Archive for the ‘population ecology’ Category

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.

Invasive potential of medfly in California and Italy

February 25, 2011 Leave a comment

Since being detected in California in 1975, the polyphagous tropical Mediterranean fruit fly (Ceratitis capitata Weid. (medfly)) has been the subject of a large-scale eradication campaign in the absence of sound knowledge of its invasive potential. We use a weather-driven physiologically-based demographic system model (CASAS) embedded in a GIS based on GRASS to examine medfly’s potential distribution across Arizona-California (AZ-CA), and Italy where its establishment is documented. AZ is unfavorable for medfly because of high summer temperatures, while much of CA, including many frost-free areas, is too cold during winter. Only the south near coastal region of CA is predicted to be potentially favorable for medfly, but in the absence of consistent measurable populations, we cannot say if medfly is established there. Medfly has been established in Italy for decades, and our model predicts a wide distribution in the southern and western regions of the country.

Gutierrez A.P., Ponti L., 2011. Assessing the invasive potential of the Mediterranean fruit fly in California and Italy. Biological Invasions, DOI 10.1007/s10530-011-9937-6.

Sardinia olive systems in a warmer climate

February 23, 2010 Leave a comment

In the Mediterranean Basin, major islands including Sardinia are considered particularly vulnerable to global warming and desertification. We used a physiologically based demographic model (PBDM) of olive and olive fly to analyze in detail this plant-pest system in Sardinia under observed weather (ten years of daily data from 48 locations), three climate warming scenarios (increases of 1, 2 and 3 °C in average daily temperature), and a 105-year climate model scenario for the Alghero (e.g. 1951-2055). GRASS GIS was used to map model predictions, and model calibration with field bloom date data was performed to increase simulation accuracy of olive flowering predictions under climate change. As climate warms, the range of olive is predicted to expand to higher altitudes and consolidate elsewhere, especially in coastal areas. The range of olive fly will extend into previously unfavorable cold areas, but will contract in warm inland lowlands where temperatures approach its upper thermal limits. Consequently, many areas of current high risk are predicted to have decreased risk of fly damage with climate warming. Simulation using a 105 year climate model scenario for Alghero, Sardinia predicts changes in the olive-olive fly system expected to occur if climate continued to warm at the low rate observed during in the past half century.

Ponti L., Cossu Q.A., Gutierrez A.P., 2009. Climate warming effects on the Olea europaea–Bactrocera oleae system in Mediterranean islands: Sardinia as an example. Global Change Biology, 15: 2874–2884.