In An English Country Garden

The title of this article is inspired by the song ‘English Country Garden’, written by Jimmie Rodgers in 1962 although surprisingly he is not English but from the US.

I am writing this having recently returned from a six-week visit to Sabah where I had the pleasure of meeting people who are contributing significantly to conservation in East Malaysia. They are part of an important state-wide debate on how Sabah’s economic and social development can be successful whilst at the same time its incredible wildlife is protected.

Talking with them and travelling around Sabah has made me realise how rapid and extensive some of the changes currently occurring are. The building programme in KK and the development of oil palm plantations are two examples: catering for tourism and earning foreign exports.

It struck me that the UK is also changing but here the conservation debate doesn’t seem to have such a high profile. I live in High Wycombe, in the South of England, with my English country garden, and because we are only 30 miles from London, there is continuous pressure for housing and there is also a major new railway planned to pass close by, linking London to Birmingham. It is also a region that is extensively farmed, with the landscape dominated in places by large fields of crops such as wheat and rape seed. Nor have I mentioned Brexit, UK’s withdrawal from the European Union, (that will eventually happen) which will require changes to laws relating to most aspects of our lives, including farming, fishing and conservation.

So how do all these changes manifest themselves in an English country garden?

One thing that I was reminded of in Sabah is how you cannot consider species in isolation: a change to a single species will have knock on effects to others, whether plants or animals. In other words, in order to study a species, you have to understand its ecology. My background is zoology and so I have chosen illustrate these changes with reference to the population of some insects that I have observed in my garden. If you like, they are ‘indicator species’, so that my observations reflect much broader changes in the garden and UK countryside beyond.

Butterflies: same species, changing numbers

In the wealthier South of England it is noticeable how much time, effort and money house owners can devote to their gardens: bird tables and feeders being obvious examples; many gardens have one or more of these, continuously supplied with a variety of seeds. Then there is the huge range of garden plants, many originating from other countries, often from South East Asia. Buddleja davidii (B. davidii), the so called butterfly bush, is an obvious example; it was introduced from China in the 1890s but is now commonly seen in gardens and growing wild. Most towns have a ‘garden centre’ where gardeners can buy all these flowers and bird food.

You might expect, therefore, that birds and butterflies would be common residents and visitors to many gardens, including my own. But is this true in the 2017? 

My garden is typical of the South of England: butterfly numbers are down. In fact the actual number of species I have seen this summer (12) compares well with what would have been seen 30 years ago but it is the number of each species that is worrying: too often I have seen just individual butterflies. I have 3 B. davidii bushes but this year have only seen a maximum of 4 butterflies together on a bush at any one time. Most UK naturalists will have fond childhood memories of B. davidii flowers being covered with Red Admirals (Vanessa atalanta), Small Tortoiseshells (Aglais urticae) and Peacocks (Inachis io) adults. The same is true for many other ‘insect friendly’ plants and shrubs that many UK gardeners are being urged to plant: butterflies in low numbers, much lower than in previous decades.

One exception to this decline occurs in my list of 12: the Comma, Polygonia c-album, which is also a lover of the butterfly bush. This is now as common as the Peacock and Red Admiral but was rarely seen when I was young; it is bucking the trend: increasing not decreasing.

However, the overall decline in butterfly numbers I am describing is part of a general fall in numbers of ‘insect pollinators’ seen in many parts of the UK. Other examples from my garden include wasps and bumblebees.

Wasps and plums

It used to be common for children to be warned about ‘drunken wasps’. In late summer (August), soft fruits such as plums ripen and are ready for picking. The ripening fruit also attracts adult wasps, usually the Common Wasp, Vespula vulgaris, which feed on the plum flesh which has begun to ferment gently in the sun. The wasps become ‘drunk’, in fact they are drowsy, and will often sting if touched by fruit pickers. I have a plum tree but this year no wasps! Not one to be seen! 

But it is not all bad news: in contrast, last year I noticed a nest of a different wasp Dolichovespula sylvestris, the tree wasp, in a hedge at the bottom of the garden. A new species in the garden!

Bumblebees

At the last count, there were 24 species of bumblebees in the UK, all belonging to the genus Bombus, with a further 3 species now reported to be extinct. 8 of the 24 species are generally regarded as ‘quite common’ and I have seen 4 of the 8 in my garden this year. Since they are relatively large and fly for long periods of the day, bumblebees are easy to spot and so I would have hoped to see more species. One of these four was Bombus hypnorum, which was only found for the first time in UK in 2000: it is an invading species, arriving from Continental Europe, and seems to be able to adapt to living close to humans.

Common trends

These three insect groups observed in my garden seem to illustrate two trends: firstly, a decline in numbers compared with recent times. Sometimes this decline coincides with a reduction in species diversity, sometimes not. This trend is not local – far from it, since in UK there is a national debate about ‘the decline of insect pollinators’ such as bumblebees, honey bees and butterflies. Often this debate is referring to the threat to commercial crops such as apples, but what I am observing in my garden seems to hold true in the greater countryside. For example, at this time of year (August), it is customary to go for a walk to pick blackberries, a tasty and very common fruit of the bramble bush Rubus fruticosus. The fruit is plentiful but the picking can be hazardous: the bramble is covered in a large number of small thorns; until recently the hazard was made worse because wasps would be attracted to the ripe berries. However, not this year: no wasps and also an absence of the butterflies that used to be disturbed by the blackberry pickers, for example the Speckled Wood, (Pararge aegeria) and the Gatekeeper or Hedge Brown (Pyronia tithonus).

The second trend is the appearance of species new to the garden, for example Bombus lucorum and Polygonia c-album. There are other examples reported more widely, for example the spread of different ladybird (Coccinellidae) and hornet species from Continental Europe.

I should emphasise that my observations are highly selective, concentrating as they do on insects that are easy to see because of their size, colour and behaviour. It does seem very likely, however, that less visible insect numbers might also be changing: such changes may be on a very large scale but not well publicised.

Why limit this discussion to insects? As I mentioned at the beginning, studying a species and how it is changing requires the study of its ecology, how it interacts with other species in its environment. Most insects feed on plants whilst most predators of insects are other animals and so the indicator species I have chosen to observe are likely to be linked to a whole range of plant and animal species. A change to any one of these may have significant effects on others. 

Why the changes?

The first point to make here is that the changes observed in my garden and in the UK in general are likely to parallel changes elsewhere in the world. The butterflies, bees and wasps of Borneo may be very different from those of Europe but they are likely to be affected by the behaviour of humans in similar ways.

For example, the deforestation of Borneo is a major issue in Sabah: trees are cut down for their wood and replaced by palm oil plantations, resulting in wholesale changes in flora and fauna. It is a very obvious example of the impact of humans on their environment for economic gain. In the UK we have long lost the majority of our native forests but the land is still used for agriculture on a large scale. Brassica napus (B. napus) is widely grown in many European countries and is more commonly known as rape seed, a plant with oil-rich seeds that make it the third largest source of vegetable oil in the world after soya and palm oil.

In the UK, B. napus is protected from arthropod pests by using chemical insecticides; the most widely used of these chemicals are the neonicotinoids, which are currently at the centre of much debate in UK. Whilst they are often the insecticide of choice for the control of the insect pests of rape seed, for example the cabbage stem flea beetle, they are regarded by many people as indiscriminate, reducing numbers of ‘non-pest’ species, including important pollinators of crops and wild flowers. Butterflies and bumblebees are part of these important pollinators; the honeybee, Apis mellifera, is also a pollinator and UK beekeepers have been blaming the use of neonicotinoids by farmers for declining numbers of honeybee colonies, resulting in lower honey yields.

This example, therefore, illustrates an interesting parallel between intensive production of rape seed oil and palm oil: different in specific detail but both illustrating the impact on native flora and fauna of methods to increase yields of commercially important crops There are other examples of the impact of humans on the environment: the concentration of people in cities requiring more housing, better roads together with sewage and waste disposal and climate change resulting in rising sea levels, lengthening of droughts and greater risks of floods and storms – the list is long and too much to discuss here.

From an English country garden to Sabah’s rainforests: we’ve come a long way but the parallels are obvious, the problems and challenges are shared.