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Conrad Gessner, Historia Plantarum. C. 1555-65

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Look closely. The beautiful may be small.

Immanuel Kant
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Knotted cords, or khipus, found at an Inca storage facility in southern Peru may have been used to keep track of taxes on crops such as chili peppers and peanuts.

https://bit.ly/2F53UmE
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Climate change has likely already affected global food production
Ray et al., 2019

Crop yields are projected to decrease under future climate conditions, and recent research suggests that yields have already been impacted. However, current impacts on a diversity of crops subnationally and implications for food security remains unclear. Here, we constructed linear regression relationships using weather and reported crop data to assess the potential impact of observed climate change on the yields of the top ten global crops–barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugarcane and wheat at ~20,000 political units. We find that the impact of global climate change on yields of different crops from climate trends ranged from -13.4% (oil palm) to 3.5% (soybean). Our results show that impacts are mostly negative in Europe, Southern Africa and Australia but generally positive in Latin America. Impacts in Asia and Northern and Central America are mixed. This has likely led to ~1% average reduction (-3.5 X 10¹³ kcal/year) in consumable food calories in these ten crops. In nearly half of food insecure countries, estimated caloric availability decreased. Our results suggest that climate change has already affected global food production.

Impact of mean climate change on crop yield (tons/ha/year). Brown colors denoted reduction in yield and green colors indicate gains in yield due to mean climate change. (a) barley; (b) cassava; (c) maize; (d) oil palm; (e) rapeseed; (f) rice; (g) sorghum; (h) soybean; (i) sugarcane; and (j) wheat. White areas are where the study was not conducted due to model (unstudied model) and dark gray areas are where the study was not conducted because of data (unstudied data). Light gray areas are where we do not have any report of the crop being harvested or the crop is insignificant and is mapped as background color in land areas. Oceans, seas, large lakes, and large water bodies are mapped in blue color.

https://bit.ly/2KgcdPX

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A Plentiful Feast from Jodeb on Vimeo.

National food production stabilized by crop diversity
Delphine Renard & David Tilma, 2019.

ncreasing global food demand, low grain reserves and climate change threaten the stability of food systems on national to global scales. Policies to increase yields, irrigation and tolerance of crops to drought have been proposed as stability-enhancing solutions. Here we evaluate a complementary possibility—that greater diversity of crops at the national level may increase the year-to-year stability of the total national harvest of all crops combined. We test this crop diversity–stability hypothesis using 5 decades of data on annual yields of 176 crop species in 91 nations. We find that greater effective diversity of crops at the national level is associated with increased temporal stability of total national harvest. Crop diversity has stabilizing effects that are similar in magnitude to the observed destabilizing effects of variability in precipitation. This greater stability reflects markedly lower frequencies of years with sharp harvest losses. Diversity effects remained robust after statistically controlling for irrigation, fertilization, precipitation, temperature and other variables, and are consistent with the variance-scaling characteristics of individual crops required by theory for diversity to lead to stability. Ensuring stable food supplies is a challenge that will probably require multiple solutions. Our results suggest that increasing national effective crop diversity may be an additional way to address this challenge.

 Determinants of national caloric yield stability. Regression coefficients (±s.e.) show the magnitude of the effect of each variable in a multiple regression of log_e(national yield stability). a, Regression coefficients using effective crop group diversity (n = 437). b, Regression coefficients using effective crop species diversity (n = 437). Each predictor variable was standardized to zero mean and unique variance across all nations and time periods (Methods) to enable the comparison of effects with a change of 1σ in each predictor on the log(stability) values. Asterisks indicate the significance of each predictor. ***P < 0.001; NS, not significant (P > 0.05).

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https://www.nature.com/articles/s41586-019-1316-y

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Context‐dependent biotic interactions predict plant abundance across altitudinal environmental gradients 
Lynn et al., 2019

Many biotic interactions influence community structure, yet most distribution models for plants have focused on plant competition or used only abiotic variables to predict plant abundance. Furthermore, biotic interactions are commonly context‐dependent across abiotic gradients. For example, plant‐plant interactions can grade from competition to facilitation over temperature gradients. We used a hierarchical Bayesian framework to predict the abundances of 12 plant species across a mountain landscape and test hypotheses on the context‐dependency of biotic interactions over abiotic gradients. We combined field‐based estimates of six biotic interactions (foliar herbivory and pathogen damage, fungal root colonization, fossorial mammal disturbance, plant cover, and plant diversity) with abiotic data on climate and soil depth, nutrients, and moisture. All biotic interactions were significantly context‐dependent along temperature gradients. Results supported the stress gradient hypothesis: As abiotic stress increased, the strength or direction of the relationship between biotic variables and plant abundance generally switched from negative (suggesting suppressed plant abundance) to positive (suggesting facilitation/mutualism). For half of the species, plant cover was the best predictor of abundance, suggesting that the prior focus on plant‐plant interactions is well‐justified. Explicitly incorporating the context‐dependency of biotic interactions generated novel hypotheses about drivers of plant abundance across abiotic gradients and may improve the accuracy of niche models.

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https://bit.ly/2W1XdfD

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Silver Laced Polish Chicken (Photo: Tim Flach)
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Floral volatiles and visitors: A meta‐network of associations in a natural community

Kantsa et a., 2019

1. Chemosensory communication between flowers and pollinators is a fundamental component of terrestrial biodiversity, given the importance of olfaction to foraging animals. In this respect, exploring chemically mediated interspecific interactions in natural assemblies may provide novel insights into the ecofunctional significance of volatile organic compounds (VOCs) for plant–insect co‐evolution. However, multispecies datasets of associations between plant semiochemicals and arthropods are still very rare and tend to lack community context. Here, we present the first insect–floral VOC meta‐network using plant–pollinator visitation data and the plants’ floral scent blends, collected in a Mediterranean scrubland.
2. We assembled the insect–VOC meta‐network by substituting each plant species in the plant–pollinator network with the blend of VOCs it emits. Furthermore, we identified the modules of the network that is the most densely connected insect–VOC groups. After describing the role of the species in the network, we focused on the bees of the community, and by building phylogenetically informed GLS models, we found the species traits predicting the degree of chemical specialization.
3. Modularity analysis of the meta‐network revealed tight associations between several classes of VOCs and pollinator groups. Linkage patterns suggest positive associations between (a) Megachilidae bees and sesquiterpenes, (b) Apidae and Andrenidae bees and benzenoids/phenylpropanoids, and (c) wasps, C6 green‐leaf volatiles and specific terpenoids. Benzenoids were found to be the least influential and most specialized chemical class in the community, whereas sesquiterpenes represented the most influential one. Furthermore, the degree of chemical generalization of the bees in the meta‐network was significantly associated with their ecological generalization, body mass and phenology, whereas their contribution to the network's structure was related to their level of sociality.
4. Synthesis. Our findings help to disclose the ecofunctional significance of the floral volatile landscape and contribute novel testable hypotheses on the behavioural trends and chemical niches of pollinators in a natural community. The insect–volatilome meta‐network is thus shown to be advantageous for detecting and visualizing patterns of chemically mediated interspecific interactions. Given the ubiquity of chemosensory biocommunication, our approach can be applied for investigating various types of ecological interactions in community contexts. 

 https://bit.ly/2QmazNT
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John Harte - Hybridizing Mechanism and MaxEnt: Ecological Theory for the Anthropocene
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Climatic controls of decomposition drive the global biogeography of forest-tree symbioses      
Steidinger et al., 2019.

The identity of the dominant root-associated microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools, sequester carbon and withstand the effects of climate change. Characterizing the global distribution of these symbioses and identifying the factors that control this distribution are thus integral to understanding the present and future functioning of forest ecosystems. Here we generate a spatially explicit global map of the symbiotic status of forests, using a database of over 1.1 million forest inventory plots that collectively contain over 28,000 tree species. Our analyses indicate that climate variables—in particular, climatically controlled variation in the rate of decomposition—are the primary drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal trees, which represent only 2% of all plant species, constitute approximately 60% of tree stems on Earth. Ectomycorrhizal symbiosis dominates forests in which seasonally cold and dry climates inhibit decomposition, and is the predominant form of symbiosis at high latitudes and elevation. By contrast, arbuscular mycorrhizal trees dominate in aseasonal, warm tropical forests, and occur with ectomycorrhizal trees in temperate biomes in which seasonally warm-and-wet climates enhance decomposition. Continental transitions between forests dominated by ectomycorrhizal or arbuscular mycorrhizal trees occur relatively abruptly along climate-driven decomposition gradients; these transitions are probably caused by positive feedback effects between plants and microorganisms. Symbiotic nitrogen fixers—which are insensitive to climatic controls on decomposition (compared with mycorrhizal fungi)—are most abundant in arid biomes with alkaline soils and high maximum temperatures. The climatically driven global symbiosis gradient that we document provides a spatially explicit quantitative understanding of microbial symbioses at the global scale, and demonstrates the critical role of microbial mutualisms in shaping the distribution of plant species.

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https://www.nature.com/articles/s41586-019-1128-0

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Gaur (Bos gaurus)
The largest extant bovine
https://en.wikipedia.org/wiki/Gaur
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Connecting plant‐soil feedbacks to long‐term stability in a desert grassland
Y. Anny Chung, Scott L. Collins, Jennifer A. Rudgers

Temporal fluctuations in plant species coexistence are key to understanding ecosystem state transitions and long‐term maintenance of species diversity. While plant microbiomes can alter plant competition in short‐term experiments, their relevance to natural temporal patterns in plant communities is unresolved. In a semiarid grassland, the frequency and magnitude of change in plant species composition through time varied from relatively static to highly dynamic among patches across the landscape. We field‐tested whether these alternative successional trajectories correlated with alternative plant‐soil interactions. In temporally stable patches, we found negative plant‐soil feedbacks, where plants grew worse with conspecific than heterospecific soil biota – a mechanism that maintains stability in mathematical models. In contrast, feedbacks in temporally dynamic patches were neutral to positive. Importantly, the magnitude of feedbacks depended on plant frequency, enabling plant species to increase in cover when rare, which theory predicts will promote long‐term, stable coexistence. While our study does not determine the direction of causality, our results reveal a novel link between plant‐microbe interactions and temporal stability of plant species coexistence and help to explain 20+ years of plant abundance dynamics at the patch‐to‐landscape scales.

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https://bit.ly/2HckLp2

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Ma Yuan's studies of the properties of water, southern Song Dynasty China. 1190 - 1225 CE
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De qué hablamos, cuando hablamos de Agroecología
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Bajar gratis: bit.ly/2YhGQZ8

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Sustainability in global agriculture driven by organic farming 
 Eyhorn et al., 2019.

Agricultural practices need to change to meet the United Nations Sustainable Development Goals by 2030. How to achieve the SDGs is heavily contested. Here we propose a policy framework that triggers the required transition. Organic agriculture, although not a silver bullet, is a useful component in such strategy. 

Sustainable agriculture and food systems need to provide sufficient and nutritious food for all, while minimizing environmental impact and enabling producers to earn a decent living. Most agree that agriculture and food systems urgently need to change to make progress on several Sustainable Development Goals (SDGs) while staying within planetary boundaries1. However, the way to achieve this is intensely debated, with two narratives dominating the discussion: incremental steps to improve efficiency in conventional agriculture while reducing negative externalities, versus transformative redesign of farming systems based on agroecological principles.

The debate is polarized for good reason. Transformative systems such as organic farming have proven sustainability benefits, including improved soil quality, enhanced biodiversity, reduced pollution and increased farm incomes but in many contexts result in lower yields so that their sustainability per unit product is sometimes questioned. Intensive conventional systems, on the other hand, can be highly productive, but have substantial negative externalities including biodiversity loss, soil erosion, pollution, reduced human health and low farm incomes. In addition, powerful agribusiness and food corporations have vested interests in continuing the conventional agroindustrial model and in perpetuating ‘Feed the World’ narratives.

The SDGs offer an opportunity to reconcile these divisions by focusing on the sustainability contributions of different farming approaches and the policies that help to accelerate the required transition. Successful transformative systems, such as organic, push–pull and evergreen agriculture, offer inspirational examples and an innovation space for transformation because they are pursuing a radically different approach based on agroecological processes. Conversely, incremental approaches, such as precision farming and reduced-tillage, developed in conventional agriculture inspire transformative systems to further improve their performance. Here we argue that policies aligned with the SDGs are needed to promote this transition.

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https://go.nature.com/2Z1vTvQ
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Soundcloud: White-handed Gibbon - Taman Negara, Malaysia
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Gert van den Bosch 
‏ @gertvanden
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