Indigenous uses of wild and tended plant biodiversity maintain ecosystem services in agricultural landscapes of the Terai Plains of Nepal

BACKGROUND: Despite a rapidly accumulating evidence base quantifying ecosystem services, the role of biodiversity in the maintenance of ecosystem services in shared human-nature environments is still understudied, as is how indigenous and agriculturally dependent communities perceive, use, and manage biodiversity. The present study aims to document traditional ethnobotanical knowledge of the ecosystem service benefits derived from wild and tended plants in rice-cultivated agroecosystems, compare this to botanical surveys, and analyze the extent to which ecosystem services contribute social-ecological resilience in the Terai Plains of Nepal. METHOD: Sampling was carried out in four landscapes, 22 Village District Committees, and 40 wards in the monsoon season. Data collection was based on transects walks to collect plant specimens, structured and semi-structured interviews, and participatory fieldwork in and around home gardens, farms, and production landscapes. We asked 180 farmers to free-list vernacular names and describe use-value of wild and tended plants in rice-cultivated agroecosystems. Uses were categorized into eight broad groupings, and 61 biomedical ailment classifications. We assessed if knowledge of plant species diversity and abundance differed with regard to caste, age, and gender. RESULTS: Nepalese farmers have a deep knowledge of the use and management of the 391 vascular plant specimens identified, which provide key provisioning, regulating, supporting, and cultural ecosystem services. Altogether, plants belong to 76 distinct plant species from 49 phylogenetic families: 56 are used to cure 61 ailments, 27 for rituals, 25 for food, 20 for timber, 17 for fuel, 17 for fodder, 11 for soil enhancement, and eight for pesticides. Four caste groups have statistically different knowledge, and younger informants report a lower average number of useful plants. CONCLUSION: Agricultural landscapes in Nepal are reservoirs of biodiversity. The knowledge of the use of wild and tended plant species in and around these farms differs by the caste and age group of land manager. Conducting research on agroecosystems will contribute to a deeper understanding of how nature is perceived by locals, to more efficient management and conservation of the breadbasket of Nepal, and to the conservation of valuable, but disappearing traditional knowledge and practice

Radiometer for the Investigation of Infrared Emissions from Flames and Rocket Plumes

A prototypical radiometer using standard one inch interference filters and a lead selenide detector was constructed for use in flame and rocket plume studies. This radiometer was designed to employ a 600 Hz chopper and chopper frequency/phase reference circuit for signal processing. Bandpass filters centered for either 2.7 mum or 4.45 mum were placed in the optical path. The passed carbon dioxide or water vapor band energy irradiated the lead selenide detector, resulting in an output voltage. This signal was then fed into a dedicated synchronous detector. The signal was then recorded by a computer system equipped with an analog-to-digital converter board. Infrared emission data was collected from two inch rocket motors and from a special burner based flame

Can Regenerative Agriculture increase national soil carbon stocks? : Simulated country scale adoption of reduced tillage, cover cropping, and ley-arable integration using RothC

ACKNOWLEDGMENTS We would like to thank Dr Andrew C. Martin for advice on our modelling framework. The authors would like to acknowledge the use of the University of Oxford Advanced Research Computing facility in carrying out this work. This work was supported by funding from the Biotechnology and Biological Sciences Research Council (BBSRC) [grant number BB/M011224/1]. PCB would like to acknowledge funding by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy [EXC 2075 – 390740016]. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Peer reviewedPostprin

Temperate Regenerative Agriculture practices increase soil carbon but not crop yield—a meta-analysis

We would like to thank R D Armstrong, S J Crittenden, J Deru, B Dumont, J Eriksen, C Garbisu, A Jacobs, T Kautz, H J Koch, B Mary, J Peigne and F Schulz for responding to requests for additional information on their studies, and Leo Petrokofsky for generating the online evidence map. Funding Information: This work was supported by funding from the Biotechnology and Biological Sciences Research Council (BBSRC) (Grant No. BB/M011224/1). PCB would like to acknowledge funding by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy (EXC 2075–390740016). Publisher Copyright: © 2022 The Author(s). Published by IOP Publishing Ltd.Peer reviewedPublisher PD

Past vegetation dynamics to infer holocene climate changes in Tenerife and La Gomera, Canary Islands

Oceanic islands in the low latitudes, as the Canary Islands, are generally considered to have been well buffered from the climate change of the Quaternary period. However, questions remain about whether past climatic changes on Atlantic islands are synchronic with those occurring in Africa and the Mediterranean coast or if the climate remained stable during the Holocene. Here we used fossil pollen and charcoal time series on Tenerife and La Gomera in order to: 1) provide the first inter-island picture of vegetation dynamics through the last 9600 years of this important biodiverse region of Europe; 2) detect the vegetation sensitivity, mainly tree communities, to past climatic changes; and, 3) provide evidences for human-induced changes at this potentially highly informative point. Preliminary analyses suggest very little climate change for the period 4000 years to present, but this requires confirmation by reference to additional coring sites. In La Gomera, we found strong evidences of a shift towards drier conditions at around 5500 years ago. The general vegetation pattern observed was a decrease in hygrophilous trees (Canarian palm and willow) and an expansion of Morella-Erica woody heath. Our results provide the first evidence to suggest that the general Northern Africa and Mediterranean shift towards drier conditions may be traced in the Canary Islands

Can Regenerative Agriculture increase national soil carbon stocks? Simulated country-scale adoption of reduced tillage, cover cropping, and ley-arable integration using RothC

Adopting Regenerative Agriculture (RA) practices on temperate arable land can increase soil organic carbon (SOC) concentration without reducing crop yields. RA is therefore receiving much attention as a climate change mitigation strategy. However, estimating the potential change in national soil carbon stocks following adoption of RA practices is required to determine its suitability for this. Here, we use a well-validated model of soil carbon turnover (RothC) to simulate adoption of three regenerative practices (cover cropping, reduced tillage intensity and incorporation of a grass-based ley phase into arable rotations) across arable land in Great Britain (GB). We develop a modelling framework which calibrates RothC using studies of these measures from a recent systematic review, estimating the proportional increase in carbon inputs to the soil compared to conventional practice, before simulating adoption across GB. We find that cover cropping would on average increase SOC stocks by 10 t·ha−1 within 30 years of adoption across GB, potentially sequestering 6.5 megatonnes of carbon dioxide per year (MtCO2·y−1). Ley-arable systems could increase SOC stocks by 3 or 16 t·ha−1, potentially providing 2.2 or 10.6 MtCO2·y−1 of sequestration over 30 years, depending on the length of the ley-phase (one and four years, respectively, in these scenarios). In contrast, our modelling approach finds little change in soil carbon stocks when practising reduced tillage intensity. Our results indicate that adopting RA practices could make a meaningful contribution to GB agriculture reaching net zero greenhouse gas emissions despite practical constraints to their uptake

Antiguos bosques de las Islas Canarias: métodos y técnicas para la reconstrucción de la vegetación

La Paleoecología es el estudio de las relaciones entre los organismos del pasado y los ambientes en los que vivían, mediante el análisis de fósiles y de los sedimentos en los que dichos fósiles se han preservado (Birks y Birks, 1980). Los fósiles son restos de organismos del pasado o indicadores de su actividad que se preservan con el paso del tiempo. Los fósiles de origen vegetal, en particular, se utilizan para reconstruir la vegetación del pasado y para determinarla influencia que los factores geológicos, climáticos, bióticos o antrópicos han tenido sobre las comunidades vegetales a lo largo del tiempo. Existen numerosos tipos de restos vegetales que pueden encontrarse en secuencias sedimentarias y que sirven para identificar las especies vegetales que habitaban en una determinada zona en el pasado. De acuerdo con su tamaño podemos diferenciar los macrofósiles vegetales, es decir aquellos que pueden ser identificados bajo la lupa (hojas, flores, frutos, semillas, maderas, carbones, etc.) y los microfósiles vegetales (granos de polen, esporas de helechos y briófitos, fitolitos, diatomeas, etc.), cuyo tamaño es tan pequeño que necesitan ser observados al microscopio. Otros fósiles de origen vegetal se pueden utilizar como indicadores de incendios ocurridos en el pasado (carbones, esporas de hongos asociadas a materiales quemados), o indicadores que proliferan como resultado de las actividades humanas,por ejemplo con la eutrofización de lagos (algas), la presencia de herbívoros domésticos (esporas fúngicas), o el incremento de incendios (carbones), además de indicadores de cambios en las propiedades físico-químicas de los lagos como resultado de cambios climáticos (diatomeas, algas)(Smol et al., 2001). Junto con los indicadores fósiles se suelen utilizar otros indicadores paleoambientales que implican el estudio de la propiedades físicas y químicas de los sedimentos. Los análisis geoquímicos indican procesos de erosión, alternancia de periodos húmedos y secos, o variaciones en los niveles de ciertos elementos químicos que a su vez pueden relacionarse con la contaminación antrópica. Las medidas de la susceptibilidad magnética detectan variabilidad en los procesos erosivos, y pueden asociarse a modificaciones de la cobertura vegetal o a determinados fenómenos climáticos. Otra propiedad de los sedimentos es la proporción de isótopos estables, que puede usarse como indicador de la temperatura del pasado, la aridez, y la concentración de CO2 atmosférico (Anderson et al., 2007). Por último, es esencial proveer de un marco temporal a las secuencias que contienen los fósiles para poder interpretar los procesos ambientales de forma ordenada en el tiempo. Para ello se aplican diferentes métodos de datación (datación radiométrica, paleomagnetismo, termoluminiscencia, o bioestratigrafía), dependiendo del material y del periodo de edad aproximado que se pretenda datar. La técnica más utilizada para el Holoceno (los últimos 11500 años de historia de La Tierra) es la datación por radiocarbono, basada en la tasa de descomposición radiactiva del carbono-14 (14C)que se encuentra en todos los organismos vivos (Roberts, 1998), y que se puede aplicar sobre materiales diversos (madera, carbones, semillas, huesos, dientes, conchas, fibras vegetales, etc.

Stability in Ecosystem Functioning across a Climatic Threshold and Contrasting Forest Regimes

Classical ecological theory predicts that changes in the availability of essential resources such as nitrogen should lead to changes in plant community composition due to differences in species-specific nutrient requirements. What remains unknown, however, is the extent to which climate change will alter the relationship between plant communities and the nitrogen cycle. During intervals of climate change, do changes in nitrogen cycling lead to vegetation change or do changes in community composition alter the nitrogen dynamics? We used long-term ecological data to determine the role of nitrogen availability in changes of forest species composition under a rapidly changing climate during the early Holocene (16k to 8k cal. yrs. BP). A statistical computational analysis of ecological data spanning 8,000 years showed that secondary succession from a coniferous to deciduous forest occurred independently of changes in the nitrogen cycle. As oak replaced pine under a warming climate, nitrogen cycling rates increased. Interestingly, the mechanism by which the species interacted with nitrogen remained stable across this threshold change in climate and in the dominant tree species. This suggests that changes in tree population density over successional time scales are not driven by nitrogen availability. Thus, current models of forest succession that incorporate the effects of available nitrogen may be over-estimating tree population responses to changes in this resource, which may result in biased predictions of future forest dynamics under climate warming

Exploring the Ecological History of a Tropical Agroforestry Landscape Using Fossil Pollen and Charcoal Analysis from Four Sites in Western Ghats, India

Contrary to expectations, some human-modified landscapes are considered to sustain both human activities and biodiversity over the long-term. Agroforestry systems are among these landscapes where crops are planted under native shade trees. In this context, ancient agroforestry systems can provide insight into how farmers managed the landscape over time. Such insight can help to quantify the extent to which tropical forests (especially habitat-specialist trees) are responding to local and landscape-level management. Here, we extracted fossil pollen (indicator of past vegetation changes) and macroscopic charcoal (indicator of biomass burning) from four forest hollows’ sedimentary sequences in an ancient agroforestry system in Western Ghats, India. We used a mixed-modelling approach and a principal components analysis (PCA) to determine past trajectories of forest change and species composition dynamics for the last 900 years. In addition, we reconstructed the long-term forest canopy dynamics and examined the persistence of habitat-specialist trees over time. Our results show that the four sites diverged to a surprising degree in both taxa composition and dynamics. However, despite these differences, forest has persisted over 900 years under agricultural activities within agroforestry systems. This long-term analysis highlights the importance of different land-use legacies as a framework to increase the effectiveness of management across tropical agricultural lands

Identifying drivers of forest resilience in long-term records from the Neotropics

Here, we use 30 long-term, high-resolution palaeoecological records from Mexico, Central and South America to address two hypotheses regarding possible drivers of resilience in tropical forests as measured in terms of recovery rates from previous disturbances. First, we hypothesize that faster recovery rates are associated with regions of higher biodiversity, as suggested by the insurance hypothesis. And second, that resilience is due to intrinsic abiotic factors that are location specific, thus regions presently displaying resilience in terms of persistence to current climatic disturbances should also show higher recovery rates in the past. To test these hypotheses, we applied a threshold approach to identify past disturbances to forests within each sequence. We then compared the recovery rates to these events with pollen richness before the event. We also compared recovery rates of each site with a measure of present resilience in the region as demonstrated by measuring global vegetation persistence to climatic perturbations using satellite imagery. Preliminary results indeed show a positive relationship between pre-disturbance taxonomic richness and faster recovery rates. However, there is less evidence to support the concept that resilience is intrinsic to a region; patterns of resilience apparent in ecosystems presently are not necessarily conservative through time