In our daily environment there are countless living organisms, only a few of which we can see, but all of them have an impact on each other and on us. Thanks to the multitude and variety of life forms around us, we have food, we enjoy the view of nature, but on the other hand we have to protect our health, crops and homes.
Biodiversity, as a concept, has recently been very popular, even overused, as a major paradigm in ecology and contemporary environmental and conservation policy.
The term “biodiversity” is a creation of M.W. Rosen, who co-organised the 1986 National Forum on Biological Diversity conference. The term was used in the context of environmental threats, particularly in relation to the issue of species extinction. Biodiversity is a concept that expresses the whole dynamism of living nature. Variation results from the deactivation of dormant genes or a change in the genome content of a species over evolutionary time due to selection influences from the environment and, for millennia, also as a result of deliberate human activity.
Biodiversity is of fundamental importance to the course of evolution and the sustainability of life-support systems in the biosphere. In order to protect biodiversity, it is necessary on the part of humans to anticipate, prevent and combat the causes of its decline or disappearance.
In 1992, at the ‘Earth Summit’ in Rio de Janeiro, the concept of biodiversity was defined. According to this convention, biodiversity is ‘the variability among living organisms in all environments and among the ecological systems of which they are a part, such variability including intraspecies diversity, interspecies diversity and ecosystem diversity’. Put simply, biodiversity is the diversity of all living organisms on Earth.
Each species has a function in the whole of the animate world and there are no organisms better or worse. We can only determine which are more beneficial to us humans and which are less so. A common feature of all living beings is their variability, which is an adaptation to the constantly changing conditions of life. This variability is individual and species-specific, taking shape over hundreds and thousands of generations, creating opportunities to adapt to changes in the environment. If these conditions change very rapidly and adversely – living organisms that cannot adapt – perish. Especially global events, such as climate change, can cause mass extinction of species.
Most species of the world’s living organisms are adapted to the environmental or food niche they occupy, and changing or eliminating it directly affects their chance of survival. There are thousands of well-known examples, from lynx in Polish forests to orangutans in Borneo. There are also species with tremendous adaptive capabilities – humans among them – that are able to survive under extremely different nutritional, environmental and social conditions. A constant principle of the living world is that it is not the strongest, not the smartest, or the largest species that survive, but those that best adapt to changes in their environment. In 2017, the International Union for Conservation of Nature published the so-called Red List – a list of all species at risk of extinction. The report included 91,523 plant and animal species.
There are many definitions of biodiversity and ways to define and measure it.
Various indicators are used to compare the biodiversity of different environments or the biodiversity of assemblages of organisms inhabiting an environment at different times. One of the most commonly used is species richness, i.e. the number of all species present in an area. However, it is difficult to interpret changes in biodiversity, which can be the result of natural trends as well as harmful human activities, because we do not know exactly the whole system of interconnections and interactions between living organisms and the climate and environment.
The overall biodiversity of our world is defined by species richness, i.e. the number of all species living on Earth – from bacteria to humans. It is estimated at more than 10 million, of which only 1.8 million have so far been described. The number of species in ecosystems depends mainly on physical (e.g. temperature, humidity) and biotic factors (food, competing and symbiotic organisms).
In agriculture, biodiversity consists not only of the variety of species and varieties of livestock and crops, but also of the wealth of other plants and animals that accompany food production. We usually refer to such plants as ‘weeds’ and animals as ‘pests’ or ‘parasites’, although in reality these are organisms that are no worse for the living world than the ones we care about. They do, however, create competition for human beings by limiting the production of food – the most strategic product on Earth – which is the reason for taking up arms against them. In contrast, the hundreds and thousands of other organisms that support us in food production, whether bacteria, fungi or insects, are called ‘beneficial organisms’. The diversity of life has both natural and economic value, a resource that is essential for producing food that is of good quality and affordable. In sustainable agriculture, biodiversity needs to be encouraged and built upon, as does soil fertility and the financial stability of the farm.
By caring for biodiversity, farmers prevent the spread of pests and diseases without the intensive use of chemicals.
Farmers do not like insects because they are ‘pests’, which is not true. Only a few percent of insects harm our crops, we know them exactly and know how to control or reduce them. All others are indifferent or beneficial to our crops. It happens that some insects or, for example, roe deer feed on our crops, but this does not yet mean that they harm them. Once the rapeseed strawberry has developed from a dangerous pest to a very valuable pollinator. The value of the damage is decisive. If the economic damage threshold is not exceeded, it is unnecessary to take any action. However, when we see that the possible damage will be greater than the cost of a protection treatment, we should carry it out. The same applies to undesirable plants (weeds) or fungi. In the case of livestock production – for epidemiological reasons – it is different and every sick animal should be treated to avoid escalating losses. The most effective protection for our crops and livestock is prevention. Where pests and diseases remain under control through a combination of organisational, cultivation and technical measures, the best and at the same time cheapest food is obtained.
Soil organisms. The living organisms that make up the soil – the basis of agriculture and food production – deserve special attention. It is a very complex system of relationships between bacteria, protozoa, algae, slime moulds, fungi and other plants and animals that determines soil quality, fertility and productivity. Each group of organisms has its own role to play, animals (e.g. earthworms, insect larvae, hundreds of arthropod species, as well as small mammals) break down organic matter, while fungi and bacteria process it biochemically. Among the approximately 100 000 species of organisms living in the soil, we can only identify a few per cent of those that can harm our crops. The others help their growth or are neutral. Soil can be good or toxic for crops – and this depends on the microorganisms in it and on human activity. By taking proper care of humus content, soil pH, soil structure and abundance – we are always promoting the improvement of soil biodiversity and soil quality. If the soil becomes acidified, bacteria overpowering fungi, anaerobic, resulting in hydrogen sulphide in the soil and toxic aluminium ions Al+3, we destroy soil fertility and the chance of a good, profitable and quality crop. For the farmer, concern for soil biodiversity always pays off.
Pollinators. Organisms that pollinate plants are of great importance for the quality of human life. These are mainly bee insects (about 25 000 worldwide, about 2 500 in Europe and about 470 species in Poland), but also butterflies, beetles, ants, hoverflies and insects belonging to other families, as well as some species of birds, bats and even lizards. Honey bees are one species in this range, very useful in agriculture, but not the only one. Therefore, when protecting and caring for pollinators we need to keep in mind the whole spectrum of them, bumblebees, solitary bees, butterflies and buzzards. Each pollinator species has its own spectrum of plants that are its preferred forage. For example, of the orchard and horticultural plants of interest, honey bees prefer raspberries, pumpkin and onions, among others, slightly less so apple trees, and hardly at all interested in pears and strawberries.
For a number of years there has been a campaign in Europe – against the obvious facts – to publicise the alleged extinction of honeybees. Its aim is to exclude plant protection products from agriculture. It has been believed by 71% of Polish citizens. However, the truth is different: according to FAO Stat research, from 1960 to 2018 the number of honeybee colonies increased by 85% worldwide, and in Europe and North America it has been growing continuously since 2000, reaching a record high of almost 17 million colonies in Europe and 3.3 million in America. In Poland, the number of 1.5 million bee colonies was exceeded for the third time in 2018. This had previously occurred in the 1920s and 1980s. On the occasion of the UN’s World Bee Day, an information campaign on bees was launched.
According to the FAO, 92% of the tonnage of food consumed by humans comes from plants that do not benefit from the assistance of pollinating organisms (cereals, maize, potatoes, cane and sugar beet, nut trees, palms, cassava, rice and many others) and from salt and fresh waters (algae, crustaceans, molluscs and fish). The remaining 8% of the tonnage of food consumed is produced by the activities of pollinators and these are hundreds of different plant species, mainly fruits and vegetables, which determine the quality of our nutrition. Pollinators do an enormous amount of work for agriculture, the value of which is estimated at USD 235-577 bn worldwide (IPBES Report 2016), and in Poland at PLN 4-6 bn per year.
In addition to edible plants, pollinators enable the persistence of thousands of species of other plants in our environment, enabling the entire animate world to exist normally and creating comfort in our lives.
Aquatic organisms. Aquatic organisms are a very diverse group of plants and animals whose permanent or partial habitats are watercourses or bodies of water, including the seas. They include plant organisms ranging from cyanobacteria and algae to seaweeds, reeds, calamus and plants growing on sea shores, and animals ranging from plankton, arthropods, molluscs, fish, amphibians, reptiles to birds and aquatic or water-related mammals.
Aquatic organisms can have a direct impact on the agricultural environment (e.g. beavers), although they themselves are much more dependent on neighbouring land from where fertilisers, other agricultural chemicals, or pollutants, industrial or municipal, can enter the water. The assemblage of aquatic organisms, especially bacteria and higher plants, do an invaluable job in cleaning up standing and flowing waters. This characteristic of bacteria is used in sewage treatment plants. However, ecosystems in midland watercourses and reservoirs are vulnerable to larger pollutants that can completely destroy them.
Birds. Changes in the biodiversity of agricultural space began to be recognised in the second half of the 20th century by observing bird populations in Western Europe. At that time, these were the only data available, documented for more than a century, to assess the changes that had occurred. To this day, the species composition and numbers of birds present in agricultural spaces is an important indicator of the biodiversity changes taking place. Analyses of changes in insect populations, as well as plant populations in some countries over the past decades, are already available. These are still partial data, but they already allow us to identify the main causes of change: loss of habitat (living, nesting and feeding sites) due to human activity and ongoing climate change.
For the preservation and enrichment of biodiversity, the restoration and diversification of habitats and human activities in this direction are of great importance. Protection of poorly or not at all transformed (so-called natural) habitats is a priority. Any piece of land that is not very suitable for agricultural production – a swamp next to a ditch, an embankment, a corner of a field inconvenient for cultivation – can be a valuable habitat for plants and animals important for maintaining biodiversity. It is also possible to create transitional habitats by leaving small patches of unplanted land in the field (so-called ‘skylark windows’) or by creating green belts at the edges of fields.
Crucial to the maintenance of biodiversity in agricultural space are:
- mid-field afforestation and shrubbery,
- ponds, wetlands and peat bogs,
- baulks and wastelands,
- extensively used meadows and pastures.
Such sites are an invaluable resource for insects, birds, reptiles, small and large mammals that do not find their habitats to live in agricultural spaces.
In forested areas, the key to maintaining biodiversity is:
- decayed trees and fallen trunks (dead wood),
- old-growth forests,
- bogs and mid-forest clearings.
Rare insects, birds of prey, aquatic birds, amphibians, reptiles and a range of small mammals will find their habitat in such places.