Strip intercropping of wheat and oilseed rape enhances biodiversity and biological pest control in a conventionally managed farm scenario

Conventional agriculture in the global north is typically characterized by large monocultures, commonly managed with high levels of pesticide or fertilizer input and mechanization. We tested the influence of strip intercropping of conventionally managed winter wheat with oilseed rape, using common machinery with 27–36 m broad strips, on arthropod predator diversity and biological pest control. We characterized spider and carabid beetle communities, calculated pest aphid and pollen beetle densities and recorded parasitism rates for both crops (number of mummified aphids on wheat and number of parasitized pollen beetle larvae on oilseed rape). We observed a significant reduction in the densities of wheat aphids (50% decrease) and pollen beetle larvae (20% decrease) in strip intercropping areas compared to monocultures.The number of parasitized pollen beetle larvae did not show the same pattern but was higher towards the centre of the oilseed rape strip. Overall, the composition of predator communities benefited from the close neighbourhood of the two crop species in the strips. Our study presents evidence of the benefits of adopting strip intercropping with relatively large strips (adapted to existing machinery) for natural predator diversity and biological pest control in a large‐scale conventionally managed farm scenario. Wheat–oilseed rape strip intercropping reduced pest densities, increased parasitism of wheat aphids and promoted equal representation of natural predator groups well beyond the areas of monoculture. Overall, by reducing the area dedicated to only one crop, the implementation of strip intercropping adapted to mechanized agricultural scenarios can be used to increase crop heterogeneity at regional scales and enhance biodiversity and biological control, even in simplified landscapes dominated by large‐scale conventional agriculture

Degradation and nitrogen cycling in the context of biodiversity-ecosystem function relationships in the inquiline bacterial community of Darlingtonia californica

Biodiversity-ecosystem function (BEF) research aims to explain how species and their environments interact with each other. Microbial communities engage in vital biogeochemical pathways in a variety of natural ecosystems, and yet there are large knowledge gaps about the specific metabolic pathways in which they are involved. Degradation specifically contributes to nitrogen cycling globally through the breakdown of large organic nitrogen compounds into small inorganic nitrogen that is necessary for the survival of many other organisms. In this study, I focused on the degradative function of the inquiline microbial communities found within the carnivorous pitcher plant, Darlingtonia californica. Darlingtonia grows in nitrogen poor soils and relies on the microorganisms inside of its pitcher to break down insect prey into bioavailable nutrients. The purpose of this study was to identify if specific nitrogen metabolic pathways are driven by Darlingtonia bacterial diversity. Fourteen known bacterial isolates were grown in monoculture as well as in mixed cultures of 2-5 species. Additionally, bacteria were collected from Darlingtonia pitchers and acclimated in the lab, and serial dilution was performed to produce a diversity gradient. These lab communities were also compared to samples collected from Shasta County, Plumas County, and Del Norte County in California to define the scope of natural diversity observed in this experiment. Communities were given fruit flies as food to compare degradation over 11 days using the broad degradation metric of fly mass loss, and the specific nitrogen function metrics of enzymatic activity of chitinase and protease, and solubilized protein, ammonia, and nitrate concentrations. While I found increases in degradation potential of higher diversity cultured communities, these positive relationships were not seen in the more complex serial dilution communities. Additionally, nitrogen processing may not be driving insect degradation, as nitrogen metrics could not describe the loss of fly mass observed in this study. Redundant and overlapping functions in this system may allow Darlingtonia to maintain insect prey consumption at a range of microbial diversity levels. The benefits of biodiversity on nutrient cycling are commonly discussed, citing positive relationships between the two, however expanding our understanding of redundant relationships between microorganisms and degradation will also strengthen our understanding of the drivers of global biogeochemical cycling and interactions between bacteria and their host

The effect of temperature and predation on performance in monoculture and in competition in three Daphniidae differing in body size

Zooplankton body size shows a strong association with temperature, competition, and predation. Global warming affects all three drivers of body size and is thus expected to lead to substantial changes in zooplankton community composition and body size distributions. To disentangle the isolated and joint effect of temperature, competition, and fish predation on species biomass and community composition in zooplankton, we monitored population biomasses of three Daphniidae species that differ in body size (Daphnia magna, Daphnia pulex, and Ceriodaphnia reticulata) for 20 days, manipulating competition (monoculture, pairwise trials, and three-species communities), temperature (20°C, 24°C, and 28°C) and presence or absence of fish predation. In the absence of predation, D. magna dominated in all competition experiments, even at high temperatures. D. magna went extinct, however, in the predation treatments at 24°C and 28°C. D. pulex outcompeted C. reticulata and was negatively affected by predation and high temperature. C. reticulata did not reduce biomass at high temperatures and was negatively affected by all competition trials, but was positively affected by predation. Our results indicate that the two larger-bodied species are more negatively affected by the combination of temperature and predation than the smallest species. While higher temperatures reduced the biomass of the larger-bodied species, it did not fundamentally change their ability to dominate over the smallest species in competition. The combined effect of warming and predation changed community composition more fundamentally, resulting in the dominance of small-bodied species. This can have important ecosystem-wide impacts, such as the transition to turbid, algae-dominated systems

Modelling approaches for mixed forests dynamics prognosis. Research gaps and opportunities

Aim of study: Modelling of forest growth and dynamics has focused mainly on pure stands. Mixed-forest management lacks systematic procedures to forecast the impact of silvicultural actions. The main objective of the present work is to review current knowledge and forest model developments that can be applied to mixed forests.Material and methods: Primary research literature was reviewed to determine the state of the art for modelling tree species mixtures, focusing mainly on temperate forests.Main results: The essential principles for predicting stand growth in mixed forests were identified. Forest model applicability in mixtures was analysed. Input data, main model components, output and viewers were presented. Finally, model evaluation procedures and some of the main model platforms were described.Research highlights: Responses to environmental changes and management activities in mixed forests can differ from pure stands. For greater insight into mixed-forest dynamics and ecology, forest scientists and practitioners need new theoretical frameworks, different approaches and innovative solutions for sustainable forest management in the context of environmental and social changes.Keywords: dynamics, ecology, growth, yield, empirical, classification

Uncertain futures: imaginaries, narratives and calculative technologies

Dynamic capitalist economies are characterised by relentless innovation and novelty and hence exhibit an indeterminacy that cannot be reduced to measurable risk. How then do economic actors form expectations and decide how to act despite this uncertainty? This paper focuses on the role played by imaginaries, narratives, and calculative technologies, and argues that the market impact of shared calculation devices, social narratives, and contingent imaginaries underlines the rationale for a new form of ‘narrative economics’ and a theory of fictional (rather than rational) expectations. When expectations cannot be anchored in objective probability functions, the future belongs to those with the market, political, or rhetorical power to make their models or stories count. The paper also explores the dangers of analytical monocultures and the discourse of best practice in conditions of uncertainty, and considers the link between uncertainty and some aspects of populism

Extractivisms, Existences, and Extinctions : Monoculture Plantations and Amazon Deforestation

Peer reviewe

Is there an ecological ethic?

Includes bibliographical references.The environment is on the world agenda, also on the ethical frontier, for the foreseeable future. Environmental ethics is about saving things past, still present. Environmental ethics is equally about future nature, without analogy in our past. Living at one of the ruptures of history, modern cultures threaten the stability, beauty, and integrity of Earth, and thereby of the cultures superposed on Earth. Environmental ethics must find a satisfactory fit for humans in the larger communities of life on Earth.Publisher version: http://www.jstor.org/stable/2379925

Contemporary British georgic writing

Do we need the modish term “eco-georgic” to help us discover the unsentimental, holistic, healing qualities in the best georgic writing of the Anthropocene? When were georgics not “eco”? Is there a “post georgic” in forms of contemporary literature that seem to reject husbandry altogether, such as rewilding texts? Do such categories serve any purpose to readers and critics in the Anthropocene? This essay argues that such careful distinctions do, indeed, matter more than ever now as we reconsider our sustainable options in husbandry, land-management and what sustainability might look like, as it is represented and explored in our fiction and non-fiction georgic literature in Britain at the present. One might expect contemporary georgic writing to exemplify the environmental engagement implied in the term “eco-georgic”. In fact, contemporary georgic can be environmentally radical or apparently indirect in its implications for sustainability. It remains as diverse, hybrid and composted in the past as Virgil’s original text. This essay begins by considering definitions, with reference to Virgil’s founding Latin text, begun in the third decade BCE, the “Georgics”. It recognises Laura Sayre’s complaint that ecocriticism has neglected georgic writing, and argues that this is certainly true for contemporary British georgic texts. This essay focuses on contemporary georgic fiction and non-fiction in relation to Virgil’s founding text. The novels of Cynan Jones, Tom Bullough, Marie-Elsa Bragg and Tim Pears are discussed and contrasted with one by Melissa Harrison that might mistakenly be thought of as georgic. Three categories of non-fiction are identified and discussed with examples: instructional georgic, personal memoir and future-oriented georgic. Consideration of the latter leads to conclusions about their inevitable overlaps and a final call for a radical mutual agency to embed animism and enchantment into contemporary georgic writing.¿Necesitamos el término de moda "eco-geórgico" para ayudarnos a descubrir las cualidades no sentimentales, holísticas y curativas en la mejor escritura geórgica del Antropoceno? ¿Cuándo no eran "eco" las geórgicas? ¿Hay un "post-geórgico" en las formas de literatura contemporánea que parecen rechazar por completo la agricultura, como los textos de retorno a la vida silvestre? ¿Sirven tales categorías para los lectores y críticos en el Antropoceno? Este ensayo argumenta que tales distinciones cuidadosas, de hecho, importan más que nunca ahora que reconsideramos nuestras opciones sostenibles en la agricultura, la gestión de la tierra y cómo podría ser la sostenibilidad, tal y como está representada y desarrollada en la literatura de ficción y no ficción en Gran Bretaña en la actualidad. Uno podría esperar que la escritura geórgica contemporánea ejemplifique el compromiso ambiental implícito en el término "eco-geórgico". De hecho, la geórgica contemporánea puede ser ambientalmente radical o aparentemente indirecta en sus implicaciones para la sostenibilidad. Sigue siendo tan diverso, híbrido y compostado en el pasado como lo es el texto original de Virgilio. Este ensayo comienza considerando las definiciones, con referencia al texto fundacional en latín de Virgilio, comenzado en la tercera década a. C., las Geórgicas. Reconoce la queja de Laura Sayre de que la ecocrítica ha descuidado la escritura geórgica, y argumenta que esto es indisputablemente cierto para los textos geórgicos británicos contemporáneos. Este ensayo se centra en la ficción contemporánea y la no ficción en relación con el texto fundacional de Virgilio. Las novelas de Cynan Jones, Tom Bullough, Marie-Elsa Bragg y Tim Pears se analizan y contrastan con una de Melissa Harrison que erróneamente podría considerarse como geórgica. Tres categorías de no ficción se identifican y son analizadas con ejemplos: geórgico instructivo, memorias personales y geórgico orientado al futuro. La consideración de estos últimos lleva a conclusiones sobre sus inevitables superposiciones y a un llamamiento final a una agencia mutua radical para integrar el animismo y el encantamiento en la escritura contemporánea