Spatial heterogeneity and irreversible vegetation change in semi-arid grazing systems

Recent theoretical studies have shown that spatial redistribution of surface water may explain the occurrence of patterns of alternating vegetated and degraded patches in semiarid grasslands. These results implied, however, that spatial redistribution processes cannot explain the collapse of production on coarser scales observed in these systems. We present a spatially explicit vegetation model to investigate possible mechanisms explaining irreversible vegetation collapse on coarse spatial scales. The model results indicate that the dynamics of vegetation on coarse scales are determined by the interaction of two spatial feedback processes. Loss of plant cover in a certain area results in increased availability of water in remaining vegetated patches through run-on of surface water, promoting within-patch plant production. Hence, spatial redistribution of surface water creates negative feedback between reduced plant cover and increased plant growth in remaining vegetation. Reduced plant cover, however, results in focusing of herbivore grazing in the remaining vegetation. Hence, redistribution of herbivores creates positive feedback between reduced plant cover and increased losses due to grazing in remaining vegetated patches, leading to collapse of the entire vegetation. This may explain irreversible vegetation shifts in semiarid grasslands on coarse spatial scales

Do norms unintentionally increase stereotypical expressions? A randomised controlled trial

INTRODUCTION: Implicit biases of health professionals could cause biased judgements. Many anti‐bias interventions seem to be ineffective, and some even counterproductive. People tend to be compliant to standards describing what the majority of people finds or does, and this could cause people to think in a stereotype‐consistent manner. This study examines whether descriptive social norms such as ‘the majority of people have stereotypes’ (majority message), as often stated in interventions, actually increase people's stereotypes. To examine the effect of descriptive social norms (Hypothesis 1) and the effect of individual perceptions and preferences (Hypothesis 2a and 2b) on stereotypical expressions towards medical students. METHODS: First, we determined which ethic stereotypes regarding medical students prevail in Dutch medical education (N = 52). Next, two similar randomised controlled trials, both with teachers and students, were carried out (N = 158 and N = 123, respectively), one with an East Asian student picture (ethnic minority) and one with a native Dutch student picture (ethnic majority). Participants were randomly assigned to either a majority‐message, minority‐message or no‐message condition, and rated the presented minority or majority picture on specific stereotypical features. Subsequently, participants described a typical day of that same student's life. These descriptions were rated for stereotypicality by two independent raters, who were blind for condition and stimulus. Inclusive work environment (IWC) and social dominance orientation (SDO) of participants were measured as indicators of individual perceptions and preferences. RESULTS: Stereotypes were expressed towards both picture stimuli, yet message condition did not affect stereotypical expressions. SDO positively related to stereotypical expressions towards the East Asian student, whereas IWC positively related to stereotypical expressions towards the native Dutch student. CONCLUSION: Interventions do not unintentionally increase stereotypes by communicating what the majority of people thinks or does. Individual perceptions and preferences are predictive of stereotypes, whereas descriptive social norms are not

Looking into the flora of Dutch Brazil: botanical identifications of seventeenth century plant illustrations in the Libri Picturati

Horizon 2020(H2020)ERC Agreement No. 715423Heritage of Indigenous PeoplesPlant science

Revisiting traditional Chinese materia medica from European historical collections and perspective for current use

Background and aim: Chinese Materia Medica (CMM) is subject to changes over time. Investigating changes in botanical ingredients, applications, plant parts used as well as name changes over time, contribute to the understanding of the history and development of CMM. Materials and methods: This study compares four historic collections of CMM, located in Europe, compiled between 1700 and the late 19th century, with a list of contemporary CMM marketed in Europe. Results: More than 1700 specimens within these five collections. The dominant families are Fabaceae (5.3-7.2%) and Asteraceae (4.1-5.7%), while half of the medicinal parts are represented by roots or rhizomes and fruits and/or seeds. Their importance has been stable in a time span of 300 years. The proportion of animal and mineral drugs gradually decreased over time. 14 plant species appeared in all five collections. A total of 47 species are shared between the three more recent collections and the modern trade list. Among these common species, most medicinal parts remain unchanged, but for several species the used plant parts changed or new medicinal plant parts appeared. All common species have unanimously been used in ancient classical TCM formulae and/or Chinese patent medicines. Conclusions: Over more than 300 years, the main body of CMM has hardly changed, with regard to plant taxa and plant parts used. The most prominent changes are related to conservation issues of threatened species, health safety and the discovery of new pharmacological applications of well-known species. Analyzing physical specimens from historic CMM collections complements literature-based research. (c) 2021 Center for Food and Biomolecules, National Taiwan University. Production and hosting by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).NaturalisPlant science

When a fly ball is out of reach: catchability judgments are not based on optical acceleration cancelation.

The optical acceleration cancelation (OAC) strategy, based on Chapman’s (1968) analysis of the outfielder problem, has been the dominant account for the control of running to intercept fly balls approaching head on. According to the OAC strategy, outfielders will arrive at the interception location just in time to catch the ball when they keep optical acceleration zero. However, the affordance aspect of this task, that is, whether or not an approaching fly ball is catchable, is not part of this account. The present contribution examines whether the scope of the OAC strategy can be extended to also include the affordance aspect of running to catch a fly ball. This is done by considering a fielder’s action boundaries (i.e., maximum running velocity and – acceleration) in the context of the OAC strategy. From this, only when running velocity is maximal and optical acceleration is non-zero, a fielder would use OAC to perceive a fly ball as uncatchable. The present contribution puts this hypothesis to the test. Participants were required to try to intercept fly balls projected along their sagittal plane. Some fly balls were catchable whereas others were not. Participants were required to catch as many fly balls as possible and to call ‘no’ when they perceived a fly ball to be uncatchable. Participants’ running velocity and –acceleration at the moment of calling ‘no’ were examined. Results showed that participants’ running velocity was submaximal before or while calling ‘no’. Also running acceleration was often submaximal. These results cannot be explained by the use of OAC in judging catchability and ultimately call for a new strategy of locomotor control in running to catch a fly ball

Scientists’ Warning on Climate Change and Medicinal Plants

The recent publication of a World Scientists’ Warning to Humanity highlighted the fact that climate change, absent strenuous mitigation or adaptation efforts, will have profound negative effects for humanity and other species, affecting numerous aspects of life. In this paper, we call attention to one of these aspects, the effects of climate change on medicinal plants. These plants provide many benefits for human health, particularly in communities where Western medicine is unavailable. As for other species, their populations may be threatened by changing temperature and precipitation regimes, disruption of commensal relationships, and increases in pests and pathogens, combined with anthropogenic habitat fragmentation that impedes migration. Additionally, medicinal species are often harvested unsustainably, and this combination of pressures may push many populations to extinction. A second issue is that some species may respond to increased environmental stresses not only with declines in biomass production but with changes in chemical content, potentially affecting quality or even safety of medicinal products. We therefore recommend actions including conservation and local cultivation of valued plants, sustainability training for harvesters and certification of commercial material, preservation of traditional knowledge, and programs to monitor raw material quality, in addition to, of course, efforts to mitigate climate change

Enhancement of urban pluvial flood risk management and resilience through collaborative modelling: a UK case study

This paper presents the main findings and lessons learned from the development and implementation of a new methodology for collaborative modelling, social learning and social acceptance of flood risk management technologies. The proposed methodology entails three main phases: (1) stakeholder analysis and engagement; (2) improvement of urban pluvial flood modelling and forecasting tools; and (3) development and implementation of web-based tools for collaborative modelling in flood risk management and knowledge sharing. The developed methodology and tools were tested in the Cranbrook catchment (London Borough of Redbridge, UK), an area that has experienced severe pluvial (surface) flooding in the past. The developed methodologies proved to be useful for promoting interaction between stakeholders, developing collaborative modelling and achieving social acceptance of new technologies for flood risk management. Some limitations for stakeholder engagement were identified and are discussed in the present paper

Scientistsʼ warning on climate change and medicinal plants

The recent publication of a World Scientistsʼ Warning to Humanity highlighted the fact that climate change, absent strenuous mitigation or adaptation efforts, will have profound negative effects for humanity and other species, affecting numerous aspects of life. In this paper, we call attention to one of these aspects, the effects of climate change on medicinal plants. These plants provide many benefits for human health, particularly in communities where Western medicine is unavailable. As for other species, their populations may be threatened by changing temperature and precipitation regimes, disruption of commensal relationships, and increases in pests and pathogens, combined with anthropogenic habitat fragmentation that impedes migration. Additionally, medicinal species are often harvested unsustainably, and this combination of pressures may push many populations to extinction. A second issue is that some species may respond to increased environmental stresses not only with declines in biomass production but with changes in chemical content, potentially affecting quality or even safety of medicinal products. We therefore recommend actions including conservation and local cultivation of valued plants, sustainability training for harvesters and certification of commercial material, preservation of traditional knowledge, and programs to monitor raw material quality in addition to, of course, efforts to mitigate climate change

African Rice (Oryza glaberrima Steud.): Lost Crop of the Enslaved Africans Discovered in Suriname1

African Rice (Oryza glaberrimaSteud.): Lost Crop of the Enslaved Africans Discovered in Suriname. African rice (Oryza glaberrima Steud.) was introduced to the Americas during the slave trade years and grown by enslaved Africans for decades before mechanical milling devices facilitated the shift towards Asian rice (O. sativa L.). Literature suggests that African rice is still grown in Guyana and French Guiana, but the most recent herbarium voucher dates from 1938. In this paper, evidence is presented that O. glaberrima is still grown by Saramaccan Maroons both for food and ritual uses. Saramaccan informants claim their forefathers collected their first “black rice” from a mysterious wild rice swamp and cultivated these seeds afterwards. Unmilled spikelets (grains with their husk still attached) are sold in small quantities for ancestor offerings, and even exported to the Netherlands to be used by Maroon immigrants. Little is known of the evolution of O. glaberrima, before and after domestication. Therefore, more research is needed on the different varieties of rice and other “lost crops” grown by these descendants of enslaved Africans who escaped from plantations in the 17th and 18th centuries and maintained much of their African cultural heritage in the deep rainforest