Biodiversity (english version)
What is biodiversity and why is it important to protect it?
Biodiversity is a collective term for diversity of species, between species and of ecosystems and it is the basis of all life on earth. It is rich nature with several different species that live together and create conditions for such basic things as clean air to breathe and water to drink. How well we protect the biodiversity today is thus crucial for our future life on earth. A dysfunctional nature not only affects the air we breathe and the water we drink, but also brings about a collapse of our food supply and economy. Biodiversity is currently declining faster than ever in human history.
One way to protect biodiversity is to carry out measures that benefit pollinators such as bumblebees and bees. These have a decisive role for biodiversity in that they prevent plant species from extinction, something that would negatively affect the entire ecosystem. In addition to this, the pollinators perform an ecosystem service through its pollination. An ecosystem service is a product or service humans get for free from nature, but which would be very costly if we were to create or perform it ourselves. Pollination is crucial for a large part of our food production, about a third of all the food we eat depends on it. Bumblebees and bees are responsible for the largest part of pollination in Sweden.
Who are the wild pollinators?
Besides bumblebees, domestic bees (honeybees) are perhaps the most known pollinators. Bumblebees are a type of wild bee and, unlike the domestic bee, belong to the wild pollinators. The wild pollinators include, in addition to bumblebees, remaining wild bees as well as flower flies and butterflies. Beetles can also visit flowers, but they generally contribute less to pollination. The different groups of wild pollinators have different needs and lifestyles.
There are approximately 300 species of wild bees in Sweden, including bumblebees. The wild bees depend on there being both nesting sites, wintering sites and food available throughout the period of the year when they are active. They can have three different ways of living; as social bees in societies, i.e. bumblebees, as solitary bees or as nest parasites. In general, solitary bees and nest parasites are more vulnerable than bumblebees. They are more dependent of a few plants or species, unlike the bumblebees, which can partake of a larger number of plant species.
The number of butterfly species in Sweden is as many as over 2500. There are great differences between these 2500 species, both in terms of size and to what degree they can be considered pollinators. The smallest ones are only a few millimeters in size and some of these do not count as pollinators because they do not transfer pollen. Some of them also live such a short time they do not eat anything. Butterflies depend on plants in several ways, with many of the larger species of butterflies and sphingidae, which can have wingspans of up to a decimeter, sucking nectar from flowers. All caterpillars feed on plants, making them vulnerable to grazing, trample or mowing at an inopportune time.
There are around 400 species of flower flies in Sweden, and they are characterized by the fact that they often stand still in the air and some of them imitate bees or wasps with their coloring. Flower flies mainly pollinates shallow flowers as they do not have a long tongue. The larvae develop in different types of environments, including in moist mud or as herbivores on relatively common plants.
Declining of species and individuals
For a long time, there has been a declining of wild pollinators, both in number of species and of individuals. Some of them are serious endangered. The declining is partly due to the landscape transformation and change in agriculture and forestry that took place, and still take place, beginning in the 20th century. The change has affected the habitats suitable for wild pollinators, for example meadows and forest pastures that have decreased in abundance. It is now increasingly longer between areas with suitable habitats, which makes it difficult for the wild pollinators to move between them. The survival of the wild pollinators now requires active work because the situation has become so serious.
Pesticides are also an underlying cause of the decline of wild pollinators. It has been shown that some pesticides negatively affect reproduction and survival of not only wild bees, but domestic bees as well. This is because certain substances in the pesticide absorbs by the entire plant that is sprayed and make the entire plant toxic to insects.
Food and nesting sites
The wild pollinators and the plant species they are associated with have adapted and evolved together over millions of years. The adaption exists so that the plant will only attract the insects that can transfer pollen from one flower to another and means that different plants favor different pollinators. The adaption can consist of, for example, the plant’s scent or color. The fact that plants and wild pollinators have adapted to each other makes the wild pollinators vulnerable in cases where wild plant species more often are being replaced with cultivated garden plants, because the pollinators cannot fully utilize cultivated plants.
In addition to access to food, the wild pollinators need nesting sites within a sufficiently short distance from the food. Sandy ground, rock cairns, water and old trees are the most important nesting sites and habitats for the wild pollinators.