Project overview

Goals of the project

The long-term goal of this project is to develop interdisciplinary tools for the analysis of ecological and agro-ecological problems that emerge at the interface between global change and biological systems (i.e., global change biology); tools to help European governmental agencies develop sound response policy to cope with these problems. Considerable progress has been made in analyzing ecosystem problems using physiologically based demographic Ecosystem Models (EM; i.e. CASAS models; see http://cnr.berkeley.edu/casas/) integrated into Geographical Information Systems (GIS). Grape and olive systems will be used as the basis for developing and implementing the EM/GIS tools in the Mediterranean Basin, a climate change and biodiversity hot-spot of global relevance. A major goal of this proposal is to link EM/GIS technology with remote sensing data (RS) to bridge the gap between bottom-up (primarily physiological and population dynamics) and top-down (climatological) GIS approaches for assessing on ground ecosystem level problems. Implementation of the EM/GIS system in the Mediterranean region will provide the basis for evaluating future challenges due to climate change, invasive species, and developing agro-biotechnologies.

Olive and grape

Available data on grape and olive culture were collected, and a review of main approaches used to estimate the potential distribution of native and invasive species in agricultural, natural and medical/veterinary vector/disease systems in the face of climate change was carried out. After CA-AZ-IT A detail study of climate warming effects on olive and its major pest olive fly (Bactrocera oleae) was performed for Sardinia as this and other major islands of the Mediterranean are considered particularly vulnerable to global warming and desertification. Model calibration with field bloom date data increased simulation accuracy of olive flowering predictions under climate change. Many areas of current high pest risk are predicted to have decreased risk of olive fly damage with climate warming (Fig. 1). The multitrophic dynamics of olive and olive fly were mapped using the open source GIS GRASS (see http://grass.osgeo.org/).

Figure 1. Average cumulative olive fly pupae (10³ season^-1 tree^-1) (a) and percent fruit attacked (e) in Sardinia (Italy) simulated under observed weather (1997-2007) and three climate warming scenarios (+1, +2 and +3 °C) (olive fly pupae: b–d; percent fruit attacked: f–h). Each scale bar is valid for subfigures on the same row. From: 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

A Mediterranean-wide analysis of olive and olive fly was performed based on ERA-40 weather data downscaled using the PROTHEUS regional climate model (see http://clima.casaccia.enea.it/PROTHEUS/) (Fig. 2). PROTHEUS provides fine-scale climate information specifically designed for climate impact assessment in the Mediterranean Basin as it includes an improved representation of the Mediterranean Sea that allows more realistic climate simulations for the region compared to previous global or regional climate models. The ERA-40 climate data layer used in the analysis includes all available satellite observations, and hence its integration into the EM/GIS system can be considered a first link to RS data. In addition to the ERA-40 present climate data, the Mediterranean-wide analysis was further run using realistic high-resolution regional climate change data also obtained via PROTHEUS and developed within the European project CIRCE (Climate Change and Impact Research: the Mediterranean Environment; see http://www.circeproject.eu/). These scenario simulations of climate change are the first to include a realistic representation of the Mediterranean Sea into the climate system.

Figure 2. Average cumulative olive fly pupae (season^-1 tree^-1) (a, b) and percent fruit attacked (e, f) in the Mediterranean Basin for the period 1958-1967 and 1988-1997. From: Ponti L., Gutierrez A.P., Ruti P.M., 2010. The olive–Bactrocera oleae (Diptera Tephritidae) system in the Mediterranean Basin: a physiologically based analysis driven by the ERA-40 climate data. Notiziario sulla Protezione delle Piante – III Serie, 1: 113-128. Available at: http://utagri.enea.it/sites/default/files/ponti-notiziarioaipp_2009.pdf

A regional analysis of grape and its key pest the European grapevine moth (Lobesia botrana) was first performed for California that was invaded by the pest in 2009. The analysis was then extended to the whole north America and the Mediterranean Basin. Lobesia botrana is the principal native pest of grape berries in the Palearctic region. It was found in Napa County, California, in 2009, and it has subsequently been recorded in an additional nine counties, despite an ongoing eradication program. A holistic physiologically-based demographic model for L. botrana linked to an extant mechanistic model of grapevine was run using observed daily weather data to simulate and map via GRASS GIS the potential distribution of the moth in California and the continental USA (Fig. 3) The model predicts L. botrana can spread statewide with the highest populations expected in the hotter regions of southern California and the lower half of the Central Valley. In the USA, areas of highest favorability include south Texas, and much of the southeast USA With climate warming, L. botrana abundance is expected to increase in northern California and in the agriculturally rich Central Valley but to decrease in the hot deserts of southern California due to high summer temperatures.

Figure 3. Predicted geographical distribution and mean relative abundance of Lobesia botrana in the USA: cumulative pupae plant^-1 year^-1 below 2000 m elevation. From: Gutierrez A.P., Ponti L., Cooper M.L., Gilioli G., Baumgärtner J., Duso C., 2012. Prospective analysis of the invasive potential of the European grapevine moth Lobesia botrana (Den. & Schiff.) in California. Agricultural and Forest Entomology, 14: 225-238. http://dx.doi.org/10.1111/j.1461-9563.2011.00566.x

Invasive species

In addition to grape and olive, other issues of global relevance were also addressed, particularly invasive species and the assessment their potential geographic distribution and relative abundance. For example, the Mediterranean fruit fly (Ceratitis capitata, medfly) and the light brown apple moth (Epiphyas postvittana, LBAM) are two invasive insect pests studied during the project. Medfly is a cosmopolitan polyphagous species of East African origins that was first detected in California in 1975, but persistent measurable populations of the pest have not been subsequently found. Yet a large-scale detection/eradication campaign has since been place in the absence of sound knowledge of the fly’s potential invasiveness and geographic distribution. Our analysis suggests that temperatures are unfavorable for medfly in much of California and hence questions the scientific basis for the ongoing eradication program (Fig. 4).

Figure 4. Annual maps of simulated medfly pupae per tree per year across California during 1996-2005 (a-j). The vertical histogram in each subfigure represents the relative range of densities compared to the maximum during 1999. From: Gutierrez A.P., Ponti L., 2011. Assessing the invasive potential of the Mediterranean fruit fly in California and Italy. Biological Invasions, 13: 2661-2676. http://dx.doi.org/10.1007/s10530-011-9937-6

Native to Australia, LBAM was first found in California in 2006 and has thereafter spread to coastal areas of the state causing no economic damage despite its broad host range. In 2007, however, a controversial program of aerial sprays was begun over urban and suburban areas to eradicate LBAM based on its predicted wide geographic range (including much of Arizona and California and the southern half of the US) and consequent economic losses estimated by the United States Department of Agriculture (USDA). The predictions of our mechanistic model differ markedly from those made by USDA using on a simple degree-day accumulation model, and show that the potential distribution of LBAM in California is, as observed, largely restricted to near coastal areas (Fig. 5). Our analysis of LBAM in California contributed to switch the LBAM eradication program to one of containment.

Figure 5. Mapping of average simulated light brown apple moth populations (larval days during 1996–2005) in Arizona and California: (a) locations where the moth has been recovered in northcentral California (from Fowler et al. 2009) and (b) the simulated average distribution below 750 m. From: 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, 12: 3319-3331. http://dx.doi.org/10.1007/s10530-010-9725-8

Other invasive species analyzed during the project include pink bollworm (Pectinophora gossypiella) on cotton, glassy-winged sharpshooter (Homalodisca vitripennis) on grape, screwworm (Cochliomyia hominivorax, a parasitic fly that attacks livestock), the tomato borer Tuta absoluta, and Asian citrus psyllid (Diaphorina citri) on citrus. Further emerging issues in global change biology such as the bioeconomics of biofuel production on marginal lands were also tackled.

Significance

The integrated EM/GIS system is a library of current knowledge about grape and olive agroecosystems that can be extended to other systems, updated with new knowledge and used to help guide multidisciplinary research on local and regional scales. The combined innovative EM/GIS/RS tool will provide European governmental agencies with the scientific basis for developing policy required to adjust to global change including climate warming.