Attracting Wildlife

Planting suitable native aquatic plants will encourage the arrival of a diversity of species which, to some extent, rely upon them. These may not be exclusively aquatic fauna, but other species that depend upon aquatic plant life, such as the large copper butterfly, which needs to lay its eggs on the great water dock (Rumex hydrolapathum). The introduction or ‘inoculation’ of the pond with local species and, perhaps, a little detritus from an established pond will also help to develop the ecological system. Starting a wildlife pool and initially attracting desirable creatures is one thing; keeping them all living in harmony, and at appropriate stocking rates, is quite another.

 

MAINTAINING BALANCE

As with the conventional garden pool, the wildlife feature must have a proper balance of plants to keep the water free from algae. The regular removal of excess growth, or introduction of fresh plants should ensure that this is achieved. It is tempting to leave a wildlife pool to take care of itself so that it develops a natural balance of its own, but this does not work; either the submerged plants swamp all – the open water space, or duckweed (Lemna minor) smothers the surface, kills the submerged plants, and the water becomes black and unpleasant.

If the plant balance can be maintained by regular attention, most other species will live happily. Fish eventually grow and breed to suit the amount of available space, but this can have a, devastating effect on other species, such as caddis flies, the larvae of which are regularly devoured by fish. If the interesting aquatic insect life disappears, fish stocks may need to be reduced. A good indicator of overstocking, in the context of a wildlife pool, is the regular occurrence of empty water snail shells floating on the surface. On some occasions, their demise may have been caused by birds, but the greater likelihood is of fish sucking the creatures from their shells and eating them. This usually only happens in a pool that is close to its maximum stocking rate.

 

DEVELOPING FULL POTENTIAL

On the other hand, conditions have to be really good for fish to develop to their full potential. Adequate food must be provided. Although the pond may be planted for wildlife, this is no guarantee that sufficient natural food will be present to ensure excellent growth, so supplementing their diet with a manufactured fish food will be beneficial. Not only will the latter provide essential nutrients, but it will protect some of the aquatic insect life which, otherwise, might find its way into the fishes’ diet. A combination of a sound feeding programme and a water pH between 7.5 and 8.0 produces the best results.

While the ecology of any pool is vulnerable, that of the wildlife feature is particularly at risk. Unlike the garden pool, where the plants and decorative fish are the most important elements, in a wildlife pool, everything is important, from the dragonfly larvae to the diving beetles. As a result, two slightly different pond management regimes apply.

In the wildlife pool, maintenance must be carefully undertaken in stages to ensure the minimum of disturbance to aquatic life. In the garden pool, however, a complete clear-out can take place whenever the gardener wishes, and apart from the possibility of an early problem with a green algal bloom when the plants are put back, life with the goldfish and orfe continues. The wildlife feature is much more vulnerable: the wholesale clearance and scrubbing out of a wildlife pool will set its ecology back at least two years.

Under such circumstances, when establishing the pool, it is useful if plantings can be phased over a two-year period, so that lifting and dividing can follow a similar programme. In this way, the pool is never naked, and at least half of the plant habitats remain undisturbed for two years. In the soil-bottomed pond, where plants are established directly into the mud, the restriction and reduction of invading species can be undertaken in a similar manner.

 

UNDERSTANDING WILDLIFE NEEDS

Cleaning out the pond should be resisted as much as possible. Even if a layer of detritus starts to build up on the floor of the pool, it should be allowed to remain, unless it is turning the water putrid, for it will be borne to myriad invertebrates. In the autumn, keep as many fallen leaves as possible out of the pool to minimize the build-up of organic material on the bottom. This should restrict the need to clean out the pond to once every eight or ten years. It also allows the micro flora and the fauna, which live in the lower reaches of the pool, to develop fully and make a major contribution to the pool’s ecology.

While carrying out maintenance within the pool is vital, caring for the surroundings is very important if wildlife is to be attracted and encouraged to stay. Although trees are not a good idea beside pools, shrubby planting in close proximity is essential, especially for birds. One of the major attractions of any pond is being able to watch the birds use it for bathing and drinking. If palatable berries can be produced on shrubs nearby, the birds will have everything they require for sustenance, as well as cover in which to hide. Encourage those plants which produce edible seeds so that wildlife can feast on the autumn bounty.