Anna Kirschbaum, Niek Scheepens (PI), Oliver Bossdorf
March 2017 - September 2020
Theory predicts that temporal and spatial
heterogeneity in environmental conditions should favour the evolution of
phenotypic plasticity, which is an organism's ability to respond adaptively to
such environmental changes. In managed grasslands, mowing, grazing and
fertilization all create strongly temporally variable environmental conditions.
In this Biodiversity Exploratories project we will investigate whether land use
intensity relates to the strength of plant phenotypic plasticity, which would
suggest rapid evolution of grassland species to land use management.
Phenotypic plasticity (PP) is one of the key
mechanisms by which plants respond to environmental changes. As there is
heritable variation in PP in most plants, PP can evolve where it is adaptive.
One such situation might be grassland management. Mowing, grazing and
fertilization all create temporally variable environmental conditions, which
should favor and thus select for increased PP, in particular the ability of
plants to rapidly exploit temporary nutrient pulses, and the ability to regrow
after damage. However, although it is well known that plants can rapidly adapt
to different land-use practices, evolution of PP in response to land use has
rarely been studied so far. This research project will take advantage of the
study plots, land use information and other environmental data in the
Biodiversity Exploratories to test the hypotheses about the evolution of PP.
(1) Increased fertilization selected for
increased PP in the ability of plants to rapidly respond to nutrient addition
(2) Plants in more intensively grazed and mown
sites show a stronger capacity for regrowth
(3) Spatial heterogeneity in vegetation
structure and temporal variation in land use generally correlates with greater
(4) Population-level genetic diversity
correlates positively with PP
We will test these predictions in three common
grassland species in the Biodiversity Exploratories: Bromus hordeaceus,
Plantago lanceolata and Veronica chamaedrys, each sampled from 60 grassland EPs
across the three Exploratories. We will carry out controlled common garden
experiments in which the response to fertilization and clipping treatments will
be measured in various functional traits (biomass, SLA, leaf C:N:P ratio and
phenology). We will also measure fitness traits and investigate whether plastic
responses are adaptive, and whether they also have a fitness cost. To test
hypothesis (3) We will correlate PP with data on spatial heterogeneity,
obtained via aerial or satellite photographs as well as from field
observations. We will also correlate PP with an index of temporal land-use
change reflecting temporal heterogeneity both within and between land-use
practices. Finally, we will link PP data to existing molecular marker data to
examine correlations between neutral genetic diversity and PP.
This project will be about a hitherto
unexplored part of genetic diversity in the Biodiversity Exploratories and will
thus increase our understanding in particular of the evolutionary consequences
of land use on plants.
Kirschbaum A, Bossdorf O, Scheepens JF (2021) Variation in regrowth ability in relation to land-use intensity in three common grassland herbs. Journal of Plant Ecology accepted. Link