Factors Controlling Germination and Early Survival in Oaks

There is little information available upon the seed and seedling characteristics of the American oaks. Among the fundamental problems in American silviculture, those which relate to seed efficiency are especially important. The future productiveness of the hardwood forests in which chestnut has been an important·element rests largely upon seed and sprout efficiency. Seed efficiency is governed by (I) seed production, (2) seed distribution, and (3) the factors affecting the reproductive value of the seed, such as viability, storage of seed in the litter of the forest floor, and destruction by insects and rodents

Akteurinnen asymmetrischer Konflikte: eine Studie zur nordirischen und palästinensischen Widerstandsgesellschaft

Die Analyse politischer Akteurinnen in Widerstandsgesellschaften beruht auf selbst erhobenem Material. Es ist eine empirische Arbeit, deren Grundlage neben Aufenthalten in den Konfliktgebieten vor allem Interviews mit Akteurinnen bilden. Hinter der Thematik steht sowohl die kritische Auseinandersetzung damit, wie Staaten mit gewaltsamen Herausforderungen umgehen, denen sehr wohl Ungerechtigkeiten zugrunde liegen, als auch damit, wie die davon Betroffenen versuchen, diese zu ihren Gunsten zu ändern und inwieweit ihre Problemdefinitionen und Widerstandsstrategien dafür geeignet sind. Im Anschluss daran erfolgen die Darstellungen der historischen Entwicklungen der Konflikte mit dem Schwerpunkt auf Frauen als Akteurinnen. Die historischen Kontexte und die jeweilige politische Partizipation von Frauen werden dann miteinander verglichen und schließlich die wichtigsten Gemeinsamkeiten und Unterschiede zusammengefasst. Zu den historischen Kontexten zählen dabei neben den politischen Entwicklungen innerhalb der Widerstandsgesellschaften auch ihre sozialen Strukturen, ökonomische Aspekte und solche der Geschlechterverhältnisse, sowie die internationalen Rahmen und kulturellen Deutungsmuster. Die Konfliktdynamik wird verstanden als eine Wechselwirkung zwischen einer Strategie der Konfliktentgrenzung des Widerstandes und die der Begrenzung durch den Staat, wobei beide Strategien Paradoxien erzeugen, die der des Gegners in die Hände spielen. In diesem Kontext werden die Strategien und die Dynamik vorgestellt, ohne die Kategorie Geschlecht zu berücksichtigen. Dies bedeutet, dass die Aussagen der Interviewpartnerinnen verwendet werden, die als typische Aussagen von Angehörigen einer Widerstandsgesellschaft bzw. ihrer Widerstandsgesellschaft gelten können. Resultat dieser Dynamik ist eine Omnipräsenz des Politischen in der Widerstandsgesellschaft, die dem Widerstand zugute kommt - allerdings nur in dem Sinne, dass er sich selbst reproduzieren kann und nicht im Hinblick auf seine angestrebten politischen Ziele. Abschließend werden die geschlechtsspezifischen Aspekte der Strategien und der daraus resultierenden Dynamik thematisiert. Es wird gezeigt, wie Weiblichkeit als politische Ressource des Widerstandes eingesetzt wird, welche Ambivalenzen innerhalb der Widerstandsgesellschaft daraus entstehen und worauf diese zurückzuführen sind. (ICF2

Seedling survival declines with increasing conspecific density in a common temperate tree

Feedbacks between plants and their soil microbial communities often drive negative density dependence in rare, tropical tree species, but their importance to common, temperate trees remains unclear. Additionally, whether negative density dependence is driven by natural enemies (e.g., soil pathogens) or by high densities of seedlings has rarely been assessed. Density dependence may also depend on seedling size, as smaller and/or younger seedlings may be more susceptible to mortality agents. We monitored seedlings of Quercus rubra, a common, canopy‐dominant temperate tree, to investigate how the density of neighboring adults and seedlings influenced their survival over two years. We assessed how the soil microbial community influenced seedling survival by growing seedlings in a glasshouse inoculated with soil collected from beneath conspecific and heterospecific mature trees. In the field, seedling survival was lower in areas with high densities of mature conspecifics but was unrelated to either conspecific or heterospecific seedling density. Smaller seedlings were also more sensitive than larger seedlings to neighboring adult conspecifics. In the glasshouse, seedlings grown with soil from beneath a conspecific adult had a higher mortality rate than seedlings grown with soil from beneath heterospecific adults or sterilized soil, suggesting that soil microbial communities drive the patterns of mortality in the field. These results illustrate the importance of negative density‐dependent feedbacks resulting from the soil microbial community in a common and ecologically important temperate tree species

Simultaneous TE Analysis of 19 Heliconiine Butterflies Yields Novel Insights into Rapid TE-Based Genome Diversification and Multiple SINE Births and Deaths

Transposable elements (TEs) play major roles in the evolution of genome structure and function. However, because of their repetitive nature, they are difficult to annotate and discovering the specific roles they may play in a lineage can be a daunting task. Heliconiine butterflies are models for the study of multiple evolutionary processes including phenotype evolution and hybridization. We attempted to determine how TEs may play a role in the diversification of genomes within this clade by performing a detailed examination of TE content and accumulation in 19 species whose genomes were recently sequenced. We found that TE content has diverged substantially and rapidly in the time since several subclades shared a common ancestor with each lineage harboring a unique TE repertoire. Several novel SINE lineages have been established that are restricted to a subset of species. Furthermore, the previously described SINE, Metulj, appears to have gone extinct in two subclades while expanding to significant numbers in others. This diversity in TE content and activity has the potential to impact how heliconiine butterflies continue to evolve and diverge

Contradictory phylogenetic signals in the laurasiatheria anomaly zone

G.M.H. was funded by a UCD Ad Astra Fellowship. C.L. was funded by a UCD Ad Astra studentship. L.R. was funded by an SFI Centre for Research Training in Genomics Data Science grant (18/CRT/6214). L.M.D. was supported in part by NSF awards 1838273 and 2032063. E.C.T. and T.L. were funded by an SFI Frontiers for the Future Programme grant (19/FFP/6790).Relationships among laurasiatherian clades represent one of the most highly disputed topics in mammalian phylogeny. In this study, we attempt to disentangle laurasiatherian interordinal relationships using two independent genome-level approaches: (1) quantifying retrotransposon presence/absence patterns, and (2) comparisons of exon datasets at the levels of nucleotides and amino acids. The two approaches revealed contradictory phylogenetic signals, possibly due to a high level of ancestral incomplete lineage sorting. The positions of Eulipotyphla and Chiroptera as the first and second earliest divergences were consistent across the approaches. However, the phylogenetic relationships of Perissodactyla, Cetartiodactyla, and Ferae, were contradictory. While retrotransposon insertion analyses suggest a clade with Cetartiodactyla and Ferae, the exon dataset favoured Cetartiodactyla and Perissodactyla. Future analyses of hitherto unsampled laurasiatherian lineages and synergistic analyses of retrotransposon insertions, exon and conserved intron/intergenic sequences might unravel the conflicting patterns of relationships in this major mammalian clade.Publisher PDFPeer reviewe