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The Effects of Cattle Grazing on the Composition of Diatom Assemblages in the Peatland Pools of the Southeastern Alps (Italy, Adamello-Brenta Nature Park)

by Floriana Rossi, Diana M. P. Galassi, Nicola Angeli, Marco Cantonati and Mattia Di Cicco

Land 2024, 13(11), 1780; https://doi.org/10.3390/land13111780 - 30 Oct 2024

Cited by 3 | Viewed by 1365

Abstract

Mires are significant C-sinks and important habitats for biodiversity conservation. Particularly in the Alpine peatlands, grazing and trampling cause mires to degrade, causing changes in plant communities that increase bulk density, peat erosion, and nutrient excesses. We took sixteen samples of epipelic and epiphytic diatoms from mire pools subjected to varying degrees of grazing in the Adamello-Brenta Nature Park (Trento, Italy). We identified >100 diatom species (ca. 70% included in Red List threat categories). We used nMDS to identify groups of diatom species. Their statistical significance was checked with an ANOSIM and, to identify the species that contributed most to the difference between the two groups, a BEST-SIMPER procedure was carried out. The multivariate analyses allowed us to identify significant differences among the most and least grazed sites, and to select the species that contributed most to this distinction. We confirmed that some species were more frequent and abundant in the most grazed sites and behaved as opportunists in the presence of a greater nutrient input, to the detriment of rare and sensitive species, which were more numerous and abundant in the less grazed sites. We provided useful information on grazing effects, underlining the importance of managing and protecting habitats of unique environmental value. Full article

(This article belongs to the Special Issue Soil Security of Peatland Ecosystems: Risk Assessment, Pollution Prevention and Restoration)

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19 pages, 5775 KB

Open AccessArticle

Temporal Evolution of Diatoms in a Temporary Pond Situated in the Massif du Sancy Mountains (Massif Central, France) and Description of a New Pinnularia Species

by Aude Beauger, Elisabeth Allain, Olivier Voldoire, Carlos E. Wetzel, Luc Ector and Bart Van de Vijver

Diversity 2020, 12(10), 367; https://doi.org/10.3390/d12100367 - 24 Sep 2020

Cited by 7 | Viewed by 3628

Abstract

A floristic survey was performed on a temporary pond, “Laqui du Seignavoux”, situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic–hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed. Full article

(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)

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