By Dr. Frank Drummond1,2, Seanna Annis1,2 and Hongchun Qu3
Climate Change and Blueberry Production (PDF)
Wild blueberry is well adapted to Maine’s climate (Drummond et al. 2009). However, commercial production of wild blueberry is restricted to the northern part of it current natural distribution (Maine, New Hampshire, Canadian maritime provinces, Michigan, and Quebec; Drummond et al. 2009), despite the fact that the major species comprising wild blueberry, Vaccinium angustifolium, can be found in the forest understory from North Carolina to northern Quebec and west to Minnesota and Manitoba (Vander Kloet 1988). However, changes in climate are already occurring in Maine. As climate continues to shift, more changes in the ecological interactions of this managed natural occurring food plant are bound to take place. We have developed a computer simulation model to investigate climate shifts in Maine wild blueberry.
Figure 1. Aerial view of a wild blueberry field, red is blueberry (A), simulated blueberry field through spring (B [prebloom] – H [fruit stage]); patches represent individual plants (clones), green represents stems in bud stage, yellow: stems in flower, orange: stems with both flowers pollinated flowers, and red: stems with fruit.
Our computer simulation model has been developed and parameterized by data collected in the laboratory and in the field in Maine wild blueberry fields. This model currently uses hourly weather conditions to simulate blueberry plant growth and development and the activity and foraging behavior of four different bee pollinator taxa (honey bees, bumble bees, digger bees, and leafcutting bees). The model also will incorporate the growth and development of mummy berry disease and its vectoring to flowers by bees. As bees visit flowers throughout the bloom season fruit set likelihoods are generated, mummy berry transmission will be estimated and yield (number of fruit and size) is calculated for each stem in the field. This model incorporates state of the art algorithms that allow simulation of a blueberry field across several scales of time (hrs, days, months) and scales of space (stems (sq. cm), clones (sq. m), and fields (sq. km).
We are currently validating the model for pollination based upon independent data collected between 2010-2016 . We are also conducting sensitivity analysis (ca. 2 million simulation runs) to identify parameters that affect fruit set and yield disproportionately. We will be adding validation of the mummy berry portion of the model with data gathered over the next few years. We have not yet added spotted wing drosophila to the model, but this should not be difficult since the foundation of the blueberry plant model has been completed.
Our hypotheses that we plan to initially test regarding climate change are:
- occurrence of wetter springs during bloom will result in:
- lower fruit set and the need for greater densities of honey bees due to less flight activity
- greater incidence of mummy berry disease AND a need to spray fungicide at more frequent intervals
- occurrence of warmer springs during bloom will result in:
- higher activity of honey bees and digger bees and less activity of bumble bees during bloom AND shorter bloom periods…thus we predict similar or higher levels of fruit set in fields that import honey bees, but less fruit set in fields that are entirely pollinated by native bees, especially bumble bees.
- occurrence of hotter summers and milder winters will result in:
- earlier and higher rates of increase and damage rates in fruit due to the spotted wing drosophila.
Drummond, F, J. Smagula, S. Annis and D. Yarborough. 2009. Organic Wild Blueberry Production. University of Maine Agricul. and Forestry Exper. Stn. Tech. Bull. 852: 43 pp.
Vander Kloet, S. P. 1988. The genus Vaccinium in North America. Publication 1828. Ottawa: Research Branch, Agriculture Canada. 201 p.
1 School of Biology and Ecology, University of Maine, Orono
2 Cooperative Extension, University of Maine, Orono
3 Division of Theoretical Research for Complex Systems, Key Laboratory of Industrial IOT and Networked Control (Chongqing University of Posts and Telecommunications), Ministry of Education, Chongqing 400065, China