Rural tranquility with a difference
"It was the nightingale and not the lark," is Shakespeare's famous quote. Today he would have difficulties with that, at least in England, because the lark is disappearing there - and with it many other birds. Industrialized agriculture is killing them.
Rural idyll: For ornithologists, these are skylarks, which trill over fields and meadows, quail, which cavort in adjacent hedges, and lapwings, whose chicks are safely hidden in the taller grass. Buzzards or kestrels circle above the scene and swallows chase after swarms of dancing mosquitoes. In the villages, barn owls dwell in church towers or old barns, tree sparrows gather around manure heaps or grain stores, and in the adjacent orchards the Ortolan flutes and little owls lie in wait for prey.
But this is a romantic image from the century before last, which at best still occurs in the more archaic farms of remote regions in Poland, Romania or the Ukraine. The reality is completely different: Instead of species-rich, nutrient-poor meadows, high-yield grasslands dominate, which can be mowed up to three times a year. Fields are drowning in manure, maize and rapeseed monocultures dominate cleared landscapes without bushes and flowering field edges. Old barns have been replaced by heavy-duty stables and church towers have been refurbished. Even the old orchards rich in structure had to give way to intensive apple orchards in many places.
This intensified agriculture brought us steadily falling prices for bread, butter and meat, but the development was devastating for the biodiversity of the cultural landscape. In Great Britain, the population sizes of most of the typical bird species have halved since 1970, and in Germany two-thirds of them are on the Red List of endangered species: In some places, former commonplace animals such as partridges, lapwings or snipes have already completely disappeared, and even those used to be a plague current tree sparrow is becoming increasingly rare.
The pressure on agriculture and the flora and fauna that depends on it will remain high or even increase in the future. This is ensured by the increasing demand for biofuels and soon, possibly, genetically modified high-performance plants that need to be more fertilized or sprayed. On the other hand, there are efforts to get so-called organic farming out of its previous niche existence. The consequences for bird life seem clear, but what would change in detail and how could further species losses be counteracted?
To answer that, Simon Butler of the University of Reading, UK, and his colleagues built a model incorporating six parameters of agricultural change [1]. Among other things, they considered increased use of pesticides, drainage of wet meadows, more frequent mowing and loss of fallow land to see how this is affecting the birds' food and nesting availability. They then tested how stocks changed under certain usage scenarios.
The result was relatively clear if more genetically modified, herbicide-resistant crops were to be used soon. The researchers estimate that the supply of food on such sugar beet or rapeseed fields will decrease again significantly, since insects and field weeds will disappear. Around forty bird species are likely to be affected: their breeding success is dwindling, and the numbers are continuing to fall. However, the status would only worsen above average for the meadow piper (Anthus pratensis) - so for the avifauna it doesn't make a big difference whether it's the previous conventional agriculture or future genetically engineered agriculture.
But what about organic farming, or conventional farming that takes more account of the natural elements in its environment than it does today? Relatively well, according to Butler and his colleagues, as long as they focus primarily on the availability of food and nesting sites and improve them in a targeted manner. A first initiative in this direction was launched in England in 2005, it has so far covered 1.5 million hectares of land and provided 47 million pounds for measures to preserve biodiversity in agricultural areas in the first year alone. However, initial evaluations indicate that they have so far focused primarily on hedges and field edges, but do not take the actual usable area into account - and thus do not compensate for the current disadvantages for the birds. Without upgraded core habitats, the species that are strictly dependent on them, such as the skylark (Alauda arvensis) or corn bunting (Miliaria calandra), are still in free fall, the researchers warn.
In addition to the changes in agriculture, people's leisure activities are also becoming problematic for the animal world, as ecologists around Antonio Rolando from the University of Turin report [2]. This is because regions that used to be difficult to access, such as the high mountains, are increasingly required: Because of the more frequent mild winters, ski slope and lift operators are moving to higher altitudes, which are still considered snow-sure, but also require major infrastructure measures - and thus endanger the creatures living there.
This is shown by a comparison by the researchers of alpine ski areas with natural meadows far away, where significantly more animals and more species were sighted than in the area converted into an amusement park. In a third of all departure areas, she did not even sight a single bird during the study period, and the populations were even thinner in the adjacent, unused areas. Sensitive species such as rock partridge (Alectoris graeca), chough (Pyrrhocorax pyrrhocorax) or wheatear (Oenanthe oenanthe) not only suffer from the direct disturbances and habitat changes caused by the leveling of slopes, mass tourism or the noise of artificial snowmaking.
The lack of food could affect them more seriously. Because insects and arachnids are obviously also disappearing from the slopes, which are themselves suffering from the decline in plant diversity - in many cases, the routes laid out and cleared with heavy equipment are then planted with a few high-performance grasses to prevent erosion. Many of the typical alpine flowers also suffer from being sprinkled with artificial snow, as it is more compact than natural snow and thaws correspondingly less well. It is also richer in nutrients, as its water often comes from specially created ponds, into which nutrients have been added themselves.
In order to prevent at least the greatest disadvantages for the bird world, Rolando recommends removing only the strongest bumps and disturbing rocks, stirring up the ground as little as possible or at least sowing native grasses and herbs for renaturation. But it shouldn't be more than cosmetics.
