From the Cover: Strong upslope shifts in Chimborazo's vegetation over two centuries since Humboldt

Global climate change is driving species poleward and upward in high-latitude regions, but the extent to which the biodiverse tropics are similarly affected is poorly known due to a scarcity of historical records. In 1802, Alexander von Humboldt ascended the Chimborazo volcano in Ecuador. He recorded the distribution of plant species and vegetation zones along its slopes and in surrounding parts of the Andes. We revisited Chimborazo in 2012, precisely 210 y after Humboldt’s expedition. We documented upward shifts in the distribution of vegetation zones as well as increases in maximum elevation limits of individual plant taxa of >500 m on average. These range shifts are consistent with increased temperatures and glacier retreat on Chimborazo since Humboldt’s study. Our findings provide evidence that global warming is strongly reshaping tropical plant distributions, consistent with Humboldt’s proposal that climate is the primary control on the altitudinal distribution of vegetation.The biological impacts of ongoing climate change (1) are already apparent in species’ poleward and upslope range shifts and earlier spring events (2–9). However, most studies stem from high-latitude areas and are generally restricted to dynamics across the past few decades (10). To our knowledge, only three previous resurveys have studied range shifts of tropical plant taxa, all at <4,000 m in elevation (7, 8, 11). Modeling (12) and paleoecological studies (13) suggest that tropical montane vegetation should be highly sensitive to climate change. However, researchers strongly debate whether tropical plants are tracking warming temperatures along elevation gradients, with most (although scarce) studies indicating they are lagging behind (cf. 14, 15). Such lags could have negative effects on the distributions of species dependent on certain plant taxa, e.g., as a food source (16). The question is particularly urgent given the growing evidence of systematically stronger warming rates in high-mountain environments (17).The legacy and works of Alexander von Humboldt (1769–1859) not only constitute the foundation of biogeography, but also what is likely the oldest dataset on altitudinal ranges of plant species. The observations recorded by Humboldt and Aimé Bonpland (1773–1858) during their travels in Central and South America, and synthesized in a Tableau of Mt. Chimborazo (summit 6,268 m above sea level) and accompanying essay (18), provide a unique opportunity to study tropical vegetation changes over a period of 210 y. To our knowledge, this period is more than twice as long as any previous resurvey study based on historical biodiversity records (11, 19). We revisited the upper slopes of the Chimborazo volcano in June 2012. Our aim was to record the current elevational distribution of plants and test for upward shifts since Humboldt’s expedition, as a response to anthropogenic global warming. We sampled plant species presence and abundance along transects every 100 m of elevation between 3,800 and 5,200 m. Three main findings, comparing our surveys to Humboldt’s data, support strong upward shifts of plant distributions: a higher upper limit for plant growth, increased elevation of vegetation zones, and upward shifts in the upper range limits of most individual taxa.     

Impacts of biodiversity and biodiversity loss on zoonotic diseases

Zoonotic diseases are infectious diseases of humans caused by pathogens that are shared between humans and other vertebrate animals. Previously, pristine natural areas with high biodiversity were seen as likely sources of new zoonotic pathogens, suggesting that biodiversity could have negative impacts on human health. At the same time, biodiversity has been recognized as potentially benefiting human health by reducing the transmission of some pathogens that have already established themselves in human populations. These apparently opposing effects of biodiversity in human health may now be reconcilable. Recent research demonstrates that some taxa are much more likely to be zoonotic hosts than others are, and that these animals often proliferate in human-dominated landscapes, increasing the likelihood of spillover. In less-disturbed areas, however, these zoonotic reservoir hosts are less abundant and nonreservoirs predominate. Thus, biodiversity loss appears to increase the risk of human exposure to both new and established zoonotic pathogens. This new synthesis of the effects of biodiversity on zoonotic diseases presents an opportunity to articulate the next generation of research questions that can inform management and policy. Future studies should focus on collecting and analyzing data on the diversity, abundance, and capacity to transmit of the taxa that actually share zoonotic pathogens with us. To predict and prevent future epidemics, researchers should also focus on how these metrics change in response to human impacts on the environment, and how human behaviors can mitigate these effects. Restoration of biodiversity is an important frontier in the management of zoonotic disease risk.     

Climate change and cancer: converging policies

Intervening on risk factors for noncommunicable diseases (including cancer) in industrialized countries could achieve a reduction of between 30% and 40% of premature deaths. In the meantime, the need to intervene against the threat of climate change has become obvious. CO₂ emissions must be reduced by 45% by the year 2030 and to zero by 2050 according to recent agreements. We propose an approach in which interventions are designed to prevent diseases and jointly mitigate climate change, the so‐called cobenefits. The present article describes some examples of how climate change mitigation and cancer prevention could go hand in hand: tobacco control, food production, and transportation (air pollution). Many others can be identified. The advantage of the proposed approach is that both long‐term (climate) and short‐term (health) benefits can be accrued with appropriate intersectoral policies.

Abbreviations

GHG

greenhouse gases

IARC

International Agency for Research on Cancer

LMICs

low‐ and middle‐income countries

NCD

noncommunicable disease

PMI

Philip Morris International

SDGs

Sustainable Development Goals

UPF

ultraprocessed food

     

Clustered patterns of species origins of nature-derived drugs and clues for future bioprospecting

Many drugs are nature derived. Low drug productivity has renewed interest in natural products as drug-discovery sources. Nature-derived drugs are composed of dozens of molecular scaffolds generated by specific secondary-metabolite gene clusters in selected species. It can be hypothesized that drug-like structures probably are distributed in selective groups of species. We compared the species origins of 939 approved and 369 clinical-trial drugs with those of 119 preclinical drugs and 19,721 bioactive natural products. In contrast to the scattered distribution of bioactive natural products, these drugs are clustered into 144 of the 6,763 known species families in nature, with 80% of the approved drugs and 67% of the clinical-trial drugs concentrated in 17 and 30 drug-prolific families, respectively. Four lines of evidence from historical drug data, 13,548 marine natural products, 767 medicinal plants, and 19,721 bioactive natural products suggest that drugs are derived mostly from preexisting drug-productive families. Drug-productive clusters expand slowly by conventional technologies. The lack of drugs outside drug-productive families is not necessarily the result of under-exploration or late exploration by conventional technologies. New technologies that explore cryptic gene clusters, pathways, interspecies crosstalk, and high-throughput fermentation enable the discovery of novel natural products. The potential impact of these technologies on drug productivity and on the distribution patterns of drug-productive families is yet to be revealed.     

Rootstock effect on serotonin and nutritional quality of tomatoes produced under low temperature and light conditions

In this study, we explored the capacity of different tomato rootstocks to improve the nutritional value of tomatoes grown in a greenhouse during the winter–spring period under low temperature and light conditions. The results showed that relative to nongrafted plants, some grafted rootstocks either did not affect or had detrimental effects on the nutritional parameters measured. In addition, the amount of serotonin was significantly lower in tomatoes from all grafted rootstocks than in tomatoes from the nongrafted plants. Nevertheless, relative to the nongrafted plants, some grafted treatments increased total macroelements (by 1.16 times), total microelements (by 1.43 times), protein content (by 17%), free total and essential amino acids (by respectively 23% and 19%), total phenolic compounds (by 11%), vitamin C (by 13.8%), lycopene (by 48%), and also total hydrocinnamic acids (by 67%) and flavonoids (by 279%). As the grafted treatments did not increase the tomato yield, we hypothesize that these compounds accumulated in the tomatoes due to the lack of increased biomass, which prevented a dilution effect on the compounds of interest in the fruits.     

ADDRESS TO THE INSTITUTE

The fire control problem deals with intensively managed softwood forest areas. The early use of the fire fighting truck in South Australia was associated with good access conditions in plantation areas. Improvement of truck performance in loose sand has been obtained by changes in gear ratio (to low gear of 8 to 1). and the size of wheels (reduced to 18 inches) and tyres (increased to 9 inches). Power pump equipment has changed from plunger pumps of low rate of delivery (5 gallons per minute) to centrifugal pumps, which are driven direct from high speed engines, and have an outlet of up to about 25 gallons pev minute.

The 4-ton truck is the standard fire fighting vehicle. This is equipped with a 500 gallon tank, power pump with outlet through two “live” reels, and a hand pump, all fixed to a steel frame. The latest power pump has a flexible performance, with a range of delivery from 2.5 to 28.8 gallons per minute, and a stream distance up to 80 feel. The assembly of this unit, loading methods and the small equipment of the truck are described.

Smaller trucks arc equipped in accordance with their capacity in the district they have to work. The water supply of the trucks depends on a system of 1,000 gallon overhead tanks, which are located at accessible and strategic places throughout the plantations. The truck tank can be filled from these at a rate of 80 gallons per minute. The gang on the truck usually consists of 8 men, each of whom has special duties.

The fire fighting truck has four main uses. These are the direct suppression of small fires, the holding of a back fire, the provision of water supplies for knapsacks, and mopping up. The scope of the equipment and the methods of its use arc described.

Possible future development of trucks and equipment and the organisation of their use are briefly outlined.     

Cost-effective global conservation spending is robust to taxonomic group

Priorities for conservation investment at a global scale that are based on a single taxon have been criticized because geographic richness patterns vary taxonomically. However, these concerns focused only on biodiversity patterns and did not consider the importance of socioeconomic factors, which must also be included if conservation funding is to be allocated efficiently. In this article, we create efficient global funding schedules that use information about conservation costs, predicted habitat loss rates, and the endemicity of seven different taxonomic groups. We discover that these funding allocation schedules are less sensitive to variation in taxon assessed than to variation in cost and threat. Two-thirds of funding is allocated to the same regions regardless of the taxon, compared with only one-fifth if threat and cost are not included in allocation decisions. Hence, if socioeconomic factors are considered, we can be more confident about global-scale decisions guided by single taxonomic groups.     

Soil animals alter plant litter diversity effects on decomposition

Most of the terrestrial net primary production enters the decomposer system as dead organic matter, and the subsequent recycling of C and nutrients are key processes for the functioning of ecosystems and the delivery of ecosystem goods and services. Although climatic and substrate quality controls are reasonably well understood, the functional role of biodiversity for biogeochemical cycles remains elusive. Here we ask how altering litter species diversity affects species-specific decomposition rates and whether large litter-feeding soil animals control the litter diversity-function relationship in a temperate forest ecosystem. We found that decomposition of a given litter species changed greatly in the presence of litters from other cooccurring species despite unaltered climatic conditions and litter chemistry. Most importantly, soil fauna determined the magnitude and direction of litter diversity effects. Our data show that litter species richness and soil fauna interactively determine rates of decomposition in a temperate forest, suggesting a combination of bottom-up and top-down controls of litter diversity effects on ecosystem C and nutrient cycling. These results provide evidence that, in ecosystems supporting a well developed soil macrofauna community, animal activity plays a fundamental role for altered decomposition in response to changing litter diversity, which in turn has important implications for biogeochemical cycles and the long-term functioning of ecosystems with ongoing biodiversity loss.     

Allee effect promotes diversity in traveling waves of colonization

Most mathematical studies on expanding populations have focused on the rate of range expansion of a population. However, the genetic consequences of population expansion remain an understudied body of theory. Describing an expanding population as a traveling wave solution derived from a classical reaction-diffusion model, we analyze the spatio-temporal evolution of its genetic structure. We show that the presence of an Allee effect (i.e., a lower per capita growth rate at low densities) drastically modifies genetic diversity, both in the colonization front and behind it. With an Allee effect (i.e., pushed colonization waves), all of the genetic diversity of a population is conserved in the colonization front. In the absence of an Allee effect (i.e., pulled waves), only the furthest forward members of the initial population persist in the colonization front, indicating a strong erosion of the diversity in this population. These results counteract commonly held notions that the Allee effect generally has adverse consequences. Our study contributes new knowledge to the surfing phenomenon in continuous models without random genetic drift. It also provides insight into the dynamics of traveling wave solutions and leads to a new interpretation of the mathematical notions of pulled and pushed waves.     

Incorporating plant functional diversity effects in ecosystem service assessments

Global environmental change affects the sustained provision of a wide set of ecosystem services. Although the delivery of ecosystem services is strongly affected by abiotic drivers and direct land use effects, it is also modulated by the functional diversity of biological communities (the value, range, and relative abundance of functional traits in a given ecosystem). The focus of this article is on integrating the different possible mechanisms by which functional diversity affects ecosystem properties that are directly relevant to ecosystem services. We propose a systematic way for progressing in understanding how land cover change affects these ecosystem properties through functional diversity modifications. Models on links between ecosystem properties and the local mean, range, and distribution of plant trait values are numerous, but they have been scattered in the literature, with varying degrees of empirical support and varying functional diversity components analyzed. Here we articulate these different components in a single conceptual and methodological framework that allows testing them in combination. We illustrate our approach with examples from the literature and apply the proposed framework to a grassland system in the central French Alps in which functional diversity, by responding to land use change, alters the provision of ecosystem services important to local stakeholders. We claim that our framework contributes to opening a new area of research at the interface of land change science and fundamental ecology.