Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

A new species of Afrothismia (Burmanniaceae; tribe: Thismieae) from the western foothills of Mount Cameroon

Afrothismia foertheriana, a new species of Burmanniaceae (tribe: Thismieae) from the peripheral zone of the Onge Forest Reserve in Cameroon’s Southwest Province is described and illustrated. The papillose, multicellular floral trichomes, the tepal’s erose margins, the small, zygomorphic perianth mouth and the dull purplish brown coloration give A. foertheriana a distinctive appearance within the genus. The species is here assessed as being critically endangered

Wild meat consumption in urban Sierra Leone during the Covid-19 pandemic

Wild meat is associated with an increased risk of zoonotic diseases. In some West African countries wild meat consumption declined as the result of official restrictions following Ebola outbreaks during 2013–2016, and was also affected by the current Covid-19 pandemic. In Sierra Leone, a country affected by these diseases, we documented wild meat use in four markets in the capital, Freetown. From a total of 197 interviews, we analysed the influence of age and gender on the types of wild meat eaten and the reasons for their consumption. We found that more men than women consumed wild meat, and for both genders taste was the main reason for eating wild meat. Age did not affect wild meat consumption amongst women. Evidence for changes in consumer behaviour in response to zoonotic disease risk was mixed. Although some consumers avoided wild meat because of disease risk, none stated this was the primary reason for not eating wild meat, and monkeys (presumed to carry a high zoonotic disease risk) were amongst the species cited as being consumed often. More work is needed to identify the best pathway towards safe and sustainable consumption of wild meat in urban Sierra Leone

Mapping species richness of plant families in European vegetation

Aims Biodiversity is traditionally studied mostly at the species level, but biogeographical and macroecological studies at higher taxonomic levels can provide valuable insights into the evolutionary processes at large spatial scales. Our aim was to assess the representation of vascular plant families within different vegetation formations across Europe. Location Europe. Methods We used a data set of 816,005 vegetation plots from the European Vegetation Archive (EVA). For each plot, we calculated the relative species richness of each plant family as the number of species belonging to that family divided by the total number of species. We mapped the relative species richness, averaged across all plots in 50 km × 50 km grid cells, for each family and broad habitat groups: forests, grasslands, scrub and wetlands. We also calculated the absolute species richness and the Shannon diversity index for each family. Results We produced 522 maps of mean relative species richness for a total of 152 vascular plant families occurring in forests, grasslands, scrub and wetlands. We found distinct spatial patterns for many combinations of families and habitat groups. The resulting series of 522 maps is freely available, both as images and GIS layers. Conclusions The distinct spatial patterns revealed in the maps suggest that the relative species richness of plant families at the community level reflects the evolutionary history of individual families. We believe that the maps and associated data can inspire further biogeographical and macroecological studies and strengthen the ongoing integration of phylogenetic, functional and taxonomic diversity concepts