How Bees’ Diversity Is Changing Globally
All around the world, insects exist in abundance and their resistance to extermination isn’t about to change that fact. However, more and more evidence is being reported about declines in insect diversity and, consequently, the negative impact this has on what are referred to as “ecosystem services.”
Bees are one of the most important groups of insects because of their role as pollinators, being key to the sexual reproduction of wild plant species and the yield of most cultivated crops. The decline in bee populations has been steeper than in other insects, explained by their dependency on flowers for food and substrates for nesting that are affected by urbanization, land conversion, and other intensive land uses.
This study aimed to assess how bees’ diversity has been changing by analyzing the available data at the global biodiversity information facility on bees.
The results show an overall decline globally in bee diversity. Since the 1990s, the global biodiversity information facility records show fewer species being reported around the world. In the 2000s and 2010s, there was a fall of about 8% and 20% in the number of bee specimens collected worldwide, respectively.
Regarding family-specific trends, the results show that the declining trend is not driven by any specific bee family but rather by a generalized decline within the bee lineage. However, there is an increasing dominance by a few species at the local and regional scale and so less diverse bee assemblages that can be associated with a reduction in quantity and quality of the fruits and seeds produced by wild or cultivated plants. Most continents (except Oceania) seem to be contributing to the observed decline in bee diversity records.
The decline in records of species richness can be due to invariant samples, or they can be a reflection of a true global biological phenomenon by which thousands of species are becoming too rare to be sampled while other species are becoming dominant and even increasing in abundance.
The recent phenomenon of decreasing bee diversity was accentuated at the beginning of the globalization era (in the 1990s). It was a period of major economic, political, and social change, which brough with it an accelerated land-use transformation. Even though bees thrived in habitats driven by humans, as long as there was the diversity of floral and nesting resources (heterogeneous habitats), with globalization the expansion of land devoted to agriculture meant a decline of these diverse resources (homogenous habitats). Aside from this, the use of pesticides and other agriculture chemical inputs contributed to more impoverished and spatially homogeneous bee populations.
The authors admit here that the best-case scenario is that thousands of bee species have become too rare to be monitored properly. On the contrary, in the worst scenario, these bee species have already gone locally or globally extinct. Either way, it is urgent to slow down or reverse habitat destruction, stop land conversion into intensive uses, implement environmentally friendly schemes in agricultural and urban settings and create programs to re-flower the world.
For animal advocates, this study alerts for the ongoing decline of bee diversity. Because of the importance of bees in many ecosystems, advocates need to try to get the attention of the public, governments, and international institutions on this issue. To protect the planet and non-human and human animals, we need to protect the bees.