 Under grazing on the other hand can result in the vegetation growing so much that it is rendered unsuitable for ground nesting birds due to its composition changing and scrub conditions prevailing.
Hay meadows replaced by silage
Another example of a species falling foul of farming changes is waders that breed in hay meadows such as the Black-tailed Godwit in the Netherlands. There are vast areas of lush Dutch meadows in which Black-tailed Godwits have found a home for many years. Hay meadows are wonderful places. Full of native plants and flowers upon which butterflies and other invertebrates can feed and breed attracting their predators. Among those predators are waders. In these meadows waders find a safe haven to breed, concealed by the growing grasses and other plants, the young are protected from prying eyes and also find plenty to eat and soon they fledge and fly to other habitats to continue their development before the hay meadows are cut in late June.
Well that is how it used to be, but these meadows are few and far between these days, they have been replaced by silage, a fast growing monoculture plant that can have several yields a year. The consequence for the natural world is that it is a much more sterile environment, no flowers grow and few other plants flourish which means there is nothing for the invertebrates and by dint, those that prey on them, to eat. Worse still, if the waders choose to breed in them they will seldom be able to bring off their young. Cutting can take place in early June before the chicks are fledged; they are defenceless against the mowing machines. If the cutting is earlier still, the chicks may be lost or the nest with eggs destroyed, earlier still and the birds find nowhere to nest at all. Either way, an entire population of birds is no longer able to reproduce and declines are inevitable as youngsters are not replacing the older birds that don’t survive each year.
In Brazil for example, there was much trumpeting about how they had reforested vast swathes of land, and therefore they were the defenders of the environment. However what was emerging was a forestry industry that planted exotic Eucalyptus trees and not native rain forest trees rendering them almost useless for all but the most adaptable of local fauna. Those areas grew quickly but then of course inevitably they too were clear felled. Whilst this did not, with the possible exception of Southern Lapwing, cause a great problem for waders, it shows that afforestation needs to be viewed with some scepticism when it comes to environmental improvement.
Worse still are the schemes where exotic forests are cultivated to the detriment of natural habitats. In the North York Moors of England for example the scars of dark green plantations stood out like acne on the face of a fresh young teenager, somehow menacing in their march across the more open landscapes desired and required by the moorland birds. The ribbons of dry stone walls and heather being engulfed by the advancing army.
In Iceland too forests have replaced heathland. These Icelandic heathlands are a veritable goldmine for those in search of breeding waders. Eurasian Golden Plovers, Eurasian Whimbrel and Common Snipe are dominant and in the more humid areas they will be joined or replaced by Black-tailed Godwits, Dunlins and Common Redshanks. The common thread that links all these birds is of course that they are not forest birds so replacing their natural habitat with trees has a devastating effect on their local population eventually wiping it out completely.
In the same way afforestation occurs in Africa where large areas of scrub and savannah are covered with trees. These trees have an entirely negative impact on grassland bird diversity even in relatively small projects. Studies have shown that if you compare the diversity of bird species that benefit or otherwise from afforestation, grassland communities possess more species and are richer in both endemics and threatened species than those to be found in plantations. The species that depend on these grasslands in