- Monoculture: this is where a farmer specialises in one crop as opposed to many. It’s attractive to farmers because by growing only the best crop it increases productivity. It also means that more than one crop can be grown and harvested each year and saves on labour costs. However, by only growing one crop genetic diversity is severely reduced. This also has possible bad consequences for the farmer because the crop is then more susceptible to disease and leaves more room for pests to prosper. It also reduces the number of other plants around which in turn reduces the insects and animals that could feed on those pests.
- Hedgerows:from the era of the Anglo-Saxons hedgerows were planted to mark out boundaries for fields. In them many species of fauna and flora flourished. However, most have now been removed due to:
- more arable farms so less need to use for keeping in livestock
- wanting more room for planting crops
- being the home of pests like rabbits as well as weeds and diseases
- not wanting to have to spend time and money maintaining them
However, hedgerows have an ecological importance. It has been calculated that they can provide the habitat for about 30 tree and shrub species, 65 nesting bird species, 1500 insect species, and 600 wild flower species. They also provide a food source and shelter for various species of animal. Clearly, removing them has had a very negative impact on species number.
- Fertilisers: soluble, inorganic fertilisers leach out quickly from the soil into local rivers and lakes. This causes eutrophication. A number of terrestrial plant species are endangered due to this as well as having disastrous effects on marine habitats.
- Pesticides: similarly, artificial pesticides contain a number of dangerous chemicals which can lead to persistence, where the pesticide stays in the environment for a long time, and bioaccumulation, where chemicals build up in food chains.