chironomidae (Diptera) from freshwater sedi-
ments with special reference to Malham Tarn (Yorks). Trans- actions
of the Society for British Entomology, 15, 41-54.
Butler, M.G. (1982). A 7-year life cycle for two Chironomus
species in arctic Alaskan tundra pools (Diptera: Chironomidae).
Canadian Journal of Zoology, 60, 58-70.
Campbell, F. (1929). Detection and estimation of chitin. Annals
oJ the Entomological Society of America, 22,401-426.
Cannings, R.A. and Scudder, G.G.E. (1978). The littoral Chirono-
midae (Diptera) of saline lakes in central British Columbia.
Canadian Journal of Zoology, 56, 1144-1155.
Carter, C.E. (1977). The recent history of Lough Neagh from the
analysis of chironomid remains in sediment cores. Freshwater
Biology, 7, 415-423.
Clair, T. (1982). Chironomidae populations in the Kejimkujik
calibrated basins. In: Kerekes, J. (ed.) Kejimkujik calibrated
catchments program on the aquatic and terrestrial effects of the
long- range transport of air pollutants. Report on the Proceedings
November 18, 1981. Atlantic Region LRTAP Monitoring and Effects
Working Group. p. 41.
Clair, T. and Paterson, C.G. (1976). Effect of a saltwater
intrusion on a freshwater Chironomidae community: a
paleolimnological study. Hydrobiologia, 48, 131-135.
Coffman, W.P. (1978). Chironomidae. In: Merrit, R .W and
Cummins, K.W. (eds) An Introduction to the Aquatic Insects of North
America. pp. 345-376. Kendall/Hunt Publishing, Dubuque, Iowa.
Cranston, P.S. (1983). 3. The larvae of Telmatogetoninae
(Diptera: Chironomidae) of the Holarctic region - - Keys and
diagnoses. Entomologica scandinavica Supplement, 19, 17-22.
Crisman, T. (1984). Personal communication. Department of En-
vironmental Engineering Sciences, University of Florida, Gaines-
ville, FL 32611, U.S.A.
Davis, M.B., Moeller, R.E. and Ford, J. (1984). Sediment
focusing and pollen influx. In: Haworth, E.Y. and Lund, J.W.G.
(eds) Lake Sediments and Environmental History, pp. 261-293.
Leicester University Press, U.K.
Deevey, E.S., Jr. (1942). Studies on Connecticut lake sediments,
llI. The biostratonomy of Linsley Pond. American Journal of
Science, 240, 233-264,313-324.
Deevey, E.S., Jr. (1955a). Paleolimnology of the Upper Swamp
Deposit, Pyramid Valley. Records qf the Canterbury Museum, 6,
291-344.
Deevey, E.S., Jr. (1955b). The obliteration of the hypolimnion.
Memorie dell'lstituto italiano di Idrobiologia, Supplement, 8,
9-38.
Dermott, R.M. (1985). Benthic fauna in a series of lakes
displaying a gradient of pH. Hydrobiologia, 128, 31-38.
D6vai, G. and Moldov~in, J~ (1983). An attempt to trace
eutrophi- cation in a shallow lake (Balaton, Hungary) using
chironomids. Hydrobiologia, 103, 169-175.
Ekman, S. (1915). Die Bodenfauna des V~ittern, qualitativ und
quantitativ untersucht, lnternationale revue der gesamten Hydro-
biologic und Hydrographie, 7, 146-204, 275-425.
Ferrington, L.C., Jr. (1985). Utilization of anterior
headcapsule structures in locomotion by tarvac of Constempellina
sp. (Diptera: Chironomidae). North American Benthological Society,
Abstracts, 33rd Annual Meeting p. 99.
Frey, D.G. (1955). L~ingsee: a history of meromixis. Memorie
dell'lstituto italiano di Idrobiologia, Supplement, 8, 141-164.
Frey, D.G. (1964). Remains of animals in Quaternary lake and bog
sediments and their interpretation. Ergebnisse der Limnologh~, 2,
1-114.
Frey, D.G. (1976). Interpretation of Quaternary paleoecology
from cladocera and midges, and prognosis concerning the usability
of other organisms. Canadian Journal of Zoology, 54, 2208-2226.
Gams, H., (1927). Die Geschicte der Lunzer Seen, Moore und
Wfilder. lnternationale revue der gesamten Hydrobiologie und
Hydrographie, 18, 305-38%
Gannon, J . E (1971). Two counting cells for the cnumcration of
zooplankton micro-crustacea. Transactions of the American Micro-
scopical Society, 90,486-490.
Goulden, C.E. (1964). The history of the Cladoceran Fauna ol
-
Chironomidae (Diptera) in Paleoecology 39
Esthwaite Water (England) and its limnological significance.
Archiv far Hydrobiologie, 60, 1-52.
Gross, H. (1937). Nachweis der Aller6dschwankung im siidund
ostbaltischen Gebeit. Botanisches Zentralblatt, Beihefte, Abteilung
B, 57, 167-218.
Giinther, J. (1983). Development of Grossensee (Holstein, Ger-
many): variations in trophic status from the analysis of subfossil
microfauna. Hydrobiologia, 103, 231-234.
Hansen, K. (1962). The dystrophic lake type. Hydrobiologia, 19,
183-191.
Henrikson, L., Olofsson, J.B. and Oscarson, H.G. (1982). The
impact of acidification on Chironomidae (Diptera) as indicated by
subfossil stratification. Hydrobiologia, 86, 223-229.
Hershey, A.E. (1985). Littoral chironomid communities in an
arctic Alaskan lake. Holarctic Ecology, 42, 483-487.
Hofmann, W. (1971a). Zur Taxonomie und Pal6kologie subfossiler
Chironomiden (Dipt.) in Seesedimenten. Ergebnisse der Lim- nologie
6, 1-50.
Hofmann, W. (1971b). Die postglaziale Entwicklung der Chirono-
miden und Chaoborus- Fauna (Dipt.) des Sch6hsees. Archiv far
Hydrobiologie, Supplement, 40, 1-74. (English translation:
Fisheries Research Board of Canada, Translation Series No.
2177).
Hofmann, W. (1978). Analysis of animal microfossils from the
Grol3er Segeberger See (F.R.G.). Archiv fiir Hydrobiologie, 82,
316-346.
Hofmann, W. (1979a). Chironomid analysis. In: Berglund, B.E.
(ed.) Palaeohydrological Changes in the Temperate Zone in the Last
15,000 Years. Subproject B. Volume 2. International Geo- logical
Correlation Programme, Project 158, pp. 259-270, Lund.
Hofmann, W. (1979b). Studies on animal microfossils of sediment
cores from northern Germany lakes. International Project on
Paleolimnology and Late Cenozoic Climate Newsletter, 2, 26.
Hofmann, W. (1980). Tierische Mikrofossilien aus Oberfl/ichen-
sedimenten einiger Eifelmaare. Mitteilungen der Pollichia, 68,
177-184.
Hofmann, W. (1983a). Stratigraphy of Cladocera and Chironomidae
in a core from a shallow North German lake. Hydrobiologia, 103,
235-239.
Hofmann, W. (1983b). Stratigraphy of subfossil Chironomidae and
Ceratopogonidae (Insecta: Diptera) in late-glacial littoral sedi-
ments from Lobsigensee (Swiss Plateau). Studies in the Late
Quaternary of Lobsigensee 4. Revue de Pal~obiologie, 2,
205-209.
Hofmann, W. (1984). Stratigraphie subfossiler Cladocera (Crus-
tacea) und Chironomidae (Diptera) in zwei Sedimentprofilen des
Meerfelder Maares. Courier Forschungsinstitut Seckenberg, 65,
67-80.
Hofmann, W. (1985). Developmental history of Lobsigensee: sub-
fossil Chironomidae, pp. 154-156. In: Lobsigensee - - late-glacial
and Holocene environments of a lake on the central Swiss Plateau.
Dissertationes Botanicae, 87, 127-170.
Hutchinson, G.E. and Wollack, A. (1940). Studies on Connecticut
lake sediments. II. Chemical analyses of a core from Linsley Pond,
North Branford. American Journal of Science, 238, 493-517.
Iovino, A.J. (1975). Extant chironomid larval populations and
the representativeness and nature of their remains in lake
sediments. Unpublished Ph.D. dissertation, Indiana University,
Indiana, U.S.A.
Jernel6v, A., Nagell, B. and Svenson, A. (1981). Adaptation to
an acid environment in Chironomus riparius (Diptera, Chironomidae)
from the Smoking Hills, NWT, Canada. Holarctic Ecology, 4,
116-119.
Kalugina, N.S. (1980). Cretaceous Aphroteniinae from north
Siberia (Diptera, Chironomidae). Electrotenia brundini gen. nov.,
sp. nov. Actu Universitatis Carolinae -- Biologica, 1978,
89-93.
Konstantinov, A.S. (1951). Istoriya fauny khironomid nekotorykh
ozer sapovednika "Borovoye" (Severniy Kazakhstan). Trudy
Laboratorii Sapropelevykh Otlozheniy, 5, 91-107.
Lastochkin, D.A. (1949). Ocherki po paleolimnologii Urala. Trudy
Laboratorii Sapropelevykh Otzloheniy, 3, 101-135.
Lawrenz, R.W. (1975). The developmental history of Green Lake,
Antrim County, Michigan. Unpublished M.S. thesis, Central Michigan
University, Michigan, U.S.A.
Lindeman, R.L. (1942). The trophic-dynamic aspect of ecology.
Ecology, 23, 399-418.
Livingstone, D.A., Bryan, K., Jr. and Leahy, R.G. (1958).
Effects of an arctic environment on the origin and development of
freshwater lakes. Limnology and Oceanography, 3, 192-214.
Lundbeck, J. (1926). Die Bodentierwelt norddeutschen Seen.
Archiv fiir Hydrobiologie und Planktonkunde, Supplement, 7,
1-473.
Megard, R.O. (1964). Biostratigraphical history of Dead Man
Lake, Chuska Mountains, New Mexico. Ecology, 45,529-546.
Meigen, J.W. (1800). Nouvelle classification des mouches ~ deux
ailes (Diptera L.) d'apr~s un plan tout nouveau. Paris. 40 pp.
Meigen, J.W. (1803). Versuch einer neuen Gattungseinteilung der
europ~iischen zweifliigeligen Insekten. Magazin Insekten (llliger),
2, 259-281.
Morgan, A.V. and Morgan, A. (1980). Beetle bits - - the science
of paleoentomology. Geoscience Canada, 7, 22-29.
Mossberg, P. and Nyberg, P. (1979). Bottom fauna of small and
acid forest lakes. Report of the Institute of Freshwater Research,
Drottningholm, 58, 77-87.
Mott, R.J. (1985). Late-glacial climatic change in the maritime
provinces. Syllogeus, 55, 281-300.
Nagell, B. and Brittain, J.E. (1977). Winter anoxia - - a
general feature of ponds in cold temperate regions, lnternationale
Revue der gesamten Hydrobiologie, 62, 821-824.
Naumann, E. (1917). Unders6kning 6fver phytoplankton och under
den pelagiske regionen fOrsiggAende gyttja och dy-bildning inom
vissa sydoch mellansvenska urbergsvatten. Kungliga svenska
Vetenskapsakademien Handlingar, 56, Stockholm.
Naumann, E. (1918). Ober die natiirliche Nahrung des iimnischen
Zooplankton. Lunds universitets drsskrift, ny f6ljd. Andra avdeln-
ingen 2.
Naumann, E. (1919). NAgra synpvnkter ang~ende planktons 6kologi
med s~irskild h~insyn till fytoplankton. Svensk Botanisk Tidskrift,
13, 129-158. (English translation - - Freshwater Biological Associ-
ation No. 49).
Naumann, E. (1920). NAgra synspunkter angAende de limniska
avlejringarnes terminologi. Sveriges geologiska Unders6kning,
Series C. No. 300.
Oliver, D.R. (1968). Adaptations of arctic Chironomidae. Annales
Zoologica Fennici, 5, 111-118.
Oliver, D.R. (1971). Life history of the Chironomidae. Annual
Review of Entomology, 16, 211-230.
Oliver, D.R., McClymont, D. and Roussel, M.E. (1978). A key to
some larvae of Chironomidae (Diptera) from the Mackenzie and
Porcupine River watersheds. Canadian Fisheries and Marine Service
Technical Report, 791, 1-73.
Oliver, D.R. and Roussel, M.E. (1983). The insects and arachnids
of Canada. Part 11. The genera of larval midges of Canada; Diptera:
Chironomidae. Agriculture Canada Publication No. 1746, 263 pp.
Paterson, C.G. and Fernando, C.H. (1970). Benthic colonization
of a new reservoir with particular reference to the Chironomidae.
Journal of the Fisheries Research Board of Canada, 27, 213-232.
Paterson, C.G. and Walker, K.F. (1974). Recent history of Tany-
tarsus barbitarsus Freeman (Diptera: Chironomidae) in the sedi-
ments of a shallow saline lake. Australian Journal of Marine and
Freshwater Research, 25, 315-325.
Raddum, G.G. and S~ether, O.A. (1981). Chironomid communities in
Norwegian lakes with different degrees of acidification. Ver-
handlungen der internationalen Vereinigung far theoretische und
angewandte Limnologie, 21,399-405.
Roback, S.S. (1970). XII. The Chironomidae. pp. 150-162. In:
Hutchinson, G.E. (ed.) Ianula: an account of the history and
development of the Lago di Monterosi, Latium, Italy. Transactions
of the American PhilosophicalSociety, 60, 1-178.
Rodhe, W. (1969). Crystallization of eutrophication concepts in
northern Europe. In: Eutrophication, causes, consequences, cor-
rectives. Nat. Acad. Sci., Washington, D.C. pp. 50-64.
Roff, J.C. and Kwaitkowski, R.E. (1977). Zooplankton and zoo-
benthos communities of selected northern Ontario lakes of different
acidities. Canadian Journal of Zoology, 55, 899-911.
S~ether, O.A. (1975). Nearctic chironomids as indicators of lake
typology. Verhandlungen der internationalen Vereinigung fiir
theoretische und angewandte Limnologie, 19, 3127-3133.
Saether, O.A. (1979). Chironomid communities as water quality
indicators. Holarctic Ecology, 2, 65-74.
S~ether, O.A. (1980). Glossary of chironomid morphology
terminol- ogy (Diptera: Chironomidae). Entomologica scandinavica,
14, 1-51.
Saether, O.A. (1983). 6. The larvae of Buchonomyiinae (Diptera:
Chironomidae) of the Holarctic region. Entomologica scandinavica
Supplement, 19, 113.
Simpson, K.W. (1982). A guide to basic taxonomic literature for
the genera of North American Chironomidae (Diptera) - - Adults,
pupae, and larvae. Bulletin of the New York State Museum, 447,
1-43.
Simpson, K.W. and Bode, R.W. (1980). Common larvae of
-
40 I.R. Walker
Chironomidae (Diptera) from New York state streams and rivers
with particular reference to the fauna of artificial substrates.
Bulletin of the New York State Museum, 439, 1-105.
Stahl, J.B. (1959). The developmental history of the chironomid
and Chaoborus faunas of Myers Lake. Investigations of Indiana
Lakes" and Streams, 5, 47-102.
Stahl, J.B. (1969). The uses of chironomids and other midges in
interpreting lake histories. Mitteilungen lnternationale
Vereinigung far Theoretische und Angewandte Limnologie, 17, 1 l
1-125.
Thienemann, A. (1915). Die Chironomidenfauna der Eifelmaare.
Verhandlungen des Naturhistischer Verein der Rheinlande und
Westfalens, 72, 1-58.
Thienemann, A. (1918). Untersuchungen uber die Bezeihungen
zwischen dem Sauerstoffgehalt des Wassers und der Zusammenset- zung
der fauna in Norddeutschen Seen. A rchiv far Hydrobiologie, 82,
316-346.
Thienemann. A. (1921). Seetypen. Die Naturwissenschaften, 18,
643-646.
Timms, B.V. (1983). A study of benthic communities in some
shallow saline lakes of western Victoria, Australia. Hydrobiologia,
105, 165-177.
Timms, B.V. (1984). Personal communication. Sci. Dept., Avondale
College, N.S.W., Australia.
Walker, I.R.. Fernando, C.H. and Paterson, ('.G. (1984). The
chironomid fauna of four shallow humic lakes and their represen-
tation by subfossil assemblages in the surficial sediments. Hvdro-
biologia, !12, 61-67.
Walker, I.R., Fernando, C.[t. and Paterson, C.G. t 1985).
Associ- ations of Chironomidac (Diptera) of shallow, acid, humic
lakes and bog pools in Atlantic Canada, and a comparison with an
earlier paleoecological investigation. Hydrobiologia, 120,
11-22.
Walker, 1.R. and Mathewes, R.W. (in press) Chironomidae
(Diptera) and postglacial climate at Marion Lake, British Colum-
bia, Canada. Quaternary Research.
Walker, I.R. and Paterson, C.G. (1983). Post-glacial chironomid
succession in two small humic lakes in the New Brunswick - - Nova
Scotia (Canada) border area. Freshwater Invertebrate Biology. 2,
61-73.
Walker, I.R. and Paterson, C.G. (1985). Efficient separation of
subfossil Chironomidae from lake sediments. Hydrobiologia, 122,
189-192.
Warwick, W.F. (1975). The impact of man on the Bay of Quinte,
Lake Ontario, as shown by the subfossil chironomid succession
(Chironomidae, Diptera). Verhandlungen der internationalen
Vereingung fiir theoretische und angewandte Limnologie, 19,
3134-3141.
Warwick, W.F. (1980). Paleolimnology of the Bay of Quinte, Lake
Ontario: 2800 years of cultural influence. Canadian Bulletin of
Fisheries and aquatic Sciences, 206, 1-117.
Weber, C.A. (1907). Aufbau und Vegetation der Moore Nord-
deutschlands. Beiblatt zu den Botanischen Jahrbuchern, 90,
19-34.
Whiteside, M.C. (1983). The mythical concept of eutrophication.
Hydrobiologia, 103, 107- 111.
Wiederholm, T. (1979). Chironomid remains in recent sediments of
Lake Washington. Northwes.t Science, 53,251-256.
Wiederholm, T. (ed.) (1983). Chironomidae of the Holarctic
region. Keys and diagnoses. Part 1 -.- Larvae. Entomologica
scandinaviea Supplement No. 19.
Wiederholm, T. and Eriksson, L. (1977). Benthos ot' an acid
lake. Oikos, 29, 261-267.
Wiederholm, T. and Eriksson, L. (1979). Subfossil chironomids as
evidence of eutrophication in Ekoln Bay, central Sweden. Hydro-
biologia, 62, 195-208.
Williams, N.E., Westgate, J,A., Williams, D.D., Morgan, A. and
Morgan, A.V. (1981). Invertebrate fossils (Insecta: Trichoptera,
Diptera, Coleoptera) from the Pleistocene Searborough Formation at
Toronto, Ontario and their paleoenvironmental significance.
Quaternaty Research, 16, 146-166.
-
本文献由“学霸图书馆-文献云下载”收集自网络,仅供学习交流使用。
学霸图书馆(www.xuebalib.com)是一个“整合众多图书馆数据库资源,
提供一站式文献检索和下载服务”的24 小时在线不限IP
图书馆。
图书馆致力于便利、促进学习与科研,提供最强文献下载服务。
图书馆导航:
图书馆首页 文献云下载 图书馆入口 外文数据库大全 疑难文献辅助工具
http://www.xuebalib.com/cloud/http://www.xuebalib.com/http://www.xuebalib.com/cloud/http://www.xuebalib.com/http://www.xuebalib.com/vip.htmlhttp://www.xuebalib.com/db.phphttp://www.xuebalib.com/zixun/2014-08-15/44.htmlhttp://www.xuebalib.com/