London Agriculture

Thursday, October 30, 2008
London Agriculture

* The effects of agricultural intensification on biodiversity in arable systems of western Europe have received a great deal of attention. However, the recent transformation of grassland systems has been just as profound. In Britain, the management of grassland has changed substantially in the second half of the 20th century. A high proportion of lowland grassland is managed intensively. The major changes include a doubling in the use of inorganic nitrogen, a switch from hay to silage, and increased stocking densities, particularly of sheep. Structurally diverse and species-rich swards have been largely replaced by relatively dense, fast-growing and structurally uniform swards, dominated by competitive species. Most of these changes have reduced the suitability of grassland as feeding and breeding habitat for birds. The most important direct effects have been deterioration of the sward as nesting and wintering habitat, and loss of seed resources as food. Short uniform swards afford poor shelter and camouflage from predators, whereas increased mowing intensities and trampling by stock will destroy nests and young. Increased frequency of sward defoliation reduces flowering and seed set, and hence food availability for seed-eating birds. The indirect effects of intensification of management on birds relate largely to changes in the abundance and availability of invertebrate prey. The effects of management vary with its type, timing and intensity, and with invertebrate ecology and phenology, but, in general, the abundance and diversity of invertebrates declines with reductions in sward diversity and structural complexity. Low input livestock systems are likely to be central to any future management strategies designed to maintain and restore the ecological diversity of semi-natural lowland grasslands. Low additions of organic fertilizer benefit some invertebrate prey species, and moderate levels of grazing encourage sward heterogeneity. There is now a need to improve understanding of how grassland management affects bird population dynamics. Particularly important areas of research include: (i) the interaction between changes in food abundance, due to changes in fertilizer inputs, and food accessibility, due to changes in sward structure; (ii) the interaction between predation rates and management-related changes in habitat; and (iii) the impact of alternative anti-helminithic treatments for livestock on invertebrates and birds.


Here is an example of how human tampering with the environment for the reasoning of making our food situation better is effecting and harming other life forms. By reducing the biodiversity of the area it is deteriorating the soil and the habitat for animals and the food source for birds. Increasing the number of sheep on the land is also a benefit for humans (more meat) but is harmful to the environment and for the sheep themselves since this is most likely not an ideal situation.

I am not sure what the solution would be though. We could raise less sheep, and put less chemicals into the ground, but would we be able to produce a comparable amount of food? Is it cost effective to change our agricultural practices to something that is more natural to the environment? Having less food for the population is not an answer, or at least would not be a practical one, so I believe London did the best they could in trying to help the people and a lack of food for the birds is an unfortunate consequence. I am not trying to say that the birds are not important and we all know most people can afford to have less food, but the people who are going to have less food and the poor, and they are not the ones deciding to pour chemicals into the ground. So it would either be unfair to the birdies, or unfair to the people.

-Niki Lesniak