a PhD
student in Plant Ecology at Department of Plant Ecology and Nature
Conservation, University of Potsdam in Germany, supervised by Dr. Katja Tielbörger
and Prof. Florian Jeltsch. Within the framework of the GLOWA Jordan
River project I focus on plant population-level studies, particularly on
changes in population dynamics of selected annuals under various scenarios of
climate change.
The aim of my research is to investigate responses of annual plants to changing rainfall conditions via regulation of seed dormancy and germination strategies, while testing several theoretical predictions, and considering consequences of such behavior for species population dynamics and for adaptive strategies within an evolutionary context.
My field studies are among the first to empirically
test for theoretical models about optimal germination rates of annual plants,
such as the Cohen’s models (Cohen 1966, 1967) predicting increase in
germination rates with increasing precipitation.
I am also testing for maternal effects on seed
germination, contradicting germination predicted by Cohen models, i.e.
germination rates negatively related to previous year’s rainfall (Tielbörger & Valleriani, unpubl.) due to sibling
competition.
I aim to separate effects of climate (Cohen’s
germination) and maternal effects on germination.
The seven
study species overlapping among four sites along the precipitation gradient
include different dormancy types. Dormancy tends to increase from grasses (Bromus
fasciculatus, Stipa capensis), to Cruciferae (Biscutella didyma,
Carrichtera annua, Reboudia pinnata) to Leguminosae (Hippocrepis
unisiliquosa, Hymenocarpos circinatus).
I use seed-addition-plots in four field sites along a natural precipitation gradient and in plots with altered rainfall regime: artificially added rainfall pulses (irrigation) and artificially subtracted rainfall (rain-out shelters). I evaluate germination rates of the study species comparing between sites (testing for Cohen germination) and treatments (testing for maternal effects).
In controlled phytotron conditions
I check for maximal germination rates of the species comparing between
stations, treatments, years and dormancy types testing for both models.
To separate climatic effects from maternal effects,
I grow plants from different climatic regions under the same conditions in an
open greenhouse until seed production, while maternally induced germination
rates of produced seeds will be investigated under controlled phytotron conditions.
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My research interests
include plant ecology
and field botany, plant demography, population and metapopulation ecology and
conservation biology, seed and seedling ecology, evolutionary ecology; desert
ecology; spatial and temporal processes in plant populations with respect to
habitat heterogeneity, climate and disturbance; mechanisms of plant species
interactions, competition and coexistence on individual and community levels,
plant clonality, plant-animal interactions including pollination ecology,
ecological modeling and related fields in plant ecology.
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I obtained BSc. and MS degrees in Biology and
Plant Ecology at the Faculty of Biological
Sciences, University of South Bohemia in České Budějovice, Czech Republic, under supervision
of Prof. Jan Lepš, thesis on population ecology of Pedicularis palustris and P. sylvatica, two rare species
of wet grasslands.
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MS thesis included 4 studies of the effects of experimental
disturbances on microsites and plant demography. Two studies focused on rare Pedicularis
sylvatica in wet meadows in the Czech Republic the other two studies on
several endemic species in xeric scrub communities in inland Florida (advised
by Dr. Eric S. Menges).