Effects of peatbog ditching in lakes: Problems in paleolimnological interpretation

Liehu, Anita; Sandman, Olavi; Simola, Heikki

doi:10.1007/bf00026692

Cited by 8 publications

(3 citation statements)

References 14 publications

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“…In fact, DI-TP declined markedly in Lake Iso Kivijärvi at this time, most likely because of the increase in T. fenestrata and the corresponding decline in A. ambigua. A similar pattern of changes in diatoms was reported from a peatland drainageaffected lake in Eastern Finland, with responses to early land use followed by more intensive changes in the 1970s (Liehu et al 1986).…”

Section: Intensive Forest Drainage In the 1960s And 1970ssupporting

confidence: 70%

Aquatic effects of peat extraction and peatland forest drainage: a comparative sediment study of two adjacent lakes in Central Finland

et al. 2016

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The aquatic effects of forestry practices and peat extraction continue to cause serious concerns. The effect mechanisms of peat extraction on water quality and aquatic ecology of the receiving surface waters are well known, but the impacts are often difficult to differentiate from those of forest management. A pairwise temporal sediment study was conducted on two adjacent lakes in Central Finland to study whether the unique effects of peat extraction can be detected in an area of intensive forest drainage. Both lakes are affected by forestry, but the reference lake has no history of peat extraction in its watershed. The deepest parts of the lakes were cored through the lacustrine sediments, and the recent carbon and dry matter sedimentation rates were compared to their site-specific reference values. Recent changes in benthic macroinvertebrates (chironomids) and diatom algae were studied to assess the ecological effects of these practices in the lakes. No significant differences in recent increases in carbon accumulation were found between the peat extraction-impacted lake and the reference lake. The pairwise comparison allowed identification of a regional pattern of impacts that is closely related to the history of land use, particularly forestry, in the region. The approach also allowed identification of the transient signs of peat extraction in the chemical and chironomid records of the impacted lake. The recent changes in chironomids and diatoms suggest eutrophication and deterioration in benthic conditions likely caused by drainage ditch network maintenance activities in the catchments.

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Section: Intensive Forest Drainage In the 1960s And 1970ssupporting

confidence: 70%

Aquatic effects of peat extraction and peatland forest drainage: a comparative sediment study of two adjacent lakes in Central Finland

et al. 2016

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“…Comparisons of diatom assemblages and DI‐TP between the core bottom and present‐day samples from this site indicate much more important changes than those between c. 1850 and present‐day, because of increased abundances of Asterionella ralfsii (a taxon that was not recorded in pre‐ c. 1850 sediments). The ecology of this taxon is not well known but appears to be indicative of peatland disturbance and nutrient enrichment (Liehu, Sandman & Simola 1986). It could therefore be argued that c. 1850 is not an appropriate reference date for Keel, and this may also be the case for several other lakes in catchments that until the mid‐19th century supported far higher human population densities than today.…”

Section: Discussionmentioning

confidence: 99%

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Leira

Jordan

Taylor

et al. 2006

Journal of Applied Ecology

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Summary1. The European Union (EU) Water Framework Directive (WFD) requires that member states establish type-specific reference conditions for all waterbodies, including freshwater lakes. This presents a problem in those locations where human activity has resulted in significant changes to the biological, chemical and physical characteristics of waterbodies. 2. Seventy-six oligotrophic and meso-oligotrophic [0 -19 µ g total phosphorus (TP) L ] lakes thought to be relatively unimpacted by human activity have been nominated as candidate reference lakes (CRL) by the Irish Environmental Protection Agency. This research has used palaeolimnological (lake sediment-based) techniques to test the actual and historical ecological site-specific status of a representative selection of these CRL. Where the temporal record of sedimentation was sufficiently long, the study adopted c. 1850  as the primary baseline date for reference conditions. 3. Short sediment cores were obtained from the deepest parts of 35 CRL, and chronologies were established from profiles of spheroidal carbonaceous particles (SCP). Twenty-two cores of sediment appeared to date back to c. 1850 on the basis of SCP concentrations. Unless the SCP chronologies suggested otherwise, diatom assemblages present in top and bottom samples from the cores were used as proxies of, respectively, present-day and reference conditions. Past lake water pH (DI-pH) and TP concentration (DI-TP) were inferred from the diatom data. Higher resolution sampling (up to five sediment samples per core) was adopted at seven sites where the SCP-based chronology was more robust and for at least one core from each of the most common types of CRL. Sediment chemistry data were determined to identify possible anthropogenic drivers of the observed changes in the diatom assemblages. 4. Ordination and dissimilarity measures identified the main patterns of variation in the diatom data. Eleven of 34 CRL for which diatom data were available showed little or no change in biological status between core top and bottom samples. Core bottom samples in six of these dated back to pre-or c. 1850 and reference (and high ecological) status could therefore be confirmed in these cases. The estimated age of core bottom samples in the remaining five cores was in the period just after c . 1850 to c. 1950  (four cores) or was impossible to determine (one core). Twenty-three (68%) of the CRL sampled showed biologically important deviation from the reference condition, with acidification and nutrient enrichment seemingly the main causes of change. Catchment disturbance, notably peat erosion possibly linked to recent afforestation, also appeared to have been a factor in some cases. 5. Synthesis and applications. This study provides the first systematic examination of changes to water quality in (perceived) pristine lakes over the last c . 150 years for Ireland, and demonstrates the potential of palaeolimnology to support the implementation of the WFD. The results indicate that diatom communities in low alkalinit...

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“…Such differences are reconcilable with known forest effects on atmospheric pollutant transfer to runoff water (Harriman & Morrison 1982;Unsworth 1984). However, unlike the RLGH, there is a major change in the diatoms at this site, beginning in the late-1970s and culminating in 1988 with a mass occurrence of , an acidophilous diatom indicative of peatland disturbance and nutrient enrichment (Liehu et al 1986). As acid deposition changes are similar to those at the RLGH it is suggested that the recent floristic changes at Loch Grannoch are an indirect result of forestry management.…”

Section: Discussionmentioning

confidence: 57%

Post-1970 water-chemistry changes and palaeolimnology of several acidified upland lakes in the U.K

Flower

Cameron

Fritz

et al. 1990

Phil. Trans. R. Soc. Lond. B

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Responses of four lakes to post-1970 changes in acid deposition, afforestation and liming are examined by using water quality measurements and palaeolimnological analysis. pH and non-marine sulphate concentrations at an undisturbed site approximately parallel trends in precipitation and indicate that lake water quality has improved since the late-1970s as atmospheric S emissions have declined. Carbonaceous particle contamination of the lake also declines in this period but diatom analysis shows that the ecological response to these changes are as yet small. However, at a similar but recently afforested site, major changes in sedimentary diatoms have occurred and we argue that fertilizer leaching is the cause. At the two limed sites the diatom response is proportional to liming intensity but at neither site has the pre-acidification diatom flora been re-established.

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Effects of peatbog ditching in lakes: Problems in paleolimnological interpretation

Cited by 8 publications

References 14 publications

Aquatic effects of peat extraction and peatland forest drainage: a comparative sediment study of two adjacent lakes in Central Finland

Aquatic effects of peat extraction and peatland forest drainage: a comparative sediment study of two adjacent lakes in Central Finland

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Post-1970 water-chemistry changes and palaeolimnology of several acidified upland lakes in the U.K

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