Samples of epibenthic diatoms were collected, between 2009 and 2010, in 22 stations located within the Natural Park of Upper Valley of Tanaro and Pesio rivers (Today in the Maritime Alps Natural Park). At the same time, the main altitudinal, land cover, hydrogeomorphological and hydro-chemical parameters of each sampling site were recorded. 131 species were identified, among which Achnanthidium minutissimum (20,46% of total individuals), Diatoma mesodon (15,21%) e Planothidium lanceolatum (10,49%) were the most abundant ones. Some rare species were found, such as Geissleria gereckei (Battegazzore & Gallino, 2010). Rheocrene springs were associated with the lowest altitudes and meadow land cover, while limnocrene ones were associated with the higher altitudes. Nitrates were also related with the lowest altitudes but with a forest cover suggesting a prevalent contribution from natural sources. Performing TWINSPAN (Two Way Specie Indicator Analysis) on the dataset stations x species (the 31 most representative ones), 6 clusters could be observed.Figure 1. Dendrogram of the TWISPAN clusters for all sampled springs and 31 most representative speciesAnalysis of the ecological requests of their preferential taxa matched with the results of correlation analysis (Spearman), while Indicator Species Analysis ISA) showed that the clusters corresponded to communities of a) calcareous springs where limnocrenes prevail over other spring types, b) shaded calcareous rheocrenes, c) more “tufa-like” springs, d) enriched nutrient rheocrene springs, e) rheocrene siliceous substrate springs with low levels of dissolved ions, and f) calcareous rheocrenes of pristine environments. In the community of type (e) a marked niche dilation of Planothidium lanceolatum associated with nitrate and forest cover was evident. The highest levels of biodiversity and species richness as well as the best value of Ecological Balance (ratio between dominance and66total number of species) were associated with the prevailingly limnocrenes and calcareous pristine springs while the lowest values of the same parameters were measured in springs with nutrients enrichment supporting the conclusion that increase in nitrate levels can adversely affect diatom communities of mountain springs.References:Battegazzore M., Morisi A., Gallino B. & Fenoglio S. (2004): “Environmental quality of Alpine springs in NW Italy using benthic Diatoms”. Diatom Research, 19(2), 149-165.Battegazzore M. and Gallino B. (2010): “Importanza dello studio di biota microscopici in ambienti “marginali” – una indagine su un gruppo di sorgenti nelle Alpi Liguri, settore cuneese””. Atti XX Congresso Nazionale della Società Italiana di Ecologia, Roma, 27-30 Settembre 2010, p. 122.Bellinger E.G., and Sigee D.C. (2010): “Algae as Bioindicators”, Chapter 3. In Freshwater Algae: Identification and Use as Bioindicators. John Wiley and Sons.pp 99 – 136Cantonati M., Angeli N., Bertuzzi E. and Spitale D. (2012): “Diatoms in springs of the Alps: springs types, environmental determinants, and substratum”. Freshwater Science, 31(2), 499-524.Falasco E., Ector L., Ciaccio E., Hoffmann L., Bona F. (2012): “Alpine freshwater ecosystems in a protected area a source of diatom diversity”. Hydrobiologia, 695, 233-251Hwang S-J, Kim N-Y, Yoon S.A., Kim B-H, Park M.H.You K-A,Lee H.Y., Kim H.S., Kim Y.J., Lee J., Lee O.M.,Shin J.K., Lee E.J., Jeon S.L. and Joo H.S.(2011): “Distribution of benthic diatoms in Korean rivers and streams in relation to environmental variables”. Annales of Limnology, 47,15-33.McCune B., Grace J. B. and Urban D.L. (2002): “Analysis of Ecological Communities”. MjM Software Design, Gleneden Beach, Oregon.Rimet F. (2012): “Diatoms: an ecoregional indicator of nutrients, organic matter and micropollutants pollution”. Sciences agricoles. Universite de Grenoble. Francais.Sabater, S. & J. R. Roca (1992): “Ecological and biogeographical aspects of diatom distribution in Pyrenean springs”. British Phycological Journal 27: 203–213.
Epibenthic diatom assemblages in alpine springs in NW Italy: detection of main factors affecting their structure
GALLO, Luana;Corapi A;LUCADAMO, Lucio
2017-01-01
Abstract
Samples of epibenthic diatoms were collected, between 2009 and 2010, in 22 stations located within the Natural Park of Upper Valley of Tanaro and Pesio rivers (Today in the Maritime Alps Natural Park). At the same time, the main altitudinal, land cover, hydrogeomorphological and hydro-chemical parameters of each sampling site were recorded. 131 species were identified, among which Achnanthidium minutissimum (20,46% of total individuals), Diatoma mesodon (15,21%) e Planothidium lanceolatum (10,49%) were the most abundant ones. Some rare species were found, such as Geissleria gereckei (Battegazzore & Gallino, 2010). Rheocrene springs were associated with the lowest altitudes and meadow land cover, while limnocrene ones were associated with the higher altitudes. Nitrates were also related with the lowest altitudes but with a forest cover suggesting a prevalent contribution from natural sources. Performing TWINSPAN (Two Way Specie Indicator Analysis) on the dataset stations x species (the 31 most representative ones), 6 clusters could be observed.Figure 1. Dendrogram of the TWISPAN clusters for all sampled springs and 31 most representative speciesAnalysis of the ecological requests of their preferential taxa matched with the results of correlation analysis (Spearman), while Indicator Species Analysis ISA) showed that the clusters corresponded to communities of a) calcareous springs where limnocrenes prevail over other spring types, b) shaded calcareous rheocrenes, c) more “tufa-like” springs, d) enriched nutrient rheocrene springs, e) rheocrene siliceous substrate springs with low levels of dissolved ions, and f) calcareous rheocrenes of pristine environments. In the community of type (e) a marked niche dilation of Planothidium lanceolatum associated with nitrate and forest cover was evident. The highest levels of biodiversity and species richness as well as the best value of Ecological Balance (ratio between dominance and66total number of species) were associated with the prevailingly limnocrenes and calcareous pristine springs while the lowest values of the same parameters were measured in springs with nutrients enrichment supporting the conclusion that increase in nitrate levels can adversely affect diatom communities of mountain springs.References:Battegazzore M., Morisi A., Gallino B. & Fenoglio S. (2004): “Environmental quality of Alpine springs in NW Italy using benthic Diatoms”. Diatom Research, 19(2), 149-165.Battegazzore M. and Gallino B. (2010): “Importanza dello studio di biota microscopici in ambienti “marginali” – una indagine su un gruppo di sorgenti nelle Alpi Liguri, settore cuneese””. Atti XX Congresso Nazionale della Società Italiana di Ecologia, Roma, 27-30 Settembre 2010, p. 122.Bellinger E.G., and Sigee D.C. (2010): “Algae as Bioindicators”, Chapter 3. In Freshwater Algae: Identification and Use as Bioindicators. John Wiley and Sons.pp 99 – 136Cantonati M., Angeli N., Bertuzzi E. and Spitale D. (2012): “Diatoms in springs of the Alps: springs types, environmental determinants, and substratum”. Freshwater Science, 31(2), 499-524.Falasco E., Ector L., Ciaccio E., Hoffmann L., Bona F. (2012): “Alpine freshwater ecosystems in a protected area a source of diatom diversity”. Hydrobiologia, 695, 233-251Hwang S-J, Kim N-Y, Yoon S.A., Kim B-H, Park M.H.You K-A,Lee H.Y., Kim H.S., Kim Y.J., Lee J., Lee O.M.,Shin J.K., Lee E.J., Jeon S.L. and Joo H.S.(2011): “Distribution of benthic diatoms in Korean rivers and streams in relation to environmental variables”. Annales of Limnology, 47,15-33.McCune B., Grace J. B. and Urban D.L. (2002): “Analysis of Ecological Communities”. MjM Software Design, Gleneden Beach, Oregon.Rimet F. (2012): “Diatoms: an ecoregional indicator of nutrients, organic matter and micropollutants pollution”. Sciences agricoles. Universite de Grenoble. Francais.Sabater, S. & J. R. Roca (1992): “Ecological and biogeographical aspects of diatom distribution in Pyrenean springs”. British Phycological Journal 27: 203–213.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
