• Energy Research

Abstract Wood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America.

Since the establishment of the Intergovernmental Panel on Climate Change (IPCC), decision-makers have realised that periodic assessments were needed to closely monitor climate change. Studies on it became widespread and include the science of greenhouse gas emissions, the composition of these gases and the extent to which humans have been responsible for climate change. In this sense, the United Nations summit has made significant progress since the Rio Conference (Eco 92), with the creation of the Conference of the Parties (COPs). However, governments should not solely focus on curbing greenhouse gas emissions into the atmosphere. In a society with broad and deep environmental problems, governments, the private sector and non-governmental organisations’ (NGOs) efforts should include biodiversity conservation in their agenda. Solving a single problem, the climate crisis is honourable and urgently needed, but to constrain our ever-increasing land-use footprints on the planet needs the tackling of another equally challenging problem, the loss of biodiversity. The destruction of ecosystems undermines nature’s ability to regulate greenhouse gas emissions and protect against extreme weather, thus accelerating climate change and increasing our vulnerability to it. Therefore, tackling environmental challenges means more than building electric cars, investing in “clean” energy and imposing fines on those who burn forests. To save the environment, scientists, industry, policy-makers and the wider society urgently need to look at other aspects of ecosystem conservation and restoration in the same way they look at the climate agenda.

Our motivation for writing this editorial is to alert the academic community about the risks of predatory publishing in Biology. By piggy-backing on the open access (OA) movement and taking advantage of the “publish or perish” culture in a system that prioritises quantity over quality, predatory publishing has grown exponentially in recent years and spread across all areas of knowledge. Thousands of predatory journals and books have emerged and (provided a fee is paid) they publish scientific papers and chapters without submitting them to rigorous peer review. Now there are even predatory meetings, which promise to accept talks and publish complete works for a fee, also without reviewing them properly. These profit-making machines can damage both academia and society, putting at risk the quality of science and public trust in it, the well-being of the population, the conservation of biodiversity and the mitigation of climate change. We show the modus operandi behind invitations to contribute to predatory journals, books and meetings and suggest ways to separate the wheat from the chaff. Finally, we discuss the need to create regulatory agencies that perform a careful and systematic evaluation of the activities carried out by publishers.

Elevation creates a variety of physical conditions in a relatively short distance, which makes mountains suitable for studying the effects of climate change on biodiversity. We investigated the importance of climate and vegetation for the distribution of butterflies from 800 to 1400 m elevation. We sampled butterflies, and woody and rosette plants and measured air temperature and humidity, wind speed and gust, and solar radiation. We partitioned diversity to assess the processes underlying community shifts across altitudes - species loss versus replacement. We assessed the strength of the association among butterfly, vegetation, and climate. Butterfly richness and abundance decreased with altitude, and species composition changed along the elevation. Changes in butterfly composition with altitude were mainly through species replacement and by abundance increases in some species being compensated by decreases in others. Since the floristic diversity decreased with altitude due to soil conditions, and butterflies are closely related to their host plants, this could explain species replacement with altitude. Overall, we found a stronger association of butterfly community with vegetation than climate, but plant community and climate were also strongly associated between them. Butterfly richness was more strongly associated with plant richness than with temperature, while the reverse was true for butterfly abundance, which was more strongly associated with temperature than with plant richness. We must consider the complementary roles of resource and conditions in species distribution.