Data for Long-term cross-scale comparison of grazing and mowing on plant diversity and community composition in a salt-marsh system

Land abandonment has been increasing in recent decades in
Europe, usually accompanied by biodiversity decline. Whether livestock grazing
and mowing can safeguard biodiversity across spatial scales in the long term is
unclear. Using a 48-year experiment in a salt marsh, we compared land
abandonment (without grazing and mowing) and seven management regimes including
cattle grazing, early season mowing, late season mowing, both early and late
season mowing, and grazing plus each of the mowing regimes on plant diversity
at the local and larger scales (i.e. aggregated local communities). Also, we
compared their effects on community composition (both in identities and
abundances) in time and space. Under land abandonment, plant diversity declined
in the local communities and this decline became more apparent at the larger
scale, particularly for graminoids and halophytes. All management regimes,
except for late season mowing, maintained plant diversity at these scales. Local
plant communities under all treatments underwent different successional
trajectories, in the end, diverged from their initial state except for that
under grazing (a cyclic succession). Year-to-year changes in local community
composition remained at a similar level over time under land abandonment and
grazing plus early season mowing, while it changed under other treatments.
Vegetation homogenized at the larger scale over time under land abandonment
while vegetation remained heterogeneous under all management regimes. Synthesis.
Our experiment suggests that late season mowing may not be sustainable to
conserve plant diversity in salt marshes. Other management regimes can maintain
plant diversity across spatial scales and vegetation heterogeneity at the
larger scale in the long term, but local community composition may change over
time.

The excel file contains
two data frames, one is coverage data for each species in each permanent plot
in the control (without grazing and mowing), cattle grazing, early season
mowing, late season mowing, both early and late season mowing, and grazing plus
each of the mowing regimes from 1972 to 2019. The other one is biomass data
from mowing and grazing plus mowing treatments. Biomass data are not available
for the control and grazing treatments.