@article{LachmuthHenrichmannHornetal.2017, author = {Lachmuth, Susanne and Henrichmann, Colette and Horn, Juliane and Pagel, J{\"o}rn and Schurr, Frank M.}, title = {Neighbourhood effects on plant reproduction}, series = {The journal of ecology}, volume = {106}, journal = {The journal of ecology}, number = {2}, publisher = {Wiley}, address = {Hoboken}, issn = {0022-0477}, doi = {10.1111/1365-2745.12816}, pages = {761 -- 773}, year = {2017}, abstract = {Density dependence is of fundamental importance for population and range dynamics. Density-dependent reproduction of plants arises from competitive and facilitative plant-plant interactions that can be pollination independent or pollination mediated. In small and sparse populations, conspecific density dependence often turns from negative to positive and causes Allee effects. Reproduction may also increase with heterospecific density (community-level Allee effect), but the underlying mechanisms are poorly understood and the consequences for community dynamics can be complex. Allee effects have crucial consequences for the conservation of declining species, but also the dynamics of range edge populations. In invasive species, Allee effects may slow or stop range expansion. Observational studies in natural plant communities cannot distinguish whether reproduction is limited by pollination-mediated interactions among plants or by other neighbourhood effects (e.g. competition for abiotic resources). Even experimental pollen supply cannot distinguish whether variation in reproduction is caused by direct density effects or by plant traits correlated with density. Finally, it is unknown over which spatial scales pollination-mediated interactions occur. To circumvent these problems, we introduce a comprehensive experimental and analytical framework which simultaneously (1) manipulates pollen availability and quality by hand pollination and pollinator exclusion, (2) manipulates neighbourhoods by transplanting target plants, and (3) analyses the effects of con- and heterospecific neighbourhoods on reproduction with spatially explicit trait-based neighbourhood models. Synthesis. By manipulating both pollen availability and target plant locations within neighbourhoods, we can comprehensively analyse spatially explicit density dependence of plant reproduction. This experimental approach enhances our ability to understand the dynamics of sparse populations and of species geographical ranges.}, language = {en} } @article{RadchukDeLaenderCabraletal.2019, author = {Radchuk, Viktoriia and De Laender, Frederik and Cabral, Juliano Sarmento and Boulangeat, Isabelle and Crawford, Michael Scott and Bohn, Friedrich and De Raedt, Jonathan and Scherer, Cedric and Svenning, Jens-Christian and Thonicke, Kirsten and Schurr, Frank M. and Grimm, Volker and Kramer-Schadt, Stephanie}, title = {The dimensionality of stability depends on disturbance type}, series = {Ecology letters}, volume = {22}, journal = {Ecology letters}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {1461-023X}, doi = {10.1111/ele.13226}, pages = {674 -- 684}, year = {2019}, abstract = {Ecosystems respond in various ways to disturbances. Quantifying ecological stability therefore requires inspecting multiple stability properties, such as resistance, recovery, persistence and invariability. Correlations among these properties can reduce the dimensionality of stability, simplifying the study of environmental effects on ecosystems. A key question is how the kind of disturbance affects these correlations. We here investigated the effect of three disturbance types (random, species-specific, local) applied at four intensity levels, on the dimensionality of stability at the population and community level. We used previously parameterized models that represent five natural communities, varying in species richness and the number of trophic levels. We found that disturbance type but not intensity affected the dimensionality of stability and only at the population level. The dimensionality of stability also varied greatly among species and communities. Therefore, studying stability cannot be simplified to using a single metric and multi-dimensional assessments are still to be recommended.}, language = {en} }