Maintaining Wildlife Pools

Maintaining Wildlife Pools

There is a common assumption that if you establish a wildlife pool with native plants, it will become a biologically stable environment, which can be enjoyed without having to be managed. However, even if a wide range of native plants is established and local fauna attracted, it must be remembered that a wildlife pool in a garden is largely an artificial environment. Given the constraints of scale, it will need as much care and attention as the manicured pool.

 

CONTROLLING GROWTH

The major problem that faces the wildlife pond owner is keeping the plants within bounds. With little competition and an ideal environment, they will flourish. Some control can be exercised by creating careful containment at planting time, and also by pond profiling, that is making some areas of water deep enough to provide a natural barrier to further encroachment. These measures will not solve the problem completely, however.

One of the most difficult aspects of plant control in a wildlife pool is seeding. On the one hand, the seeds of many species attract wildlife, but on the other, those very same seeds establish indiscriminate colonies of plants wherever they find a convenient niche. Really troublesome species, like the water plantains or alismas, which do not greatly benefit wildlife, but have extremely numerous and viable seeds, should have their flower stems removed immediately the tiny blossoms fade. The same applies to the coarse species of sedge and where practicable, the rushes. Both groups can become invaders if not controlled very carefully. In these cases, the removal of old flowering material is beneficial, but does not detract from the overall well-being of the feature.

manna grass (Glyceria fluitans)

credit: wikipedia.org

Invasive rhizomes or stolons, especially of plants like the manna grass (Glyceria fluitans) can cause serious management problems in a small wildlife pool, even when planted in a container. This plant often appears of its own accord and is to the water garden what couch grass is to ordinary beds and borders. Despite what the natural history books may tell you about its benefits to wildlife, if you find any hint of this plant in your wildlife pool, remove it, as it can be the cause of perpetual heartache. It looks similar to couch grass, but is of a much lighter green and tends to have soft downy foliage.

The methods for dealing with other invasive wildlife plants will depend on their mode of growth. If reedmace, or typhas, become a problem, they should be cut below water level in the autumn, allowing the hollow cut stems to fill with water during the winter and rot. Sometimes the main terminal growth of the rhizome, which is yet to appear above water, will survive, but it will produce an individual plant that is easily removed. Bur-reeds, on the other hand, are easier to dispose of during late summer. If the main plants invading the pool are removed, it is almost certain that the remainder of the spreading root system will die.

 

THE IMPORTANCE OF CONTROLLING GROWTH

Visually, it is important to have a variety of species and not to allow one dominate the others, but there are also very practical ecological reasons for control. Since the wildlife pool is a naturally planted feature in an unnatural environment, it will require management, particularly as most water gardeners will want to achieve an ecosystem that is at a particular stage of succession: the stage at which it is visually appealing, with a range of plants offering a diversity of opportunities to as much aquatic life as possible. Indeed, we have to consider that what we are attempting is comparable with, for example, the maintenance of a natural heathland area which, if not tended properly, would revert to scrub.

By maintaining a wildlife pool in this manner, the diversity of plants satisfies our desire for cultivating different species, but also offers special riches to individual groups of aquatic life. If a small area is maintained clear of tall vegetation, it can serve as a spot for birds that want to bathe or, if, the feature is large enough, as a nesting site.

Reducing the amount of plant growth also admits light, which is not only vital for the successful growth of some of the valuable smaller species that otherwise may be shaded out, but also beneficial for creatures such as dragonflies that prefer open sunny conditions. Live green plant growth should be rationalized together with any that is showing signs of decomposing in the water. Decaying vegetation creates most unpleasant conditions for any wildlife, de-oxygenating the water and often impairing the growth of adjacent desirable aquatic plants.

Submerged aquatics rarely present the same problems in the wildlife pool, unless planted unrestricted on a muddy pond floor. Here they may invade the territory of other emergent deep-water aquatics, but for the most part, it is a case of the more, the merrier. Any submerged plants that produce vast quantities of foliage, which will either create serious oxygen depletion problems at night or restrict the activities of true aquatic life, can be cut back at will. However, do not shear them heavily during the summer, as you may induce a green algalbloom. When removing such debris, shake it carefully over the pond to dislodge and preserve many of the tiny creatures to which it will almost certainly be home.

 

WELCOME INHABITANTS

A wildlife pool must be tended in the same way as a manicured garden pool, but greater attention should be paid to its inhabitants. In an ordinary garden pool, some of the creatures that the wildlife gardener may welcome, such as caddis flies, will be anathema to the true gardener, since their larvae will demolish waterlilies. Frogs and toads may inhabit either pool, and both the water and wildlife gardener should be aware of the implications of spawning. In the wildlife pool, such an invasion will be seen as desirable, but in the garden pool, it may be regarded as a nuisance, although doubtless the resultant young frogs will be welcome, if not devoured while still tadpoles by hungry goldfish.

 

18. March 2011 by admin
Categories: Organics, Vegetable Gardening | Tags: , | Comments Off on Maintaining Wildlife Pools

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