| Title | Modern and pre-Industrial Age distributions of Cladocera in Italian and Swiss Alpine lakes |
| Abstract | We compared contemporary and pre-Industrial Age (before 1850 AD) fossil assemblages of Cladocera in sediment cores from 25 lakes in the Italian and Swiss Alps to investigate the impact of mounting anthropogenic stresses over the last 150 years on community composition. In addition, we sought relationships between specific species and their environments by measuring nutrients, major ions, pH, alkalinity, conductivity, chlorophyll, and lake and catchment morphological features at the time of core collection for comparison with surface sediment fossil assemblages. The modern (surface sediment) communities of the study lakes consisted mainly of benthic chydorids, primarily Alona affinis, A. quadrangularis, Acroperus harpae, and Chydorus sphaericus-type, with Daphnia as the sole planktonic genus. Principal component analysis (PCA), relating the modern Cladocera assemblages to environmental variables at the time of sampling, indicated that A. affinis and A. quadrangularis are influenced by altitude and dissolved inorganic nitrogen (PCA axis 1) whereas Acroperus harpae and C. sphaericus-type are more influenced by potassium (PCA axis 2). Redundancy analysis, however, identified lake water pH and potassium as the measured variables most impacting modern cladoceran assemblages, and especially the distribution of C. sphaericus-type and A. harpae. Pre-Industrial Age samples contained more Daphnia (longispina-type primarily) than modern samples, and some harbored Eurycercus lamellatus, which has since been extirpated from these lakes. The directional shifts in Cladocera assemblages from the pre-industrial period to the present, illustrated as changes in the sample scores along the PCA axes 1 and 2, were associated with the secondary PCA gradient in almost all lakes, and thus were probably the indirect responses to a cascade of limnological alterations, perhaps initiated by large anthropogenic forcing factors such as atmospheric pollution or fish introductions. |
| Source | Hydrobiologia (The Hague. Print) 676 (1), pp. 173–185 |
| Keywords | The AlpsAtmospheric pollutionFossil cladoceransPaleolimnologyPredationTop-bottom approach |
| Journal | Hydrobiologia (The Hague. Print) |
| Editor | Kluwer Academic Publishers, Boston, Paesi Bassi |
| Year | 2011 |
| Type | Articolo in rivista |
| DOI | 10.1007/s10750-011-0802-5 |
| Authors | Liisa Nevalainen; Tomi P. Luoto; Suzanne Levine; Marina Manca |
| Text | 308882 2011 10.1007/s10750 011 0802 5 ISI Web of Science WOS 000296739300011 The Alps Atmospheric pollution Fossil cladocerans Paleolimnology Predation Top bottom approach Modern and pre Industrial Age distributions of Cladocera in Italian and Swiss Alpine lakes Liisa Nevalainen; Tomi P. Luoto; Suzanne Levine; Marina Manca Austrian Academy of Sciences; University of Helsinki; University of Vermont; CNR Inst Ecosyst Studies We compared contemporary and pre Industrial Age before 1850 AD fossil assemblages of Cladocera in sediment cores from 25 lakes in the Italian and Swiss Alps to investigate the impact of mounting anthropogenic stresses over the last 150 years on community composition. In addition, we sought relationships between specific species and their environments by measuring nutrients, major ions, pH, alkalinity, conductivity, chlorophyll, and lake and catchment morphological features at the time of core collection for comparison with surface sediment fossil assemblages. The modern surface sediment communities of the study lakes consisted mainly of benthic chydorids, primarily Alona affinis, A. quadrangularis, Acroperus harpae, and Chydorus sphaericus type, with Daphnia as the sole planktonic genus. Principal component analysis PCA , relating the modern Cladocera assemblages to environmental variables at the time of sampling, indicated that A. affinis and A. quadrangularis are influenced by altitude and dissolved inorganic nitrogen PCA axis 1 whereas Acroperus harpae and C. sphaericus type are more influenced by potassium PCA axis 2 . Redundancy analysis, however, identified lake water pH and potassium as the measured variables most impacting modern cladoceran assemblages, and especially the distribution of C. sphaericus type and A. harpae. Pre Industrial Age samples contained more Daphnia longispina type primarily than modern samples, and some harbored Eurycercus lamellatus, which has since been extirpated from these lakes. The directional shifts in Cladocera assemblages from the pre industrial period to the present, illustrated as changes in the sample scores along the PCA axes 1 and 2, were associated with the secondary PCA gradient in almost all lakes, and thus were probably the indirect responses to a cascade of limnological alterations, perhaps initiated by large anthropogenic forcing factors such as atmospheric pollution or fish introductions. 676 Published version ID_PUMA cnr.ise/2011 A0 087 Modern and pre Industrial Age distributions of Cladocera in Italian and Swiss Alpine lakes 2011_A0_087.pdf Articolo in rivista Kluwer Academic Publishers 0018 8158 Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia. The Hague. Print Hydrobiologia Dordrecht The Hague. Print Hydrobiologia Boston The Hague. Print Hydrobiologia London The Hague. Print marinamarcella.manca MANCA MARINA MARCELLA TA.P02.014.001 Alterazioni ecosistemiche a livello funzionale e strutturale indotte da cambiamenti globali |
