TY - GEN A1 - Wagner, Markus A1 - Pywell, Richard F. A1 - Knopp, Tatjana A1 - Bullock, James M. A1 - Heard, Matthew S. T1 - The germination niches of grassland species targeted for restoration BT - effects of seed pre-treatments T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Restoration of semi-natural grassland communities involves a combination of (1) sward disturbance to create a temporal window for establishment, and (2) target species introduction, the latter usually by seed sowing. With great regularity, particular species establish only poorly. More reliable establishment could improve outcome of restoration projects and increase cost-effectiveness. We investigated the abiotic germination niche of ten poorly establishing calcareous grassland species by simultaneously exploring the effects of moisture and light availability and temperature fluctuation on percentage germina- tion and speed of germination. We also investigated the effects of three different pre-treatments used to enhance seed germination – cold-stratification, osmo- tic priming and priming in combination with gibberellic acid (GA 3 ) – and how these affected abiotic germination niches. Species varied markedly in width of abiotic germination niche, ranging from Carex flacca with very strict abiotic requirements, to several species reliably germinating across the whole range of abiotic conditions. Our results suggest pronounced differ- ences between species in gap requirements for establishment. Germination was improved in most species by at least one pre-treatment. Evidence for positive effects of adding GA 3 to seed priming solutions was limited. In several species, pre-treated seeds germinated under a wider range of abiotic conditions than untreated seeds. Improved knowledge of species-specific germination niches and the effects of seed pre-treatments may help to improve species establishment by sowing, and to identify species for which sowing at a later stage of restoration or introduction as small plants may represent a more viable strategy. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 675 KW - abiotic germination niche KW - calcareous grassland species KW - cold-stratification KW - osmotic seed priming KW - seed sowing KW - temperature fluctuation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413438 SN - 1866-8372 IS - 675 SP - 117 EP - 131 ER - TY - JOUR A1 - Risbey, James S. A1 - Lewandowsky, Stephan A1 - Cowtan, Kevin A1 - Oreskes, Naomi A1 - Rahmstorf, Stefan A1 - Jokimäki, Ari A1 - Foster, Grant T1 - A fluctuation in surface temperature in historical context BT - reassessment and retrospective on the evidence JF - Environmental research letters N2 - This work reviews the literature on an alleged global warming 'pause' in global mean surface temperature (GMST) to determine how it has been defined, what time intervals are used to characterise it, what data are used to measure it, and what methods used to assess it. We test for 'pauses', both in the normally understood meaning of the term to mean no warming trend, as well as for a 'pause' defined as a substantially slower trend in GMST. The tests are carried out with the historical versions of GMST that existed for each pause-interval tested, and with current versions of each of the GMST datasets. The tests are conducted following the common (but questionable) practice of breaking the linear fit at the start of the trend interval ('broken' trends), and also with trends that are continuous with the data bordering the trend interval. We also compare results when appropriate allowance is made for the selection bias problem. The results show that there is little or no statistical evidence for a lack of trend or slower trend in GMST using either the historical data or the current data. The perception that there was a 'pause' in GMST was bolstered by earlier biases in the data in combination with incomplete statistical testing. KW - climate variability KW - climate trends KW - temperature fluctuation KW - pause hiatus Y1 - 2018 U6 - https://doi.org/10.1088/1748-9326/aaf342 SN - 1748-9326 VL - 13 IS - 12 PB - IOP Publ. Ltd. CY - Bristol ER - TY - GEN A1 - Risbey, James S. A1 - Lewandowsky, Stephan A1 - Cowtan, Kevin A1 - Oreskes, Naomi A1 - Rahmstorf, Stefan A1 - Jokimäki, Ari A1 - Foster, Grant T1 - A fluctuation in surface temperature in historical context BT - reassessment and retrospective on the evidence T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - This work reviews the literature on an alleged global warming 'pause' in global mean surface temperature (GMST) to determine how it has been defined, what time intervals are used to characterise it, what data are used to measure it, and what methods used to assess it. We test for 'pauses', both in the normally understood meaning of the term to mean no warming trend, as well as for a 'pause' defined as a substantially slower trend in GMST. The tests are carried out with the historical versions of GMST that existed for each pause-interval tested, and with current versions of each of the GMST datasets. The tests are conducted following the common (but questionable) practice of breaking the linear fit at the start of the trend interval ('broken' trends), and also with trends that are continuous with the data bordering the trend interval. We also compare results when appropriate allowance is made for the selection bias problem. The results show that there is little or no statistical evidence for a lack of trend or slower trend in GMST using either the historical data or the current data. The perception that there was a 'pause' in GMST was bolstered by earlier biases in the data in combination with incomplete statistical testing. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1023 KW - climate variability KW - climate trends KW - temperature fluctuation KW - pause hiatus Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468041 SN - 1866-8372 VL - 13 IS - 1023 ER -