Honeybees, for example, are not native to North America. They’ve since developed quite a track record in ecosystems around the world, including southern California and southern Spain. Their numbers have exploded since the 1960s, especially in areas with diverse floral resources. Both serve extremely important roles in agricultural landscapes. Given their sheer population size and the increased risk of outcompeting native pollinators or harming plants’ health, the question remains on whether these bees should be utilized.
Near Los Angeles in southern California, honeybees are thriving in the coastal scrub habitat. Incredibly, wild honeybees account for a jaw-dropping 98% of all bee biomass in the National Park. Their rapid spread has raised serious debates over the ecological impact of their establishment. Managed honeybee colonies, frequently placed for agricultural pollination, leak out into flower-rich forests once the local crops flower. This alarming phenomenon has initiated great concern about the impact of honeybees on our native plants and animals.
The Proliferation of Honeybees
The opposite has been true in southern Spain, where honeybee numbers have more than tripled since the 1960s. That growth is fueled by the region’s dynamic agriculture. This is especially true during the peak bloom season of orange groves, when thousands of colonies of managed bees are released into the wild. Dillon Travis, an ecologist studying pollinator dynamics, remarked on the impact of this influx, saying, “For this approximately month-long period, the impact of honeybees on native pollinators is likely huge.”
In some agricultural areas of Australia and America, honeybee densities can exceed 100 colonies per square kilometer. These non-native populations thrive and have a tendency to outcompete native species for limited food resources. Consequently, native pollinators—essential to the health of our ecosystems and biodiversity—are left competing for limited resources. Travis further emphasized the competition faced by these native species: “Native pollinators need to compete with millions of honeybees for limited food sources.”
Removal of pollen by honeybees appears to be particularly effective. Research suggests that honeybees can remove 95% of all pollen within minutes. The latest research out of southern California uncovered just how efficient honeybees are. Even on the first day of flower opening, they cleaned up an amazing 80% of pollen coming from flowering plants. This unsustainable race to consume resources has a profound impact on the overall health of nearby ecosystems.
The Ecological Impact of Honeybee Competition
This increase in competition between honeybees and native pollinators has ecologists, among others, worried for good reason. Introduction of non-native honeybees often results in poorer health of native plant populations. At least one researcher has documented that San Diego County native plants suffer health consequences when pollinated by non-native honeybees. Those plants prosper once pollinated by their local bee fauna. Pollinator ecologists are deeply concerned and increasingly frustrated by the ecological consequences of honeybee primacy.
Hung, an ecologist studying these dynamics, expressed concern over the overwhelming presence of honeybees: “I got to my field sites and all I was seeing were honeybees.” He compared the situation to an avid birder encountering feral pigeons in a pristine forest: “Imagine as an avid birder: you get to a pristine forest and all you are seeing are feral pigeons. That’s what was going on with me when I set foot in this habitat. It came as a shock.”
Furthermore, this competition for pollen isn’t simply a case of quantity versus quality, but instead one of timing. Honeybees are diurnal foragers and tend to forage earlier in the morning, stripping the majority of pollen before native bees even start their food hunt. This phenomenon can force native bee species out of their natural foraging patterns, playing a primary role in their decline.
The Global Perspective on Honeybee Invasions
Honeybees are exotic pollinators, having been shipped by humans around the world to every continent except Antarctica. Their expansion is regarded as one of the “most spectacular biological invasions of all time.” European honeybees are originally from Europe. Their introduction into non-native ecosystems raises important questions concerning their ecological effects.
Fortunately as ecologists such as Visick have recently pointed out, even relatively low densities of wild-living honeybee colonies can exist without harmful effects to other wild pollinators. He stated, “At these densities, wild-living colonies are unlikely to have a negative impact on other wild pollinators.” As honeybee populations, one of the planet’s greatest agricultural success stories, continue to boom, the balance is oftentimes lost.
Hung highlighted the challenges posed by such high densities of honeybees. “It is very difficult to imagine a scenario where a single species can remove four-fifths of all the pollen … without having too much of an impact on that ecosystem.” This quote highlights the unintended consequences for native plants and animals when honeybee colonies are allowed to propagate without limitation.