Page 95 - Ecuador's Banana Sector under Climate Change

chapter 4: assessment of climate change impact on banana production and suitability in ecuador, and general assessment of global banana trends under climate change scenarios
be considered as a latent risk under climate change effects (Tonnang et al., 2013).
In order to estimate the effect of temperature projections on the phenology
of the stem weevil, the Insect Life Cycle Modeling software (ILCYM - version
3.0) was used. ILCYM was developed by the International Potato Center and facilitates the development of pest insect phenology models and provides analytical tools for studying pest population ecology. Based on literature reviews about the development of the banana weevil under different temperature conditions and through the use of statistical tools, the necessary input data
to run ILCYM was generated. ILCYM was used to simulate the phenology of
C. sordidus and to predict the establishment risk and potential pest activity, according to temperature records. Linked with geographic information systems and atmospheric temperature models, three spatially referenced pest risk indices, displaying the risk of establishment, numbers of generations per annum, and an activity index were computed spatially and used to predict future changes in pest distribution and infestation due to global warming.
The simulation is based on maximum and minimum temperatures as inputs. For simulations, the set of global climate layers (grids) with a spatial resolution of 10 arc minutes (available at http://www.worldclim.org) and described in Hijmans
et al. (2005) were used. For predicting response to climate change, similar maps - using the same resolution - were generated for climate change scenarios (using an atmospheric general circulation model). These are downloadable from the CCAFS general circulation model data portal (http://www.ccafs-climate.org/data/).
In Figure 22, the risk mapping about generation index for C. sordidus is presented. Our results show an increase in the generation index, suggesting a shorter biological cycle of the stem weevil, estimating a higher mean number of generations that may be produced within a year. From Figure 22, it can be noticed that the areas, where banana is currently grown, display the highest number of generations per annum because they provide better conditions for the development of C. sordidus in terms of temperature. Furthermore, new areas in the mountain region appear to be more likely to present optimal conditions for the stem weevil.
The activity index (Figure 23), which is explicitly related to the finite rate of population increase considers the entire life history of the pest. As an example,
an index value of 4 would illustrate a potential population increase by a factor of 10 000 within one year. Figure 23 indicates an increase of C. sordidus’ population in areas where temperature could become optimum for its development. This increase in population only represents the potential growth under a specific temperature regime; all other population-limiting factors, including food availability, are neglected.
The activity index identifies areas in which C. sordidus may survive and become permanently established. The index is 1 when a certain proportion
of all immature life stages of the pest survive throughout the year. Otherwise, the number of days in which a single stage would not survive are counted and divided by 365 (Tonnang et al., 2013).
Comparing current conditions with the projections for the establishment index, we found arease in suitable areas where the insect could establish due to the
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