Experimental plant communities develop phylogenetically overdispersed abundance distributions during assembly

The importance of competition between similar species in driving community assembly is much debated. Recently, phylogenetic patterns in species composition have been investigated to help resolve this question: phylogenetic clustering is taken to imply environmental filtering, and phylogenetic overdispersion to indicate limiting similarity between species. We used experimental plant communities with random species compositions and initially even abundance distributions to examine the development of phylogenetic pattern in species abundance distributions. Where composition was held constant by weeding, abundance distributions became overdispersed through time, but only in communities that contained distantly related clades, some with several species (i.e., a mix of closely and distantly related species). Phylogenetic pattern in composition therefore constrained the development of overdispersed abundance distributions, and this might indicate limiting similarity between close relatives and facilitation/complementarity between distant relatives. Comparing the phylogenetic patterns in these communities with those expected from the monoculture abundances of the constituent species revealed that interspecific competition caused the phylogenetic patterns. Opening experimental communities to colonization by all species in the species pool led to convergence in phylogenetic diversity. At convergence, communities were composed of several distantly related but species-rich clades and had overdispersed abundance distributions. This suggests that limiting similarity processes determine which species dominate a community but not which species occur in a community. Crucially, as our study was carried out in experimental communities, we could rule out local evolutionary or dispersal explanations for the patterns and identify ecological processes as the driving force, underlining the advantages of studying these processes in experimental communities. Our results show that phylogenetic relations between species provide a good guide to understanding community structure and add a new perspective to the evidence that niche complementarity is critical in driving community assembly.

Transatlantic Echoes. Alexander von Humboldt in World Literature

Alexander von Humboldt (1769–1859) was a world traveler, bestselling writer, and versatile researcher, a European salon sensation, and global celebrity. Yet the enormous literary echo he generated has remained largely unexplored. Humboldt inspired generations of authors, from Goethe and Byron to Enzensberger and García Márquez, to reflect on cultural difference, colonial ideology, and the relation between aesthetics and science. This collection of one-hundred texts features tales of adventure, travel reports, novellas, memoirs, letters, poetry, drama, screenplays, and even comics—many for the first time in English. The selection covers the foundational myths and magical realism of Latin America, the intellectual independence of Emerson, Thoreau, Poe, and Whitman in the United States, discourses in Imperial, Weimar, Nazi, East, and West Germany, as well as recent films and fiction. This documented source book addresses scholars in cultural and postcolonial studies as well as readers in history and comparative literature.

Cosmos and Colonialism. Alexander von Humboldt in Cultural Criticism

Alexander von Humboldt explored the Spanish Empire on the verge of its collapse (1799–1804). He is the most significant German travel writer and the most important mediator between Europe and the Americas of the nineteenth century. His works integrated knowledge from two dozen domains. Today, he is at the center of debates on imperial discourse, postcolonialism, and globalization. This collection of fifty essays brings together a range of responses, many presented here for the first time in English. Authors from Schiller, Chateaubriand, Sarmiento, and Nietzsche, to Robert Musil, Kurt Tucholsky, Ernst Bloch, and Alejo Carpentier paint the historical background. Essays by contemporary travel writers and recent critics outline the current controversies on Humboldt. The source materials collected here will be indispensable to scholars of German, French, and Latin and North American literature as well as cultural and postcolonial studies, history, art history, and the history of science.

"Fascinating Voids: Alexander von Humboldt and the Myth of Chimborazo"

When Alexander von Humboldt reached the village of Calpi in the Andes on 22 June 1802, he was greeted with reverence and enthusiasm. Triumphal arches adorned with cotton, cloth, and silver decorated his path. The natives performed a dance in festive dress. A singer praised the explorer's expedition, which had departed three years earlier from the Spanish port of La Coruña. Like Odysseus on the isle of the Phaeacians, the traveler listened to a local rhapsodist singing about his heroic deeds. Before his adventure ended, it had already spun a popular myth. This episode, which Humboldt recorded in his diary, occurred at a significant moment. One day later, the “Second Discoverer of America” rose to even greater fame on an excursion marking in more ways than one the climax of his enterprise. Humboldt set out to climb Chimborazo (6,310 m/20,702 ft.), the mountain then thought to be the highest in the world. He was accompanied by the French botanist Aimé Bonpland (1773–1858) and the Creole nobleman and future activist Carlos Montúfar (1780–1816), as well as native guides and assistants. They climbed to heights never reached before, setting a new record and catapulting Humboldt to fame on both continents.