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Alexander von Humboldt Anniversary

September 14th 2019 marks 250 years since the birth of explorer-naturalist Alexander von Humboldt. This collection celebrates his life and legacy by bringing together articles on ecology, global change, and geoscience from across six Nature journals.

Organised into four of the major scientific themes of his life, and with a particular focus on Latin America where many of his pioneering ideas were first forged, this collection serves to highlight the highly interdisciplinary nature of his legacy.

An accompanying Editorial highlights how his view of the world as an interconnected system of biological and physical processes changed the way subsequent generations would understand the natural world, and discusses how his influence still lives on in contemporary science.

Biogeography and mountain biodiversity

Explorer-naturalist Alexander von Humboldt’s contributions to the fields of ecology, global change and geoscience fundamentally altered the way we view the natural world and our place in it. On the 250th anniversary of his birth, we look back over his life and compile a collection of articles inspired by his legacy.

Editorial | | Nature Ecology & Evolution

Data from more than 200 million observations of plants, animals and fungi provide support for the concept that terrestrial biodiversity patterns reflect distinct ecoregions.

Article | | Nature Ecology & Evolution

Terrestrial animals can be classified into distinct biogeographic regions, but less is known about what shapes these global boundaries. Here, the authors identify geological and climatic factors that determine the separation of realms through time.

Article | | Nature Ecology & Evolution

Differential responses of plant and animal functional diversity to climatic variation could affect trait matching in mutualistic interactions. Here, Albrecht et al. show that network structure varies across an elevational gradient owing to bottom-up and top-down effects of functional diversity.

Article | Open Access | | Nature Communications

Explaining species richness patterns is a key question in ecology. Peterset al. sample diverse plant and animal groups across elevation on Mt. Kilimanjaro to show that, while disparate factors drive distributions of individual taxa, diversity overall decreases with elevation, mostly driven by effects of temperature.

Article | Open Access | | Nature Communications

Predictions suggest that a high proportion of plant species will be threatened with extinction in the near future. A global assessment of the threat status of cacti suggests that these iconic plants are amongst the most threatened taxonomic groups, with 31% of the 1,478 evaluated species at risk of extinction.

Article | | Nature Plants

Next to the latitudinal biodiversity gradient, the decline in species richness with elevation is one of the most ubiquitous ecological patterns. Yet consensus about the processes that underlie this gradient is lacking. Ignacio Quintero and Walter Jetz examine the evolutionary underpinnings of elevational gradients in bird species richness in the 46 main mountain systems of the world. They find that across all mountain ranges, species richness decreases linearly with elevation, whereas rates of diversification increase. The findings go against the idea that higher diversification rates support the build-up and maintenance of greater species richness at high elevations, and point to the role that ongoing and recent diversification has in maintaining the highly adapted biodiversity of higher elevations.

Letter | | Nature

Interconnected systems and keystone species

Droughts are intensifying under climate change. Research into the resilience of stream food webs to drought now shows that ‘rewiring’ of food web structure in the face of species losses helps to buffer changes to the overall network structure.

Letter | | Nature Climate Change

Physically connected habitats are required for terrestrial species to shift their liveable ranges as the tropics warm. The authors show that over half of tropical forest area is currently unable to provide such climate connectivity, and that loss of connectivity is accelerating with deforestation.

Letter | | Nature Climate Change

The immense biodiversity of tropical ecosystems is threatened by multiple interacting local and global stressors that can only be addressed by the concerted efforts of grassroots organizations, researchers, national governments and the international community.

Review Article | | Nature

Relatively little is understood about seasonal effect of climate change on the Amazon rainforest. Here, the authors show that Amazon forest loss in response to dry-season intensification during the last glacial period was likely self-amplified by regional vegetation-rainfall feedbacks.

Article | Open Access | | Nature Communications

Plant diversity affects ecosystem function in myriad ways, but the effect on food webs has received less investigation. Here, the authors use high-resolution food web data from a grassland diversity experiment to show that apparent and exploitative competition motifs increase with plant diversity.

Article | Open Access | | Nature Communications

Intensifying drought has caused massive die-offs in ecosystems worldwide. Here, Angelini et al.use observations, experiments, and models in US salt marshes to show that a key mutualism increases ecosystem resilience by maintaining stress-resistant habitat patches that aid post-drought recovery.

Article | Open Access | | Nature Communications

Climate change is spatially asymmetrical and so will alter the behaviour of generalist consumer species, affecting food webs in two ways. Movement into novel ecosystems will affect the topology of food webs, while changes within an ecosystem will affect interaction strengths.

Perspective | | Nature Ecology & Evolution

Secondary foundation species, such as epiphytes, form structurally complex habitats on primary foundation species. A meta-analysis shows that they significantly enhance the abundance and richness of inhabitants compared to primary foundation species alone.

Article | | Nature Ecology & Evolution

Land-use and climate change

Industrial mining contributes to deforestation in the Amazon, and the extent of effect could occur beyond areas of land explicitly permitted for mining. Here, Sonter et al. show that deforestation in 70-km buffer zones around mines has led to an estimated 9% of Brazilian Amazon deforestation since 2005.

Article | Open Access | | Nature Communications

Selecting economically viable forest management strategies that deliver carbon storage and biodiversity benefits can be a difficult task. Now, research in the western Andes of Colombia shows that naturally regenerating forests can quickly accumulate carbon and support diverse ecological communities at minimal cost.

Letter | | Nature Climate Change

Palaeoenvironmental analysis reveals the ecological history of the Andean–Amazonian corridor, where European colonization resulted in depopulation, land-use decline and forest succession such that by the nineteenth century the region came to be seen as a pristine natural environment.

Article | | Nature Ecology & Evolution

The Amazon forest both responds to and drives much of the variability in climate and biogeochemistry from annual to millennial time scales. But highly resolved records of past climate variability in the region are hard to come by, and until now it has not been clear whether the Amazon forest was wetter or drier during the Last Glacial Maximum (LGM). Xianfeng Wang et al. have now collected oxygen isotope data covering the past 45,000 years from stalagmite calcite deposits in the Paraíso Cave in eastern Amazonia. Their data show that rainfall was about half that of today during the LGM (around 21,000 years ago) but was some 50% greater during the mid-Holocene (6,000 years ago), broadly coinciding with global changes in temperature and carbon dioxide. Although the Amazon was drier during the glacial period, the rainforest persisted throughout. Whether or not it can be sustained in the future, however, remains an open question.

Letter | | Nature

Volcanoes and geomagnetism

The Altiplano-Puna magma body is located in the world's second highest plateau, the Altiplano-Puna, but the influence of melt production in the surface uplift of the Central Andes is unclear. Perkinset al. link surface topography and isotactic modelling to constrain the melt production in the magma body.

Article | Open Access | | Nature Communications

Oceanic shield volcanoes flank failures can generate large tsunamis. Here, the authors provide evidence that two tsunamis impacted the coast of Tenerife 170 Ma, the first generated by volcano flank failure and the second following a debris avalanche of the edifice during an on-going ignimbrite-forming eruption.

Article | Open Access | | Nature Communications

Rapid and spatially localized geomagnetic field variations around 1000 BC are hard to reconcile with expected field behaviour arising from the core dynamo. Here, the authors show that the intensity spike is consistent with an intense flux patch on the core-mantle boundary (8–22°) located under Saudi Arabia.

Article | Open Access | | Nature Communications

Arc volcanism emits higher metal fluxes to Earth’s atmosphere than hotspot volcanism. The systems’ unique gas compositions are controlled by magmatic water content and redox state, as shown by a compilation of volcanic gas and aerosol metal data.

Article | | Nature Geoscience

Eruptive styles at a single volcano may transition from explosive to effusive behaviour (or vice versa) at any given time. This review examines the underlying controls on eruptive styles such as magma viscosity, degassing and conduit geometry at volcanoes with silicic compositions.

Review Article | Open Access | | Nature Communications