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Analysis of invasive insects: links to climate change

September 12, 2014 Leave a comment

Climate change is expected to alter the geographic distribution and abundance of many species, to increase the invasion of new areas by exotic species and, in some cases, to lead to extinction of species. This chapter reviews some of the links between invasive insects and climate change. The effects of climate change on insect pest populations can be direct, through impacts on their physiology and behaviour, or indirect, through biotic interactions (i.e. bottom-up and top-down eff ects). Anthropogenic climate and global change is expected to be a major driver in the introduction, establishment, distribution, impact and changes in the efficacy of mitigation strategies for invasive species. To address these problems, we must be able to predict climate change impacts on species distribution and abundance. Commonly used ecological niche modelling approaches have implicit assumptions about the biology of the target species and attempt to characterize the ecological niche using aggregate weather and other factors in the area of recorded distribution. More holistic physiologically based demographic modelling approaches explicitly describe the biological and physiological responses of species to weather and the species they interact with on fine temporal and spatial scales. The geographic distribution and relative abundance of four invasive insect pests are reviewed under observed and +2°C weather scenarios across the USA and Mexico: the tropical New World screwworm, the pink bollworm, the Mediterranean fruit fly (i.e. medfly) and the olive fly. The distribution of the olive fly is examined across the Mediterranean basin to illustrate the transferability of the model to analyses of new regions and climate change scenarios.

Gutierrez A.P., Ponti L., 2014. Analysis of invasive insects: links to climate change. In: Ziska L.H., Dukes J.S., (eds.), Invasive Species and Global Climate Change. CABI Publishing, Wallingford, UK. ISBN: 978-1780641645. http://www.cabi.org/bookshop/book/9781780641645

Dry matter partitioning in a ladybeetle PBDM.
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Olive bioeconomics under climate warming

March 25, 2014 Leave a comment

Inability to determine reliably the direction and magnitude of change in natural and agro-ecosystems due to climate change poses considerable challenge to their management. Olive is an ancient ubiquitous crop having considerable ecological and socioeconomic importance in the Mediterranean Basin. We assess the ecological and economic impact of projected 1.8 °C climate warming on olive and its obligate pest, the olive fly. This level of climate warming will have varying impact on olive yield and fly infestation levels across the Mediterranean Basin, and result in economic winners and losers. The analysis predicts areas of decreased profitability that will increase the risk of abandonment of small farms in marginal areas critical to soil and biodiversity conservation and to fire risk reduction.

Ponti L., Gutierrez A.P., Ruti P.M., Dell’Aquila A., 2014. Fine scale ecological and economic assessment of climate change on olive in the Mediterranean Basin reveals winners and losers. Proceedings of the National Academy of Sciences, USA, http://dx.doi.org/10.1073/pnas.1314437111

Ultra-low, cryptic tropical fruit fly populations

March 12, 2014 Leave a comment

A comment appeared in Proceedings B reviews a study by Papadopoulos, Plant, and Carey (2013; “From trickle to flood: the large-scale, cryptic invasion of California by tropical fruit flies.” Proc. R. Soc. B: Biol. Sci. 280: http://dx.doi.org/10.1098/rspb.2013.1466) and suggests an alternative approach that addresses the biology of invasive species. In summary, inference of establishment of fruit flies based on recurrence data as performed by Papadopoulos et al. (2013) is neither explanatory nor provides confirmation of establishment in California. By contrast, physiologically based demographic models for medfly and olive fly accurately predict the potential distribution of the two fruit flies in California and elsewhere, and provide explanation for species phenology and dynamics that is critical for risk assessment and policy development for these and other invasive species under current climate and climate change scenarios.

Gutierrez A.P., Ponti L., Gilioli G., 2014. Comments on the concept of ultra-low, cryptic tropical fruit fly populations. Proceedings of the Royal Society B: Biological Sciences, 281, http://dx.doi.org/10.1098/rspb.2013.2825

http://www.faculty.ucr.edu/~legneref/cover/p13.jpg

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.
http://dx.doi.org/10.1016/j.proenv.2013.06.014

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.

http://dx.doi.org/10.1111/j.1365-2486.2009.01938.x

Can climate change influence olive pests and diseases?

September 26, 2009 Leave a comment

Climate change will make the Mediterranean Basin vulnerable to desertification, and this will affect many species such as olive in largely unknown ways. Olive is the base of a tri-trophic food web that includes pest, disease and their natural enemy species, each of which will be affected differently by climate change. The effects of extant weather and climate change scenarios on the tri-trophic interactions can be examined using biologically-rich physiologically-based demographic models developed from field and laboratory data. Studies from Sardinia, Italy and California show how the same model can be applied to these areas, and by inference, to other areas of the Mediterranean basin and elsewhere globally. Specifically, the model enables the examination of climate change on the range of olive and olive fly. The effect of climate change on natural enemies are illustrated using the olive scale/parasitoid interactions. The same system can also be used to examine the distribution and abundance of diseases. No model is complete, and required improvements can serve as a basis for interdisciplinary regional IPM research.

Gutierrez A.P., Ponti, L., 2009. Can climate change have an influence on the occurrence and management of olive pests and diseases? 4th European Meeting of the IOBC/WPRS Working Group “Integrated Protection of Olive Crops”, Córdoba, Spain, 1-4 June 2009. (Keynote address)

Mediterranean-wide analysis of the olive-olive fly system

August 6, 2009 Leave a comment


The Mediterranean Basin is expected to be particularly vulnerable to climate change including pronounced climate warming and desertification. Olive (Olea europaea) is of eco-social importance in the Mediterranean where it was domesticated, and it is also considered a sensitive climate indicator. This crop and its major pest, the olive fly Bactrocera oleae are a suitable model system to study Mediterranean climate. A weather-driven physiologically-based demographic model (PBDM) of olive and olive fly (http://cnr.berkeley.edu/casas/) is being used to analyze this plant-pest system in the Mediterranean region based on ERA-40 weather data (http://www.ecmwf.int/) downscaled via the regional climate model RegCM3 coupled to the MIT ocean model. PBDM predictions are mapped with the open source GIS GRASS (http://grass.osgeo.org/).

Ponti L., Gutierrez A.P., Ruti P.M., 2009. The olive–Bactrocera oleae system in the Mediterranean Basin: a physiologically based analysis driven by the ERA-40 climate data. 5th Study days “Models for Plant Protection”, Piacenza, Italy, 27-29 May 2009.
http://www.grimpp.it/v_giornate_di_studio.htm