Long-term changes in benthic Cladocera populations in Lake Myvatn, Iceland

Einarsson, Árni; Örnólfsdóttir, Erla Björk

doi:10.1023/b:aeco.0000032060.29256.95

Cited by 24 publications

(28 citation statements)

References 38 publications

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“…Accordingly, cladoceran richness is higher in the Faroese lakes compared with the colder subarctic Icelandic lakes (Antonsson, 1992;Einarsson & Ornó lfsdó ttir, 2004), arctic north-eastern Greenland lakes (Jeppesen et al, 2001a) and western Greenland lakes (Lauridsen et al, 2001, Jeppesen et al, unpubl. data).…”

Section: Discussionmentioning

confidence: 99%

Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes – evidence from contemporary data and sediments

Amsinck¹,

Strzelczak²,

Bjerring

et al. 2006

Freshwater Biology

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1. This study describes the environmental conditions and cladoceran community structure of 29 Faroese lakes with special focus on elucidating the impact of fish planktivory. In addition, long-term changes in biological structure of the Faroese Lake Heygsvatn are investigated. 2. Present-day species richness and community structure of cladocerans were identified from pelagial snapshot samples and from samples of surface sediment (0-1 cm). Multivariate statistical methods were applied to explore cladoceran species distribution relative to measured environmental variables. For Lake Heygsvatn, lake development was inferred by cladoceran-based paleolimnological investigations of a 14 C-dated sediment core covering the last ca 5700 years. 3. The 29 study lakes were overall shallow, small-sized, oligotrophic and dominated by brown trout (Salmo trutta). Cladoceran species richness was overall higher in the surface sediment samples than in the snapshot samples. 4. Fish abundance was found to be of only minor importance in shaping cladoceran community and body size structure, presumably because of predominance of the less efficient zooplanktivore brown trout. 5. Canonical correspondence analysis showed maximum lake depth (Z max ) to be the only significant variable in explaining the sedimentary cladoceran species (18 cladoceran taxa, two pelagic, 16 benthic) distribution. Multivariate regression trees revealed benthic taxa to dominate in lakes with Z max < 4.8 m and pelagic taxa to dominate when Z max was > 4.8 m. 6. Predictive models to infer Z max were developed using variance weighted-averaging procedures. These were subsequently applied to subfossil cladoceran assemblages identified from a 14 C-dated sediment core from Lake Heygsvatn and showed inferred Z max to correspond well to the present-day lake depth. A recent increase in inferred Z max may, however, be an artefact induced by, for instance, eutrophication.

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Section: Discussionmentioning

confidence: 99%

Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes – evidence from contemporary data and sediments

Amsinck¹,

Strzelczak²,

Bjerring

et al. 2006

Freshwater Biology

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“…The long period between emergence peaks (seven to 14 generations) indicates that depleted resources may be slow to regenerate. Einarsson & Örnólfsdóttir (2004) suggest that cycling of food resources and sediment conditions associated with chironomid populations also affects benthic Cladocera in Lake Myvatn. Imbedded within studies of interannual variation and cycles can be the impact of severe disturbances that occur naturally, are relatively rare and can have long‐lasting effects.…”

Section: Recent Contributions To Lotic and Lentic Ecologymentioning

confidence: 99%

Long‐term studies of freshwater macroinvertebrates: a review of the frequency, duration and ecological significance

2006

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1. The importance of a long-term ecological perspective is well documented, yet the availability of long-term data remains limited. This paper highlights the value of long-term ecological studies of freshwater macroinvertebrates by reviewing both the availability of long-term data and recent ecological contributions based on them. 2. A survey of recent literature on stream macroinvertebrates identified 46 papers published between 1987 and 2004 that included long-term (i.e. ‡5 years) data. Most recently published long-term studies of stream macroinvertebrates began collecting data in the 1970s and 1980s and their duration (time between first and last year sampled) was relatively brief (median ¼ 9 years, maximum ¼ 96 years). Most studies did not expand their temporal perspective by incorporating older data collected by other researchers. 3. Recent long-term studies of macroinvertebrates have made major contributions to our understanding of interannual variation and cycles, complex abiotic and biotic interactions, and natural and anthropogenic disturbance and recovery. Without these studies, we would know much less about the magnitude of natural temporal variation, the importance of physical and biological disturbance and interactions, the role of pathogens and introduced species, the overall impact of pollution and the effectiveness of protection and remediation efforts. 4. If we are to encourage long-term perspectives in our science, we need to facilitate the transfer of individual studies, as well as knowledge and data, among scientists. This includes efforts to archive and annotate data more effectively, so that they can be more easily incorporated into future research.

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“…The ecosystem of Lake Mývatn in northern Iceland has been monitored since 1975, revealing extreme fluctuations in important food web components such as chironomids and cladocerans (Einarsson & Örnólfsdóttir, 2004; Einarsson et al. , 2004; Gardarsson et al.…”

Section: Introductionmentioning

confidence: 99%

Matching thirty years of ecosystem monitoring with a high resolution microfossil record

et al. 2010

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1. Monitoring of the ecosystem of Lake Mý vatn, Iceland, since 1975 has revealed extreme fluctuations in important food web components, such as chironomids and cladocerans, with amplitudes of several orders of magnitude and a period of 5-8 years. This study uses sediment cores from the lake to examine if the food web fluctuations appear in the microfossil record of the sediment. 2. Dating was achieved by means of a combination of 137 Cs and volcanic tephra and was fine-tuned by wiggle-matching of chironomid microfossil and monitoring data. 3. Cladocera exuviae and chironomid egg capsules in the uppermost 34 cm of sediment were compared with the monitoring record that consisted of 30 years of window trap catches of flying chironomids and a 16-year record of chydorid Cladocera caught in activity traps. 4. The observed chironomid and cladoceran population fluctuations were reflected in the sediment record of chironomid eggs and of the exuviae of three of seven cladocerans: Alonella nana, Alona rectangula and Eurycercus lamellatus, which also had the most extreme fluctuations in the monitoring data (3-4 orders of magnitude). Chydorus sphaericus, and to some extent Alona quadrangularis and Acroperus harpae, showed regular fluctuations in the core that the monitoring did not reveal. Density of subfossil chironomid eggs correlated positively with that of larval head capsules but not with other microfossils. 5. This study shows a reasonably good correspondence between the fossil records of chironomids and cladocerans on the one hand and biomonitoring data on the other. The results pave the way for an extension of the food web history to much earlier time intervals of the ecosystem, allowing the study of long-term variation in the food web dynamics, including the impact of climatic variation and other external forcing. The results also indicate the usefulness of chironomid egg capsules in palaeolimnological studies.

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Long-term changes in benthic Cladocera populations in Lake Myvatn, Iceland

Cited by 24 publications

References 38 publications

Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes – evidence from contemporary data and sediments

Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes – evidence from contemporary data and sediments

Long‐term studies of freshwater macroinvertebrates: a review of the frequency, duration and ecological significance

Matching thirty years of ecosystem monitoring with a high resolution microfossil record

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