Species-specific responses of Late Quaternary megafauna to climate and humans

Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary remain contentious. We use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, underscoring the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.This paper is in the memory of our friend and colleague Dr. Andrei Sher, who was a major contributor of this study. Dr Sher died unexpectedly, but his major contributions to the field of Quaternary science will be remembered and appreciated for many years to come. We are grateful to Dr. Adrian Lister and Dr. Tony Stuart for guides and discussions. Thanks to Tina B. Brandt, Dr. Bryan Hockett and Alice Telka for laboratory help and samples and to L. Malik R. Thrane for his work on the megafauna locality database. Data taken from the Stage 3 project was partly funded by Grant #F/757/A from the Leverhulme Trust, together with a grant from the McDonald Grants and Awards Fund. We acknowledge the Danish National Research Foundation, the Lundbeck Foundation, the Danish Council for Independent Research and the US National Science Foundation for financial suppor

Global patterns in endemicity and vulnerability of soil fungi

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms

Global patterns in endemicity and vulnerability of soil fungi

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms

Influence of Substrate Microstructure on the Transport Properties of CVD-Graphene

We report the study of electrical transport in few-layered CVD-graphene located on nanostructured surfaces in view of its potential application as a transparent contact to optoelectronic devices. Two specific surfaces with a different characteristic feature scale are analyzed: semiconductor micropyramids covered with SiO₂ layer and opal structures composed of SiO₂ nanospheres. Scanning tunneling microscopy (STM) and scanning electron microscopy (SEM), as well as Raman spectroscopy, have been used to determine graphene/substrate surface profile. The graphene transfer on the opal face centered cubic arrangement of spheres with a diameter of 230 nm leads to graphene corrugation (graphene partially reproduces the opal surface profile). This structure results in a reduction by more than 3 times of the graphene sheet conductivity compared to the conductivity of reference graphene located on a planar SiO₂ surface but does not affect the contact resistance to graphene. The graphene transfer onto an organized array of micropyramids results in a graphene suspension. Unlike opal, the graphene suspension on pyramids leads to a reduction of both the contact resistance and the sheet resistance of graphene compared to resistance of the reference graphene/flat SiO₂ sample. The sample annealing is favorable to improve the contact resistance to CVD-graphene; however, it leads to the increase of its sheet resistance

Species-specific responses of Late Quaternary megafauna to climate and humans

Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, emphasizing the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat chang