Convergence and impoverishment of fen communities in a eutrophicated agricultural landscape of the Czech Republic

Abstract

Abbreviations EUNIS = European Nature Information System; PERMDISP = Test of homogeneity of dispersion; RMANOVA = Analysis of variance for dependent samples; RMSEP = Root meansquared error of prediction. Nomenclature Ku cera et al. (2012) for bryophytes; Danihelka et al. (2012) for vascular plants; Chytr y (2012) for plant communities AbstractQuestions: On-going rapid loss of fen biodiversity in Central Europe is well known, but rigorous testing of this is complicated. We compared historical and present-day vegetation plot records from a cultural landscape rich in fishponds, where recent eutrophication and water table manipulations threaten the unique fen diversity. We assess species composition change over the last 50 yr.Location: T rebo n Basin, Czech Republic.Methods: First, we revisited historical vegetation plots to collect present-day data and then identified the most similar present-day record (the present-day counterpart) because no permanent plots were available. Second, we inferred water level, pH and conductivity (a proxy of mineral richness) using a training set of present-day field measurements, and calculated Ellenberg indicator values. Then we applied modified TWINSPAN classification, CCA, PERMANOVA, PERMDISP and RMANOVA in order to test changes in the species composition, b-diversity and environmental conditions between the historical records and their present-day counterparts.Results: Fen vegetation has persisted on half of the sites. Out of four vegetation types, poor fens and especially flooded fens were over-represented in the present-day subset, while rich fens and quaking fens were under-represented. Overall species composition differed between historical plots and their presentday counterparts, even within individual vegetation types. Historical rich fens showed significantly higher b-diversity than their present-day counterparts, which predominantly represent flooded fens. Inferred water level and its fluctuation, Ellenberg moisture and nutrient values have increased, while inferred pH, conductivity and Ellenberg light value have decreased. Conclusions:The historically wide array of fen vegetation has turned into a homogeneous and floristically depauperate set of acidic yet productive flooded fens with a high water level. Rich and quaking fens that were both low in nutrient availability and had a stable water level near the moss layer experienced a large and substantial reduction and have become rare in the landscape. Eutrophication combined with a lack of management has resulted in fen species persisting only in flooded fens. However, fluctuating water levels and high nutrient availability in flooded fens favour productive Sphagnum fens over the other vegetation types, and, importantly, do not support some endangered fen species.

Changes in functional, phylogenetic and taxonomic diversities of lowland fens under different vegetation and disturbance levels

“…Plant diversity of fen peatlands can vary significantly and be influenced by a myriad of factors, including soil fertility (Øien et al 2018), soil water level and chemistry (Navrátilová et al 2017) and changes to hydrological conditions like drainage and rewetting (Mälson et al 2008). Vegetation management practices like mowing (Kozub et al 2019) and grazing (Merriam et al 2018) can also affect fen plant diversity, since the abandonment of fens may result in changes to vegetation composition (Navrátilová et al 2017) and the encroachment of shrubs over herb fens (Wheeler and Shaw 1995). Regular mowing and grazing and the maintenance of water and nutrient levels can have positive effects on the long-term survival of characteristic open fen vegetation (Stammel et al 2003).…”

Livestock exclusion alters plant species composition in fen meadows

“…Contrary to our expectations, fencing reduced the frequency of peat‐forming species, and increased the frequency of upland and facultative upland species. Some authors have found that in the absence of mowing or grazing, species composition can shift to reflect the underlying hydrology (Fojt & Harding, ) or nutrient status (Navrátilová, Hájek, Navrátil, Hájková, & Frazier, ) of the fen. Although species composition in fens is primarily determined by the depth of the water table, pH and nutrient availability, livestock grazing can modify species composition by influencing species competitive interactions and tolerances to soil moisture and nutrient status (Fossati & Pautou, ; Schrautzer et al., ).…”

“…Navrátilová et al. () concluded that eutrophication and lack of management has resulted in near extinction of nutrient‐poor, alkaline fens (i.e. rich fens) and their associated species across Central Europe.…”

“…rich fens) and their associated species across Central Europe. Eutrophication triggers succession toward non‐fen vegetation because nutrient‐requiring non‐fen species can easily out‐compete fen specialists when nutrients are abundant (Wesche et al., ; Navrátilová et al., ). In addition to atmospheric deposition, livestock manure can be a significant source of nutrient addition, and our study sites have likely experienced increased nutrient availability over their long history of livestock use.…”

Resurvey of historical vegetation plots: a tool for understanding long‐term dynamics of plant communities

“…; Navrátilová et al. ; Schweiger & Beierkuhnlein ), four in forests (Becker et al. ; Heinrichs & Schmidt ; Reczyńska & Świerkosz ; Vild et al.…”