Determining reference conditions of hemiboreal lakes in Latvia, NE Europe: a palaeolimnological approach

Annales de Limnologie: International journal of limnology

article

Normunds Stivrins¹  Ieva Grudzinska³  Kati Elmi⁴  Atko Heinsalu⁴  Siim Veski⁴ 

[1] Department of Geography, Faculty of Geography and Earth Sciences, University of Latvia;Department of Geosciences and Geography, University of Helsinki;Lake and Peatland Research Centre;Institute of Geology, Tallinn University of Technology;Institute of Plant Sciences, University of Bern;Oeschger Centre for Climate Change Research, University of Bern;Institute of Biology, University of Latvia

关键词: Algae;    anthropogenic impact;    turnover rates;   

DOI  :  10.1051/limn/2018014

学科分类：地球科学(综合)

来源: EDP Sciences

【 摘 要 】

The current status of a lake can be evaluated via monitoring, but such data can only provide information about the last few decades to a century at best. In most cases, the natural state of a lake cannot be ascertained. This is even more challenging if the apparent anthropogenic effects on the environment over the last millennia are considered. We used data on fossil algae from five evenly distributed hemiboreal lakes in geographically different regions in Latvia, NE Europe to assess the amount of compositional change or turnover ( i.e. , the beta-diversity) in the algae datasets for the last 2000 years by using a Detrended Canonical Correspondence Analysis. Our results show that the algae turnover increases towards the present day with distinct shifts during times characterised by extensive and intensive agriculture establishment, and political and economic changes. Because the anthropogenic impact on the landscape and lakes before AD 1200 was relatively minor, we propose that algae composition at that time can be assumed to represent the natural reference conditions for most Latvian lakes.

【 授权许可】

CC BY