Agriculture: les abeilles sont-elles indispensables?

Les terres agricoles représentent plus de 35 % de la surface terrestre dépourvue de glace. L’agriculture s’étend et s’intensifie actuellement dans de nombreuses régions pour répondre aux besoins des populations . Cette tendance menace la biodiversité et les services écosystémiques dont dépend l’agriculture, tels que la pollinisation des cultures. En effet, des études récentes ont mis en évidence la façon dont ces pressions anthropiques provoquent le déclin des pollinisateurs sauvages comme les abeilles, les mouches, les coléoptères et les papillonsFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Mito y realidad de una crisis global de la polinización en la agricultura

Mounting evidence shows that pollinators are declining as a result of widespread environmental degradation. This loss raises concerns that a global pollination crisis could threaten the human food supply by decreasing crop yield and even promote famine under a hypothetical scenario of total pollinator extinction. This catastrophic possibility has prompted intense interest from scientists, politicians and the general public. However, three lines of evidence do not support such an apocalyptic scenario. First, even though the abundance and diversity of wild pollinators are declining worldwide, the global population of managed honey-bee hives has increased by ~80% since the early 1960s. Second, agricultural production would decrease by <10% in the total absence of bees because relatively few crops are completely pollinator dependent. Lastly, despite widespread pollination deficits, current evidence is inconsistent with deceleration in yield growth with increasing pollinator dependence at a global scale, probably due to improvements in crop breeding and external agricultural subsidies. Overall, this evidence refutes simplistic claims of human starvation caused by a hypothetical total pollinator extinction. Nevertheless, pollination problems may loom. Although pollinators are responsible for a minor fraction of global agriculture production, this fraction has increased ~600% since 1961, greatly outpacing human population growth and the growth of the global population of managed honey bees. This large production increase is explained to a considerable extent by the rapid expansion of pollinatordependent monocultures at the expense of natural and diverse agricultural habitats. By driving pollinator decline, this land-use transformation could worsen pollination deficits and promote further crop expansion given sustained market demands. Therefore, although the human food supply is not currently subject to a global pollination crisis, a spiralling positive-feedback between the impacts of agriculture expansion and pollinator decline on crop yield could accelerate precipitous biodiversity loss by promoting further habitat destruction and homogenization.Los polinizadores están disminuyendo como consecuencia de la degradación generalizada del medio ambiente. Esta pérdida ha suscitado la preocupación de que una crisis global de polinización pueda estar amenazando nuestro suministro de alimentos vía una reducción en el rendimiento agrícola. Sin embargo, tres líneas de evidencia no apoyan tal expectativa. Primero, aunque la abundancia y la diversidad de los polinizadores silvestres están disminuyendo en todo el mundo, la población mundial de colmenas de abejas melíferas manejadas ha aumentado en un ~80% desde principios de la década de 1960. Segundo, la producción agrícola disminuiría sólo <10% en ausencia total de abejas ya que relativamente pocos cultivos dependen completamente de los polinizadores. Por último, a nivel global no parece existir una desaceleración del crecimiento en el rendimiento con el incremento en la dependencia de los polinizadores. Sin embargo, la expansión de cultivos dependientes de polinizadores puede tener un alto costo ambiental. Aunque los polinizadores son responsables de una fracción menor de la producción agrícola mundial, esta fracción ha aumentado en un ~600% desde 1961, superando el crecimiento de la población mundial de abejas melíferas manejadas. El incremento de esta fracción de la agricultura se explica en gran medida por la rápida expansión de monocultivos dependientes de polinizadores. A través de incrementar la pérdida de polinizadores silvestres, esta transformación en el uso de la tierra puede causar un incremento en los déficits de polinización y promover la expansión de cultivos dependientes de polinizadores en respuesta a demandas sostenidas del mercado. Por lo tanto, una espiral de retroalimentación positiva entre la expansión de la agricultura y un declive de los polinizadores que afecte al rendimiento de los cultivos podría acelerar la enorme pérdida de biodiversidad en curso al promover la destrucción de los hábitats naturales remanentes y la homogeneización de los paisajes agrícolas.Fil: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Harder, Lawrence. University of Calgary; Canad

Honeybees are far too insufficient to supply optimum pollination services in agricultural systems worldwide

Evidence of a decline in wild pollinators is increasing across global and local habitats. However, with regional variation, the number of managed pollinators has increased globally. Whether these managed pollinators can sufficiently meet the agricultural pollination demand given wild pollinator declines remains unclear. Data on 49 honeybee-pollinated crops cultivated worldwide and stocked honeybee colonies were analysed to assess the pollination demand and pollination service capacity between 1989 and 2019. We found a rapidly increasing demand for honeybee pollination but a decreasing pollination service capacity of honeybee colonies. Globally, the demand for honeybee pollination rose approximately 2.3 times higher than the stocked number of honeybee colonies in 2019, growing 1.78% annually, almost 2 times faster than honeybee colonies (0.95%). On average, the pollination service capacity, growth rates of demands for honeybee colony stocks and honeybee pollination, and diversity of honeybee-pollinated crops varied regionally. Nevertheless, fluctuation of the honeybee-pollination demand increased with increased fluctuation of crop diversification. Oil crops accounted for over 70% of the world's honeybee-pollination demand in 2019, with soybean and rapeseed accounting for 39% and 16%, respectively. This was the case in less diversified countries, where a few crops dominated the demand for honeybee pollination, including American countries such as Argentina, Brazil, and the USA, compared to more diversified countries such as China, India, and Japan in Asia. Our study shows that managed pollinators are far too insufficient to adequately supply the agricultural pollination demand worldwide. This emphasises the importance of ongoing calls for protecting pollinators and the integrated management of honeybees and wild pollinator assemblages for a sustainable food-secure future world.Fil: Mashilingi, Shibonage K.. Chinese Academy of Sciences; República de ChinaFil: Zhang, Hong. Chinese Academy of Sciences; República de ChinaFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: An, Jiandong. Chinese Academy of Sciences; República de Chin

Diversity, functionality, and resilience under increasing harvesting intensities in woodlands of northern Patagonia

Sustainable forest management relies on the understanding of biodiversity response to disturbance and the ecological resilience of the system. The dynamic equilibrium hypothesis (DEM) predicts that site productivity will modulate the effects of disturbance gradient on biodiversity. Also, considering functional diversity (eco-morfo-phisicological traits related to resource usage) is needed to understand the effect of species gains and losses on ecosystem functionality. Here we assess the response of understory plant taxonomic and functional diversity to increasing harvesting intensities (0, 30, 50 and 70% of basal area removed) at three woodland sites of contrasting biomass growth (productivity) in northern Patagonia. Also, we assessed resilience based on comparisons with undisturbed treatments four years after initial harvest. In agreement with DEM, both taxonomic and functional diversity peaked at high, medium, or low harvesting intensities in the high-, medium-, or low-productivity site, respectively. Taxonomic composition was clearly determined by site productivity (biomass growth), while no pattern emerged for functional composition. Functional traits related to light use showed different responses: specific leaf area was only affected by site productivity while leaf chlorophyll content was affected by an interaction between harvesting intensity and site productivity. Interestingly, there was no effect of harvesting intensity on the resilience of taxonomic diversity and functional composition. Only for functional diversity, harvesting intensity was as important as site productivity. In the high and intermediate productivity sites the traits that characterizes the system were more resilient and resembled the control treatment after four years of low or high (but not intermediate) harvesting intensities. Our results support the use of the DEM on forest interventions and the importance of considering both taxonomic and functional composition, as the consideration of functional traits related to resource use strategies have different implications when considering the resilience of the system.info:eu-repo/semantics/acceptedVersio

Ambiguities in scientific terms: The use of “error” and “bias” in statistics

El uso correcto de la estadística es clave para los profesionales que responden preguntas a partir de datos; entre ellos están los ecólogos. Sin embargo, a estos profesionales, la estadística les suele resultar confusa; en parte, esto se debe a dificultades relacionadas con la terminología. Muchas de estas dificultades derivan de los múltiples significados que tiene un término, tanto dentro como fuera del ámbito estadístico. Para los profesionales de habla hispana, la traducción de términos desde el inglés también aporta a esta confusión. En este trabajo exponemos (e intentamos clarificar) algunos de estos problemas a partir de dos de los términos que conforman la base de un curso de estadística introductorio: error y sesgo. Estos términos son discutidos en los diferentes contextos que se atraviesan en la resolución de problemas utilizando la estadística: muestreo, medición, inferencia y predicción. El error es inherente a la estadística y, según el contexto, se lo usa para cuantificar distintos tipos de variabilidad o para indicar la posibilidad de equivocarse al tomar una decisión. El sesgo, en cambio, refleja la tendencia hacia ciertos valores o elementos y, de no evitarse, conlleva a conclusiones erróneas. Proponemos que los problemas asociados con la ambigüedad léxica se aborden desde la enseñanza universitaria, y sobre esa base brindamos algunas recomendaciones. En este sentido, si bien el presente artículo provee una guía para que los profesionales hagan un uso adecuado de algunos términos estadísticos, también brinda un aporte para el ejercicio docente.The proper use of statistics is key for professionals who answer questions from data, including ecologists. However, statistics is generally confusing for these professionals, in part due to difficulties related to its terminology. Many of these difficulties derive from the multiple meanings that a term has, both inside and outside the statistical scope. For Spanish-speaking professionals, the translation of English terms also contributes to this confusion. In this paper we show (and intend to clarify) some of these problems from two key terms of an introductory statistics course: error and bias. These terms are discussed in the different contexts that involve problem resolution using statistics: sampling, measurement, estimation, inference and prediction. Error is inherent to statistics and is used to quantify different types of variability or to indicate the possibility of making mistakes on decision making, depending on the context. On the other hand, bias reflects the tendency towards certain values and/or elements, and leads to erroneous conclusions if not avoided. We propose that the problems associated with lexical ambiguity should to be addressed from university teaching and based on this, we offer some recommendations. Thus, the present article not only offers a guide for professionals to make an adequate use of some statistical terms but also provides a contribution for teaching.Fil: Oddi, Facundo José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Andina; ArgentinaFil: Aristimuño, Francisco Javier. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Coulin, Carolina. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Stingless bee further improve apple pollination and production

The use of Africanised honeybee (Apis mellifera scutellata Lepeletier) hives to increase pollination success in apple orchards is a widespread practice. However, this study is the first to investigate the number of honeybee hives ha-1 required to increase the production of fruits and seeds as well as the potential contribution of the stingless bee Mandaçaia (Melipona quadrifasciata anthidioides Lepeletier). We performed tests in a 43-ha apple orchard located in the municipality of Ibicoara (13º24’50.7’’S and 41º17’7.4’’W) in Chapada Diamantina, State of Bahia, Brazil. In 2011, fruits from the Eva variety set six seeds on average, and neither a greater number of hives (from 7 to 11 hives ha-1) nor a greater number of pollen collectors at the honeybee hives displayed general effects on the seed number. Without wild pollinators, seven Africanised honeybee hives ha-1 with pollen collectors is currently the best option for apple producers because no further increase in the seed number was observed with higher hive densities. In 2012, supplementation with both stingless bees (12 hives ha-1) and Africanised honeybees (7 hives ha-1) provided higher seed and fruit production than supplementation with honeybees (7 hives ha-1) alone. Therefore, the stingless bee can improve the performance of honeybee as a pollinator of apple flowers, since the presence of both of these bees results in increases in apple fruit and seed number.Fil: Blandina Felipe, Viana. Universidade Federal da Bahia; BrasilFil: da Encarnação Coutinho, Jeferson Gabriel. Universidade Federal da Bahia; BrasilFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Rio Negro. Sede Andina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bragança Gastagnino, Guido Laercio. Universidade Federal da Bahia; BrasilFil: Gramacho, Katia Peres. Katia Peres; BrasilFil: Oliveira da Silva, Fabiana. Universidade Federal da Bahia; Brasi

Impacto de la deposición de ceniza volcánica sobre la productividad foliar y la herbivoría por insectos en bosques deciduos del norte de la Patagonia

Volcanism has been a major force shaping the dynamics of Andean landscapes during the Holocene. Yet we still know little about the consequences of modern volcanic events on forest functioning. Ash fall may elicit multiple direct and indirect effects on key ecosystem attributes, with disturbance severity likely varying with distance to the crater. We examined the impact of ash deposition on foliage productivity and insect herbivory after the 2011 eruption of the Volcán Puyehue-Cordón Caulle system, in Nothofagus pumilio forests of northern Patagonia, Argentina. Tree leaf litterfall, a surrogate for annual foliar production, was measured before and after the event in wet and dry forest sites, which were located 22 km and 80 km east from the crater and were affected by mass deposition of coarse- and fine-grained tephra, respectively. Leaf damage by insects was monitored over a 10-year span (2004-2013) including the volcanic event. Foliar productivity in 2012 dropped by 60% in the wet forest, but did not change in the dry forest. Leaf area damaged by insects decreased abruptly in 2012, with post-eruption herbivory levels falling outside the range of annual variation recorded before the event. The impact was most severe in the dry forest wich normally supports the highest endemic herbivory. In contrast, leaf damage remained high in another dry forest located 98 km southeast from the crater and little affected by ashfall. Changes in foliar production and insect herbivory persisted for two years after the event. Our results show a widespread disruption of canopy-herbivore interactions in areas heavily affected by tephra. Remarkably, volcanic ash acted as a broad-spectrum insecticide on canopy herbivores. In the short-term, ashfall constrained the energy flow through the forest canopy and the arthropod consumer community, and thus temporarily overwhelmed previously existing differences in productivity and herbivory between wet and dry forest habitats.Impacto de la deposición de ceniza volcánica sobre la productividad foliar y la herbivoría por insectos en bosques deciduos del norte de la Patagonia: El vulcanismo ha moldeado la dinámica de los paisajes andinos durante todo el Holoceno. Sin embargo, aún se conoce poco sobre las consecuencias de eventos volcánicos modernos en el funcionamiento de los bosques nativos. La caída masiva de cenizas puede generar múltiples efectos directos e indirectos sobre procesos clave del ecosistema. Aquí evaluamos el impacto de la deposición de cenizas emitidas por la erupción del complejo Volcán Puyehue-Cordón Caulle en junio de 2011, sobre la productividad foliar y la herbivoría por insectos del dosel en bosques de Nothofagus pumilio del norte de la Patagonia Argentina. La producción de hojas fue medida antes y después de la erupción, en bosques húmedos y secos situados a 22 y 80 km del volcán y afectados por la caída de pumicita gruesa y fina, respectivamente. El área foliar dañada por insectos fue monitoreada durante 10 años (2004-2013), incluyendo al evento volcánico. La productividad foliar en 2012 cayó un 60% en el bosque húmedo pero no cambió en el bosque seco. El daño foliar se redujo abruptamente en 2012; los niveles de herbivoría post-erupción cayeron por debajo del rango de variación interanual registrado antes de la erupción. El impacto fue más severo en el bosque seco, donde los niveles endémicos de herbivoría son más elevados. En cambio, la herbivoría se mantuvo elevada en otro bosque seco localizado a 98 km del cráter y que recibió pocas cenizas. Los cambios en productividad y herbivoría persistieron por dos años después del evento. Estos resultados muestran una fuerte disrupción de las interacciones planta-herbívoro en áreas boscosas afectadas por la erupción volcánica. Las cenizas actuaron como un biocida de amplio espectro sobre los insectos defoliadores. En el corto plazo, la deposición de cenizas limitó el flujo de energía a través del dosel arbóreo y hacia los consumidores artrópodos.Fil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas A la Agricultura; ArgentinaFil: Mazía, Noemí. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal; ArgentinaFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Rio Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chaij, Jaquelina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal; ArgentinaFil: Kitzberger, Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentin

Local Weather Have Direct and Indirect Influence on Apple Quality

In a changing climate, altered temperature and precipitation patterns can affect the production and quality of various crops, such as fruits. However, crop production could also be modified indirectly by weather changes through modifying ecological communities and in turn ecosystem functions. These ecosystem functions, including biomass decomposition, biological control of pests and pollination, can influence food production and crop quality. Therefore, fruit and seed set can be affected, both directly through temperature- induced effects on crops, and indirectly, through e.g. changes in pollination success. Apple is a pollination dependent crop sensitive to low temperatures. We evaluated effects of local weather on pollinator visits and pollination success of apples. This was done by observing flower visiting insects and temperature logging in apple orchards in Sweden and Argentina. We found both direct and indirect effects of local temperatures on apple quality. For example, pollination success increased with temperature at flowering, which was correlated with higher sugar content in ripe fruit. Furthermore, fruits at harvest were heavier had they developed in higher temperature. We conclude that temperature variations may have several effects on apple production and quality. Both direct effects of temperatures and responses mediated through changes in pollinator behaviour are of importance. This is important to consider in management decisions related to apple production in a changing climate.Trabajo publicado en Acta Bioquímica Clínica Latinoamericana; no. 52, supl. 2, parte II, diciembre de 2018.Universidad Nacional de La Plat

Functional Traits in Bees: the Role of Body Size and Hairs in the Pollination of a Passiflora Crop

Pollination is a vitally important function in nature and becomes an ecosystem service because it influences the food and nutritional security for people. However, the contribution of different functional traits of insects for pollen transport of plants is still poorly known. We explore the relationship between pollinator insect functional traits and the transport of pollen of sweet granadilla (Passiflora ligularis Juss) in eight crops. We sampled flower-visiting insects of this crop and recorded 10 functional traits (five by direct measurements and five from the literature) that were related to the amount of pollen carried by each insect. Bees (Apidae) were not only the most abundant insects but also the ones that loaded the highest amounts of pollen. Within these, the most abundant species was the exotic common honeybee (Apis mellifera (Linnaeus)) making up almost half of the specimens collected; however, this bee carried less pollen grains than other native bees. Bombus hortulanus (Smith) was one of the large-bodied native bees that carried more sweet granadilla pollen, despite not being an abundant species in the community. Body size was the most important trait determining the transport of sweet granadilla pollen, while the traits related to body hairs were not significant for the body’s pollen load. None of the functional traits evaluated was influenced by taxonomy at species-level. Our results suggest that large body sizes in bees are the most important traits in granadilla pollen transport, regardless of other changes in composition and structure of pollinating insect assemblages in the crop.Fil: Cortés Gómez, Angela M.. Pontificia Universidad Javeriana; ColombiaFil: González Chaves, Adrián. Universidade de Sao Paulo; BrasilFil: Urbina Cardona, Nicolás. Pontificia Universidad Javeriana; ColombiaFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural.; Argentin

Effects of firewood harvesting intensity on biodiversity and ecosystem services in shrublands of northern Patagonia

Background: Forest management has historically focused on provisioning of goods (e.g. timber, biomass), but there is an increasing interest to manage forests also to maintain biodiversity and to provide other ecosystem services (ES). Methods: We evaluated the effects of firewood harvesting intensity on biodiversity and different ES in three contrasting shrubland sites in northern Patagonia (Argentina). At each site, four harvesting treatments, representing various levels of harvest intensity, were randomly assigned to eight permanent sample plots of 31.5 m × 45 m during 2013–2014. Results: We found that the effects of increasing harvesting intensity on plant diversity changed from negative to positive (and from nonlinear to more linear responses) with increasing site productivity. Harvesting intensity showed contrasting effects on variables related to fire protection ecosystem service, since it reduced fuel amount (potentially reducing fire spread) but also reduced live fuel moisture content (potentially increasing flammability) at the three sites. Two variables related to soil formation and protection ES, leaf litter cover and aerial soil cover, decreased with harvesting intensity at the three sites. Conclusions: We conclude that shrubland management for firewood production may enhance biodiversity without compromising certain important ES. The intensity of harvesting should be determined according to site conditions and forecasted impacts on biodiversity, fire and soil formation and protection.Fil: Goldenberg, Matías Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Oddi, Facundo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Gowda, Juan Janakiram Haridas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecología y Desarrollo Rural; Argentin