Data from: Comparing the responses of bryophytes and short-statured vascular plants to climate shifts and eutrophication

Few experimental studies have tested how abundance and diversity of
grassland bryophytes respond to global environmental changes such as
climate shifts and eutrophication. Because bryophytes in grasslands are
low-statured, and because plant height is a key functional trait governing
plant responses to resource gradients, their responses to these factors
could resemble those of better-studied small vascular plants.
Alternatively, traits unique to bryophytes could lead to qualitatively
different responses than those of small vascular plants. In a semi-arid
Californian grassland system, where bryophytes are at relatively low
abundance and their ecology has been little studied, we compared changes
in cover and species richness of bryophytes and short-statured vascular
plants in response to 5 years of experimental fertilization, springtime
watering and fertilization + watering, which produced strong gradients in
vascular plant biomass. Supporting our hypotheses, the cover and richness
of both bryophytes and short vascular plants were negatively related to
total community biomass and tall vascular plant cover, and declined in
response to the fertilization + watering treatment, in which the cover of
tall vascular plants most strongly increased. Two divergent responses were
also observed as follows: watering alone increased the cover of bryophytes
but not short vascular plants, while fertilization alone reduced the cover
of short vascular plants but not bryophytes. Bryophytes and short-statured
vascular plants in grasslands both may be expected to decline under
projected global changes in climate and nutrient deposition that enhance
total community biomass and competitive pressure. However, shifts in
either precipitation or eutrophication regimes alone may have differential
effects on bryophytes and short vascular plants in grasslands, and
organism-specific plant functional traits must also be considered.