TY - JOUR A1 - Heger, Tina A1 - Nikles, Gabriele A1 - Jacobs, Brooke S. T1 - Differentiation in native as well as introduced ranges BT - germination reflects mean and variance in cover of surrounding vegetation JF - AoB PLANTS N2 - Germination, a crucial phase in the life cycle of a plant, can be significantly influenced by competition and facilitation. The aim of this study was to test whether differences in cover of surrounding vegetation can lead to population differentiation in germination behaviour of an annual grassland species, and if so, whether such a differentiation can be found in the native as well as in the introduced range. We used maternal progeny of Erodium cicutarium previously propagated under uniform conditions that had been collected in multiple populations in the native and two introduced ranges, in populations representing extremes in terms of mean and variability of the cover of surrounding vegetation. In the first experiment, we tested the effect of germination temperature and mean cover at the source site on germination, and found interlinked effects of these factors. In seeds from one of the introduced ranges (California), we found indication for a 2-fold dormancy, hindering germination at high temperatures even if physical dormancy was broken and water was available. This behaviour was less strong in high cover populations, indicating cross-generational facilitating effects of dense vegetation. In the second experiment, we tested whether spatial variation in cover of surrounding vegetation has an effect on the proportion of dormant seeds. Contrary to our expectations, we found that across source regions, high variance in cover was associated with higher proportions of seeds germinating directly after storage. In all three regions, germination seemed to match the local environment in terms of climate and vegetation cover. We suggest that this is due to a combined effect of introduction of preadapted genotypes and local evolutionary processes. KW - Bet-hedging KW - competition KW - eco-evolutionary experience KW - facilitation KW - genetic adaptation KW - physical and physiological dormancy KW - preadaptation Y1 - 2018 U6 - https://doi.org/10.1093/aobpla/ply009 SN - 2041-2851 VL - 10 IS - 1 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Latimer, Andrew M. A1 - Jacobs, Brooke S. A1 - Gianoli, Ernesto A1 - Heger, Tina A1 - Salgado-Luarte, Cristian T1 - Parallel functional differentiation of an invasive annual plant on two continents JF - AoB PLANTS N2 - Rapid local adaptation frequently occurs during the spread of invading species. It remains unclear, however, how consistent, and therefore potentially predictable, such patterns of local adaptation are. One approach to this question is to measure patterns of local differentiation in functional traits and plasticity levels in invasive species in multiple regions. Finding consistent patterns of local differentiation in replicate regions suggests that these patterns are adaptive. Further, this outcome indicates that the invading species likely responds predictably to selection along environmental gradients, even though standing genetic variation is likely to have been reduced during introduction. We studied local differentiation in the invasive annual plant Erodium cicutarium in two invaded regions, California and Chile. We collected seeds from across strong gradients in precipitation and temperature in Mediterranean-climate parts of the two regions (10 populations per region). We grew seeds from maternal families from these populations through two generations and exposed the second generation to contrasting levels of water and nutrient availability. We measured growth, flowering time and leaf functional traits across these treatments to obtain trait means and plasticity measures. We found strong differentiation among populations in all traits. Plants from drier environments flowered earlier, were less plastic in flowering time and reached greater size in all treatments. Correlations among traits within regions suggested a coordinated evolutionary response along environmental gradients associated with growing season length. There was little divergence in traits and trait intercorrelations between regions, but strongly parallel divergence in traits within regions. Similar, statistically consistent patterns of local trait differentiation across two regions suggest that local adaptation to environmental gradients has aided the spread of this invasive species, and that the formation of ecotypes in newly invaded environments has been relatively consistent and predictable. KW - Erodium cicutarium KW - flowering time KW - functional trait correlations KW - invasive species KW - life-history strategy KW - local adaptation KW - parallel evolution KW - phenotypic plasticity Y1 - 2019 U6 - https://doi.org/10.1093/aobpla/plz010 SN - 2041-2851 VL - 11 IS - 2 PB - Oxford University Press CY - Oxford ER - TY - GEN A1 - Heger, Tina A1 - Nikles, Gabriele A1 - Jacobs, Brooke S. T1 - Differentiation in native as well as introduced ranges BT - germination reflects mean and variance in cover of surrounding vegetation T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Germination, a crucial phase in the life cycle of a plant, can be significantly influenced by competition and facilitation. The aim of this study was to test whether differences in cover of surrounding vegetation can lead to population differentiation in germination behaviour of an annual grassland species, and if so, whether such a differentiation can be found in the native as well as in the introduced range. We used maternal progeny of Erodium cicutarium previously propagated under uniform conditions that had been collected in multiple populations in the native and two introduced ranges, in populations representing extremes in terms of mean and variability of the cover of surrounding vegetation. In the first experiment, we tested the effect of germination temperature and mean cover at the source site on germination, and found interlinked effects of these factors. In seeds from one of the introduced ranges (California), we found indication for a 2-fold dormancy, hindering germination at high temperatures even if physical dormancy was broken and water was available. This behaviour was less strong in high cover populations, indicating cross-generational facilitating effects of dense vegetation. In the second experiment, we tested whether spatial variation in cover of surrounding vegetation has an effect on the proportion of dormant seeds. Contrary to our expectations, we found that across source regions, high variance in cover was associated with higher proportions of seeds germinating directly after storage. In all three regions, germination seemed to match the local environment in terms of climate and vegetation cover. We suggest that this is due to a combined effect of introduction of preadapted genotypes and local evolutionary processes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 650 KW - bet-hedging KW - competition KW - eco-evolutionary experience KW - facilitation KW - genetic adaptation KW - physical and physiological dormancy KW - preadaptation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-424642 SN - 1866-8372 IS - 650 ER -