One strongly negative aspect of most gardens is noise and disturbance from traffic, people and pets. Some of our rarer birds are very intolerant of disturbance, and could never nest in any but the biggest, most deeply rural gardens. Some of our familiar songbirds seem to have adapted to disturbance and tolerate lots of noise, but have been found to have to sing louder, or in higher notes, to make themselves heard and maintain their territories.
Dogs and cats, particularly the latter, are a significant source of disturbance by day and by night. This is one of many areas where gardeners could make useful observations and help our understanding of garden ecology.
Another generally negative aspect of urban gardens is their high level of light pollution, such that some urban children may never have seen the stars. Wildlife is definitely affected, with birds singing earlier in the year and later into the evening. Many insects are attracted to light, and some killed by exhaustion, or by bats, which find street lights a benefit by attracting their prey.
Pollution and chemicals
Pollution is nothing like as bad in British cities as it was fifty or more years ago before the Clean Air Act, but we still
suffer from traffic fumes and some industrial air pollution. We know this has significant effects on plants in controlled experiments, but remain ignorant of how much effect it has in garden wildlife in different built up areas.
One other issue here is the tendency of many gardeners to over-fertilise their soils. This isn’t a great problem, but it
can cause poor water quality in garden ponds, and it certainly makes it easy for grass and other weeds to out-compete slower growing and delicate flowering plants.
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Page written by Steve Head reviewed by Ken Thompson