Archive for the ‘Modeling’ Category

Agrobiodiversity in a changing world

July 19, 2015 Leave a comment

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

July 19, 2015 Leave a comment

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.

Asian citrus psyllid and citrus greening disease

December 2, 2013 Leave a comment

The invasive Asian citrus psyllid Diaphorina citri Kuwayama vectors the bacterial pathogen ‘Candidatus Liberibacter asiaticus’ that is the putative causal agent of citrus greening disease (Huanglongbing disease) in citrus in many areas of the world. The capacity to predict the potential geographic distribution, phenology and relative abundance of the pest and disease is pivotal to developing sound policy for their management. A weather-driven physiologically based demographic model (PBDM) system is developed that summarizes the available data in the literature, and used to assess prospectively the geographic distribution and relative abundance of citrus, the psyllid, its parasitoid (Tamarixia radiata Waterston), and citrus greening disease in North America and the Mediterranean Basin. The potential for natural and biological control of citrus psyllid is examined prospectively.

Gutierrez A.P., Ponti L., 2013. Prospective analysis of the geographic distribution and relative abundance of Asian citrus psyllid (Hemiptera: Liviidae) and citrus greening disease in North America and the Mediterranean Basin. Florida Entomologist, 96:1375-1391.

Process-based soil water balance for olive

August 1, 2013 Leave a comment

Olive is of major eco-social importance for the desertification-prone Mediterranean Basin, a climate change and biodiversity hotspot of global relevance where remarkable climate change is expected over the next few decades with unknown ecosystem impacts. However, climate impact assessments have long been constrained by a narrow methodological basis (ecological niche models, ENMs) that is correlative and hence largely omits key impact drivers such as trophic interactions and the effect of water availability. To bridge this gap, mechanistic approaches such as physiologically-based weather-driven demographic models (PBDMs) may be used as they embed by design both the biology of trophic interactions and a mechanistic representation of soil water balance. Here we report progress towards assessing climate effects on olive culture across the Mediterranean region using mechanistic PBDMs that project regionally the multitrophic population dynamics of olive and olive fly as affected by daily weather and soil water balance.

Ponti, L., Gutierrez, A.P., Basso, B., Neteler, M., Ruti, P.M., Dell’Aquila, A. and Iannetta, M., 2013. Olive agroecosystems in the Mediterranean Basin: multitrophic analysis of climate effects with process-based representation of soil water balance. Procedia Environmental Sciences, 19:122-131.

Potential distribution of light brown apple moth

February 23, 2010 Leave a comment

The highly polyphagous light brown apple moth (LBAM) (Epiphyas postvittana (Walk.): Tortricidae) is indigenous to Australia and was first found in California in 2006. It is currently found in 15 coastal counties in California, but nowhere has it reached outbreak status. The USDA projects the geographic range of LBAM will include much of Arizona and California and the southern half of the U.S., which together with economic estimates of potential crop losses have been used as the rationale for an eradication program in California. We report a temperature-driven demographic model to predict the likely distribution and relative abundance of LBAM using the detailed biology reported by W. Danthanarayana and colleagues, and climate data from 151 locations in California and Arizona for the period 1995 to 2006. The predictions of our model suggest that the near coastal regions of California are most favorable for LBAM, the northern Central Valley of California being less favorable, and the desert regions of Arizona and California being unfavorable.

Gutierrez A.P., Mills N.J., Ponti L., 2010. Limits to the potential distribution of light brown apple moth in Arizona-California based on climate suitability and host plant availability. Biological Invasions, DOI 10.1007/s10530-010-9725-8.