Ecologist Karin Albers on the importance of wild bees for biodiversity12 May 2023
Mobilane’s Green Talk series features experts speaking on a variety of topics. This time we spoke with drs. Karin Albers from the Netherlands; an enthusiastic and expert ecologist with an enormous passion and knowledge of nature and biodiversity. She gives more insight about the importance of wild bees for biodiversity.
Why wild bees are in trouble
Insects are a very important part of biodiversity. They are vital for a healthy ecosystem. They are pollinators of both wild plants and food crops and are themselves eaten by many other animals. Unfortunately, insect populations are declining at an alarming rate. Several studies report a loss in insect biomass of 70-80% in Europe in the last 3 decades. Wild bees in particular are suffering and this is mainly due to declines in the number and variety of flowering, native plants. A report that formed the basis for a study on the decline of bees states: “In the Netherlands, the threats to the bees are largely linked to intensive agriculture, which has dramatically changed the Dutch landscape since the mid-20th century. Fertilisation, flower poverty, desiccation and pesticide use have the greatest negative impact. ”
Another reason for the decline in bee numbers is the lack of nesting sites. More than 70% of all bee species nest in the ground. They dig holes in the sand, or they use existing cavities in the ground. Tiled gardens or tight, bright green lawns do not provide shelter for these ground-nesting bees.
About 20% of wild bee species nest above ground. Dead branches and old tree trunks and stumps provide nesting sites for these bees. But these are often cleared away and roadsides are mowed, which also prevents these bees from finding nesting or feeding sites.
Appreciation of local flora to support biodiversity
Cities are an ecosystem in themselves. Few are aware of this. Nature desperately needs all habitats, so nature-rich greenery and nature-inclusive building should become the norm. Ecologically, horizontal or vertical greenery does not matter, as long as it complements nature in the built-up area. This should ideally be as natural as possible. Green should therefore be more than just greenery; it should be local nature as much as possible. However, native plants are often considered less beautiful and therein lies a problem. People prefer colourful, exotic flowers and plants around them.
Among bees, there are generalists and specialists. Some species collect pollen from every flower they come across, while others are picky and only like pollen from one species. In addition, some plants are more suitable for honey bees while others are important for various wild (solitary) bee species. Importantly for both wild and honey bees, there is a wide variety of different plants and therefore different types of pollen. Much of the original local flora is replaced by homogeneous opportunistic species that thrive everywhere. For insects, a small habitat is enough. Green roofs and green facades have a huge potential area where, in terms of nature, much can still be achieved.
Biodiversity in urban areas
Biodiversity is vitally important. It is not just about having as many species as possible within an area, genetic variation within the same species is also important. It is the function of species within an ecosystem and the variation within it. Animals eat each other and look after each other and plants too are not just food and shelter but also part of the big chain. Without biodiversity, life on earth is no longer possible. Simply put, biodiversity provides clean air, drinking water, food, fertile soil and the pollination of crops.
There are too few natural areas, which is why it is so important to boost biodiversity in urban areas. It has been calculated that letting insects disappear even further, poses huge risks. It will cost billions. The more organisations contribute to recovery, the faster it goes, because there are many gains to be made.
Only nature-inclusive building and living can save natural values. Maintaining current natural areas is not enough, more nature needs to be added. Urban areas are such new places full of potential. Animals adapt quickly; a wall of a house, for instance, will be seen as a rock wall and a green roof will be seen as a meadow. You already see this with swallows, who think they live in caves, because the walls in our cities and villages resemble them. Bees too can live just fine in our gardens and on our roofs if we give them the opportunity.
Tips to help the bees and biodiversity
To help the bees in our area, there are a number of things we can do ourselves:
– Provide as much native planting as possible. Learn to appreciate the less exotic plants as well
– Install facades and green roofs on houses or barns and sheds
– Place bee hotels on sheltered south-facing walls
– Note that bird nesting boxes and bat boxes should not face south, as it gets too hot for them
– Placing a bee hotel also involves making sure the buffet is good. Plant flowers for both early and late species. Lungwort, for example, is an early flowering plant that is very popular with bees
– Willow and oak are the most important trees for insects so plant these if there is room for them
– Maintain the most natural and living soil possible in the garden and adapt the layout and species choice to the soil, rather than the soil to the species
– Provide structural variation in the immediate habitat. For example, create open sandy areas or make room for dead wood and branch rills, stones or shells. This also works well on a flat roof
– Leave dead branches and cut grass or fallen leaves until the first spring sun comes out. All insects that have overwintered there will come out of their hiding places with the spring sunshine
drs. Karin Albers
Karin Albers has over 20 years of experience in setting up and growing the ecological consultancy Ecologica. Sharing ecological knowledge is her passion. She has worked on numerous projects in design, management, monitoring, planning and policy-making. Her broad knowledge and experience in landscape ecology focuses on both flora and fauna, and she is at home in both urban and forest nature. She has also enthusiastically organised the ‘Symposium Ecology and Practice’, which always brings together over 300 professionals, for many years. She is a lecturer herself and seeks cooperation with specialists to offer specific course topics. Besides teaching courses, Karin also has extensive experience as a speaker, presenter and chairman of the day.