The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody vegetation. There is thus an incomplete understanding of how woody vegetation responds to socio-economic and environmental change.
Deforestation in Africa has been high on the environmental agenda for decades. In a new study published in NatureEcology and Evolution, researchers used a passive microwave Earth observation data set to demonstrate that the realities are more complex.
Ethnobotany: the world natural and cultural heritage of plants
Ethnobotany is a discipline which has advanced with the progress of natural and social sciences. It is a defining behavior of the cultural heritage of social groups, both for its reference to its profits and the human uses of plants. Advances in ethnobotany have enabled the preservation of biodiversity from a natural perspective (genetics, taxonomy, ecosystem, etc.) as well as cultural, such as the preservation of popular knowledge on the world of plants, their management and relation of human societies with plants over the years.Knowing popular uses of plants is essential to discover new medicines and foods, and therefore improve the health and nutrition of many populations. According to Joan Vallès, coordinator of the study and professor of Botany at the University of Barcelona, “lots of drugs and nutraceutical, alimentary, cosmetic products -and others for people’s wellbeing- come from plants. An important amount of these products comes from lore and traditional uses that were maintained over generations of people”.At the moment, only 62 out of the 457 families of angiosperms (flowering plants) and gymnosperms (non-flowering plants) are usually used for their medicinal features. Paclitaxel, an isolated product from the Pacific’s yew (Taxus brevifolia) and also present in the European yew (Taxus baccata), is one of the most cited examples as natural product applied in cancer treatments. Star anise (Ilicium verum), an Asiatic plant known in traditional Chinese medicine, was the base for oseltamivir, the most promising medicine against the avian flu epidemic, identified in a campaign of enthnobotany and pharmacology prospection promoted by the World Health Organization (WHO). With the discovery of artemisinin –derived from the plant Artemisia annua– also used in popular Chinese medicine-, pharmacologist Tu Youyou was distinguished with the Nobel Prize in Medicine (2015).
Knowing popular uses of plants is essential to discover new medicines and foods (image: Lavandula stoechas)
Coincidences in use and thus, in the plants’ traits, can be understood regarding the study of evolutionary and parenting relations (image: Arnica montana)
Omics revolution in ethnobotany
Omics are widening the lines of knowledge in biology, biomedicine and other related areas. New knowledge on molecular phylogeny, for instance, changed the scientific view of taxonomy classification of many living beings.According to Josep Peñuelas, (CSIC-CREAF), awardee of Ramon Margalef in Ecology 2016, “the continuous development of new techniques on metabolomics provides an essential tool to discover a new generation of natural products inspired in the application of the new concept of phylogenetic convergence and ethnobotanical studies”.In the context of ethnobotany, studies on molecular phylogeny enabled creating the concept of enthonotanical convergence, a clear step forward to improve the election of plants of interest. This together with the recent revolution of omics –in particular, genomics and metabolomics –will enable the identification of new potential applications of natural products from plants.“The uses of the same species or similar ones, by human groups belonging to different cultures and which didn’t have contact among them, shows that this knowledge has been acquired independently” says Teresa Garnatge, director of the Botanical Institute of Barcelona. “These plants –says the researcher- which show similar traits (evolutionary convergence), can be also used in a similar way (ethnobotanical convergence)”.
The functional traits of plants in regions of the world with a Mediterranean climate have been shaped to tolerate periods of water deficit. These species are adapted to summer droughts but may not be able to cope with future increases in drought intensity, duration, and/or frequency.
In a new study published in Plant Ecology & Diversity researchers review the mechanisms and traits of drought resistance and recovery of the holm oak (Quercus ilex), which they propose as a model species for Mediterranean-type ecosystems. The aim of the study was to understand the differences and links between the responses of Q. ilex to summer droughts, extreme droughts, and long-term drought experiments. A main goal was to provide an integral picture of drought responses across organizational and temporal scales for identifying the most relevant processes that are likely to contribute to determining the future of Mediterranean vegetation. Evidence from long-term drought experiments showed that acclimation processes from the molecular (e.g. epigenetic changes) to the ecosystem level (e.g. reductions in stand density) mitigate the effects of drought.
Els ecosistemes aquàtics propers a zones densament poblades de tot el món presenten valors molt alts de fòsfor i descompensats entre nitrogen i fòsfor. Això altera el funcionament d’aquests ecosistemes, en dificulta la conservació i redueix la qualitat de l’aigua.
La vida depèn, entre altres coses, de la proporció de nitrogen (N) i fòsfor (P) que hi ha al medi. Normalment hi ha molt més nitrogen disponible que fòsfor, i les espècies han evolucionat per viure en aquestes condicions. Però, si aquesta proporció s’altera, els organismes redueixen la seva capacitat de creixement i manteniment de les funcions vitals.
Un estudi publicat a la revista Ecology Letters, en el que han col·laborat Josep Peñuelas, investigador del CSIC al CREAF, i Jordi Sardans, investigador del CREAF, ha analitzat la proporció de nitrogen i fòsfor en diferents ecosistemes d’aigua dolça del món. Els investigadors han constatat que aquesta proporció s’està alterant en les conques fluvials on l’activitat humana és més intensa i on hi ha més població.
In a new study published in the Nature journal Scientific Reports, researchers have found that soil carbon loss is more sensitive to climate change compared to carbon taken up by plants. In drier regions, soil carbon loss decreased but in wetter regions soil carbon loss increased. This could result in a positive feedback to the atmosphere leading to an additional increase of atmospheric CO2 levels.
Scientists analysed data from seven climate change experiments across Europe to show how European shrubland plant biomass and soil carbon loss is affected by summer drought and year-around warming.
The research was conducted by a group of European and American scientists including Marc Estiarte and Josep Peñuelas from CSIC-CREAF.
The authors showed that soil carbon loss is most responsive to change in soil water. Soil water plays a critical role in wet soils where water logging limits decomposition processes by soil biota resulting in a build-up of soil carbon as peat. Drying of the soil removes this limitation resulting in soil carbon loss. In contrast in drier soils, reduced rainfall reduces soil water below the optimum for soil biota resulting in a decrease in soil carbon loss.