The California almond industry continues to expand every year, while the population of honeybees, beset by a host of problems, struggles to keep pace. Estimated almond bearing acreage in 2020 is 1.26million acres, up from 770,000 acres in 2010. Meanwhile over the same time period the stocks of beehives available in January each year have remained static at around 2.7million colonies(1). Beekeepers have kept pace with demand by supplying an ever-increasing proportion of the available stock of hives; which has increased from 57% in 2010 to 87% in 2019 (Figure 1)(2).
Although new orchard planting has slowed a little in recent years, the total bearing acreage is expected to continue increasing as the non-bearing acreage is still above what is needed for the replacement of old orchards. CDFA figures on nursery sales show that over the last 3 years, 56% of all trees sold were for new orchards(3). As a result, almond acreage is likely to reach around 1.4 million acres within a few years. This represents a maximum pollination requirement of about 2.7million hives (at current industry-standard stocking rates). Thus the demand for hives could exceed the number of colonies that exist. The trend analysis shows that unless something changes, available hive capacity could be exceeded by 2023 (Figure 2).
Concerns about bee shortages have been raised in the past, and disaster has not struck yet, but the issue is now acute as the number of available hives is nearing capacity. A hive shortage could lead to price increases and potentially a pollination crisis. Some growers are hedging their bets by contracting for more bees than they actually need, a strategy that could exacerbate the situation.
Furthermore, hive availability and colony strength vary year to year, depending on winter mortality rates. High winter mortality rates not only mean a lower supply of colonies overall but also a lower proportion of strong colonies (4) (Figure 3). Also, as the hives are needed in almond orchards in February, the industry is particularly vulnerable to changing winter mortality rates. There is no opportunity for beekeepers to split hives and build colonies to replace winter losses. Growers typically enter pollination agreements in the Fall, but have no visibility of colony status in the intervening time, only becoming aware of actual hive numbers and strengths when the hives are moved to orchards ready for pollination. This can create a last-minute scramble for hives if beekeepers are unable to meet contractual requirements. This situation is likely to worsen as hive numbers approach capacity.
Figure 3 Source: The Pollination Connection (2016); vanEngelsdorp et al. (2011, 2012); Spleen et al. (2013); Steinhauer (2013); Lee et al. (2015); Seitz et al. (2016); and Kulhanek et al. (2017); Goodrich, B.K. (2019)
The industry is taking steps to reduce its dependence on honey bees, such as the development of self-fertile almond varieties that require fewer bees for pollination and evaluating the benefits of other pollinators such as blue orchard mason bees. These are long term developments, and it will be many years before they make any real impact. Self-fertile almonds currently make up about 5% of bearing acreage, and new plantings of these varieties have slowed recently after strong initial growth.
The Almond Board of California has introduced a Pollinator Protection Plan which includes a range of initiatives aimed at improving honey bee health. This includes Honey Bee Best Management Practices, programs to increase floral diversity in orchards, and investment in honey bee health research. Reducing overwinter colony losses would increase the number of healthy hive stocks available for almond pollination in February.
A major part of the solution could be to re-evaluate the pollination metrics and practices used by the industry. The current industry-standard practice is to deploy an average of 2 hives per acre but this is based on research that is nearly 50 years old. The real pollination input is the number of bees per tree, rather than the number of hives per acre. A range of factors will influence pollination efficacy such as the timing of introduction and removal of the hives, their location and distribution in the orchard, tree variety, and density as well as external influences such as weather conditions and crop treatments. Currently, colony strength inspections sample 10-20% of hives (and are not always carried out) so growers never have full knowledge of the number of bees deployed in their orchards - the true pollination input is unknown. This calls into question not only the validity of the current rule of thumb for the deployment of honey bee hives but the whole economics and management of this vital agricultural input.
The application of precision agriculture technologies to the management of beehives and delivery of pollination services create opportunities for data-driven solutions.Optimum pollination input to suit different situations can be achieved by using sensors and data analytics to monitor hive health and bee activity. What is a dramatically different approach has the potential to reverse the current trends, help to improve bee health, and ensure the sustainable delivery of pollination services for almond orchards.