Turnover and change in plant species composition in a shielded salt marsh following variation in precipitation and temperature

Abstract

Questions: Temperature and precipitation variation between years may affect plant species composition directly or indirectly. We wish to investigate whether salt marsh edaphic conditions and plant species composition change as a result of climatic variation. Further, whether areas with the largest edaphic variations also experience the largest change in species composition and turnover. Finally, do temperature and precipitation variations change the way the plant community is able to respond to natural edaphic gradients? Location: Bygholmengen, a shielded salt marsh in Vejlerne, Denmark, Northern Europe. Methods: Botanical surveys were conducted and soil samples collected from 40 plots during a wet and dry summer to register changes in vegetation cover, species richness composition and edaphic factors (moisture, nutrients, salinity). These data were used to calculate dissimilarities in species composition, temporal turnover and environmental dissimilarity between years. A linear mixed-effects model was used to link species richness with the measured edaphic factors.Results: We found that the precipitation and temperature variations altered the edaphic conditions; furthermore, the vegetation cover and species richness decreased when conditions were dry whereas the number of salt marsh species increased. Further, species composition changed significantly between years, and sampling plots that experienced the least edaphic change also retained more species between years. Species richness responded more to changes in nutrient availability during wet than dry conditions. Conclusion: Our results pointed toward the climatic variations, and subsequent change in edaphic conditions, being responsible for the significant change in species composition as areas with the least change in edaphic factors retained most species between years. Dry conditions favored salt marsh-adapted species and the extent to which increased nutrient levels led to a higher species richness decreased in dry compared to wet conditions. K E Y W O R D S biodiversity, coastal habitat, Denmark, environmental dissimilarity, salt meadow, species richness, temporal turnover, vegetation 466 | Additional supporting information may be found online in the Supporting Information section. Appendix S1. A map of the study site along with images of the area in 2017 and 2018 Appendix S2. List of salt marsh species How to cite this article: Andersen LH, Skaerbaek ASK, Sørensen TB, et al. Turnover and change in plant species composition in a shielded salt marsh following variation in precipitation and temperature. J Veg Sci. 2020;31:465-475.

Reed bed vegetation structure and plant species diversity depend on management type and the time period since last management

“…In tall‐herb fens, species richness increased after 2–4 years of grazing due to a decrease in the abundance of common reed (Ausden et al, 2005), and in our study, the initial increase in species richness following management could be explained by the removal of common reed and decreased reed density in the young compared with the old reed beds. In our case, grazing of the reed bed would likely also result in reed bed drawback since the area adjacent to the study reed beds is a grazed marsh where common reed growth is limited (Andersen et al, 2020a). We only observed an age effect on species richness in May, where the species richness was significantly higher in recently harvested (0‐ and 3‐year‐old) compared to the 25‐year‐old reed bed, and by August, species richness no longer differed between the treatments.…”

eDNA Metabarcoding- and Microscopic Analysis for Diet Determination in Waterfowl, a Comparative Study in Vejlerne, Denmark

“…The four species occur in high numbers in the Danish scientific reserve Vejlerne [ 23 ], in which this study was conducted. Many different plant species can be found on the salt marsh and in the reed beds in Vejlerne [ 24 , 25 , 26 ]. By combining microscopic analysis with DNA barcoding on the undigested and undegraded plant material in the faecal samples, we investigated the capabilities of the two different methods to answer the questions, ‘Which plants do the four different species feed upon, and is there a food overlap among the species?’…”