Wednesday, November 18, 2015

New agroecology book in Italian

Agroecology: a viable agricultural path for a planet in crisis. It is now clear that humanity needs an alternative agricultural development paradigm, one that encourages more ecologically, biodiverse, resilient, sustainable and socially just forms of agriculture. The basis for this new systems are the myriad of ecologically based agricultural styles developed by over a billion smallholders, family farmers and indigenous people on hundreds of millions of small farms which currently produce most of the global agricultural output for domestic consumption largely without agrochemicals. Agroecology is this paradigm: a dialogue between traditional agricultural knowledge and modern agricultural science that uses ecological concepts and principles for designing and managing sustainable agroecosystems in which external inputs are replaced by natural processes such as natural soil fertility and biological control. This book explains why agroecology is the most robust food provisioning pathway for humanity to take in the twenty-first century under current and predicted and difficult climate, energy, financial and social scenarios.

Altieri M.A., Nicholls C.I., Ponti L., 2015. Agroecologia: una via percorribile per un pianeta in crisi. Edagricole, Bologna. 336 pp. | Get book from publisher

Friday, August 28, 2015

Indian cotton: weather, yields and suicides

Cotton with coevolving pests has been grown in India for more than 5000 years. Hybrid cotton was introduced in the 1970s with increases in fertilizer and in insecticide use against pink bollworm that caused outbreaks of bollworm. Hybrid Bt cotton, introduced in 2002 to control bollworm and other lepidopteran pests, is grown on more than 90 % of the cotton area. Despite initial declines, year 2013 insecticide use is at 2000 levels, yields plateaued nationally, and farmer suicides increased in some areas. Biological modeling of the pre-1970s cotton/pink bollworm system was used to examine the need for Bt cotton, conditions for its economic viability, and linkage to farmer suicides. Yields in rainfed cotton depend on timing, distribution, and quantity of monsoon rains. Pink bollworm causes damage in irrigated cotton, but not in rainfed cotton unless infested from irrigated fields. Use of Bt cotton seed and insecticide in rainfed cotton is questionable. Bt cotton may be economic in irrigated cotton, whereas costs of Bt seed and insecticide increase the risk of farmer bankruptcy in low-yield rainfed cotton. Inability to use saved seed and inadequate agronomic information trap cotton farmers on biotechnology and insecticide treadmills. Annual suicide rates in rainfed areas are inversely related to farm size and yield, and directly related to increases in Bt cotton adoption (i.e., costs). High-density short-season cottons could increase yields and reduce input costs in irrigated and rainfed cotton. Policy makers need holistic analysis before new technologies are implemented in agricultural development.

Gutierrez A.P., Ponti L., Herren H.R., Baumgärtner J., Kenmore P.E.. 2015. Deconstructing Indian cotton: weather, yields, and suicides. Environmental Sciences Europe, 27: 12. | Open access

Simulated phenology of cotton fruiting and pink bollworm in irrigated and rainfed cotton during 2005. The movement of adults to rainfed cotton during late summer is indicated by the broad arrow.

Sunday, July 19, 2015

Agrobiodiversity in a changing world

Exotic species that invade new areas cause economic loss annually nearly tenfold that of natural disasters. The economic impact of such biological invasions has been considerable also in agriculture, with many major agricultural pests being invasive species, which number is expected to increase given the combined action of climate warming and globalization, particularly in the Mediterranean Basin. This region is rich in natural and agricultural biodiversity but also considerably vulnerable to biological invasions that threaten key elements of Mediterranean agro-biodiversity such as the traditional perennial crops grape and olive. Currently, most major threats to grape and olive culture are invasive species - often vector borne diseases so serious that the only control method is removal and destruction of infected crop plants. However, how to assess the potential impact of such invasive threats, and hence how to manage them, remains an unresolved and largely unexplored problem. Gaps exist between theory and management of invasive species, mostly due to a limited ability to assess their ecological and economic impact. Mechanistic process-based demographic approaches such as physiologically-based demographic models (PBDMs) have the capacity to bridge these gaps, as they address many of the shortcomings that affect mainstream methods currently used to assess invasive species under climate change.

Ponti L., Gutierrez A.P., 2015. Climate change and invasive species, with a particular focus on vine and olives. A (bio) diverse world: agro-biodiversity in a changing world, EXPO Milano 2015, Milano, Italy, 6 May 2015.

Risk assessment for tiger mosquito in Europe

The Asian tiger mosquito (Ae. albopictus) is indigenous to the oriental region, but is now widespread throughout the world. It is an aggressive mosquito, which causes nuisance and is well known vector of important human disease. It is one of the world’s most invasive species and is now invading Europe by both natural means and human assisted dispersal. Currently, there is no consensus on the limits of its potential geographic distribution in Europe. For this reason, studying the role that environmental driving variables, mainly temperature, play in determining the spatial variation of the potential population abundance of the mosquito should be considered a high priority. To assess the risk posed by Ae. albopictus to Europe, a lattice model based on the temperature-dependent physiologically based demographic modelling approach has been developed and is being tested against field observations. The area of potential distribution of this insect is simulated as driven by current climate and climate change scenarios. An index of population abundance is derived in order to investigate the average annual abundance as well as the change in the pattern of population dynamics as a function of the local climatic conditions. Uncertainty affecting model parameters is also considered and the implication on model simulation is evaluated.

Gilioli G., Pasquali S., Ponti L., Calvitti M., Moretti R., Gutierrez A.P., 2015. Modelling the potential distribution and abundance of Aedes albopictus in Europe under climate change. Impact of Environmental Changes on Infectious Diseases, Sitges, Spain, 23-25 March 2015.

Area of potential establishment for the tiger mosquito in Europe under +2 °C climate warming.