580 Pflanzen (Botanik)
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wo assumptions underlie current models of the geographical ranges of perennial plant species: 1. current ranges are in equilibrium with the prevailing climate, and 2. changes are attributable to changes in macroclimatic factors, including tolerance of winter cold, the duration of the growing season, and water stress during the growing season, rather than to biotic interactions. These assumptions allow model parameters to be estimated from current species ranges. Deterioration of growing conditions due to climate change, e.g. more severe drought, will cause local extinction. However, for many plant species, the predicted climate change of higher minimum temperatures and longer growing seasons means, improved growing conditions. Biogeographical models may under some circumstances predict that a species will become locally extinct, despite improved growing conditions, because they are based on an assumption of equilibrium and this forces the species range to match the species-specific macroclimatic thresholds. We argue that such model predictions should be rejected unless there is evidence either that competition influences the position of the range margins or that a certain physiological mechanism associated with the apparent improvement in growing conditions negatively affects the species performance. We illustrate how a process-based vegetation model can be used to ascertain whether such a physiological cause exists. To avoid potential modelling errors of this type, we propose a method that constrains the scenario predictions of the envelope models by changing the geographical distribution of the dominant plant functional type. Consistent modelling results are very important for evaluating how changes in species areas affect local functional trait diversity and hence ecosystem functioning and resilience, and for inferring the implications for conservation management in the face of climate change.
Background: The European beech is arguably the most important climax broad-leaved tree species in Central Europe, widely planted for its valuable wood. Here, we report the 542 Mb draft genome sequence of an up to 300-year-old individual (Bhaga) from an undisturbed stand in the Kellerwald-Edersee National Park in central Germany.
Findings: Using a hybrid assembly approach, Illumina reads with short- and long-insert libraries, coupled with long Pacific Biosciences reads, we obtained an assembled genome size of 542 Mb, in line with flow cytometric genome size estimation. The largest scaffold was of 1.15 Mb, the N50 length was 145 kb, and the L50 count was 983. The assembly contained 0.12% of Ns. A Benchmarking with Universal Single-Copy Orthologs (BUSCO) analysis retrieved 94% complete BUSCO genes, well in the range of other high-quality draft genomes of trees. A total of 62,012 protein-coding genes were predicted, assisted by transcriptome sequencing. In addition, we are reporting an efficient method for extracting high-molecular-weight DNA from dormant buds, by which contamination by environmental bacteria and fungi was kept at a minimum.
Conclusions: The assembled genome will be a valuable resource and reference for future population genomics studies on the evolution and past climate change adaptation of beech and will be helpful for identifying genes, e.g., involved in drought tolerance, in order to select and breed individuals to adapt forestry to climate change in Europe. A continuously updated genome browser and download page can be accessed from beechgenome.net, which will include future genome versions of the reference individual Bhaga, as new sequencing approaches develop.
Die Bestände des in Deutschland stark gefährdeten Sand-Zwerggrases Mibora minima, für deren Erhalt das Land Hessen eine besondere Verantwortung trägt, gehen seit vielen Jahren zurück. In dieser Arbeit wurden als Beitrag zum Artenhilfsprogramm der Botanischen Vereinigung für Naturschutz in Hessen (BVNH) die noch vorhandenen Populationen erfasst sowie die botanischen und edaphischen Gegebenheiten an den Standorten untersucht. Dabei wurde durch Vergleich von Flächen mit und ohne Bewuchs des Zwerggrases der Frage nachgegangen, ob und inwieweit die Verbreitung der Art durch die Beschaffenheit und Nährstoffversorgung des Bodens bestimmt wird. Es wurde ein weiterer deutlicher Rückgang der südhessischen Populationen um etwa 60 % seit 1999 festgestellt, der am stärksten die Standorte um Mörfelden-Walldorf betrifft. Dagegen haben sich die Bestände bei Rüsselsheim-Königstädten möglicherweise durch Pflegemaßnahmen stabilisiert. Ein bestimmender Einfluss edaphischer Parameter auf die Verteilung der Art innerhalb der kalkfreien Flugsande konnte nicht festgestellt werden. Der indigene floristische Status der Art wird in Frage gestellt und stattdessen ihre Einstufung als Epökophyt westmediterraner Herkunft angenommen.